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HomeMy WebLinkAboutCDP 13-30; DE ANDA RESIDENCE; UPDATED PRELIMINARY GEOTECHNICAL EVALUATION; 2008-10-15UPDATED PRE~lNIINARY GE;OTECHNICALEVALUATION APN 155-140-41, CARLSBAD SAN DIEGO COUNTY, CALJFORl'\HA FOR MR. ROBERT G. BECKER 96031J2TH AVENUE NE KIRKLAND, WASHINGTON mm33 W.0.5763-A-SC 0CT0B1::ft 15, 2008 PLAN CHECK h\1 -!y. J ,., Geoteetmica! ® Geologic ® Coastal • Em,ironmental 57 41 Palmer Way • Carlsbad, Ca!lfomia 92010 • (760) 438-3i 55 , FAX (760) 931 -0915 Mr. Robert G. Becker 9603 112th Avenue NE Kirkland, Washington 98033 October 15, 2008 W.O. 5763-A-SC Subject: Updated Preliminary Geotechnical Evaluation, APN 155~ 140-41, Carlsbad, San Diego County, California Dear Mr. Becker: In accordance with your request, GeoSoiJs, Inc. (GSJ), has reviewed site conditions and the referenced reports prepared by GSI (1993 and 2003), with respect to the proposed development of the subject site. This report supercedes our previous report for the site (see Appendix/\). For convenience, data from our previous investigations is included herein and modified as appropriate, based on new data/plans. The following comments and/or additional recommendations are based on GSl's understanding of the proposed development, previous and supplemental field exploration, a review of site conditions, and a review of the referenced documents. EXECUTIVE SUMMARY Based on GS l's review of the available data (see Appendix A), as well as supplemental field exploration, laboratory testing, and geologic and engineering analysis, development of the property appears to be feasible from a geotechnical viewpoint, provided the recommendations presented in the text ofthis report are properly incorporated into design and construction of the project The most significant elements of this study are summarized below: " Based on the site plan provided by Becker Architects (BA, 2006), it appears that the proposed development will consist of a two-story residence, with a two-car garage, associated driveway, an outdoor pool, and underground utility improvements. We further understand that the building is proposed as a slab-on-grade with continuous footings. As a result of the topography and creep forces, and owing to the extremely low tolerances for distress inherent to pools/spas, GSI recommends that the proposed pool/spa be supported by a pile foundation system. .. All vegetation and/or deleterious materials should be removed from the site and properly disposed of where settlement-sensitive improvements are proposed within their influence. Removals of compressible artificial fill, colluvium/topsoil, and the reprocessing of any weathered Quaternary-age terrace deposits will be necessary prior to any fill placement, if fills are proposed. Depths of removals are outlined in the "Earthwork Construction Recommendations" section ofthis report. In general, removals wilt be on the order of ±2 to ±4 feet across a majority of the site, in areas proposed for fill and/or settlement sensitive improvements. However, localized deeper removals cannot be precluded. Local remedial grading in the area of remnant foundations and seepage pit will be necessary and exceed this estimate. Based on the seepage pit exposed during our current site evaluation, removals may be on the order of ±81h feet near exploratory Test Pit TP-3 (see Plate 1). Areas with planned fills less than 5 feet should be overexcavated a minimum 5 feet or 24 inches of compacted fill beneath the footings, whichever is greater, in order to proVide uniform support under planned foundations. .. Although not considered a hazardous waste, any buried septic system should be properly removed and abandoned following health department guidelines. GSf'sslopestabilityanalysis indicatesafactor-of-safetygreaterthan 1.5 (static) and 1.1 (seismic) against failure for the existing maximum height of the natural slope. The surficial stability ofthe natural slope has also been analyzed. GSl's evaluation generally indicated a surficial factor,,.of-safety greater than 1.5 (static) forthe existing slope, under normal conditions of rainfall (semi-arid). In addition to the stability analysis, the site is located on the perimeter of Buena Vista lagoon and generally not subject to marine erosion, but may be subject to sub-areal erosion. Provided that the recommendations contained herein and in the referenced GSI reports are properfy implemented, the proposed development appears reasonably safe from coastal and geotechnical hazards over its estimated ?S~year economic life expectancy, assuming normaleare, maintenance, and rainfall. Site soils\ however, are erosive. .. The expansion potential attested on site soils is generally very low (Expansion Index [E.L] <20), however, low expansive soils (El. 21 to 50) with a plasticity index (P.I.) greater than 15may be encountered during construction. Post-tension foundations are indicated for soils having a P. I. of 15, or greater, per the California Buif ding Code ([CBC], California Building Standards Commission [CBSC], 2007). Conventional foundations may only be used for soils with very low expansion (El.Oto 20) or low expansive (EL 21 to 50) and a PJ. less 15. We have provided earthwork and foundation design criteria that pertain to this type of soil condition in this report. .. Sulfate testing indicates that site soils have a negligible exposure to concrete, in accordance with Section 1904.3 of the (CBC [CBSC, 2007]); and further results indicate the soils are moderately corrosive to ferrous metals, etc., based on saturated resistivity. Based on our review of Section 1904.3 (CBC (CBSC, 2007]), and ACI 318 Sections 4.2, 4.3, and 4.4, site soils are considered to be mildly alkaline with regard to acidity/alkalinity. A corrosion specialist should be consulted for the appropriate mitigation recommendations, as needed. Mr. Hobert G. Becker Fiie:e:\wp9\5700\5763a.upg lne .. W.O. 5763-A-SC Page Two .. Regional groundwater was not encountered during our field exploration and is not expected to be a major factor during construction of the proposed buildings. Regional groundwater is anticipated to generally be coincident with a couple feet of Mean Sea Level (MSL), and tidal fluctuations; more than about 50 feet below existing grade at top of the slope. However, due to the nature ofthe site materials, seepage and/or perched groundwater conditions may develop throughout the site in the future, both during and subsequent to development, especially along boundaries of contrasting permeabilities Q.e., fill lifts, fill/bedrock contacts, joints/fractures~ discontinuities, etc.), and should be anticipated. This potential should be disclosed to all interested/affected parties. Thus, more onerous slab design is necessary for any slab-on-grade floor (State of California, 2008). Recommendations for reducing the amount of water and/or water vapor through slab-on-grade floors are provided in the "Soil Moisture Considerations" sections of this report It should be noted that these recommendations should be implemented if the transmission of water or water vapor through the slab is undesirable. Should these mitigative measures not be implemented, then the potential for water or vapor to pass through the foundations and slabs and resultant distress cannot be precluded, and would need to be disclosed to all interested/affected parties. .. Our evaluation indicates that the site currently has a Jaw potential for liquefaction, due to the relatively dense nature of the Quaternary-age terrace deposits, and deeper Tertiary-age Santiago Formation that underlies the site. lfthe earthwork and foundation recommendations, provided herein, are properly implemented during design and construction, the potential for post-construction liquefaction to significantly affect the site building is considered to be very low, from a geotechnicat standpoint.. " The seismic acceleration values and design parameters provided herein should be considered during the design of the proposed development. The adverse effects of seismic shaking on the structure(s) will likely be wall cracks, some foundation/slab distress, and some seismic settlement However, it is anticipated that the structure will be repairable in the event of the design seismic event. This potential should be disclosed to all interested/affected parties. .. Adverse geologic features that would preclude project feasibility were not encountered. • The recommendations presented in this report should be incorporated into the design and construction considerations of the project. Mr. Robert G. Becker Flle:e:\wp9\5700\5763a.upg GeoSoils, Ine .. W.O. 57$3-A-SC Page Three The opportunity to be of service is greatly appreciated. If you have any questions concerning this report, or if we may be of further assistance, please do not hesitate to contact the project geologist, Bryan E. Voss, at (760) 438-3155. Respectfully submitted, BV/JPF/BBS/jk Distribution: (4) Addressee Mr. Robert G. Becker Fi!e:e'.\wp9\5700\5763a.upg W.O. 5763·-A-SC Page Four TABLE OF CONTENTS SCOPE OF SERVICES ................................................... 1 SITE CONDITIONS/PROPOSED DEVELOPMENT .............................. 1 SITE EXPLORATION ...............................•..................... 3 REGIONAL GEOLOGY ......................... , ......................... 3 SITE GEOLOGY ......................................................... 4 Undocumented Artificial Fill (Map Symbol -Afu) ......................... 4 Colluvium/T opsoH (Not Mapped) ...................................... 4 Older Alluvium (Map Symbol -Qoa) ..................................... 4 Terrace Deposits (Map Symbol -Qt) , .................................. 4 Santiago Formation (Map Symbol -Tsa) ................................ 5 GEOLOGIC STRUCTURE ............................... , ................. 5 FAULTING AND REGIONAL SEISMICITY .....................................• 5 Regional Faults .................................................... 5 local Faulting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . ..... 7 Seismicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Seismic Shaking Parameters ............................ · ............. 8 Seismic Hazards ..........•........................................ 8 GROUNDWATER .......... , ............................................. 9 LIQUEFACTION POTENTIAL .............................................. 9 OTHER GEOLOGIC HAZARDS ............................................ 10 LABORATORY TESTING ................................................. 11 General ......................................•.................. 11 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Moisture-Density Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Expansion Potential . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . 11 Direct Shear Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...... , ... · . . 12 Saturated Resistivity, pH, and Soluble Sulfates ......................... 12 PRELIMINARY EARTHWORK FACTORS .................................... 12 SLOPE STABILITY ..............................•....................... 13 Gross Stability Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Surficial Slope Stability ..................... , . . . . . . . . . . . . . . . . . . . . . . . 13 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS .................... 13 EARTHWORK CONSTRUCTION RECOMMENDATIONS ............... , ....... 15 General .....•................................................... 15 Demolition/Grubbing .......•...................................... 16 Removals (Unsuitable Surficial Materials) .................... , .......• , i 6 Overexcavation/T ransitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . i 6 Temporary Slopes ................................................ 17 PRELIMINARY FOUNDATION DESIGN RECOMMENDATIONS .................. 17 General ...................................................•..... 17 Foundation Design ............. , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Foundation Settlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Footing Setbacks ................................................. i 8 Construction . , •..... · ............................. , ............... 18 Very low to Low Expansion Potential {El. o to 50) and Plasticity <15 ....... 19 POST-TENSIONED SLAB SYSTEMS ....................................... 20 Stiffened Slabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Mat Slabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Slab Underlayment ........•..............•................ , ....... 21 Pre-soaking ................ · ....................................... 21 Soil Support Parameters ........................................... 21 CORROSlON ...........•.............................................. 23 SOIL MOISTURE CONSIDERATIONS ...................................... 23 WALL DESIGN PARAMETERS ............................................ 24 Conventional Retaining Walls ....................................... 24 Restrained Walls .................................................. 25 Cantilevered Walls . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . 25 Retaining Wall Backfill and Drainage .................................. 25 Wall/Retaining Wall Footing Transitions ............ , ........... , ...... 29 DRIVEWAY, FLA 1WOHK, AND OTHER IMPROVEMENTS ....................... 30 PRELIMINARY OUTDOOR POOLJSPA AND POOL DECK DESIGN RECOMMENDATIONS .......................... 32 General ......................................................... 32 Design and Construction Workmanship .......... , .................... 36 DEVELOPMENT CRITERIA ....•.......................................... 37 Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Erosion Control ...•............................................... 37 Landscape Maintenance ........ ., .................................. 37 Gutters and Downspouts . , ...........••............................ 38 Mr. Robert G. Becker File:e:\wp9\5700\5763aupg Table of Contents Page ii Subsurface and Surface Water ............................ , ......... 38 Site Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Tile Flooring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Additional Grading ................................................ 39 Footing Trench Excavation .... , .................................... 39 Trenching{f emporaty .Construction Backcuts .......................... 39 Utility Trench Backfill .............................................. 40 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICALOBSERVATION AND TESTING .......................................•...•............ 40 OTHER DESIGN PROFESSIONALS/CONSULTANTS .......................... 41 PLAN REVIEW .............................•........................... 42 LIMITATIONS .......................................................... 42 FIGURES: Figure 1 -Site Location Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Figure 2 -California Fault Map ........................................ 6 Detail 1 ......................................................... 26 Detail 2 ......................................................... 27 Detail 3 ......................................................... 28 A IT ACHMENTS: Appendix A-References .......................•........... Rear of Text Appendix B -Explorations .................................. Rear of Text Appendix C-EQFAULT, EQSEAHCH, AND FRISKSP ............ Rear of Text Appendix D -Laboratory Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . Rear of Text Appendix E .. Slope Stability Analysis ......................... Rear of Text Appendix F -General Earthwork, Grading Guidelines, and Design Criteria ......................... , .· ............................ Rear of Text Plate 1 -Geotechnical Map . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text in Folder Plate 2 -Cross Section A-A' ......................... Rearof Text in Folder Mr. Robert G. Becker File:e:\wp9\5700\5763a.upg Table of Contents Page iii UPDATED GEOTECHNICAL EVALUATION APN 155-140..41, CARLSBAD SAN DIEGO COUNTY, CAUFORNIA SCOPE OF SERVICES The scope of our services has included the following: 1. Review of the referenced geotechnical reports (GSI, 1993 and 2003), available published g.eologic literature for the region (see Appendix A). 2, Geologic field reconnaissance mapping and the excavation of four test pit excavations to verify subsurface data presented in (GSI, 1993 and 2003), to obtain samples of repre~:.mntative materials, and delineate soil and geologic parameters that may affect the proposed development (see Appendix B). 3. General areal seismicity (see Appendix C). 4. laboratory testing of representative soil samples collected during our subsurface exploration program (see Appendix D). 5. General liquefaction evaluation. 6. Slope Stability Analysis (see Appendix E). 7. Appropriate engineering and geologic analysis of data collected and preparation ofthis report SITE CONDITIONS/PROPOSED DEVELOPMENT The property is a roughly rectangular-shaped lot bounded by Jefferson Street on the east, an adjacent residential property to the south, and a condominium complex to the north. Buena Vista Lagoon is located along the western edge of the property (see Figure 1, Site Location Map). The property itself consists of a relatively level pad area adjacent to Jefferson Street and a large natural slope, which descends approximately 50 feet westward from the pad area to Buena Vista Lagoon. Between the pad elevation of approximately 65 feet Mean Sea Level (MSL) and an elevation of approximately 25 feet MSL, the slope descends at an approximate gradient of 2%:1 (horizontal: vertical [h:v]). From an elevation of 25 feet MSL to the lagoon level, the slope flattens to a gradient of approximately 4%:1 (h:v). Existing improvements to the property consist of remnants of an old foundation system (concrete slab} and seepage pit, located in the northern portion of the existing pad area. Vegetation on the property in the vicinity of the pad area consists of some small trees and scattered grasses. Vegetation on the slope consists of primarily grasses. Drainage within GeoSoils, lne., Base Map: TOPOI® ©2003 National Geographic, U.S.G.S. San Luis Rey Quadrangle, California -- San Diego Co., 7.5 Minute, dated 1997, current 1999. Base Map: The Thomas Guide, San Diego County, Street Guide and Directory, 2008 Edition, by Thomas Bros. Maps, page 1106. Reproduced with permission granted by Thomas Bros. Maps This map Is copyrighted by Thomas Bros. Maps. It Is unlawful to copy or reproduce all or any part thereof, whether for personal use or resale, without permission. All rfghts reserved. N W.O. 5763-A-SC SITE LOCATION MAP Figure 1 the property is predominately by sheet flow directed toward Jefferson Street or down the slope face toward Buena Vista Lagoon. It is our understanding thatthe existing foundation will be demorished. The proposed site development will consist of preparing the pad for construction of a new residential structure. Cut and fill grading techniques would be utilized to create design grades for the proposed single-family residential structure and pool. It is anticipated that the residential development will consist of a two-story structure with slab-on-grade and continuous footings, utilizing masonry and/or wood-frame construction. Building loads are assumed to. be typical for this type of relatively light construction. The need for import soils is unknown. It is anticipated that sewage disposal will be tied into the regional municipal system. SITE EXPLORATION Surface observations and subsurface explorations conducted during our evaluation of the site consisted of excavating four test pits with a rubber tire backhoe within the lot to verify near surface soil and geologic conditions presented in GSl's previous reports (GSI, 1993 and 2003). The borings were Jogged by a geologist from our firm. Representative bulk and in-place samples were taken for appropriate laboratory testing. Logs of the test pits and previous explorations are presented in Appendix B. The approximate locations of the fourtest pits and five previous exploratory borings (GSI, 1993 and 2003), are shown on Plate 1. REGIONAL GEOLOGY The subject property is located within a prominent natural geomorphic province in southwestern California known as the Peninsular Ranges. It is characterized by steep, elongated mountain ranges and valleys that trend northwesterly. The mountain ranges are underlain by basement rocks consisting of pre-Cretaceous metasedimentary rocks, Jurassic metavolcanic rocks, and Cretaceous plutonic rocks of the southern California batholith. In the San Diego region, deposition occurred during the Cretaceous Period and Cenozoic Era in the continental margin of a forearc basin. Sediments, derived from Cretaceous-age plutonic rocks and Jurassic-age volcanic rocks, were deposited into the narrow, steep, coastal plain and continental margin of the basin. These rocks have been Uplifted, eroded and deeply incised. During early Pleistocene time, a broad coastal plain was developed from the deposition of marine terrace deposits. During mid to late Pleistocene time, this plain was uplifted, eroded and incised. Alluvial deposits have since filled the lower valleys, and young marine sediments are currently being deposited/eroded within coastal and beach areas. Mr. Robert G. Becker APN i 55-i 40-4 i , Carlsbad Fi!e:e:\wp9\5700\5763a.upg lne., W.O. 5763-A-SC October 15, 2008 Page3 SITE GEOLOGY The site geologic units encountered on the site consist of undocumented artificial fill, colluvium/topsoil, older alluvium, terrace deposits, and Santiago Formation. The estimated limits of earth materials are shown on Plate 1. Undocumented Artificial Fm (Map Symbol -Afu) Undocumented artificial fill onsite was found to generally consist of a brown, damp to moist, loose, silty sand. Thickness of the soil is approximately ±1 to +8%feet (seepage pit area at the northwestern edge existing foundation area [see Test Pit TP-3]). Minor fills are also presented along the outside edges of the pad. The existing fill at the subject site is considered potentially compressible in its present state, and considered unsuitable for support of additional fill and/or settlement sensitive improvements. These materials wm require removal and recompaction, should settlement sensitive improvements be proposed within their influence. This unit typically has a very low expansion potential. Colh.1vium/Topsoil (Not Mapped) Surficial colfuvium/topsoil onsite was found to generally consist of a brown, dry, loose, silty sand with occasional rounded pebbles. Thickness of the soil is approximately ± 1 to ±2% feet Colluviumftopsoil at the subject site is considered potentially compressible in its present state. Accordingly, these soits are considered unsuitable for support of additional fill and/or settlement-sensitive improvements in their existing state and will require removal and recompaction, should settlementsensitive improvements be proposed within their influence. This unit typically has a very low expansion potential. Older Alluvium (Map Symbol -Qoa) Older alluvium was encountered below an approximate elevation of 40 feet MSL on the descending slope. Where encountered, the older alluvium generally consists of reddish brown, damp to moist, silty sand, and is loose to medium dense with depth. Due to the relatively soft and weathered condition of the upper +2 feet, these sediments should be removed, moisture conditioned, and recompacted and/or processed Jn place, should settlement-sensitive improvements be proposed within their influence. At the time of this report, these materials are located beyond the anticipated limits of proposed construction and are not anticipated to significantly affect site development. This unit typically has a very low to low expansion potential. Terrace Deposits (Map Symbol-Qt) Underlying the col!uvium/topsoU, Quaternary-age terrace deposits were encountered to a depth of approximately 16 feet below existing grade in Boring B-1 (GSI, 1993) and in Test Pits TP-1 through TP-4 during this current study. As encountered, the terrace deposits Mr. Robert G. Becker APN 155-i 40-41 , Carlsbad File:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page4 .. generally consist of reddish brown to orange brown, dry to moist, silty sand, and are medium dense to dense with depth. Due to the relatively soft and weathered condition of the upper ±1 foot, these sediments should be removed, moisture conditioned, and recompacted and/or processed in place, should settlement-sensitive improvements be proposed within their influence. This unit typically has a very low to low expansion potential. Santiago Formation {Map Symbol -Tsa) Bedrock materials underlie the project site at depth, and. have been mapped by Tan and Kennedy (i 996} as belonging to the Eocene--age Santiago Formation. As encountered, the formational materials generally consist of a light brown to olive brown, damp to moist fine to medium-grained clayey sandstone tosandysiltstone, and is medium dense/medium stiff to dense/stiff with depth, with minor claystone interbeds (probably paleosols) This unit typically has a very low to medium expansion potential, depending on the clay content of the matrix materials. At the time of this report, these materiafs are located approximately ± 16 feet below the proposed construction of the single-family residence and are not anticipated to affect the proposed structure. However, the pool foundation system may be affected bythe sandstone unit ofthe Santiago Formation and has been considered herein. GEOLOGIC STRUCTURE Nearly horizontal contacts were observed in our exploratory boring between terrace deposits and the underlyir,g Santiago Formation. Clayey interbeds within the Santiago Formation also displayed relatively horizontal contacts within the bounding sandstone units (GSI, 1993 and 2003). Both units were relatively thickJy bedded .. Regional mapping by Tan and Kennedy (1996) indicates approximately horizontal to very gently dipping bedding structures. Based on the available data, adverse geologic structures are generally not anticipated to adversely affect the proposed development. FAULTING AND REGIONAL SEISMICITY Regional Faults Our review indicates that there are no known active faults crossing this site, and the site is not within an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). However, the site is situated in an area of active faulting. These include, but are not limited to: the San Andreas fault; the San Jacinto fault; the Elsinore fault; the Coronado Bank fault zone; and the Newport-Inglewood -Rose Canyon fault zone (NIRCFZ). The location of these, and other major faults relative to the site, are indicated on Figure 2 (California Fault Map). The possibility of ground acceleration, or shaking at the site, may be considered as approximately similar to the southern California region as a whole. Major active fault zones Mr. Robert G. Becker APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg Inc .. W.O. 5763-ASC October 15, 2008 Page5 CALIFORNIA FAULT MAP Becker Residence 1000 900 700 600 500 400 300 200 100 0 -100 ~~~ 400 -300 -200 -100 0 1 00 200 300 400 500 600 HTVERSlDE CO. C., ORANGE CO. SAN DIEGO CO. CALIFORNIA FAULT MAP Fi ure 2 W,O, 5763-A-SC DATE 09/08 SCALE NTS that may have a significant affect on the site, should they experience activity, are listed in Appendix G (modified from Blake, 2000a}. Local Faulting No local faulting was observed to transect the site during the field investigation. Additionally, a review of regional geologic maps does not indicate the presence of local faults crossing the site. Seisrnicity The acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999), Sadigh, et al. {1997), and Campbell and Bozorgnia (1994 andl997) have been incorporated into EQFAULT (Blake, 2000a). EQFAULT is a computer program developed by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using digitized California faults as earthquake sources. The program estimates the closest distance between each fault and a given site. If a fault is found to be within a user-selected radius, the program estimates peak horizontal ground acceleration that may occur at the site from an upper bound ("maximum credible") earthquake on that fault. Site acceleration (g) was computed by one user-selected acceleration-attenuation relation that is contained in EQFAUL T. Based on the EQFAULT program, a peak horizontal ground acceleration from an upper bound event at the site may be on the order of 0.56 g to 0.63 g. The computer printouts of pertinent portions of the EQFAULT program are included within Appendix G. Historical site seismicity was evaluated with the acceleration-attenuation relation of Campbell and Bozorgnia(1997), and the computer program EQSEAHCH (Blake, 2000b). This program performs a search of the historical earthquake records for magnitude 5.0 to 9.0 seismic events within a 100-kilometer radius, betweentheyears 1800 through June 2008. Based on the selected acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated, which may have effected the site during the specific event listed. Based on the available data and the attenuation relationship used, the estimated maximum (peak} site acceleration during the period 1800 through June 2008 was 0.25 g. A historic earthquake epicenter map and a seismic recurrence curve are also estimated/generated from the historical data. Computer printouts of the EQSEARGH program are presented in Appendix C. A probabilistic seismic hazards analyses was performed using FRISKSP (Blake, 2000c), which models earthquake sources as 3-dimensional planes and evaluates the site specific probabilities of exceedance for given peak acceleration levels or pseudo-relative velocity levels. Based on a review of this data, and considering the relative seismic activity of the southern California region, a peak horizontal ground acceleration of O .30 g was calculated. Mr. Hobert G. Beck.er APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg lne .. W.O. 5763-A--SC October i5, 2008 Page7 ,. This value was chosen as it corresponds to a 1 O percent probability of exceedance in 50 years (or a 475-year return period). Computer printouts of the FRISKSP program are included in Appendix C. Seismic Shaking Parameters Based on the site conditions, the table below summarizes the site.:.specific design criteria obtained from the California Building Code ([CBC], California Building Standards Commisison [CBSC], 2007), Chapter 16 Structural Design, Section 1613. We used the computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the U.S.G.S. The short spectral response uses a period of0.2 seconds. Spectral fiesponse -(short), S,, 1.30g Figure 1613.5(3) Spectra! Response -(1. sec), S1 0.49g Figure 1613,5{4) Site Coefficient, Fa 1.0 Table 1613.5.3(1) Site Coefficient, E, 1.51 Table 1613.5.3(2) Maximum Considered Earthquake Spectral 1.30g Section 1613.5.3 Response Acceleration (short), SMs (Eqn 16-37) Maximum Considered Earthquake Spectral 0.74g Section 1613.5.3 Response Acceleration (1 sec), SM1 {Eqn 16-38) 5% Damped Design Spectra! Response 0.86g Section 1613.5.4 Acceleration {short), Sos (Eqn 16-39) 5% Damped Design Spectral Response 0.49g Section 1613.5.4 Acceleration (1 sec}, S01 (Eqn 16-40) Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur in the event of a large earthquake. The primary goal of seismic design is to protect life, not to eliminate all damage, since such design may be economically prohibitive. The cumulative effects of significant seismic events (Mw>4.5) is unknown. Seismic Hazards The following list includes other seismic related hazards that have been considered during our evaluation of the site. The hazards listed are considered negligible and/or mitigated as a result of site location, soil characteristics, and typical site development procedures: Mr. Robert G. Becker APN 155-i 4041, Carlsbad File:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October i5, 2008 Pages • Dynamic Settlement • Surface Fault Rupture • Ground Lurching or Shallow Ground Rupture • Tsunami " Seiche It is important to keep in perspective that in the event of an upper bound or maximum credible earthquake occurring on any of the nearby major faults, strong ground shaking would occur in the subject site's general area. Potential damage to any structure{s) would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass than from those induced by the hazards considered above. Following implementation of remedial earthwork and design of foundations described herein, this potential would be no greater than that for other existing structures and improvements in the immediate vicinity that comply with current and adopted building standards. GROUNDWATER Regional groundwater was not encountered during our field exploration and is not expe.ctet::I to be a major factor during construction of the proposed buildings. Regional groundwater rs anticipated to generally be coincident with MSL; and tidal fluctuations; greater than about 50 feet below existing grade at top of the sf ope. However. due to the nature of the site materials, seepage and/or perched groundwater conditions may develop throughout the srte in the future, both during and subsequent to development, especially along boundaries of contrasting permeabilities (Le., fill lifts, fill/bedrock, fill/formation contacts, joints/fractures, discontinuities, etc.), and should be anticipated. This potential should be disclosed to all interested/affected parties. Thus, more onerous slab design is necessary for any slab-on-grade floor (State of California, 2008). Recommendations for reducing the amount of water and/or water vapor through slab-on-grade floors are provided ln the "Soil Moisture Considerations" sections of this report It should be noted that these recommendations should be implemented if the transmission of water or water vapor through the slab is undesirable. Should these mitigative measures not be implemented; then the potential for water or vapor to pass through the foundations and slabs and resultant distress cannot be precluded, and would need to be disclosed to all interested/affected parties. LIQUEFACTION POTENTIAL Seismically-induced liquefaction is a phenomenon in which cyclic stresses, produced by earthquake-induced ground motion, create excess pore pressures in soils. The soils may thereby acquire a high degree of mobility, and lead to lateral movement, sliding, sand boils, consolidation and settlement ofloose sediments, and other damaging deformations. Mr. Robert G. Becker APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page9 This phenomenon occurs only below the water table; but after liquefaction has developed, it can propagate upward into overlying, non-saturated soil as excess pore water dissipates. Typically, liquefaction has a relatively low potential at depths greater than 45 feet and is virtually unknown below a depth of 60 feet. Liquefaction susceptibility is related to numerous factors and the following conditions should be concurrently present for liquefaction to occur: i) sediments must be relatively young in age and not have developed a large amount of cementation; 2) sediments generally consist of medium to fine grained relatively cohesion less sands; 3) the sediments must have low relative density; 4) free groundwater must be present in the sediment; and 5) the site must experience a seismic event of a sufficient duration and magnitude, to induce straining of soil particles. The condition of liquefaction has two principal effects. One is the consotidation of loose sediments with resultant settlement of the ground surface. The other effect is lateral sliding. Significant permanent lateral movement generally occurs only when there is significant differential loading, such as fill or natural ground slopes within susceptible materials. No such lqading conditions exist on the site. It should be noted thatthroughout our site observations and subsurface investigation, there was no evidence of upward- directed hydraulic force that was suddenly applied, and was of short duration, nor were there any features commonly caused by seismically induced liquefaction, such as dikes, sills, vented sediment, lateral spreads, or soft-sediment deformation. These features would be expected if the site area had been subject to liquefaction in the past (Obermeier, i 996). Inasmuch as the future performance of the site with respect to liquefaction should be similar to the past, excluding the effects of urbanization (irrigation), GSI concludes that the site generally has not been subject to liquefaction in the geologic past, regardless of the depth of the localized water table. In the site area, we found there is a potential for seismic activity, and relatively high regional groundwater. However, the site is underlain by terrace deposits and the Santiago Formation, which because of its age and relatively dense nature, is generally not considered susceptible to damaging effects owing to liquefaction. Since at least two or three of the five required concurrent conditions discussed above do not have the potential to affectthe site simultaneously, and considering the recommended remedial removals of low density surficial soils, our evaluation indicates that the potential for liquefaction and associated adverse effects within the site is low, even with a future rise in groundwater levels. Therefore, it is our opinion that the liquefaction potential does not constitute a significant risk to site development. OTHER GEOLOGIC HAZARDS Mass wasting refers to the various processes by which earth materials are moved down slope in response to the force of gravity. Examples of these processes include slope Mr. Robert G. Becker APN 155-140-41 , Carlsbad File.:e:\wp9\5700\5763a.upg GeoSoils, lne~ W.O. 5763-A-SC October 15, 2008 Page 10 creep, surficial failures, and deep-seated landslides. Creep is the slowest form of mass wasting and generally involves the outer 5 to 1 o feet of a slope surface. During heavy rains, such asthose in 1969, 1978, 1980, 19831 1993, 1998, and 2004/2005 creep-affected materials may become saturated, resulting in a more rapid form of downslope movement (i.e., landslides and/or surficial failures). Significant examples of these types of slope instability were not apparent within the site. LABORATORY TESTING Genera.I Laboratory tests were performed on representative samples of the onsite earth materials in order to evaluate their physical characteristics. The test procedures used and results obtained are presented below. Classification Soils were classified visually according to the Unified Soils Classification System (Sowers and Sowers, 1979). The soil classifications are shown on the Boring Logs in Appendix B. Moisture-Density Relations The field moisture contents and dry unit weights were evaluated for selected undisturbed samples in the laboratory. The dry unit weight was determined in pounds per cubic foot (pcf), and the field moisture content was determined as a percentage of the dry weight The results of these tests are shown on the Logs in Appendix B. Expansion Potential Expansion testing was performed on a representative sample of site soil in general accordance with ASTM D 4829. The results of expansion testing are presented in the following table. TP-1@ 1-3 Mr. Robert G. Becker APN 155--i 40-41, Carlsbad File:e:\wp9\5700\5763a.upg <20 Very Low I W.O. 5763-A-SC October 15, 2008 Page i 1 Direct Shear Test Shear testing was performed on a relatively undisturbed sample of site soil in general accordance with ASTM test method D 3080 in a Direct Shear Machine of the strain control type. The results of shear testing are presented in the following table and Appendix D. B-1 @2 317 33 275 33 B-i @26 NA* NA* 325 33 TP-1 @4 187 32 184 32 NA = Not available Saturated Resistivity. pH. and Soluble Sulfates GSI conducted sampling of onsite materials for soil corrosivity on the subject project Laboratory test results were completed by Schiff & Associates (consulting corrosion engineers). The testing included evaluation of pH, soluble sulfates, and saturated resistivity. Test results indicate that the soil presents a negligible sulfate exposure to concrete, in accordance with Section 1904.3 ofthe CBC (CBSC, 2007); and further results indicate the soils are moderately corrosive to ferrous metals, etc., based on saturated resistivity. Based on our review of Section 1904.3 (CBC [CBSC, 2007]), and ACI 318 Sections 4.2, 4.3 and 4.4, site soils are considered to be mildly alkaline with regard to acidity/alkalinity. A corrosion specialist should be consulted for the appropriate mitigation recommendations, as needed. Test results are presented in Appendix D. Additional testing of site materials is recommended when site earthwork is complete to corroborate the findings. PRELIMINARY EARTHWORK FACTORS Preliminary earthwork factors (shrinkage and bulking) for the subject property have been estimated based upon our field and laboratory testing, visual site observations, and experience with similar projects. It is apparent that shrinking would vary with depth and with areal extent over the site based on previous site use. Variables include vegetation, weed control, discing, and previous filling or exploring. However, all these factors are difficult to define in a three-dimensional fashion. Therefore, the information presented below represents average shrinkage/bulking values: Mr. Robert G. Becker APN 155-140-41, Car!sbad Fi!e:e:\Wp9\5700\5763a.upg Jne .. W.O. 5763-A-SC October 15, 2008 Page 12 Undocumented Artificial Fill ...... , " . . . . . . . . . . . . . . . . . . . . . . . . . 10-20% shrinkage Colluviumffopsoil ........•................................ 10-20% shrinkage Quaternary Terrace Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10% shrinkage Tertiary Santiago Formation ............•...................... 0-6% shrinkage An additional shrinkage factor item would include the removal of root systems of individual large plants or trees. These plants and trees vary in size, but when pulled, they may generally result in a loss of% to 1 ~ cubic yards. This factor needs to be multiplied by the number of Significant plants, trees, or tree roots present to determine the net loss: The above facts indicate that earthwork balance for the site would be difficult to define and flexibility in design is essential to achieve a balanced end product. SLOPE STABIUTY Conventional slope stability analyses were performed utilizing the PC version of the computer program GSTABL7 v.2. The program performs a two-dimensional limit equilibrium anaJysis to compute the factor of safety for a layered sf ope using the simplified Bishop or Janbu methods. A representative geologic cross section was prepared for analysis, utilizing field and laboratory data from our referenced report and this report and the 10-scale design study, depicting maximum. existing slopes, as indicated on Cross Section X-X' (see Plate 2). The results ofthe analyses are included in Appendix E. Gross Stability Analysis A calculated factor-of-safety greater than 1.5 or 1 .1 (Code) has been obtained for the existing, maximum height df the natural slope, when analyzed from a static or seismic viewpoint, respectively. The results of the analyses are included in Appendix E. Surficiaf Slope Stability The surficial stability of the existing slope has been analyzed. Our evaluation generarly indicates a surficial safety factor greater than 1.5 for the existing slope, under normal conditions of rainfall (semi-arid). The results of the analyses are included in Appendix E PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS Based on our supplemental field exploration, laboratory testing, and geotechnical engineering analysis, it is our opinion that the site appears suitable for the proposed additional developmentfrom a geotechnical engineering and geologic viewpoint, provided that the recommendations presented in the following sections are properly incorporated into the design and construction phases o·f site development. The primary geotechnical concerns with respect to the currently proposed development are: Mr. Robert G. Becker APN 155-140-41, Carlsbad Fife:e:\wp9\5700\5763a.upg CeoSoils, lne .. W.O, 5763-A~sc October 15, 2008 Page 13 .. Earth materials characteristics and depth to competent bearing material. .. On-going expansion, corrosion, and erosion potential of site soils. .. Potential for perched groundwater to occur during and after development • Potential for slope creep to affect the proposed pool/spa and associated ffatwork. .. Temporary slope stability .. ... Regional seismic activity. The recommendations presented herein consider these as well as other aspects of the site. The engineering analyses, performed, concerning site preparation and the recommendations presented herein have been completed using the information provided and obtained during our field work. In the event that any significant changes are made to proposed site development, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the recommendations of this report are evaluated or modified in writing by this office. Foundation design parameters are considered preliminary until the foundation design, layout, and structural loads are provided to this office for review. 1. Soil engineering, observation, and testing services should be provided during grading to aid the contractor in removing unsuitable soils and in his effort to compact the fill, should grading be necessary. 2. Geologic observations should be performed during any grading to verify and/or further evaluate geologic conditions. Although unlikely, if adverse geologic structures are encountered, supplemental recommendations and earthwork ma.y be warranted" 3. The undocumented artificial fiJI, colluvium/topsoil, and weathered near-surface terrace deposits, are typically porous, loose, and subject to settlement. In the near surface, they are considered potentially compressible in their existing state, and have a very low to moderate potential for hydrocollapse; thus, undocumented artificial fill, colluvium/topsoil, and weathered near-surface terrace deposits may settle appreciably under additiom:d fill, foundation, or improvement loadings and will require removal and recompaction if settlement-sensitive improvements are proposed within their influence. In general, removals will be on the order of ±2 to ±4 feet across the majority of the site, however, deeper removals cannot be precluded. Removals will be on the order of +8% feet in the area of the existing seepage pit. Removals should be performed to at least 5 feet outside any proposed settlement-sensitive improvements (structures, pools, hardscape, etc.). 4. GS! performed a liquefaction screening evaluation of existing conditions using the available data. It ls our opinion that the area site proposed for development atthis time, is generally underlain by dense/stiff formational sediments, which have a very low potential for liquefaction. Mr. Robert G. Becker APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg WO. 5763-A-SC October i 5, 2008 Page 14 5. Regional groundwater is generally not anticipated to affect site development, providing that the recommendations contained in this report are incorporated into final design and construction, and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions along zones of contrasting permeabilities should not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. 6. Our laboratory test results and experience on nearby sites generally indicate that soils with a very low to low expansion potential underlie the site, atthe near surface. This should be considered during project design and construction. Preliminary foundation design and construction recommendations are provided herein for the very low expansion potential classification. This potential should be re-evaluated prior to actual foundation construction/excavation, and/ or at the conclusion of grading. 7. The seismicity-acceleration values provided herein should be considered during the design and construction of the proposed development. 8. General Earthwork, Grading Guidelines, and Preliminary Criteria are provided at the end of this report as Appendix F. Specific recommendations are provided below. EARTHWORK CONSTRUCTION RECOMMENDATIONS General Minor remedial earthwork may be necessary for the support of exterior settlement-sensitive improvements. If grading is required, it should conform to the guidelines presented in the Uniform Building Code ([UBC]/CBC (International Conference of Building Officials [ICBO], 1997 and 2001; CBSC, 2007), the requirements of the City, and the Grading Guidelines presented in Appendix E, except where specifically superceded in the text of this report. In case of conflict, the more onerous code or recommendations should govem. Prior to grading, a GSI representative should be present at the preconstruction meeting to provide additional grading guidelines, if needed, and review the earthwork schedule. During earthwork construction, all site preparation and the general grading procedures of the contractor should be observed and the fill selectively tested by a representative(s) of GSI. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and, if warranted, modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Health Act (OSHA), and the Construction Safety Mr. Robert G. Becker APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg GeoSoils, lne .. W.O. 5763-A-SC October i 5, 2008 Page 15 ' Act should be met. It is the onsite general contractor and individual. subcontractors responsibility to provide a safe working environment for our field staff who are onsite. GSI does not consult in the area of safety engineering. Demolition/Grubbing 1. Existing structures, vegetation, and any miscellaneous debris should be removed from the areas of proposed grading/earthwork:. 2. Any previous foundations, irrigation lines, cesspools, septic tanks, seepage pits, leach fields, or other subsurface structures uncovered during the recommended removal should be observed by GS! so that appropriate remedial recommendations can be provided. 3. Cavities or loose soils remaining after demolition (in the patio. landscape, and driveway areas) and site clearance should be cleaned out and observed by the soil engineer. The cavities should be replaced with fill materials that have been moisture conditioned to at least optimum moisture content and compacted to at least 90 percent of the laboratory standard. Removals (Unsuitable Surficlal Materials) All undocumented artificial fill, coHuvium/topsoil, and weathered near-surface terrace deposits, are typically porous, loose, and subject to settlement In the near surface, they are considered potentially compressible in their existing state, and have a very low to moderate potential for hydrocoflapse; thus, undocumented artificial fill, colluvium/topsoil, and weathered near-surface terrace deposits may settle appreciably under additional fill, foundation, or improvement loadings and will require removal and recompaction (and/or processing in-place) if settlement-sensitive improvements are proposed within their influence. In general, removals will be on the order of ±2 to +4 feet across the majority of the site, however, deeper removals cannot be precluded. Removals will be on the order of ±8% feet in the area of the existing seepage pit near Test Pit TP-3. Removals should be performed to at least 5 feet outside any proposed settlement sensitive improvements (structures, pools, hardscape, etc.). OverexcavationfTransitions In order to provide for the uniform support of the proposed settlement-sensitive improvements, a minimum 5-foot thick compacted fill blanket is recommended within this building footprint containing earth material transitions (i.e., fill juxtaposed against terrace deposits), as discussed herein. Any cut portion of a transition with planned fills less than 5 feet should be overexcavated a minimum 5 feet below finish pad grade in order to provide for a minimum 5-foot compacted fill blanket or 24 inches of compacted fill beneath the footings, whichever is greater. The maximum to minimum fill thickness, below Mr. Robert G. Becker APN 155-140-4 i , Carlsbad File:e:\wp9\5700\5763a.upg lne. W.n 5763-A-SC October 15, 2008 Page 16 settlement-sensitive improvements, should not exceed a ratio of 3: 1 (maximum:minimum). The overexcavation should be completed per the UBC/CBC (ICBO'! 1997 and 2001; CBSC, 2007). Temporary Slopes As a result of the relatively non-cohesive, sandy soils at depth on portions of the site, vertical excavations shall conform to Cal-OSHA and/or OSHA requirements for Type "C" soils. Temporary cut slopes, up to a maximum height of ±20 feet, may be excavated at a 1112:1 {h:v) gnidient, or flatter, based on the available data, provided adverse geologic conditions or groundwater are not present. PRELIMINARY FOUNDATION DESIGN RECOMMENDATIONS General This report presents minimum design criteria for the design of slabs, foundations and other elements possibly applicable to the project These criteria should not be considered as substitutes for actual designs by the structural engineer. The proposed foundation sys,ems should be designed and constructed in accordance with the guidelines contained in the UBC/CBC (ICBO, 1997 and 2001; CBSC, 2007). In the event that the information concerning the proposed development plan is not correct, or any changes in the design, location or loading conditions of the proposed structure are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this officec The information and recommendations presented in this section are not meant to supersede design by the project structural engineer or civil engineer specializing in structural design. Upon request, GSI could provide additional input/consultation regarding soil parameters, as related to foundation design. Foundation Design 1. The foundation systems should be designed and constructed in accordance with guidelines presented in the latest adopted edition of the UBC/CBC. All new foundations should be embedded into compacted fill. 2. An allowable bearing value of 1,500 pounds per square foot (pst) may be used for design of footings that maintain a minimum width of i 2 inches and a minimum depth of 12 inches, and founded into compacted fill. This value may be increased by 20 percent for each additional 12 inches in depth to a maximum value of Mr. Robert G. Becker APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg W.0. 5763-A-SC October 15, 2008 Page 17 2,500 psf. In addition, this value may be increased by one-third when considering short duration seismic or wind loads; Isolated pad footings should have a minimum dimension of at least 24 inches square and a minimum embedmentof 24 inches into compacted fill, excluding any landscaped zone or topsoil/coUuvium or weathered terrace deposits. 3. Passive earth pressure may be computed as an equivalent fluid having a density of 250 pd, with a maximum earth pressure of 2,500 pst 4. An allowable coefficient of friction between soil and concrete of 0.35 may be used with the dead load forces. 5. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. 6. Soil generated from footing excavations to be used onsite should be moisture conditioned to at least optimum moisture content and compacted to at least 90 percent minimum relative compaction, if it is to be placed in the yard/right..cof-away areas. This material must not alter positive drainage patterns that direct drainage away from the structural area and toward the street. Foundation Settlement Foundation systems should be minimally designed to accommodate a differential settlement of at least 1 inch in a 40-foot span. Footing Setbacks Footings for structures adjacent to retaining walls (including pool/spa walls)should be deepened so as to extend below a 1 :1 projection from the heel of the walL Alternatively, walls may be designed to accommodate structural loads from bui1dings or appurtenances as described in the Retaining Wall Section of this report. Construction The following foundation construction recommendations are presented as a minimum criteria from a soils engineering standpoint. The onsite soil expansion potential is generally very low (Expansion Index [El.] Oto20) with a plasticity index (P.I.) lessthan 15. However, low expansive soils (EL 21 to 50) with a PJ. greater than 15 may be encountered during construction. For very low to low expansive soil conditions with a P.L of 15, or less, conventional foundations may be used. For very low to low expansive soil conditions with a P.I. of 15, or greater, post-tensioned slab systems are recommended. Mr. Robert G. Becker APN 155-140-41, Carlsbad flle:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page 18 Recommendations by the project's design-structural engineer or architect, which may exceed the soils engineer1s recommendations, should take precedence over the following minimum requirements. Final foundation design will be provided based on the expansion potential and P.I. of the near-surface soils encountered during any grading. Very Low to Low Expansion Potential {EJ. 0 to 50} and Plasticity < 15 1 . Exterior and interior footings should be founded at a minimum depth of 12 inches for one-story floor loads, and 18 inches for two-story floor loads, into compacted fill. Isolated column and panel pads, or wall footings, should be founded at a minimum depth of 24 inches into compacted fill, and should be connected in both directions. All footings should be reinforced with two No. 4 reinforcing bars, once placed near the top and one placed near the bottom of the footing. Footing widths should be as indicated in UBC/CBC (ICBO, 1997 and 2001},aswell as the CBC (CBSC, 2007). 2. A grade beam, reinforced as above, and at least i 2 inches square, should be provided across large (e.g., doorways) entrances. The base of the grade beam should be at the same elevation as the bottom of adjoining footings. Isolated, exterior square footings should be tied within the main foundation in at least one direction with a grade beam. 3. Concrete slabs, where moisture condensation is undesirable, should be underlain with a vapor retarder consisting of a minimum of 10-mil vapor retarder, with all laps sealed. This membrane should be covered above with a minimum of 2 inches of sand to aid in uniform curing of the concrete, and to protect the membrane from puncture. For moisture considerations, please see the "Soil Moisture Considerations" section for recommendations. 4. Concrete slabs should be a minimum of 5 inches thick and should be minimally reinforced with No. 3 reinforcing bar at 18 inches on center in both directions. All slab reinforcement should be supported to ensure placement near the vertical midpoint of the concrete; "Hooking" of reinforcement is not considered an acceptable method of positioning the reinforcement 5. Garage slabs should be reinforced as above and poured separately from the structural footings and quartered with expansion joints or saw cuts. A positive separation from the footings should be maintained with expansion joint material to permit relative movement. 6. Presaturation is not required for these anticipated soil conditions. The moisture content ofthe subgrade soils should be equal to, or greater than, optimum moisture content in the slab areas, prior to concrete placement 7. As an alternative, an engineered post-tension foundation system may be used. Mr; Robert G. Becker APN 155-140-41 , Carlsbad File:e:\wp9\5700\5763a.upg GeoSoil.1, lne .. W.O. 5763,A-SC October 15, 2008 Page 19 POST-TENSIONED SLAB SYSTEMS Recommendations for using post-tensioned systems for very low to low expansive soils is also presented, as an option. However, post-tensioned systems are recommended for sons with a P. L greater than 15. The recommendations presented below should be followed in addition to those contained in the previous sections, as appropriate. The information and recommendations presented below in this section are not meant to supercede design by a registered structural engineer or civil engineer familiar with post:-tensioned slab c:Jesign. Post-tensioned slabs should be designed using sound engineering practice and be in accordance with local and/or national code requirements. Upon request, GSI can provide additional data/ consultation regarding soil parameters as related to post-tensioned slab design. From a soil expanslon/shrinkage standpoint, a common contributing factor to distress of structures using post-tensioned slabs is a 11dishing11 or '1arching''ofthe slabs. This is caused by the fluctuation of moisture content in the soils below the perimeter of the slab primarily due to climatic and seasonal changes, and the presence of expansive soils. When the outside soil environment surrounding the slab has a higher moisture content than the area beneath the slab, moisture tends to migrate underneath the slab edges to a distance beyond the slab edges known as a moisture variation distance, and cause the slab edges to lift Conversely, when the outside soil environment is drier, the moisture regime is reversed and the soils underneath the slab edges lose their moisture and shrink. This process leads to dropping of the slab at the edges, which leads to what is commonly referred to as the center lift condition. Therefore; post-tensioned slabs should have sufficient stiffness and rigidity to resist excessive bending due to non-uniform swell and shrinkage of subgrade soils, particularly within the moisture variation distance, near the sfab edges. The following preliminary recommendations for the design of post tensioned slabs have been prepared in general compliance with the requirements of the recent Post-Tensioning lnstitute's (PTl's) publication titled "Design of Post-Tensioned Slabs on Ground, Third Edition" together with it's subsequent addendums. In accordance with this publication since the soil support parameters for final design of the slabs are dependent on the actual soil conditions encountered within the upper 9 feet of the finished pad grades, the following design parameters should be construed as preliminary, and for the budgeting purposes only. Stiffened Slabs For a typical slab designed with interior ribs, or stiffeners, the slab should be at least 5 inches thick. The ribs should be provided in both transverse and longitudinal directions. The interior rib spacing and depth should be provided by the project structural engineer responsible for the design of the post tensioned slabs; The perimeter beams, however, should be embedded at least 12 inches for soils with very low to low expansion potentials. Mr. Robert G. Becker APN 155-i 40-4i, Carlsbad Fife:e:\wp9\5700\5763a.upg GeaSoils, Ine .. W.O. 5763-A-SC October iS, 2008 Page 20 The embedment depth should be measured downward from the lowest adjacent grade surface to the bottom of the beam. Mat Slabs If the slabs are designed as a post tensioned mat without interior ribs, the slabs should be at least 8 inches thick for very low expansive soils conditions. In addition, a deepened perimeter beam should also be provided to reduce thernoisture fluctuation below the slab edges. Perimeter beams should have a minimum embedment depth of 12 inches for very low expansive soil conditions. Slab Underlayment For very low expansive soil conditions, the slab underlayment should consist of a 1 o-mil thick vapor retarder, placed over the subgrade soH, and covered with at least 2 inches of clean sand (SE = 30, or better). The vapor retarder should be adequately sealed to provide a continuous water-proof barrier under the entire slab, For moisture considerations, please see the ''Soil Moisture Considerations'' section for recommendations. Pre-soaking For a very low to low expansive soils, the moisture content of the subgrade soils should be 1 to 2 percentage points above the optimum moisture content to a depth of 12 inches below grade. Soil Support Parameters The preliminary recommendations for soil support parameters have been provided based on an assumed typical soil index properties for soils with a very low expansion potential. The assumed soil index properties are typically the upper bound values based on our experience and practice in the Southern California area, and are provided in the table below: Suction Compression lnclex-Swell Suction Compression Index-Shrink Upper Bound Liquid Limit (LL) Upper Bound Plasticity Index {P.I.) Mr. Robert G. Becker APN 155-140-4 i, Carlsbad Rle:e.:\wp9\5700\5763a.upg lne., 5.0feet 2.5 feet 15 10 5.0 feet 3.5 feet 35 20 W.O. 5763-A-SC October 15, 2008 Page 21 Upper Bound Percent Fines (:·#200) 15 30 Upper Bound Percent Clay 10 15 Soil Fabric Factor (Ff) 1.0 1.0 Modified Unsaturated Diffusion Coefficient -a' Swen (Edge lift:) 5.69 E-03 5.00 E-03 Modified Unsaturated Diffusion Coefficient-a' Shrink {Center lift} 5.69 E-03 5.02E-03 Equilibrium Suction pF 3.9 3.9 Thomthwaite Index 0 to -20 Oto -20 Based on the above, the recommended preliminary soil support parameters are tabulated below: "" ,, : so1L sUr» PAHAIViet em center lift em edge lift Y m center lift y edge lift 9.0 feet 9.0 feet 5.5 feet 5.0feet 0.20 inch 0.50 inch 0.25 inch 0.60 inch The coefficients are considered minimums and may not be adequate to represent worst case conditions such as adverse drainage and/or improper landscaping and maintenance. The above parameters are applicable provided structures have positive drainage tha,t is maintained away from structures. In addition no trees with significant root systems are planted within 15 feet of the perimeter foundations. Therefore, it is important that information regarding drainage, site maintenance, trees, settlements, and effects of expansive soils be passed on to future owners. The values tabulated above may not be appropriate to account for possible differential settlement of the slab due to other factors, such as excessive settlements. If a stiffer slab is desired, higher values of Ym may be recommended. Mr. Robert G. Becker APN 155-i 40-41 • Carlsbad File:e:\Wp9\5700\57&1a.upg W.O. 5763-A-SC October 15, 2008 Page 22 CORROSION Upon completion of grading, additional testing of soils (including import materials) for corrosion to concrete and metals should be performed prior to the construction of utilities and foundations. SOIL MOISTURE CONSIDERATIONS Site soils generally are in the very low to low expansion potential categories, based on ASTM D 4829. Accordingly, GSI has evaluated the potential for vapor or water transmission through the slabs, in light of typical residential floor coverings and improvements. Please note that slab moisture emission rates, range from about 2 to 27 lbs/24 hours/1,000 square feet from a typical slab (Kanare, 2005), whileffoor covering manufacturers generally recommend about 3 Ibs/24 hours as an upper limit. Thus, the client will need to evaluate the following in light of a cost v. benefit analysis, along with disclosure to all interested/affected parties. Considering the E.1. test results and anticipated typical water vapor transmission rates, floor coverings and improvements (to be chosen by the client) that can tolerate those rates without distress, the following alternatives are provided: 1. Concrete slabs should be a minimum of 5 inches thick. 2. Concrete slab underlayment should consist of a 10-to 15-mil vapor retarder, or equivalent, with all laps sealed per the UBC/CBC (ICBO, 1997 and 2001; CBSC, 2007) and the manufacturer's recommendation. The vapor retarder should comply with the ASTM E 17 45 -Class A criteria, and be installed in accordance with ACI 302.1R-04. The 10-to 15-mil vapor retarder (ASTM E 1745-CfassA) shall be installed per the recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting, rebar, etc.). 3. Slab underlayment should consist of 2 inches of washed sand placed above a vapor retarder consisting of 10-to 15-miJ polyvinyl chloride, or equivalent, with all laps sealed per UBC (ICBO, 1997). The vapor retarder shall be underlain by 4 inches of pea gravel (1h to % subangular to angular clean crushed rock, O to 5 percent fines) placed directly on the slab subgrade, and should be sealed to provide a continuous water-resistant barrier under the entire slab, as discussed above. All slabs should be additionally sealed with suitable slab sealant 4. Concrete should have a maximum water/cement ratio of 0.50. This does not supercede Table 19-A-4ofthe UBC/CBC (ICBO, 1997 and 2001; CBSC, 2007) for corrosion or other corrosive requirements. Additional concrete mix design recommendations should be provided by the structural consultant and/or Mr. Robert G. Becker APN 155-140-41, Carlsbad File :e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page23 waterproofing specialist Concrete finishing and workablity should be addressed by the structural consultant and a waterproofing specialist 5. Where slab water/cement ratios are as indf;cated above, and/or admixtures used, the structural consultant should also makl changes to the concrete in the grade beams and footings in kind, so that the coricrete used in the foundation and slabs are designed and/or treated for more uniform moisture protection. 6. Owner(s} and all interested/affected parties should be specifically advised which areas are suitable for tile flooring, wood flooring, or other types of water/vapor-sensitive flooring and which are not suitable. In all planned floor areas, flooring shall be installed per the manufactures recommendations. 7. Additional recommendations regarding water or vapor transmission should be provided by the architecVstructural engineer/slab or foundation designer and should be consistent with the specified floor coverings indicated by the architect. Regardless of the mitigation, some limited moisture/moisture vapor transmission through the slab should be anticipated. Construction crews may require special training for installation of certain product(s), as well as concrete finishing techniques. The use of specialized product(s) should be approved by the slab designer and water-proofing consultant. A technical representative of the flooring contractor should review the slab and moisture retarder plans and provide comment prior to the construction of the residential foundations or improvements. The vapor retarder contractor should have representatives onsite during the initial installation. WALL DESIGN PARAMETERS Conventional Retaining Walls The design parameters provided below assume that e.ither non expansive soils (typically Class 2 permeable filter material or Class 3 aggregate base) or native onsite materials (up to and including an E.I. of 50) are used to backfill any retaining walls_ The type of backfill (Le., select or native), should be specified by the wall designer, and clearly shown on the plans. Building walls, below grade, should be water-proofed. The foundation system for the proposed retaining walls should be designed in accordance with the recommendations presented in this and preceding sections of this report, as appropriate. Footings should be embedded a minimum of 18 inches below adjacent grade (excluding landscape layer, 6 inches) and should be 24 inches in width. There should be no increase in bearing for footing width. Recommendations for specialty walls (i.e., crib, earthstone, geogrid, etc.) can be provided upon request, and would be based on site specific conditions. Mr. Robert G. Becker APN 155-140-41, Carlsbad Fi!e:e:\wp9\5700\5763a.upg GeoSoils, lne .. WD. 5763~A-SC October 15, 2008 Page 24 Restrained Walls Any retaining walls that wm be restrained prior to placing and compacting backfill material or that have re-entrant or male comers, should be designed for an at-rest equivalent fluid pressure (EFP) of 65 pcf, plus any applicable surcharge loading. For areas of male or re-entrant comers, the restrained wall design should extend a minimum distance of twice the height of the wall (2H) laterally from the comer. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 feet high. Design parameters for walls less than 3 feet in height may be superceded by City standard design. Active earth pressure may be used for retaining wall.design, provided the top of the wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request 35 50 45 60 * level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without a slope for a distance of 2H behind thewall. ** As evaluated by testing, PJ. <15, E.L <21, SE >30,and <10%passing No. 200sieve. *** As evaluated by testing, El. <50, S.E. >25. Retaining Wall Backfm and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outlets. A backdrain system is considered necessary for retaining walls that are 2 feet or greater in height Details 1, 2, and 3, present the backdrainage options discussed below. Back drains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either Class 2 permeable filter material or %-inch ta 11h-lnch gravel wrapped in approved filterfabric (Mirafi 140 or equivalent). For low expansive backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot For native backfill that has up to an EL of 50, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (Le., full height) behind the wall, and it should be constructed in accordance Mr. Robert G. Becker APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg GeoSail", lne .. W.O. 5763-A-SC October i 5, 2008 Page 25 Structural footing or settlement-sensitive improvement \ (1) Waterproofing membrane-~ CMU or reinforced-concrete wall -Proposed grade t - sloped to drain per precise civil drawings (5) Weep hole --- -, \ '\ \\--~\\ y" ~\~Y\\~~~~ Footing and wall design by others,~..- (1) Waterproofing membrane. (2) Gravel: Clean, crushed,% to 1Yi inch. Provide surface drainage via an engineered V-ditch (see civil plans for details) 1:1 {h:v) or flatter backcut to be properly benched ~ (6) Footing (3) Filter fabric: Mirafi 140N or approved equivalent. (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient sloped to suitable, approved outlet point (perforations down). (5) Weep hole: Minimum 2-inch diameter placed at 20-foot centers along the wall and placed 3 inches above finished surf ace, Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. (6) Footing: If bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant RETAINING WALL DETAIL -ALTERNATIVE A Detail 1 \ 0) Waterproofing membrane (optional)-----. Structural footing or settlement-sensitive improvement Pro:'"*' suriace_ drainage via engineered l CMU or reinforced-concrete. waif l 6inches -t (5) Weep hole r Proposed grade sloped to drain per precise civil V-ditch (see civil plan details) , drawings ~\\'§(\~~~~(\~\ Footing and wall design by others~ 1:1 (h:v) or flatter backcut to be properly benched =-,;....._..:..__._· "--I· .. ,, ------·-{ 6) 1 cubic foot of %-inch crushed rock ~ (7) Footing (1) Waterproofing membrane (optional): Liquid boot or approved mastic equivalent. (2) Drain: Miradraih 6000 or J-drain 200 or equivaleni for non-waterproofed walls; Miradrain 6200 or J-drain 200 or equivalent for waterproofed walls (all perforations down). (3) Filter fabric: Mirafi 140N or approved equivalent; place fabric flap behind core. (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). (5) Weep hole: Minimum 2-inch diameter placed at 20-foot centers along the wan and placed 3 inches above finished surf ace. Design civil engineer to provide drainage at toe of wait No weep holes for below-grade walls. (6) Gravel: Clean, crushed, % to 1>'2 inch. (7) Footing: lf bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant RETAINING WALL DETAIL -ALTERNATIVE B Detail 2 .. ' (1) Waterproofing membrane/ Structural footing or CMUor reinforced-concrete wall\ -=1= :ti2 inches --f (5) Weep hole H rProposed grade sloped to drain J per precise civil ~ drawings --(0\S\~\"1~;;\/ Footing and wall design by others settlement-sensitive improvement ·--Provide surface drainage 2:1 (h:v) slope :::::::::::::::.·:.·. ::: · ~: v' (8) Native backfill ::::::::::<:::):////:::::::: :-<·>, .. :: :···~ ~ (6) aean .·::::::::::::::.::::::. · :: · .. · ·· '· sand backfill -·---1=1 (h;v) or flatter backcut to be properly benched (3) Filter fabric (2) Gravel (4) Pipe (7) Footing (1) Waterproofing membrane: Liquid boot or approved masticequiva!ent (2) Gravel: Clean, crushed, % to 1~ inch. (3) Filter fabric: Mirafi i40N or approved equivalent. (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40; or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). (5) Weep hole: Minimum 2-inch diameter placed at 20-foot centers along the wall and placed 3 inches above finished surf ace. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. (6) Clean sand backfill: Must have sand equivalent value {SE) of 35 or greater; can be denslfied by water jetting upon approval by geotechnical engineer. (7) Footing: If bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant (8) Native backfill; If EL {21 and SE !_35 then all sand requirements also may not be required and will be reviewed by the geotechnical consultant RETAINING WALL DETAIL -ALTERNATIVE C Detail 3 . ·"' with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail}. For limited access and confined areas, (panel) drainage behind the waif may be constructed in accordance with Detail 2 (Retaining Wall BackfiH and Subdrain Detail Geotextile Drain). Materials with an El. potential of greater than 50 should not be used as backfill for retaining walls. For more onerous expansive situations, backfill and drainage behind the retaining wall should conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than ±100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes, only, in walls higher than 2 feet1 is not recommended. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (E.1. <50). Proper surface drainage should also be provided. For additional mitigation, consideration should be given to applying a water-proof membrane to the back of all retaining structures. The use of a waterstop should be considered for all concrete and masonry joints. Wall/Retaining Wall Footing Transitions Site walls are anticipated to be founded on footings designed in accordance with the recommendations in this report. Should wall footings transition from cut to fill, the civil designer may specify either: a) A minimum of a 2-foot overnxcavation and recompaction of cut materials for a distance of 2H, from the point of transition. b) Increase of the amount of reinforcing steel and Wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1 /360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be placed no greater than 20 feet on-center, in accordance with the structural engineer's/wall designer's recommendations, regardless of whether or nottransition conditions exist Expansion joints should be sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational material (i.e., deepened footings). If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation "a" (above) and until such transition is between 45 and 90 degrees to the wall alignment. Mr. Robert G. Becker APN 155-140-4 i, Carlsbad Fi!c:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page 29 DRIVEWAY. FLATWORK. AND OTHER IMPROVEMENTS Some of the soif materials on site may be expansive. The effects of expansive soils are cumulative, and typically occur over the lifetime of any improvements. On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to cause heaving and distress to flatwork and other improvements. The resulting potential for distress to improvements may be reduced, but not totally eliminated. To that end, it is recommended that any interested/affected parties be notified of thi$ long-term potential for distress. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork: 1 . The subgrade area for concrete slabs should be compacted to achieve a minimum 90 percent relative compaction, and then be presoaked to 2 to 3 percentagepoints above (or 125 percent of) the soils' optimum moisture content, to a depth of 18 inches below subgrade elevation. If very low expanstve soils are present, only optimum moisture content, or greater, is required and specific presoaking is not warranted. The moisture content of the subgrade should be proof tested within 72 hours prior to pouring concrete. 2. Concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete. If very low expansive soils are present, the. rock or gravel or sand may be deleted. The layer or subgrade should be wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. 3. Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and approaches should additionally have a thickened edge (12 inches) adjacent to all landscape areas, to help impede infiltration of landscape water under the slab. 4. The use of transverse and longitudinal control joints are recommended to help control. slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. If subgrade soils within the top 7 feet from finish grade are very low expansive soils (i.e., El. <20}, then 6x6-W1 .4xW1.4 welded-wire mesh may be substituted for the rebar, provided the reinforcement is placed on chairs, at slab mid-height The exterior slabs should be scored or saw cut, 1h to 3/a inches deep, often enough so that no section is greater than 1 o feet by 1 O feet For sidewalks or Mr. Robert G. Becker APN 155-140-41, Carlsbad Flle:e:\wp9\5700\5763a.upg W.O. 5763--A-SC October 15, 2008 Page30 narrow slabs, control joints should be provided at intervals of every 6 feet The slabs should be separated from the foundations and sidewalks with expansion joint filler material. 5. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 pounds per square inch (psi). 6. Driveways, sidewalks, and patio slabs adjacent to the house. should be separated from the house with thick expansion joint fiHer material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be additionaUy sealed with flexible mastic. 7. Planters and walls should not be tied to the house. 8. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. If very low expansion soils are present; footings need only be tied in one direction. 9. Any masonry landscape walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long. These segments should be keyed m doweled together. 1 o. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. 11 • Positive site drainage should be maintained at all times. Finish grade on the lots should provide a minimum of 1 to 2 percent fall tothe street, as indicated herein. It should be kept in mind. that drainage reversals could occur, including post-construction settlement, if relatively flat yard drainage gradients are not periodically maintained by the owners or interested/affected parties. i 2. Air conditioning (NC) units should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. NC waste water lines should be drained to a suitable non-erosive outlet. 13. Shrinkage cracks could become excessive if proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association Guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. Mr. Robert G. Becker APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page 31 PREUMINARY OUTDOOR POOL/SPA AND POOL DECK DESIGN RECOMMENDATIONS The following preliminary recommendations are provided for consideration in pool/spa design and planning. The recommendations provided below are designed for soil exhibiting a very low to low EL The project structural engineer should take this into consideration for their design. General 1. The planned pool/spa is located on a slope. Therefore, to obtain firm support, and the required foundation setback, the pool should be supported by deep piers. The piers should be embedded at least 5 feet into unweathered bedrock. In addition, the outer row of piers should be deepened to accommodate a horizontal setback of at least 20 feet from toe of the pier to the face of slope. 2. The piers should be a minimum 18 inches in diameter, spaced no closer than 3 diameters apart, and as determined by the project structural engineer. 3. The allowable tip capacity for the piers may be taken as 3,500 psf. The skin friction (only in bedrock) may be assumed as 300 pst 4. The piers should be tied together by grade beams at the top in both directions, or if the bottom slab is designed to act as a diaphragm, the bottom slab should be at least 8 inches thick. The grade beams should be at least 18 inches wide and 12 inches deep and provided with one #5 reinforcing bar at the top, and one #5 reinforcing bar at the bottom. 5. The equivalent fluid pressure to be used for the pool/spa design should be 65 pounds per cubic foot (pcf) for pool/spa walls with level backfill; and 75 pcf for a 2:1 sloped backfill condition. In addition, backdrains should be provided behind pool/spa walls subjacent to slopes. 6. Passive earth pressure may be computed as an equivalent fluid having a density of 150 pd, to a maximum lateral earth pressure of i ,000 psf. 7. An allowable coefficient of friction between soil and concrete of 0.30 may be used with the dead load forces. 8. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. 9. Where pools/spas are planned near structures, appropriate surcharge loads need to be incorporated into design and construction by the pool/spa designer. This Mr. Robert G. Becker APN 155-140-41 , Carlsbad File:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page 32 includes, but is not limited to landscape berms, decorative walls, footings, built-in barbeques, utility poles, etc. 10. All pool/spa walls should be designed as "free standing" and be capable of supporting the water in the pool/spa without soil support. The shape of pool/spa in cross section and plan view may affect the performance of the pool, from a geotechnical standpoint -(Not possible with proposed pool location). 11. The soil beneath the pool/spa bottom should be uniformly moist with the same stiffness throughout If a fill/cut transition occurs beneath the pool/spa bottom, the cut portion should be over-excavated to a minimum depth of 24 inches, and replaced with compacted fill, such that there is a uniform blanket below the pool/spa shell. Engineered fill should be compacted to 90 percent relative compaction at over optimum moisture. The potential for grading and/or re-grading of the pool/spa bottom, and attendant potential for shoring and/or slot excavation, needs to be considered during all aspects of pool/spa planning, design, and construction. 12. If the pool/spa is founded entirely in compacted fill placed during rough grading, the deepest portion ofthe pool/spa should correspond with the thickest fill on the lot. 13. Hydrostatic pressure relief Valves should be incorporated into the pool and spa designs. A pool/spa under-drain system is also recommended, with an appropriate outlet for discharge. 14. All fittings and pipe joints, particularly fittings in the side of the pool or spa,, should be properly sealed to prevent water from leaking into the adjacent soil, and be fitted with slip or expandable joints between connections transecting varying soil. conditions. 15. An elastic expansion joint (flexible waterproof sealant) should be installed to prevent water from seeping into the soil at all deck joints. 16. A reinforced grade beam should be placed around skimmer inlets to provide support and mitigate cracking around the skimmer face. 17. In order to reduce unsightly cracking, deck slabs should minimally be 4 inches thick, and reinforced with No. 3 reinforcing bars at 18 inches on-center. A!! slab reinforcement should be supported on chairs to ensure proper mid-slab positioning during the placement of concrete. Wire mesh reinforcing is specifically not recommended. Deck slabs should not be tied to the pool/spa structure. Deck slabs nearthe slope within the H/3 zone, where His the height of the slope (in feet), will have an increased potential for distress relative to other areas outside of the H/3 zone. if distress is undesirable, improvements, deck slabs or flatwork should not ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~·· Mr. Robert G. Becker APN 155-140-41 , Carlsbad File:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page 33 be constructed closer than H/3 or 7 feet (whichever is greater) from the slope face, in order to reduce, but not eliminate, this potential. 18. Pool/spa bottom or deck slabs should be founded entirely on competent bedrock, or properly compacted fill. Fill should be compacted to achieve a minimum 90 percent relative compaction, as discussed above. Pre-moistening and/or pre-soaking of the slab subgrade is recommended; to a depth of 12 inches (optimum moisture content), for very low to low expansive soils. This moisture content should be maintained in the subgrade soils during concrete placement to promote uniform curing of the concrete and minimize the development of unsightly shrinkage cracks. Slab underlayment should consist of a 1-to 2-inch leveling course sand (S.E.>30) and between 4 to 6 inches of Class 2 base compacted to 90 percent 19. In order to reduce unsightly cracking, the outer edges of pool/spa decking to be bordered by landscaping, and the edges immediately adjacent to the poof/spa, should be underlain by an .8-inch wide concrete cutoff shoulder (thickened edge) extending to a depth of at least 12 inches below the bottoms of the slabs to mitigate excessive infiltration of water under the pool/spa deck, These thickened edges should be reinforced with two No. 4 bars, one at the top and one at the bottom. 20. Surface and shrinkage cracking of the finish slab may be reduced if a low slump and water-cement ratio are maintained during concrete placement. Concrete utilized should have a minimum compressive strength of 4,000 psL Excessive water added to concrete prior to placement is likely to cause shrinkage cracking, and should be avoided. Some concrete shrinkage cracking, however, is unavoidable, 21. Joint and saw cut locations for the pool/spa deck should be evaluated by the design engineer and/or contractor. However, spacing should not exceed i Ofeet on center. 22. Considering the nature of the onsite earth materials, it.should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees), should be anticipated. All excavations should be observed by a representative of the geotechnical consultant, including the project geologist and/or geotechnical engineer, prior to workers entering the excavation or trench, and minimally conform to Cal-OSHA, state, and local safety codes. Should adverse conditions exist, appropriate recommendations should be offered atthattime by the geotechnlcal consultant. GS! does not consult in the area of safety engineering and the safety of the construction crew is the responsibility of the pool/spa builder. 23. It is imperative thatadequate provisions for surface drainage are incorporated by the homeowners into their overall Improvement scheme. Ponding water, ground saturation and f!ow over slope faces, are all situations which must be avoided to Mr. Robert G. Becker APN 155--140-41, Carlsbad File:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page 34 enhance longterm performance ofthe pool/spa and associated improvements, and reduce the likelihood of distress. 24. Regardless ofthe methods employed, once the pool/spa is filled with water, should it be emptied, there exists some potential that significant distress may occur. Accordingly, once filled, the pool/spa should not be emptied unless evaluated by the geotechnical consultant and the pool/spa builder. 25. The temperature of the water lines for spas and pools may affect the corrosion properties of site soils, thus, a corrosion specialist should be retained to review all spa and pool plans, and provide mitigative recommendations, as warranted. Concrete mix design should be reviewed by a qualified corrosion consultant and materials engineer. 26. All pool/spa utility trenches should be compacted to 90 percent of the laboratory standard, under the full-time observation and testing of a qualified geotechnical consultant Utility trench bottoms should be sloped awaYfrom the primary structure· on the property (typica!fythe residence). 27. Pool and spa utility lines should not cross the primary structure's utility lines (Le., not stacked, or sharing oftrenches, inc.). 28. The pool/spa or associated utilities should not intercept, interrupt, or otherwise adversely impact any area drain, roof drafn, or other drainage conveyances. If it Is necessary to modify, move, or disrupt existing area drains, subdrains, ortightlines, then the design civil engineer shouf d be consulted, and mitigative measures provided. Such measures should be further reviewed and approved by the geotechnical consultant, prior to proceeding with any further construction. 29. The geotechnical consultant should review and approve all aspects of pool/spa and flatwork design prior to construction. A design civil engineer should review afl aspects of such design, including drainage and setback conditions. Prior to acceptance of the pool/spa construction, the project builder, geotechnlcal consultant and civil designer should evaluate the performance of the area drains and other site drainage pipes, following pool/spa construction. 30. All aspects of construction should be reviewed and approved by the geotechnical consultant, including during excavation, prior to the placement of any additional fill, prior to the placement of any reinforcement or pouring of any concrete. 31. Any changes in design or location of the pool/spa should be reviewed and approved by the geotechnical and design civil engineer prior to construction. Field adjustments should not be allowed until written approval of the proposed field changes are obtained from the geotechnical and design civil engineer_ Mr. Robert G. Becker APN 155-140-41, Carlsbad flle:e:\wp9\5700\5763a.upg W.O. 5763-ABC October i 5, 2008 Page 35 32. The expected future distress within the creep zone is significantly reduced by utilizing grade beams and pier foundation system, as recommended herein. However, future distress cannot be completely ruled out. Therefore, disclosure should be made to owners and builders, contractors, and any interested/affected parties, that pools/spas built within about 15 feet of the top of a slope, and/or H/3, where His the height of the slope (in feet), may experience some movement or tilting. While the pool/spa shell or coping may not necessarily crack, the levelness of the pool/spa will likely tilt toward the slope, and may not be esthetically pleasing. The same is true with decking, fiatwork and other improvements in this zone. 33. Local seismicity and/or the design earthquake will cause some distress to the pool/spa and decking or flatwork, possibly including total functional and economic loss. 34. Failure to adhere to the above recommendations will significantly increase the potential for distress to the pool/spa, flatwork, etc. 35. The information and recommendations discussed above should be provided to any contractorsand/orsubcontractors, orhomeowners, interested/affected parties, etc., that may perform or may be affected by such work. Design and Construction Workmanship To reduce the potential for future crack development within the pool shell, the following recommendations should be adhered to during construction: 1. To reduce reflective cracking (cracks that generally follow the pattern of the reinforcement or piping inside the pool wall), proper gunite or shotcrete mix should be utilized and applied at the right velocity and thickness. 2. To reduce horizontal cracking in the waterline tile, the concrete deck should be completely separated from the pool's bond beam via an expansion joint that extends through the full depth ofthe deck. This prevents loading of the bond beam by the expanding deck. 3. To reduce shrinkage cracking ( random cracks, angular, intermittent, that generally run throughout the pool) water should not be added to the proper shotcrete or gunite mix during application. Typically this is done during construction for ease of operation. In addition proper hydration and curing of the shotcreted or gunited material is crucial. Mr. Robert G. Becker APN 155~ 140-4 i , Carlsbad Fi!e:e:\wp9\5700\5763a.upg W.O. 5763-A-SC October i 5, 2008 Page36 DEVELOPMENT CRITERIA Drainage Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, hardscape, and slopes. Surface drainage should be sufficient to mitigate ponding of water anywhere on a lot, and especially near structures and tops of slopes. Lot surface drainage should be carefully taken into consideration during fine grading, landscaping, and building construction. Therefore, care should be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within lots and common areas should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. In general, the area within 5 feet around a structure should slope away from the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of 1 percent sloping away from structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construction of planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s}. Although not a geotechnical requirement, root gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Down spouts, or drainage devices should outlet a minimum of 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing thrs effect could be provided upon request. Erosion Control Cut and fill slopes will be subject to surficial erosion during and after grading. Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint .landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas wlll adversely affect proposed site improvements. We would recommend that any proposed open-bottom planters adjacent to proposed structures be eliminated for a minimum distance of 1 O fe.et. As an alternative, closed-bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If planters are constructed adjacent to structures, the sides and bottom of the planter should be provided with a moisture retarder to mitigate penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation Mr. Robert G. Becker APN 155-140-4 i , Carlsbad Fi!e:e:\Wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 2008 Page37 water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Gutters and Downspouts As previously discussed in the drainagesection, the installation of gutters and downspouts should be considered to collect roof water that may otherwise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or other non-erosive devices (e.g., paved swales or ditches; below grade, solid tight-lined PVC pipes; etc.), that will carry the water away from the structure, to an appropriate outlet, in accordance with the.recommendations of the design civil engineer. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage is incorporated into project design (as discussed previously). Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided that the recommendations contained in this report are incorporated into final design and construction and that prudent surface and subsurface drainage practices are Incorporated into the construction plans. Perched groundwater conditions along zones of contrasting permeabilities may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s} and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrlgation, rainfall, or other factors. Site Improvements If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. Pools and/or spas should not be constructed without specific design and construction recommendations from GSI, and this construction recommendation should be provided to all interested parties. This office should be notified in advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench and retaining wall backfills, flatwork, etc. Mr. Robert G. Becker APN 155-140-41, Carlsbad File;e;\wp9\5700\5763a.upg W.O. 5763-A-SC October 15, 20D8 Page38 ' Tile Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between tile and concrete slabs on grade. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes completion of grading in the street, driveway approaches, driveways, parking areas, and utility trench and retaining wall backfills. Footing Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observations is to evaluate that the excavations have been made into the recommended bearing material and to the minimum widths and depths recommended for construction. It loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction of the subgrade materials would be recommended at that time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed from the site. Trenching/I emporary Construction Backcuts Considering the nature of the onsite earth materials, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25. to 45 degrees [except as specifically superceded within the text of this report]), should be anticipated. All excavations should be observed by an engineering geologist or soil engineer from GSI, prior to workers entering the excavation or trench, and minimally conform to Cal-OSHA, state, and local safety codes. Should adverse conditions exist, appropriate recommendations would be offered at that time~ The above recommendations should be provided to any contractors and/or subcontractors, or property owners, etc., that may perform such work. Mr. Robert G. Becker APN i 55-140-4 i, Carlsbad File:e:\wp9\5700\5763a,upg W.O. 5763-A-SC October 15, 2008 Page39 Utility Trench Backfm 1 . All interior utility trench backfill should be brought to at least 2 percent above optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent ofthe laboratory standard. As an alternative for shallow (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater may be utilized and jetted or flooded into place. Observation, probing and testing should be provided to evaluate the desired results. 2. Exterior trenches adjacent to, and within areas extending below a 1 : 1 plane projected from the outside bottom edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Compaction testing and observations, along with probing, should be accomplished to evaluate the desired results. 3. All trench excavations should conform to Cal-OSHA, state, and local safety codes. 4. Utifities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAl OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the foHowing construction stages: .. During grading/recertification. .. During excavation. .. During placement of subdrains, toe drains, or other subdrainage devices, prior to placing fill and/or backfill. .. After excavation of building footings, retaining wail footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. .. Prior to pouring any slabs or flatwork, after presoaking/presaturation of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break {Le_, sand, pea-gravel, etc.), or vapor retarders (i.e., vlsqueen, etc~). Mr. Robert G. Becker APN 155-140-41, Carlsbad File:e:\wp9\5700\5763a.upg lne .. W.O. 5763-A-SC October 15, 2008 Page 40 .. During retaining wall subdrain installation, prior to backfill placement • During placement of backfill for area drain. interior plumbing, utility line trenches, and retaining wall backfill. When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. When any owner improvements, such as flatwork, spas. pools, walls, etc., are constructed, prior to construction. • A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER. DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer, architect, landscape architect, wall designer, etc .. , should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. This report presents minimum design criteria for the design of slabs, foundations and other elements possibly applicable to the project These criteria should not be considered as substitutes for actual designs by the structural engineer/designer. Please note that the recommendations contained herein are not intended to entirely preclude the transmission of water or vapor through the slab or foundation. The structural engineer/foundation and/or slab designer should provide recommendations to not allow water or vapor to enter into the structure so as to cause damage to another building component, or so as to limit the installation of the type of flooring materials typically used for the particular application. The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various slab, foundation, and other elements in order to develop appropriate, design-specific details" As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. it is considered likely that some, more restrictive details will be required. If the structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or otherwise transmit their requests to GSL In order to mitigate potential distress, the foundation and/or improvement's designer should confirm to GS! and the governing agency, in writing, that the proposed foundations and/or improvements Mr. Robert G. Becker APN 155-i 40-41 , Carlsbad File:e:\wp9\5700\5763a.upg W.O. 5763-A~sc October 15, 2008 Page 41 can tolerate the amount of differential settlement and/ or expansion characteristics and other design criteria specified herein. PLAN REVIEW Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.), should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review; supplemental recommendations and/or further geotechnical studies may be warranted. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty, either express or implied, is given. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. fn addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion ofthe project All samples will be disposed of after 30 days, unless specifically requested by the client, in writing. Mr. Roberi G. w .... ,. • .,,, ... APN 155-140-4 i, Carlsbad FHe:e:\wp9\5700\5763a.upg W. 0. 5763-A-SC October 15, 2008 Page42 APPENDIX A REFERENCES APPENDIX A REFERENCES ACI Committee 302, 2004, Guide for concrete floor and slab construction, ACI 302.1 R-04, dated June. ASTM E 1745-97, 2004, Standard specification for water vapor retarders used in contact with soil or granular fill under concrete slabs. Becker Architects, 2006, New site plan, new site sections, ground information. Blake, Thomas F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. __ , 2000b, EQSEARCH, A computer program for the estimation of peak horizontal acceleration from California historical earthquake catalogs; Updated to June, 2003, Windows 95/98 version. __ , 2000c, FRISKSP, A computer program for the probabilistic estimation of peak acceleration and uniform hazard spectra using 3-D faults as earthquake sources; Windows 95/98 version. Bozorgnia, Y., Campbell K.W., and Niazi, M., 1999, Vertical ground motion: Characteristics, relationship with horizontal component, and building-code implications; Proceedings of the SMlP99 seminar on utilization of strong-motion data, September 15, Oakland, pp. 23-49. Bryant, W.A., and Hart, EW.,2007, Fauft-rupturehazardzonesin Ca!ifomia,Alquist-Priolo earthquake fault zoning act with index to earthquake fault zones maps; California Geological Survey, Special Publication 42, interim revision. California Building Standards Commission, 2007, California building code. California Department of Transportation (Caltrans), 1999. Standard specifications, State of California, Business, Transportation, and Housing Agency, Department of Transportation, dated July. California, State of, 2001, Senate Bill 800; Burton. Liability: construction defects, February 23; approved by Governor September 20, 2002; filed with Secretary September 20, 2002; effective January 1, 2003. Campbel!, K.W. and Bozorgnia, Y_, 1997, Attenuation relations for soft rock conditions; in EQFAUL T, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version~ Blake, 2000a. GeoSoils, , 1994, Near.,.source attenuation of peak horizontal acceleration from worldwide --. accelerograms recorded from 1957 to 1993; proceedings, Fifth U.S. National Conference on Earthquake Engineering, Vat Ill, Earthquake Engineering Research Institute, pp. 283-292. GeoSoifs, Inc., 2003, Update preliminary geotechnical evaluation, APNs 155-140-37 and 155-140-38, City of Carlsbad, San Diego County, California, W.O. 3213-A-SC, dated September 1 R __ ., 1993, Preliminary geotechnical evaluation, Parcel 155-140-09, Carlsbad, California, W.O. 1624-SD, dated November 2. Hart, E.W. and Bryant, W.A. 1997, Fault-rLiptt,ire hazard zones in California, Alquist-Priolo Earthquake Fault zoning act with index to earthquake fault maps; California Division of Mines and Geology Special Publication 42. Idriss, I.M., 1994, Attenuation coefficients for deep and soft soil conditions; in EQFAULT, A computer program for the .estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version, Blake, 2000a. International Code Council, Inc., 2006, International building code and international residential code for one-and two-fc;tmHy dwellings. International Conference of Building Officials, 2001, California building code, California code of regulations title 24, part 2, volume i and 2. --, 1997, Uniform building code: Whittier, California, International conference of building officials, Volumes i, 2, and 3: especially Chapter 16, Structural forces (earthquake provisions); Chapter 18, Foundations and retaining walls; and Chapter A-33, Excavation and grading. Jennings, C.W., i 994, Fault activity map of California and adjacent areas: California Division of Mines and Geology, Map sheet no. 6, scale 1 :750,000. Joyner, W. B., and Boore, D.M., 1982a, Estimation ofresponse-spectral values as functions of magnitude, distance and site conditions; in eds., Johnson, J.A., Campbell, K.W., and Blake, T.F., AEG short course, seismic hazard analysis, dated June 18, 1994. , 1982b, Prediction of earthquake response spectra, U.S. Geolo.gical Survey Open-File Report 82-977, 16p. Kanare, Howard, M., 2005, Concrete Floors and Moisture, Engineering Bulletin 119, Portland Cement Association. Kuhn, G.G., Legg, M.A., Johnson, J.A., Shlemon, A.G., and Frost, E.G., 1996, Paleo liquefaction evidence for large pre-historic earthquakes(s) in north-coastal San Mr. Robert G. Becker Rle:e:\wp9\5700\5763a.upg Appendix A Page2 Diego County, California, in Munasinghe, T., and Rosenberg, eds,, Geology and natural resources of coastal San Diego County, California, guidebook to accompany the 1996 annual field trip of the San Diego Association of Geologists, dated September. Obermeier, S.F., 1996, Using liquefaction-induced features for paJeoseismic analysis, Chapter 7, in McCafpin, J.P., ed, Paleoseismology, Acedemic Press Petersen, Mark D., Bryant, W.A., and Cramer, C.H., 1996, interim table offault parameters used by the California Division of Mines and Geology to compile the probabilistic seismic hazard maps of California. Sadigh, K., Egan, J., and Youngs, R, 1987, Predictive ground motion equations reported in Joyner, W.B., and Boore, D.M., 1988, !!Measurement, characterization, and prediction of strong ground motion," in Earthquake Engineering and Soil Dynamics II, Recent Advances in Ground Motion Evaluation, VonThun, J.L., ed.: American Society of Civil Engineers Geotechnical Special Publication No. 20, pp. 43-102; Sowers and Sowers, 1979, Unified soil classification system (After U; S. Waterways Experiment Station and ASTM 02487-667) in Introductory soil mechanics, New York. State of California, 2008, Civil Code, Sections 895 et seq. Tan, S.S., and Kennedy, Michael P., 1996, Geologic maps of the northwestern part of San Diego County, California: California Division of Mines and Geology, Open File Report 96-02. Mr. Robert G. Becker Fi!e.:e:\wp9\5700\5763a.upg Appendix A Page3 APPENDIX B TEST PIT AND BORING LOGS 111---· __ u_N_I_F_IE_o_s_o_1_L_C_LA_s_s_1F_1c_A.,..T_1_o_N_s_v_s_T_E_M ____ ~TENCY OR RELATIVE DENSITY Major Divisions Highly Organic Soils C: ., "' "O a, C: -<ti 0(1) Cobbles 3• Group Symbols GW GP GM GC Typical Names Well-graded gravEo!ls and gravel- sand mixtures, little or no fines Poorly graded gravels and gravel-sand mixtures, little or no fines Silty gravels grave!-sand-sltt mixtures Clayey gravels, gravel-sand-day mixtures SW I Well-graded sands and gravelly sands, little or no fines SP SM SC ML CL OL MH CH OH PT Poorly graded sands and gravelly sands, little or no fines Silty sands, sand-silt mixtures crayey sands, sand-day mixtures Inorganic sifts, very tine sands, rock flour, silty or clayey fine sands Inorganic days of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays Organic silts and organic silty clays of low plasticity Inorganic silts, micaceous or diatomaceous fine sands or silts, elastic silts Inorganic clays of high plasticity, fat clays Organic clays of medium to hlgh plasticity Peat, mucic, and other highly organic soils 3/4" #4 Gravel CRITERIA Standard Penetration Test Penetration Resistance N Relative (blows/ft) Density 0-4 Very loose 4-10 Lornse 10-30 Medium 30-50 Dense >50 Very dense Standard Penetration Test Penetration Resistance. N (blows/ft} <2 2-4 4-8 B • i5 15-30 >30 #10 Sand Unconfined Compressive Strength Consistency (tons/ft") Very Soft <0.25 Soft 0.25-.050 Medium 0.50-1.00 Stiff 1.00-2.00 Very Stiff 2.00-4.00 Hard >4.00 #40 #200 U.S. Standard Sieve Slit or Clay Unified Soil Classification ! coarse I fine coarse I medium I fine MOISTURE CONDITIONS Dry Slightly Moist Molst Very Moist Wet Absence of moisture: dusty, dry to the touch Below optimum moisture content for compaction Near optimum moisture content Above optimum moisture content Visible free water; below water table BASIC LOG FORMAT: MATERIAL QUANTITY trace 0-5% few 5-10% little 10-25% some 25-45% OTHER SYMBOLS C Core Sample S SPTSample B Btllk Sample 'V Groundwater Qp Pocket Penetrometer Group name, Group symbol, (grain slze), color, moisture, consistency or relative density. Additional comments: odor, presence of roots, mica, gypsum, coarse grained particles, etc. EXAMPLE: Sand (SP), fine to medium grained, brown, moist, loose, !race silt, little fine gravel, few cobbles up to 4" in size, some hair roots and rootlets. Flle:Mgr: c;\SoilClassit wpd PLATE B-1 • TEST DEPTH GROUP SAMPLE . PIT NO. EL.EV. {ft.) SYMBOL DEPTH {ft;) TP-1 0-2% ML Bulk@0-3 2%-3 ML 3-5 ML Ring@3 Ring@4 TP-2 0-2% ML 2%-8112 8%-10 ML ,I w.0.5763-A~sc • Becker Project Location Logged By: BEV August29,2008 LOG OF EXPLORATORY TEST PITS MOISTURE ·FIELD DRY (%) ·· .. oeNsrrv DESCRIPTION (pcf} ... .,. .· COLLUVIUM/TOPSOIL: SIL TY SAND, brown, dry, loose; porous, roots and rootlets, scattered rounded pebbles. WEATHERED TERRACE DEPOSITS: SILTY SAND, reddish brown, damp, medium dense; porous. 7.5 1 i9.3 TERRACE DEPOSITS: SIL TY SANO, reddish to orange brown, damp 7.8 106.6 to moist, medium dense. Total Depth = 5' No Groundwater Encountered Backfilled 8-29-2008 ARTIFICJAL FILL: SILTY SAND, brown, dry to damp, loose. Seepage pit encountered, gravels to cobbles, light brown, dry, very loose; well rounded. TERRACE DEPOSITS: SIL TY SAND, orange brown, damp, medium dense. Total Depth = 1 O' No Groundwater Encountered BackfHled 8·29-2008 PLATE B-2 TEST DEPTH GROUP SAMPLE PITNO. ELEV. {ft.) SYMBOL DEPTH (ft.) TP-3 0-2% ML 21,12-3% ML 3%-6 ML Ring@5 TP-4 0-2Yz ML 21h-31h ML 3%-6 ML Rlng@5 ~ W.0.5763-A-SC ~ Becker Project Location Logged By: BEV August29,2008 LOG OF EXPLORATORY TEST PITS MOISTURE FIELD DRY (%) DENSITY DESCRIPTION .c (pcf) COLLUVIUM{TOPSOIL: SIL TY SAND, brown, dry, loose; porous, roots and rootlets, scattered rounded pebbles, WEATHERED TERRACE DEPOSITS: SILTY SAND, brown to reddish brown, dry to damp, medium dense; porous, minor roots and rootlets. 2.7 109,0 TERRACE DEPOSITS: S!L TY SAND, orange to brown to reddish brown, dry, medium dense. Total Depth = 5' No Groundwater Encountered Backfilled 8-29-2008 COLLUVIUM{IOPSOIL~ SIL TY SAND, brown, dry, loose; porous, roots and rootlets, scattered rounded pebbles, WEATHERED TERRACE DEPOSITS: SILTY SAND, light brown to yellow brown, dry to moist, medium dense; porous, roots and roottets. 2.3 104.7 TERRACE DEPOSITS: SILTY SAND, yellow brown, dry, medium dense; SAND@ 5.-6 feet. Total Depth = 61 No Groundwater Encountered Backfilled 8-29-2008 PLATEEl-3 GEOSOILS, INC. BORING LOG SAMPLE +-"" : (D ' -Ill 0 :ii {/1..0 0 u .E (,l) .. ::.n Ill ::un SM 3 SM Cl!EIH MICB:AEL REED WORK ORDER NO. 1624-SD PARCEL l.55-140-09, CARLSBAD DATE EXCAVATED SAMPLE METHOD AUGER DRILLING RIG 30" DIAMETER BUCKET BO!HNG NO. __ B_-_1 __ SHEET __!_ OF i + :r +,.., 'i: .... ::i 0 IL ::.n·"' I.. 0 123.3 m I'.. .r~ m'"' -0 :c 7.4 DESCRIPTION OF MATERIAL 0-1' TOPSOIL: Dark yellowish brown silty SAND; dry, loose, hard and porous, trace rootlets. @1 1 TERRACE DEPOSITS (Ot): Reddish brown silty SAND; sli9'htly moist, medium dense. @2 1 Becomes moist. l SM 1.11. 5 5. 4 @5' Yellowish brown fine SAND with some silt;. siightly moist, medium dense. 15 20 25- 30 35 FORM 88/9 4 SP 100. 0 4. 2 @10' Brownish yellow, .clean fine SAND with trace w~ll rounded pebbles; slightly moist and medium dense. @13.5" Grades to clean fine SAND with well rounded cobbles. @15' Becomes fine SAND. =,1--...,,l---ir-----1-::1=-2-:::-5=·~. --=3-r-=1--=1-.-4::--~m @16 r Abrupt, approximately horizontal basal contact. 10 20 ~ @16" .SANTIAGO FORMATION (Tsa): Light gray SANDSTONE with trace clay; moist and medium dense to dense. 128.2 10.3 @18"-19' Zone of slight water seepage into boring. @19' Sandstone becomes denser~ @23.5' Abrupt, and approximately horizontal contact of S·ANDSTONE over li;rht olive brown sandy CLAYSTONE; slightly moist and very 5 stiff, with randomly oriented irregular llB. 14 ·._o_. --~ olished fracture surfaces. @27~-28' ,Gradat;!-01;-a:i, approximately horizontal transitional zone from claystone to light gray SANDSTONE; moist. and dense. @33' Observed water seepage into hole from near vertical fracture in SANDSTONE, fracture trends north.35 degrees east. @34' Becomes.very moist, slight seepage from boring sidewalls observed to bottom of boring. Plate B-4 GEOSOILS, INC .. BORING LOG SAivfPLE + ... "' ID I ,:i '\; J:. jJ) II) ll'l 0 + :,L -.o 3 I/JD !l. -1' L 0 Oe 0) :1 C ::1 -1/J :n 0 £l'.l :::l+-tt:i ::)fl) 45 30 50 CLIENT MICHAEL REED WORK ORDER !JO. PARCEL155-l.40-09, CARLSBAD DATE EXCAVATED SAMPLE METHOD AUGER DR:tLLING RIG 3Q11 DIAMETER BUCKET BOlUNG NO. __ B_-_1 __ . +-:::r + Ill DESCRIPTION OF MATERIAL -r. L "" i;:<1-.; ~ ::) 0 II.. m'"' J) V' l 0 0 :c 121 .. 9 13. 0 l.624-SD SHEET__£_ OF2 @52' Increased seepage into boring from SANPSTONE. --1---1-+----+-----+-----~---+.:::/~iih::;1-,·t @52 ~5' Olive brown fractured claystone; 55 slightly moist to moist and very stiff. @54' Li<Jht yellow gray SANDSTONE; moist to very moist, dense. 60 65 70 75 FORM 88/9 Total depth= 55 feet Seepage at 18 to 19 feet and below 34 feet Increased seepage at 52 feet No caving Hole. backfilled Plate B-5 .. Hand Auger Depth (ft} 0-1 1-1.5 HA-2 0-1 1-2 2-7 HAND AUGER LOG Material Description ·TOPSOIL: Yellowish brown silty fine SAND; dry, loose, porous, friable, few rootlets. TERRACE DEPOSITS (Qt): Red brown silty SAND; slightly moist, loose to medium dense, slightly hard. Becomes s!tghtly moist to moist and medium dense .. Total depth= 2 feet No groundwater Hole backfilled COLLUVIUM: Brown sandy SILT; dry, loose, few roots. TERRACE DEPOSITS (Qt): Red brown fine SAND with some well rounded pebbles; sllghtfy moist, !oos~ to medium dense, friable. SANTIAGO FORMATION (fsa): Light yellow gray fine grained SANDSTONE; slightly moist to moist, medium dense. Tatar depth= 7 feet No groundwater Hole backfilled Plate 8-6 MR. MICHAEL REED W.O. 1624-SD Hand Auger Depth {fl.} HA-3 2-3 3-8 HA-4 0-1.5 1.5-7.5 7.5-8 NOVEMBER 2, 1993 HAND AUGER LOG Material Oescrigtion COLLUVIUM: Dark brown silty tine SAND with some weU rounded coarse pebbles; dry, loose. SANTIAGO FORMATION (Tsa}: Red brown SANDSTONE with some clay; moist, loose to med.ium dense. Grade? ·to yellow brown SANDSTONE; moist, medium dense. Total depth= 8 feet No groundwater Hole backfilled COLLUV!UM: Brown silty SAND; dry and loose. OLDER ALLUVIUM (Qoa): Red brown silty fine SAND; moist, loose to medium dense. SANTIAGO FORMATION (Tsa}: SANDSTONE; moist, medium dense; Total depth= 8 feet No groundwater Hole backfilled Yelfow brown Plate B-7 APPENDIXC EQFAULT, EQSEARCH, ANDFRISKSP *********************** ;'<. ~">t * E Q f A iJ L T * * * * version 3.00 * * * *********************** DETERMINISTIC ESTIMATION OF PEAK ACCELERATION FROM DIGITIZED FAULTS JOB NUM~ER: 5763~A-SC JOB NAME: Becker Residence CALCULATION NAME~ Test RLH1 Anal ysi S DATE: 09-04-2008 FAULT-DATA-FILE NAME: C:\Program r-i1es\EQFAULT1\CG5FLTE.DAT SIT!;:: COORDINATES! SITE LATITUDE: 33.1700 SITE LONGITUDE: 117.3487 SEARCH RADXUS: 62.14 mi ArTENUATION RElATION: 13) Bozorgtda Campbell Niazi (1999) Hor.-Hard Roc.k-Cor. UNCERTAINTY (M:::;Mediant S==Sigma): s Ntmiber of Sigmas: LO DISTANCE MEASURE: cdist SCOND: 1. Basement Depth: .70 km Campbell SSR: O Campbell SHR: 1 COMPUTE PEAK HORIZONTAL ACCELERATION FAULT-D.ATA FILE USED! C\Program Files\EQFAULTl\CGSFLTE.DAT MINIMUM DEPTH VALUE (km): 3.0 W.O. 5763-A-SC Plate C-1 EQFAULT SUMMARY DETERMINISTIC SITE PARAMETERS Page l ----------------------------------------------w -+--------------------!ESTIMATED MAX. EARTHQUAKE EVENT APPROXIMATE 1----------------------· ·. ----- ABBREVIATED ! DISTANCE I MAXIMUM I PEAK ! EST. SITE FAULT NAME I mi (km) l EARTHQUAKE I SITE 'INTENSITY I I MAG.(Mw) I ACCEL g JMOO.MERC. === -==;::.:;,::===---~=====-. -====(-==-=;=~~==l==========l====:=-:~=~~l=======,== NEWPORT-INGLEWOOD (off,shore) l 5.:1( l:LZ)I 6.9 I 0.531 ] x ROSECANYON I 5.7( 9.2)! 6.9 I 0.610 l X CORONADO BANK I 2L4( 34,4)! 7.6 I 0.237 l IX ELSINORE (TEMEOJLA) . 23.8( 38.3) 6.8 I 0.122 i 'VII ELSINORE (JULIAN) l 24.2( 38.9)1 7.1 I 0.147 I VIII . ELS,INORE·. (GLEN IVY) I 32 ,7( 52. 7) [ 6 .8 f 0.087 I VII SAN JOAQUIN HILLS l 34.3( 55.2) I 6 .. 6 I 0.103 VII PALOS VERDES ! 3S.1( S6.S) 7.3 I 0.115 ! VII EARTHQUAKE VALLEY I 44.4( 7LS) I 65 I 0.051 ] VI NEWPORT-'.l:NGLEWOOCJ (LA.Basin) I 44.9( 72.3') I 6,9 I 0.077 l VII SAN JACINTO-ANZA . I 46. 3( 74. S) I 7. 2 I O. 080 I VII SAN JACINTO-SAN .JACINTO VALLEY I 46. 7 ( 75 , l) f 6. 9 I (L 064 ! VI C!-lINO-CENTRALAVE. (Elsinore) I 4.6.7.( 7.5.1) .. 1 6.7 I 0.079 I vu t-iHITTIER · 50.5( 813)! 6,8 I o.oss I VI SAN JACINTO-COYOTE CREEK I 52,6( 84,6) j 6.6 j 0.046 l VI ELSINORE (COYOTE MOUNTAIN) I 58.S( 94.'7) ! 6,8 I 0.047 i VI SANJA<::INTO-SANBERNARDINO I 58.9( 94,8)! 6.7 I {L044 j VI PUENTE HILLS BLIND THRU;ff I 60.4( 97.2)! 7.1 . J 0.080 l VI! ******************************************************************************* -END OF SEARCH.. 18 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. THE NEWPORT-INGLB•JOOD (Offshore) FAJJLT IS CLOSEST TO THE SITE, IT IS ABOUT S.1 MILES (8,2 km) AWAY. LARGEST .MAXIMUM-EARTHQUAKE;: SITE ACCELERATION: 0.6312 g Page 2 W.O. 5763-A-SC Plate C-2 Inc .. .. .01 .001 ,1 W.O. 5763-A-SC MAXIMUM EARTHQUAKES 1 Becker Residence ·10 Distance (mi) 100 Plate C-3 JOB NUMBER.:. 5763-A-SC ************************* * * * E Q s E A R C H w * i't * Version 3.00 * * ";,f.;:· ************************* ESTIMATION OF PEAK ACCELERtffI()N FROM CALIFORNIA EARTHQUAKE CATALOG::> DATE: 09-12-2008 J(>B NAMEt Secker Residence EARTHQUAKE-CATALOG-FILE NAt"1E: ALLQUAKE.DAT SITE COORDINATES: SITE LATITUDE!. 33. :J.700 SITE LONGITUDE; 117.3487 SEARCH DATES: START DATE: 1800 END DATE: 2007 SEARCH RADIUS: 62.1 mi 100.0 km ATTENUATION RELATICH\!; 14) Campbell & Bozorgnia (1997 Rev.) ·~ UNCERTAINTY (M,::;Median, S=Sigma); s Nu.mbet o-i= Sigmas: ASSUMED SOURCE TYPE: ss [S$::.Strike-s1ip, DS=Reverse-slip, scor,m: 1 Depth source: A Basement Depth: , 70 km Campbel 1 SSR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION MINIMUM DEPTH Vl\LUE (km) : 3. 0 Page 1 W.O, 5763-A-SC Alluvium LO BT=Bl i mi-thrust] 0 Plate C-4 EARTHQUAKE St.ARCH RESULTS Page 1 . . . ---~----------------~--------------------------------------------l I I I TIME I i l SITE l SITE( APPROX. FIJ..E. I LAT. i LONG. I DATE I (UTC) l DE.PTH I QUAKE! ACL I MM. j DISTANCE CODE! NORTH I WEST I IHM $eel (km)! MAG,! g !INLj mi (km] ----+------+--------+ --·------+·------+~----+-----+-------+--·-+------------ DMG 133,0000ll.17.3000!11/22/1800!2130 0,01 0.01 6,50! 0.2 .. 4. 8 I IX l 12.1( 19.A) MGI ! 33.0000 l 117 .0000 l09/21/1S56 I 730 0.01 o.o 5.00 l 0, 033 I v I 2:L 3( 37. 6) MGI 132,80001117.1000!05/25/18031 0 0 0.01 Q.01 5.00! 0.024 I VI 29.3( 47.2) PAS 132.97101117.8700107/13/1986!1347 8,21 6.01 5.30! 0,027 V [ 33.1( 53.3) DMG 132..70001117.2000IOS/27/1862120 0 0.01 0.01 5.901 0.046 I VI ! 33.6( 54,0) T-A l32.6700. l117.17001101.211 21. o o 0.0.1 (LOI s.o.QI 0.0:1.s ! IV 1 3£5.0( 58.o) T-A l 32 .6700 I 117 .1700112/00/ 61 0 0 (LO I (LO I 5. 00 O .018 l rv I 36.0( SiLO) T-A 132.670011,1].1700 OS/24/18651 oo 0.01 <Loi s.ool 0.01s l rv 1 3610( ss.o) DMG [33.70D0l117.4000 QS/13/19101 620 o.ot 0.0 '.LOO 0.018 I IV I 36.7( 59.1) OMG 133.7000 .. 1117.4000\04/11/.19101 757 0.0! <LOl 5.001 0.018 l IV I 36.7( 59.1) DMG 33.7000il17.4000J05/15/191011547 O.O! 0.01 6.00! 0.044 I VI 36.7( 59.1) DMG l33.20001116.7000l01/01/1920I 235 0.01 0.01 5.001 0.017 ! IV I 37.S( 60.4) DMG [33.6990l117.S110l0S/3l/l938t 83455.41 10.0l 5.SOI {L027 f V ! 37.7( 60,7) DMG !32.8000!116.SOOOl10/23/1894L23 3 0.01 0.01 5.70! 0.029 ! v I 40.8( 6$.6) MGI 133. 20001116.6000 I 10/12:/1920 I 1748 (LO I 0.01 5. 301 0.019 I IV j 43. 3( 69. 7) DMG 133. 7100 I 116.9250109/23/1963 I 144152 .61 16. 5 I 5 .OO! O .014 I IIIi 44. 6( 71. 7) DMG 133.75001.117 .0000 I 06/06/1918 l.2232 0 .. o I 0.0 I 5. 00 I 0.014 I I!Il 44. 8( 72 .1) DMG l33,7500lll7.0000l04/21/191~l22322:5.0I o.o 6.801 0.069 I VI! 44.8( 72,1) MGI J33.8000!l17.6000J04/22/1Sl8!2115 O.Oj 0.01 :LOOJ 0.013 I III! 45.8( 73.8} DMG !33.5750l117.9830i03/11/1933f 518 4.0] 0.01 5.201 0.016 IV I 46.0( 74.1) DMG l33.6170l117.9670l03/11/1933l 154 7.8j 0,01 6.301 0.041 I v l 47.1( 75.9) DMG J3:L8000!J.17.0.000l12/25/. 189911225 0.01 o.o. ! 6,401 0.044 i V.I I 4}.9( 77.1) OMG 133.6170!118.0170103/14/1933)19 150.01 0,01 5.10 0.013 I IIIj 49.4(. 79.4) PMG !33.90001117.2000!12/19/1880! 0 0 0,0 0,0! (LOOJ 0.028 ! V J 51.1( 82.3) GSP I 33. 52901116. 5720!06/12/2005 I 154146. 5 ! 14.0 i 5.20l O .014 l III j 51. 2( 82. 4) PAS 133.50101116.5130102/25/19$01104738.5! 13.6! S.SO! 0.017 I IV l 53.3( 85,8) GSP l33.5080!116.S140l10/31/2001[075616.61 15.0l 5.101 0.012 ! IHI 53~5( 86.1) DMG l33.6830l11&.0500I03/11/1933! 658 3.01 0.01 5.$01 (L017 I IV I 53.7( 86.S) or0c; l33···s·o·oo111 .. 6 .. sooo10 .. 9./30/1 ... 9 .. 1.6! 21.1 0,01 0.01 s.001 c1.011 I In .. I s4.oc au.9) DMG l33.00001116.4BO!DEV04/1940llo3s 8.31 0.01 s.101 o.ou · rni 54.SC 87,3) DMG f 33, 1000111.s. 0670J03/11/19n I sw22.o l o. o I 5,101 0.011 i I:u I ss .2( 88, 9) DMG [33,7000ll18.0670l03/l1/19.33I SS457.0! 0.01 s:.101 0.011 I HI] 55.2( 88,9) oMG !34.00001111.2soo107/23/l.9231 73026.0l 0.01 6.251 o.o::m t v 1 57.5( 92:.7) MGI 134.0000J117.5000jl2/16/1858!10 0 O.OJ 0.0! 7.001 0.058 ! VI I S8,0( 93.3) !)MG 3:l.7500!118.0830 03/11/19331 323 0.01 0.01 5.001 0.009 ! III! 58.2( 93,7) DMG !33.7S00l118.0830!03/11/1933i 2 9 0.01 0.01 5.001 0.009 I III! 58.2( 93.7) l)MG !33.7500ll]JL0830l03/l1/l933I 230 0.0[ 0.0j 5.10l OJHO I XII! 58.2( 93.7) DMG l33.7500l118.0830l03/13/1.933113182iLOj 0.0! 5.301 0.012 I III! 53,2( 93.7) DMG 133.7SOO!llZ.0830l03/11/l933 ~10 0,01 0.0! 5,l.O 0.010 ! III! S&.2( 93.7) OMG 13:L3430ill6.3460l04/28/l96:9!232042,.91 20.0l 5.&0l 0.019 ! IV I S9.l( 95.1) DMG !33.9S00l116.8500I09/28/19461 719 9.01 O.Ol 5.001 Q.00$ l r:n:! !$LO( 98.2) DMG l 33. 7830 !118.1330110/02/1933 I 91017. 61 0.0 I 5 .40 I 0.013 i III I 6L9( 99.6) *******.*********************************************************************** Page 2 W.O. 5763-A-SC Plate C-5 -END OF SEARCH-42 EARTHQUAKES FOUND WI'r'HIN THE SPECIFIED SEARCH AREA. TIME PERIOD OF SEARCH: LENGTH OF SEAR CH TIME: 1800 TO 2007 208 years THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 12,1 MILES (19.4 km) AWAY. LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS: 7.0 LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH: 0. 248 g COEFFICIENTS FOR GUTENBERG & RICHTER RECURRENCE RELATION: a-value= 0.983 b-value= 0.383 beta-value= 0.883 TABLE OF MAGNITUDES AND EXCEED.ANCES: Earthquake I Number of Times. I cumulative Magnitude I EXO.:!eded I No. / Year ----------+-----------------+------------4.0 ! 42 I 0.20290 4.s i 42 I 0.20290 s.o I 42 I 0.20290 s.s ! 14 I o.06763 6.o l 8 I 0.0~865 6. 5 l 3 ! 0 _ 01449 7 ,0 l 1 I o.00483 P<;!ge 3 WD. 5763-A-SC Plate C-6 EARTHQUAKE EPICENTER MAP 1000 - 900 800 700 r soo r 4001 3001 200 J LEG!=ND 100 0 -100 · x M=4 M:::;;:5 M;;;;:;6 Becker Residence -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 5763-A-SC Plate C-7 ,._ ro Cl) >- ~ z ,..__ 00 -1--' C: © > w -0 ,._ (1) ...0 E ::, z (1) > '.,Q' ~ ::, E E ::, 0 EARTHQUAKE RECURR,ENCE CURVE 1 .1 .01 .001 Becker Residence 3.5 4.0 45 5,0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 Magnitude (M) W.0. 5763-A-SC Plate C-8 ~ ~ ~ I ~ ~ J2 a (J:l () I <D l1f ,,,.......,_ if) 1-.. ~ .........,, u 0 ,_., J.... ID 0... :J +.I ID [( ... ,.,,,,, .... ,.,.,,.,,, .. _. ________________ ~----- T'URN' PERIOD v·s. ACCE·-. 10---· BOZ, AL.(1999)HOR PS COR 2 1000000 100000 1 0000 L. _____ _ 1000 -~~ 100·~~~~ 1 l LL I T I T T T L I I I I I I I l I -I I I r I Il I Q.00 0.25 0.50 0. 75 1.00 1.25 1.50 Acceleration (Q) ,,..--.., ~ 0 ._,, >, .:t:: -..... ..a ro ..a 0 !..... (L © 0 C: co u (1) (1) 0 X w PRO ABILITY OF EXCEED CE BOZ. ET AL.(1999)HOR PS COR 2 100 90 80 70 60 50 40 30 20 10 0 0.00 I• I 25 yrs I••! 75 rs I • I 50 yrs L.! ... 1 100 rs 0.25 0.50 0.75 1.00 1.25 1.50 Acceleration (r1) W.O. 5763-A-SC Plate C-10 APPENDIXD LABORATORY DJ.\T A 3,000 2,500 """"" "' .. •o>" .. 2,000 I/ V 1,000 500 V 0 0 500 '1,000 v••, • '"<••• ,./)! / / V / ' / 1,500 2,500 3,000 NORMAL PRESSU~E, psf Sample Depth/El. Range Classification @ TP-3 4.0 Si!tySand 0 TP-3 4.0 Note: Sample .lnnundated prior to testing GeoSoils, Inc. 5741 PalmerWay Carlsbad, CA 92008 Telephone: (760) 438-3155 Fax: (760) 931,-0915 Sample Type MC% Undisturbed 109.7 7.8 187 Residual Shear Undisturbed 109.7 7.8 184 DIRECT SHEAR TEST Project BECKER Number: 5763-A-SC Date: September :2008 Plate: D-i 32 32 u. a:, X I :::c l-e; z w a:: !-1.5j--~~~~-+~~~~~-t-~~~~--.J~~-,,<c.__~-+~--,--~~~+-~~~~---l co C!i z 0: < UI :r: Cl) NORMAL PRESSURE-KSF EXPlANA TION 0 RESHEAR -AT SATURATED MOISTURE CONTENT 11!1 PEAK -AT SATURATED MOISTURE CONTENT Dlf!ECT SHEAR REMOLDED TO. SO% RELATIVE DENSITY; THEN SATURATED PCF % MO!STURE % SATURATED MOISTURE CONTENT UNDISTURBED NATURAL SHEAR SATURATED 'lEi SATURATED MOISTURE CONTENT SHEAR TEST DIAGRAM u(h.£>/$~x&e:P S)l€'Afi:.. -B-/ 2. Z.6 /;;e::.r- DATE Soil Mechanics ® Geology ® R:mndath:m Engineering FORM 87 /8-2A Plate D-2 SCHIFF ASSOCIATES www .schiffassociates.com Consulting Corrosion Engineers-Since 1959 Sample ID Resistivity as-received saturated pH Electrical Conductivity Chemical Analyses Cations calcium Ca2+ magnesium Mg2+ sodium Nai+ potassium K'+ Anions carbonate cot Table 1 -Laboratory Tests on Soil Samples Units ohm-cm ohm-cm mS/cm mg/kg mg/kg mg/kg mg/kg mg/kg GeoSoils, Inc. Becker Your#S763-A-SC, SA #08-106:JLAB 3-Sep-08 TP-l @0-3' 72,000 5,200 7A 0.16 104 15 64 37 ND bicarbonate HC03 1• mg/kg 369 flouride pl· mg/kg 1.4 chloride c11• mg/kg 7.2 sulfate so/ mg/kg 51 phosphate PO/ mg/kg ND Other Tests ammonium NH41+ mg/kg 1.5 nitrate N031. mg/kg ND sulfide g2· qual na Red ox mV na Electrical conductivity in millisiemens/cm and chemical analysis were made on a 1 :5 soil-to-water extract. mg/kg = milligrams per kilogram (parts per million) of dry soil. Redox = oxidation-reduction potential in millivolts ND = not detected na = not analyzed 431 West Baseline Road · Claremont CA 91711 Phone: 909 .626.0967 · Fax: 909 .626.33 l 6 Page 1 of 1 Plate D-3 APPENDIXE .. SLOPESTA.BILITY ANALYSIS 2-DIMENSIONAL SLOPE STABILITY ANALYSIS INTRODUCTION OF GSTABL7 v.2 COMPUTER PROGRAM Introduction GSTABL7 v.2 is a fully integrated slope stability analysis program'. It permits the engineer to develop the slope geometry interactively and perform slope stability analysis from within a single program. The slope analysis portion of GSTABL7 v.2 uses a modified version of the popular STABLprogram, originally developed at Purdue University. GSTABL7 v.2 performs a two dimensional limit equilibrium analysis to compute the factor ofsafetyfor a layered slope using the simplified Bishop or Janbu methods. This program can be used to search for the most critical surface or the factor of safety may be determined for specific surfaces. GSTABL7, Version 2, is programmed to handle: 1. Heterogenous soil systems 2. Anisotropic soil strength properties 3. Reinforced slopes 4. Nonlinear Mohr-Coulomb strength envelope 5. Pore water pressures for effective stress analysis using: a. Phreatic and piezometric surfaces b. Pore pressure grid c. R factor d. Constant pore water pressure 6. Pseudo-static earthquake loading 7. Surcharge boundary loads 8. Automatic generation and analysis of an unlimited number of circular, noncircular a,nd block-shaped failure surfaces 9. Analysis of right-facing slopes 10. Both SI and Imperial units General Information If the reviewer wishes to obtain more information concerning slope stability analysis, the following publications may be consulted initially: 1. The Stability of Slopes, by E.N. Bromhead, Surrey University Press, Chapman and Hall, N.Y., 41i pages, ISBN 412 01061 5, 1992. 2. Rock Slope Engine.fillog, by E. Hoek and J.W. Bray, Inst of Mining and Metallurgy, London, England, Third Edition, 358 pages, ISNB O 900488 573, 1981. 3. !,glndslides: Analysis and Control, by R.L Schuster and R.J. Krizek (editors), Special Report 176, Transportation Research Board, National Academy of Sciences, 234 pages, ISBN O 309 02804 3, 1978. GSTABL7 v.2 features The present version of GSTABL? v.2 contains the following features: 1. Allows user to calculate factors of safety for static stability and dynamic stability situations. 2. Allows user to analyze stability situations with different failure modes. 3. Allows user to edit input for slope geometry and calculate corresponding factor of safety. 4. Allows user to readily review on-screen the inputslope geometry~ 5. Allows user to automatically generate and analyze unlimited number of circular, non-circular and block-shaped failure surfaces (Le;, bedding plane, slide plane, etc.). fnput Data Input data includes the following items: 1. Unit weight, residual cohesion, residual friction angle, peak cohesion, and peak friction angle of fill material, bedding plane, and bedrock, respectively. Residual cohesion and friction angle is used for static stability analysis, where as peak cohesion and friction angle is for dynamic stability analysis. 2. Slope geometry and surcharge boundary loads: 3. Apparent dip of bedding plane can be specified in angular range (i.e., from o to 90 degrees. 4. Pseudo-static earthquake loading (an earthquake loading of 0.12 i was used in the analysis). Seismic Discussion Seismic stability analyses were approximated using a pseudo-static approach. The major difficulty in the pseudo-static approach arises from the appropriate selection of the seismic coefficient used in the analysis. The use of a static inertia force equal to this acceleration during an earthquake (rigid-body response) would be extremely conservative for several reasons including: (1) only low height, stiff/dense embankments or embankments in confined areas may respond essentially as rigid structures; (2) an earthquake's inertia force is enacted on a mass for a short time period. Therefore, replacing a transient force by a pseudoc.static force representing the maximum acceleration is considered unrealistic; (3) Mr. Robert G. Becker Fi!e:e:\wp9\5700\5763a.upg lne .. Appendix E Page2 Assuming that total pseudo-static loading is applied evenly throughout the embankment for an extended period of time is an incorrect assumption, as the length of the failure surface analyzed is usually much greater than the wave length of seismic waves generated by earthquakes; and (4) the seismic waves would place portions of the mass in compression and sorne in tension, resulting in only a limited portion of the failure surface analyzed moving in a downslope direction, at any one instant of time. The method developed by Krinitzsky, Gould, and Edinger (1993) whichwas in tum based on Taniguchi and Sasaki. 1986 (f&S, i986), was referenced. This method is based on empirical data and the performance of existing earth embankments during seismic loading. Our review of "Guidelines for Evaluating and Mitigating Seismic Hazards in California (Davis, 1997) indicates the State of California recommends using pseudo-static coefficient of 0.15 for design earthquakes of M 8.25 or greater and using 0.1 for earthquake parameter M 6.5. Therefore, for conservatism a seismic coefficient of 0. i 2 i was used in our analysis. Output Information Output information includes: i . All input data. 2. Factors of safety for the ten most critical surfaces for static and pseudo-static stability situation. 3. High quality plots can be generated. The plots include the slope geometry, the critical surfaces and the factor of safety. 4. Note, that in the analysis, a minimum of 100 trial surfaces were analyzed foreach section for either static or pseudo-static analyses. Results of SIQRe Stability Calculation Table E-1 shows parameters used in slope stability calculations. Summaries of the slope stability analysis are presented in Table E-2. Detailed output information is presented in Plates E-1 to E-4. A typical cross-section representing the highest proposed fill slope at a gradientof 2:1 (h:v) was utilized for analyses. Mr. Robert G. Becker File:t~:\wp9\5700\5763a.upg Appendix E Page3 Mr. Robert G. Beeker Fl!e:e:\wp9\5700\5763a.upg TABLE E-1 SOIL PARAMETERS USED Terrace Deposits 250 32 Santia o Formation 225 33 TABLE E-2 SUMMARY OF SLOPE ANALYSIS GeoSoil.s, Appendix E Page4 =E b 200 u, '1 0) Ci,) )> I Cf) 0 BECKER.. W.0.5763-A-SC SECTION x .. x· .. STATIC c:\program files\g72sw\5763.p!2 Run By: GEOSOILS' 9/25/2008 05:12PM # FS Solf Soil t T9ta_l Sa\~rat17d Cohesi_o_n Friction Pore Pres~1.m, Pfez.· ·1 Load Value a 2.180 Oesc. Type; Urnt Wt. Unit Wt Intercept Angle Pressure Conslant Surface LI 150 psf b 2.185 No. r (pcf) (pcf) (psfJ (deg) Pa.ram. (psf) No. c 2.186 Tsa 1 : 130.0 120.0 225.0 33.0 0.00 0.0 Wi d 2.189 Qt 2 ; i 25.0 120.0 250.0 32.0 0.00 0.0 W1 e 2.200 f 2 • .205 g 2.207 h 2.211 150 i 2.2i6j : : . : . , ·1 .. 2:228 · •. . .. .• (" : · . • . ; • · •.• : : : : ; i ! : : : : : .r ! ' ' i : : : : .: ] f t ; { , ~ : ~ : : i i 1 : : : . a : 100 i l ~~ i . j -··················································1···-·· -·:··.-·~'Co/L·····, r····· -········: I -~~~ ! ' 50 :../.47~/7•·-··--·-··i··-··-;·-,---:-··-··"'-··-··'--~----··-··-··-··-:-·--··-·--1;11 J ' 1 ' 0 0 50 100 150 200 250 300 '"U ~- G) G$TABL7 v.2 FSmim=2.180 Safety Factors Are Calculated By The Modified BJsho p Method m GSTABL7. I ...... ~ 0 U1 '-I Ci) w )> CJ) 0 1J e Cl) m I\) BECKER.. W.0.5763-A-SC SECTION XwX1 • SEISMIC c:\program files\g72sw\5763s.pl2 Run By; GEOSOILS 9/29/2008 02:32PM 200 r-------, r 150 100 5.0 0 # FS a Ui50 b 1.553 So!l Soil: Total Saturated Cohesion Friction Fore Pres~we Piez. Desc. Type: Unit Wt. Unit Wt rnterc<%pt Angle Pressure Constant Surface Load : Value L1 ; 250psf c 1.55411 Tsa I d 1.554. Qt . e 1,568'--~~~~~~~~~~~~~~~~~~~~~~--' No. ! (pcQ (pcf) (psf} (deg) Param. (psf) No. 1 : 130.0 120.0 225.0 33.0 0.00 0,0 W1 2 : 125.0 120.0 250.0 32.0 0,00· OJ~ W1 Peak(A) ;0.300(g} kh Coef. 0. 120(g)< f i.570 g 1.571 hum l 1.578 , , , , , · r 1.saoj ! · 1 ! · ! · ; · l ; f • I : ~ ; : : t ~ t : ; / i 1 I i ! ! 1 ! t I ! l : a : ···· ....... " ....... · .. r· .............................. r-·--·· ··-·· ·· ·-··· ·1 ··--·----------·· 4 ... .. : : ! ..N"'--~~--,f+--,f'tMf"~-+--'-...,......~~:...,......~~~~~~--4 , 1 1 I ' ' ' i l--~: ,,_, ! i~ I /~ ! I -··-··-··-··-··--·~1 h1l J ,_ ···-------:--··~ ·----r·--·----·-··-·-r·- ~''' .... ~ ~ : .:·~ 1 l I ! .. , 0 50 100 150 200 250 300 GST ABL.7 v:2 FSmln=1.550 Safety Factors Are CalculatE1d Sy ihe Modified Bishop Method ~STABL~ Assume: Given: SURFICIAL SLOPE STABILITY Date: October, 2008 Slope Surfa e F.S. = Factor of Safety C = Cohesion of Soil Ys = Unit Weight of Soil Temporary Water Tab! \ Potential Failure Surface m = Fraction ofz such that mz is the vertical height of the temporary water table above the failure surface r,,, = Unit Weight of Water z = Vertical Depth of Failure Surface J3 = Slope Angle q> = Friction Angle of Soil C= zso· psf Ys:::: 129 pcf m= 1.00 yo:,= 62{4 pcf z= 4.00 feet (3 = 26,6 , degrees <1>= 32 degrees F.S. = C + (Ys -my0Jz cos2p tan q> Ys z sin f3 cos f3 F.S. = 1.85 GeoSoils, Inc f3 in radians 0.46426 qi in radians 0.55851 ----·-------=·""'"'"'-"-··--·· Client: Becker Residence Project APN 155-140-41, ± 65 foot 2.5:1 to 4.5:1 Natural Slop Project No: 5763-A-SC PJate: E-3 APPENDIXF GENERAL EARTHWORK, GRADING GUIDELINES, AND DESIGNCRJTERIA GENERAL EARTHWORK. GRADING GUIDELINES, AND PRELIMINARY CRITERIA Genera! These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installation of subdrains, excavations, and appurtenant structures or flatwork, The recommendations contained in the geotechnical report are part of these earthwork and grading guidelines and would supercede the provisions contained hereafter in the case of conflict Evaluations performed by the consultant during the course of grading may result in new or revised recommendations which could supercede these guidelines or the recommendations contained in the geotechnical report. Generalized details follow this text The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions ofthe project plans and specifications and latest adopted code. In the case of conflict, the most onerous provisions shall prevail. The project geotechnical engineer and engineering geologist (geotechnical consultant), and/or their representatives, should provide observation and testing services, and geotechnical consultation during the duration of the project EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for general conformance with the recommendations of the geotechnical report(s), the approved grading plans, and applicable grading codes and ordinances. The geotechnical consultant should provide testing and observation so that an evaluation may be made thatthe work is being accomplished as specified. It is the responsibility of the contractor to assist the consultants and keep them apprised of anticipated work schedules and changes, so that they may schedule their personnel accordingly. All remedial removals, dean-outs, prepared ground to receive fill, key excavations, and subdrain installation should be observed and documented by the geotechnical consultant prior to placing any fill. lt is the contractor's responsibility to notify the geotechnical consultant when such areas are ready for observation. laboratory and Fiefd Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D-i557. Random or representative field compaction tests should be performed in GeoSoils, lne .. accordance with test methods ASTM designation D-1556, D-2937 or D-2922, and D-3017, at intervals of approximately ±2 feet of fill height or approximately every l ,000 cubic yards placed. These criteria would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant. All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by a geotechnical consultant, and staged approval by the governing agencies, as applicable. It is the contractor's responsibility to prepare the ground surface to receive the fill, to the satisfaction of the geotechnical consultant, and to place, spread1 moisture condition, mix, and compact the fill in accordance with the recommendations of the geotechnical consultant The contractor should also remove all non-earth material considered unsatisfactory by the geotechnical consultant Notwithstanding the services provided by the geotechnical consultant, it is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish , the earthwork in strict accordance with applicable grading guidelines, latest adopted codes or agency ordinances, geotechnical report(s), and approved grading plans. Sufficient watering apparatus and compaction equipment should be provided by the contractor with due consideration for the fiii materiai, rate of placement, and climatic conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such as questionable weather, excessive oversized rock or deleterious material, insufficient support equipment; etc., are resulting in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the conditions, and if necessary, stop work until conditions are satisfactory. During construction; the contractor shall properly grnde all surfaces to maintain good drainage and prevent ponding of water. The contractor shall take remedial measures to control surface water and to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed. SITE PREPARATION All major vegetation, including brush, trees, thick grasses, organic debris, and other deleterious material, should be removed and disposed of off-site. These removals must be concluded prior to placing fill. In-place existing fill, soil, alluvium, colluvium, or rock materials, as evaluated by the geotechnical consultant as being unsuitable, should be removed prior to any fill placement Depending upon the soil conditions, these materials may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the geotechnical consultant. Mr. Robert G. Becker File: e:\wp9\5700\5763a.upg Appendix F Page2 Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading, are to be removed or treated in a manner recommended by the geotechnical consultant Soft, dry, spongy, highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overexcavated down to firm ground and approved by the geotechnical consultant before compaction and filling operations continue. Overexcavated and processed soils, which have been properly mixed and moisture conditioned, should be re-compacted to the minimum relative compaction as specified in these guidelines. Existing ground, which is determined to be satisfactory for support of the fills, should be scarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnical consultant. After the scarified ground is brought to optiml,!m moisture content, or greater and mixed, the materials should be compacted as specified herein, If the scarified zone is greater than 6 to 8 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to about 6 to 8 inches in compacted thickness. Existing ground which is not satisfactory to support compacted fill should be overexcavated as required in the geotechnical report, or by the on-site geotechnical consultant. Scarification, disc harrowing, or other acceptable forms of mixing should continue until the soils are broken down and free of large lumps or clods, until the working surface is reasonably uniform and free from ruts, hollows, hummocks, mounds, or other uneven features, which would Inhibit compaction as described previously. Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical [h:v]), the ground should be stepped or benched. The lowest bench, which will act as a key, should be a minimum of 15 feet wide and should be at least 2 feet deep into firm material, and approved by the geotechnical consultant In fill-over-cut slope conditions, the recommended minimum width of the rawest bench or key is also 15 feet, with the key founded on firm material, as designated by the geotechnical consultant. As a general rule, unless specifically recommended otherwise by the geotechnicaf consultant, the minimum width of fill keys should be equal to 1h the height of the slope. Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials, although it is understood that the vertical height of the bench may exceed 4 feet Pre-stripping may be considered for unsuitable materials in excess of 4 feet in thickness. All areas to receive fill, including processed areas, removal areas, and the toes of fill benches, should be observed and approved by the geotechnlcal consultant prior to placement of fill. Fills may then be properly placed and compacted until .design grades (elevations) are attained. Mr. Robert G. Becker File: e: \wp9\5700\5763a.upg Appendix F Page3 ,, COMPACTED FILLS Any earth materials imported or excavated on the property may be utilized ih the filf provided that each material has been evaluated to be suitable by the geotechnical consultant These materials should be free of roots, tree branches, other organic matter, or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the geotechnical consultant Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated by the consultant as unsuitable and may require blending with other soils to serve as a sati$factory fill material. Fill materials derived from benching operations should be dispersed throughout the fill area and blended with other approved materiaL Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Oversized materials defined as rock, or other irreducible materials, with a maximum dimension greater than 12 inches, should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the geotechnical consultant Oversized material should be taken offsite, or placed in accordance with recommendations of the geotechnical consultant in areas designated as suitable for rock disposal. GSI anticipates that soils to be utilized as fill material for the subject project may contain some rock. Appropriately, the need for rock disposal may be necessary during grading operations on the site. From a geotechnical standpoint, the depth of any rocks, rock fills, or rock blankets, should be a sufficient distance from finish grade~ This depth is generally the same as any overexcavation due to cut-fill transitions in hard rock areas, and generally facilitates the excavation of structural footings and substructures. Should deeper excavations be proposed (i.e., deepened footings, utility trenching, swimming pools, spas, etc.), the developer may consider increasing the hold-down depth of any rocky fills to be placed, as appropriate. In addition, some agencies/jurisdictions mandate a specific hold-down depth for oversize materials placed in fills. The hold-down depth, and potential to encounter oversize rock, both within fills, and occurring in cut or natural areas, would need to be disclosed to all interested/affected parties. Once approved by the governing agency, the hold-down depth for oversized rock (i.e., greater than 12 inches) in tills on this project is provided as 1 o feet, unless specified differently in the text of this report. The governing agency may require that these materials need to be deeper, crushed, or reduced to less than 12 inches in maximum dimension, at their discretion. To facilitate future trenching, rock (or oversized material), should not be placed within the hold-down depth feet from finish grade, the range offoundation excavations, future utilities, or underground construction unless specifically approved by the governing agency, the geotechnical consultant, and/or the developer's representative. If import material is required for grading, representative samples of the materials to be utilized as compacted fill should be analyzed in the laboratory: by the geotechnical consultant to evaluate it's physical properties and suitability for use onsite. Such testing Mr. Robert G. Becker File: e:\wp9\5700\5763a.upg Appendix F Page4 should be performed three (3) days prior to importation. If any material other than that previously tested is encountered during grading, an appropriate analysis of this material should be conducted by the geotechniqal consultant as soon as possible. Approved fill material should be placed in areas prepared to receive fill in near horizontal layers, that when compacted, should not exceed about 6 to 8 inches in thickness. The geotechnical consultant may approve thick lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer should be spread evenly and blended to attain uniformity of material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mlxed, and wet fill layers should be aerated by scarification, or should be blended with drier material. Moisture conditioning, blending, and mixing of the fill layer should continue until the fill materials have a uniform moisture content at, or above, optimum moisture. After each layer has been evenly spread, moisture conditioned, and mixed, it should be uniformly compacted to a minimum of 90 percent of the maximum density as evaluated by ASTM test designation D-1557, or as otherwise recommended by the geotechnical consultant. Compaction equipment should be adequately sized and should be specifically designed for soil compaction, or of proven reliability to efficiently achieve the specified degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture is in evidence, the particular layer or portion shall be re-worked until the required density and/or moisture content has been attained. No additional fill shall be placed in an area until the last placed lift offiU has been tested and found to meet the density and moisture requirements, and is approved by the geotechnical consultant. In general, per the 1997 UBC and/or latest adopted version of the California Building Code (CBC), fill slopes should be designed and constructed ata gradient of 2:1 (h:v), or flatter. Compaction of slopes should be accomplished by over-building a minimum of 3 feet horizontally, and subsequently trimming back to the design slope configuration. Testing shall be performed as the fill is elevated to evaluate compaction as the fill core is being developed. Special efforts may be necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. A final evaluation of fill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (h:v), prior approval from the governing agency, specific material types, a higher minimum relative compaction. special reinforcement, and special grading procedures will be recommended. Mr. Robert G. Becker Fire: e:\wp9\5700\5763a.upg Appendix F Page5 If an alternative to over-building and cutting back the compacted fill slopes is selected, then special effort should be made to achieve the required compaction in the outer 1 O feet of each lift of fill by undertaking the following: 1. An extra piece of equipment consisting of a heavy, short-shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the slopes, and extend out over the slope to provide adequate compaction to the face of the slope. 2. Loose fill should not be spilled out over the face of the slope as each lift is compacted. Any loose fill spilled over a previously completed slope face should be trimmed off or be subject to re-rolling. 3. Field compaction tests will be made in the outer (horizontal) ±2 to ±8 feet of the slope at appropriate vertical intervals, subsequent to compaction operations. 4. After completion of the slope, the slop~ face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compaction to near the slope face. Subsequentto testing to evaluate compaction, the slopes should be grid-rolled to achieve compaction to the slope face. Final testing should be used to evaluate compaction after grid rolling. 5. Where testing indicates less than adequate compaction, the contractor will be responsible to rip, water, mix, and recompact the slope material as necessary to achieve compaction. Additional testing should be performed to evaluate compaction. SUBDRAIN INSTALLATION Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or materials shm.tld not be changed or modified without approval of the geotechnical consultant The geotechnical consultant may recommend and direct changes in subdrain line, grade, and drain material in the field, pending exposed conditions. The location of constructed subdrains, especially the outlets, should be recorded/surveyed by the project civil engineer. Drainage at the subdrain outlets should be provided by the project civil engineer. EXCAVATIONS Excavations and cut slopes should be examined during grading by the geotechnical consultant. If directed by the geotechnical consultant, further excavations or overexcavation and refilling of cut areas should be performed, and/or remedial grading of Mr. Robert G. Becker File: e:\wp9\5700\5763a.upg Appendix F Page6 cut slopes should be performed. When fill-over-cut slopes are to be graded, unless otherwise approved, the cut portion of the slope should be observed by the geotechnical consultant prior to placement of materials for construction of the fill portion of the slope. The geotechnical consultant should observe all cut slopes, and should be notified by the contractor when excavation of cut slopes commence. If, during the course of grading, unforeseen adverse or potentially adverse geologic conditions are encountered, the geotechnical consultant should investigate, evaluate, and make appropriate recommendations for mitigation of these conditions. The need for cut slope buttressing or stabilizing should be based on in-grading evaluation by the geotechnical consultant, whether anticipated or not. Unless otherwise specified in geotechnical and geological report(s), no cut slopes should be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. Additionally, short-term stability of temporary cut slopes is the contractor's. responsibility. Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the geotechnical consultant. COMPLETION Observation, testing, and consultation by the geotechnical consultant should be conducted during the grading operations in order to state an opinion that all cut and fill areas are graded in accordance with the approved project specifications. After completion of grading, and after the geotechnical consultant has finished observations of the work, final reports should be submitted, and may be subject to review by the controlling governmental agencies. No further excavation or filling should be undertaken without prior notification of the geotechnical consultant or approved plans. All finished cut and fill slopes should be protected from erosion and/or be planted in accordance with the project specifications and/or as recommended by a landscape architect Such protection and/or planning should be undertaken as soon as practical after completion of grading. JOB SAFETY General At GS!, getting the job done safely is of primary concern. The following is the company's safety considerations for use by all employees on multi-employer construction sites. On-ground personnel are at highest risk of injury, and possible fatality, on grading and construction projects. GSI recognizes that construction activities will vary on each site, and Mr. Robert G. Becker File: e:\wp9\5700\5763a.upg Appendix: F Page7 that site safety is the prime responsibility of the contractor; however, everyone must be safety conscious and responsible at all times. To achieve our goal of avoiding accidents, cooperation between the client, the contractor, and GSI personnel must be maintained. In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of field personnel on grading and construction projects: Safety Meetings: GSI field personnel are directed to attend contractor's regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel, at all times, when they are working in the field. Safety Flags: Two safety flags are provided to GSl field technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on aJl test pits. Flashing Ughts: All vehicles stationary in the grading area shall use rotating or flashing amber beacons, or strobe lights, on the vehicle during all field testing. While operating a vehicle in the grading area, the emergency flasher on the vehicle shall be activated. In the event that the contractor1s representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location. Orieratation, and Clearance The technician is responsible for selecting test pit locations. A primary concern should be the technician's safety. Efforts will be made to coordinate locations with the grading contractor's authorized representative, and to select locations following or behind the established traffic pattern, preferably outside of current traffic. The contractor's authorized representative (supervisor, grade checker, dump man, operator, etc.) should direct excavation of the pit and safety during the test period. Of paramount concern should be the soil technician's safety, and obtaining enough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away from oncoming traffic, whenever possible. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates the fill be maintained in a driveable condition. Alternatively, the contractor may wish to park a piece of equipment in front of the test holes, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits. No grading equipment should enter this zone during the testing procedure. The zone should extend approximately 50 feet outward from the center of the test pit. This zone is established for safety and to avoid excessive ground vibration, which typically decreases test results. Mr. Robert G, Becker Fife: e:\wp9\5700\5763a,upg Appendix F Pages When taking slope tests, the technician should park the vehicle directly above or below the test location. If this is not possible, a prominent flag should be placed at the top of the slope. The contractor1s representative should effectively keep all equipment at a safe operational distance (e.g., 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location, wen away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads, cut and fill areas or other factors that may affect site access and site safety. In the event that the technician's safety is jeopardized or compromised as a result of the contractor's failure to comply with any ofthe above, the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractor's representative wm be contacted in an effort to affect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill placed can be considered unacceptable and subject to reprocessing, recompaction, or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor bring this to the technician's attention and notify this office. Effective communication and coordination between the contractor's representative and the soil technician is strongly encouraged in order to implement the above safety plan. Mr. Robert G. Becker File: e:\wp9\5700\5763a.upg Appendix F Pages Trench and Vertical Excavation It is the contractor's responsibility to provide safe access into trenches where compaction testing is needed. Our personnel are directed not 10 enter any excavation or vertical cut which: i) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of instability, has any loose rock or other debris which could fall into the trench; or 3) displays any other evidence of any unsafe conditions regardless of depth. All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters, should be shored or laid back. Trench access should be provided in accordance with Cal/OSHA and/or state and local standards. Our personnel are directed not to enter any trench by bejng lowered or "riding down" on the equipment If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify' his/her supervisor, The contractor's representative wm be contacted in an effort to affect a solution. All backfill not tested due to safety concerns or other reasons could be subjectto reprocessing and/or removal. lf GSI personnel become aware of anyone working beneath an unsafe trench wall or vertical excavation, we have a legal obligation to put the contractor and owner/developer on notice to immediately correct the situation. if corrective steps are not taken, GSI then has an obligation to notify Cal/OSHA and/or the proper contro!llng authorities. Mr. Robert G. Becker File: e:\wp9\5700\5763a.upg Appendix F Page 10 TYPE A TYPE B Selection of alternate subdrain details, location, and extent of subdrains should be evaluated by the geotechnical consultant during grading. CANYON SUBDRAIN DETAIL Plate F-1 12-inch minimum --6-inch minimum A-1 8-1 Filter material: Minimum volume of 9 cubic feet per lineal foot of pipe. FILTER MATERIAL Perforated pipe: 6-inch-diameter ABS or PVC pipe or approved substitute with minimum 8 perforations <Y.i-inch diameter) per lineal foot in bottom half of pipe (ASTM D-2751, SDR-35, or ASTM D-1527, Schd. 40). For continuous run in excess of 500 feet, use 8-inch-diameter pipe (ASTM D-3034, SDR-35, or ASTM D-1785, Schd. 40). Sieve Size 1 inch % inch % inch No.4 No. 8 No.30 No.50 No.200 Percent Passing 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 AL TERNA TE 1: PERFORATED PIPE AND FIL TEA MATERIAL \~ 6-inch minimum I I _) \ "'/ I \ I / '--6-inch -- 1 1 6-inch minimum A-2 minimum Gravel Material: 9 cubic feet per lineal foot. Perforated Pipe= See Alternate 1 Gravel= Clean %-inch rock or approved substitute. Filter Fabric= Mirafi 140 or approved substitute. I ALTERNATE 2: PERFORATED PIPE, GRAVEL, AND FILTER FABRIC CANYON SUBDRAIN ALTERNATE DETAILS Plate F-2 Original ground surf ace to be restored with compacted fill I I~ Back-cut varies. For deep removals, backcut should be made no steeper than 1=1 (HV), or flatter as necessary for safety considerations. 2D / Toe of slope as shown on grading plan / < ?.' -······: .:· <----. ,<":-. ·· ... '··: · · · .. : .. Compac~~d. Fill -'. :.= · ·. :· · .. ~··_ .. ,~-<:-::·--:.-.-,.:·:·::'· · .. ·::.:::·_ .. _·:·:'.:"...:<,-.: ... ·::· .. ·_···.:··:: ·.· ······;_· .· .· · .. 0.tf~ / I \__Original ground surface ~ q_< / D = Anticipated removal of unsuitable material -i'/ (depth per geotechnical engineer) ~~/ ~ Provide a 1=1 (HV) minimum projection from toe of slope as shown on grading plan to the recommended removal depth. Slope height, site conditions, and/ or local conditions could dictate flatter projections. FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON DETAIL Plate F-3 Proposed grade~ ---- ,---Previously placed, temporary compacted fill for drainage only ------ Proposed additional compacted fill Existing co +~id >•• (ii••••c12z24••{;••~·?•~ .· mpacted 11·11 ~-·(:::-:-:-:-:-::.-:·:-:-:-:-::::-:::C:-." ... , ... · un· s· u··,·1·, b . ; ...... : . · .. , ... ·.,, ·. ··., ~ ,._... .... ../.. a le · · · .. .,,·,,,.' ·.'''/ . . . . . . . . . ·. . mater·1·a· 1 c··t . . . "> ::;·•·•·•·•••••''"· · · ••. · · • ... ·, ·: · ,· · · · .· · .. · ', · · •· · . o. bei· rem · ·.· .•. ·.·.·.. . ···· . . . . . · ... · ·-:?.· 7:\/-,Y>; /'. · . .. oved) \ \\"'<\~~\)>\\/'\~ \?~~~~\\ /0\\\ ~v::,;<~Y\\0 y\\\:,::' y'/\ ,\'.(<\ /\ \,s \'(/ ~\y\ \ /'Yk <'• \ /\ \ ,, \ \ / y \____ Bedrock or a native mat . pproved erial ,e______ To be removed before placing --- additional compacted fill REMOVAL ADJACENT TO EXISTING FILL ADJOINING CANYON FILL DETAIL Plate F-4 • Drainage per design civil engineer / Blanket fill (if recommended by the geotechnical consultant) Design finish slope -~ / / -110-foot minimum / 25-foot maximum/ ---/-,. I Buttress or stabilization fill I 15 toot I --.. ---I minimum I I 4-inch-diameter non-perforated 2-Percent Gradient Typical benching (4-foot minimum) outlet pipe and backdrain (see detail Plate F-6). Outlets to be spaced at 100-foot maximum intervals and shall extend 2 feet beyond the face of slope at time Bedrock or approved native material recommended by geotechnical consultant of rough grading completion. At the completion of rough grading. the design civil engineer should provide recommendations to convey any outlet's discharge to a suitable conveyance, utilizing a non-erosive device. TYPICAL STABILIZATION / BUTTRESS FILL DETAIL Plate F-5 ,, • " I .,. ~-~oot ., 1 I m1n1mum I I -----1-..... ........ J ........ . . . . . . . . . . . 4-inch minimu : . ·:. ·:. ·:::. ·:. 3 foot I pipe · · · · · · · · · · · · · 2-inch minimum ;===--->~>/>{-_J_ I 2-foot I 1 .. minimu~ I . -----. . r ~~:~~~ t t -~ -------4-inch minimu 2-inch ] pipe minimum Filter Material= Minimum of 5 cubic feet per lineal foot of pipe or 4 cubic feet per lineal feet of pipe when placed in square cut trench. Alternative in Lieu of Filter Material= Gravel may be encased in approved filter fabric. Filter fabric shall be Mirafi 140 or equivalent. Filter fabric shall be lapped a minimum of 12 inches in all joints. Minimum 4-lnch-Diameter Pipe: ABS-ASTM D-2751, SDR 35; or ASTM D-1527 Schedule 40, PVC-ASTM D-3034, SDR 35; or ASTM D-1785 Schedule 40 with a crushing strength of 1,000 pounds minimum, and a minimum of 8 uniformly-spaced perforations per foot of pipe. Must be installed with perforations down at bottom of pipe. Provide cap at upstream end of pipe. Slope at 2 percent to outlet pipe. Outlet pipe to be connected to subdrain pipe with tee or elbow. Notes: 1. Trench for outlet pipes to be backfilled and compacted with onsite soil. 2. Backdrains and lateral drains shall be located at elevation of every bench drain. First drain located at elevation just above lower lot grade. Additional drains may be required at the discretion of the geotechnical consultant. Filter Material shall be of the following specification or an approved equivalent. Sieve Size 1 inch % inch % inch No.4 No. 8 No. 30 No.SO No.200 Percent Passing 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 Gravel shall be of the following specification or an approved equivalent. Sieve Size 112 inch No. 4 No. 200 Percent Passing 100 50 8 TYPICAL BUTTRESS SUBDRAIN DETAIL Plate F-6 Toe of slope as shown on grading plan Natural slope to be restored with compacted fill ,,,,.----Proposed grade --\ / / / / Compacted fill / / / / . ~--;: ___ :-: .. • __ .--••-•:,: _);;,.j;a:IJJ~.: '.>••·--·.-~ . . . . . .. . . . .. . . ·. ·. ·.. .. ., c· o· ~\\l"'urn, . . . . . . ... . .. . , ........ ~ L ---·-_-_.--- --°"' -_ -. - -------'_;,--I\' ,---#,( . ---· •. ---. ----"· .,,o'l.0 \<>?I'-..... -. -; . -... ---,, • -~ -\ \ :,.<,;.,; - 2-foot m" .---. -" '/ ---..,a,... --.. · ---~ / · \ ' . .-v . irnmum ~. 1· • --- -' ""' -• -----,, --• - - - ----..,_:.c---..o--/ \' , 4-fool mi - r =:" or -, ' , . : ; .. 'l-$!Y-<: ' ~ ,,,_-"' '.(,?,;-;,. y\ \\'..--;\ , - - - - -..,... =--eanh malenal ~-;: • • ' • :;!< -~ -1 y\ \ '.-;(0,~\ \\ f\_ r r --. --c" -· -.. , ~ \\ ::.,;;\,/"'.: y--::\, /\'\ I ---~~' ..q_____ ;\ ,\/-\/,\y\\ [__ Benchwldlh ~ '·\ w,, :r,; 2-f'ercent Q-a....;.--->;,-_ _ ' I 3-foot minimum 1 ( 4 -may ~a~ ~ ~ ., \ \ :....:-\ // Y.\ -\ ---f_ foot minimum} I Bedrock o Backcut varies I • "'\A\/ ---r 15-foot minimu :.f --approved I -;:2 ....,.. "~,"' I I native material e "°"" -I T Subdrain as recommended by geotechnical consultant NOTES: 1. Where the natural slope approaches or exceeds the design slope ratio, special recommendations would be provided by the geotechnical consultant. 2. The need for and disposition of drains should be evaluated by the geotechnical consultant, based upon exposed conditions. FILL OVER NATURAL (SIDEHILL FILL) DETAIL Plate F-7 • .-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"""~ H = height of slope Cut/fill contact as shown on grading plan Cut/fill contact as shown on as-built plan ----. Original (existing) grade Proposed grade / /' /' Compacted fill Subdrain as recommended by geotechnical consultant NOTE= The cut portion of the slope should be excavated and evaluated by the geotechnical consultant prior to construction of the fill portion. FILL OVER CUT DETAIL Plate F-8 ... ---------------------------------------------------------------------------------------------------------------------------------------------------------------------.""' Natural slope . .. '-----.. ·. . . . . . . . . ·.· ··.. :• Proposed finish grade _______ -------------- ···· ',. . . ·.. : .. ·. ·: .. · .. ·.. ...... .. . :: . ·. . : .· •, ;.······ .... ···i· ' ,-: ,,i· ::_ Typical benching (4-foot minimum) .......•...... ·····.p !~"· / / / '• . ·. . Compacted stablization fill --Bedrock or other approved native material --If recommended by the geotechnical consultant, the remaining cut portion of the slope may require removal and replacement with compacted fill. Subdrain as recommended by geotechnical consultant NOTES: 1. Subdrains may be required as specified by the geotechnical consultant. 2 W shall be equipment width (15 feet) for slope heights less than 25 feet. For slopes greater than 25 feet, W shall be evaluated by the geotechnical consultant. At no time, shall W be less than H/2, where H is the height of the slope. c .. 1 STABLIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN CUT SLOPE DETAIL Plate F-9 ,-----------------------------------------------------------------------------------------------------------------------------------------------------------------------~ Proposed finish grade Natural grade - ---- ----------- -- -- - --- ---~------ H = height of slope ~ ···-~··.-.. ·· ·: . : ~ ,•:. : . . . . .. . . . . •, key depth -~ minimum \\~U\y\ ~y l\Y/('S,::~ ~\\\'<(\~ .,,../,,.........~~~~\ ~\ X,(\ ,Z_ .... ~,..../ ..... _ ,....Y~\\~~ Bedrock or ....,....,,,...,...,,..../,~~:\ approved \ \~ native material Typical benching (4-foot minimum) Subdrain as recommended by geotechnical consultant NOTES= 1. 15-foot minimum to be maintained from proposed finish slope face to back cut. 2. The need and disposition of drains will be evaluated by the geotechnical consultant based on field conditions. 3. Pad overexcavation and recompaction should be performed if evaluated to be necessary by the geotechnical consultant. SKIN FILL OF NATURAL GROUND DETAIL Plate F-10 " .---------------------------------------------------------------------------------------------------------------------------------------------------------------------....~ Natural grade · ... Reconstruct compacted fill slope at 2=1 or flatter (may increase or decrease pad area) . ~. . . Overexcavate and recompact replacement fill ·. ,... ·. ::·:.cp·· ····7' ..... : ... ···.··. :_:R~'!l?Ye. :·:·_ ...... ···.-/ [Proposed Back-cut varies --------, · ... : · .. ·.:. ·: . .._: .. ~8~~~1~ ;\:;'.·· ···: 1 finish grade .. /.>.-:·~.--.::-::.:.·:---.. ~ - -'-- Avoid and/ or clean up spillage of materials on the natural slope .... ·.. · .. ,/ .... : . :. · · · · .. : :· .. :. : : 3-foot minimum fill blanket . ·. .~ ,'.: --><. :. : .•. :.--, :· :.· .. ~ L \;· < < >, , / /V ,\ , <., < < ,-,: < ::I' X 9 < , V, , V // / · .... , .. ···#/· · ... · .. ·.:: ~ ~\, . . . . .: .:·/! .. : · ....... ·.· . . . . \ \.\ /. ·.. .·.. ..· o'o/ . . . ... . . . .. '»' ·. . ··. .. . . · .. :. . . . \,~y. . . ··. . . . <· .. ···;.-:::: v-:: ~ ::--<\\/ ... ~ ...... / ~ y\,\< . . . ··§, ' .... . , .. -: \,. : -.._ ... · : . ·,_. .· .. -i;:t,~ <·_. '· ·: . · · · ~ Bedrock or approved 2-tootm!nimum A··:···.·:· .. : .. :\·.· ... ·.·:: .. ,.~t··:··./ ,i:>-\\,\\ native material [ keyw1dth . ·.. .·.·. ··. . .. /_ / \\ . . ., ... ·· :· .. : ·:· · .·· ·:·· .. =.·. · · ·. ,/.·· '( Typical benching -----.... ~ ·.7· ~:·~ .~· .:'"-:.:.i. ··2-percent gradient ~ (4-foot minimum) .... '• . . . ·.· ·. \\\ -f A·----·-~. .;,_\\ _..·.· :·.< · ... ··.:-.~··.·.::: .. :.····~~~\\\:=,,;\~~\v\\ \;,-..... · . .-··.:: .... .'., .... · .. \\V' . ., : ......... .-: .. : . .-..... ·.·.· .... ,._ .. · .. :AV' "'------Subdrain as recommended by · · .. : . · .. ··\ ,~V geotechnical consultant ~'(;:) NOTES= 1. Subdrain and key width requirements will be evaluated based on exposed subsurface conditions and thickness of overburden. 2. Pad overexcavation and recompaction should be performed if evaluated necessary by the geotechnical consultant. DAYLIGHT CUT LOT DETAIL Plate F-11 • '·------------------------------------------------------------------------------- Natural grade Proposed pad grade . . . ··: . ·.: ·.·: .. ·". ' -······-····· ' >'.:~~5········~--------J_ . : : ... : ·. '• ... --~--~-- CUT LOT OR MATERIAL -TYPE TRANSITION Typical benching ( 4-foot minimum) Natural grade ... . ····: . . . · .. ..... :·.-... _.,·-~ . . .. ·.·.·· .. :. . . . J_ ·.·:--~---·-.:~~---- Bedrock or approved native material * Deeper overexcavation may be recommended by the geotechnical consultant in steep cut-fill transition areas, such that the underlying topography is no steeper than 3=1 (H:V) CUT-FILL LOT (DAYLIGHT TRANSITION) TRANSITION LOT DETAILS Plate F-12 NOTES= VIEW NORMAL TO SLOPE FACE Proposed finish grade ~ (E)~ ~ ,---~ , f (E) Hold-down depth / ,,cco c:::co oJ / ~\ / CCC) oJ I (A) I I c0-15-foot----ccci f_ oJ C)I JS-toqt._ I minimum ccci (D) CCC) CCCl (F) ~0.~\K\~~~~~\iS)i~0~\%< \; Bedrock or approved minimum native material VIEW PARALLEL TO SLOPE FACE A. One equipment width or a minimum of 15 feet between rows (or windrows). B. Height and width may vary depending on rock size and type of equipment. Length of windrow shall be no greater than 100 feet. C. If approved by the geotechnical consultant, windrows may be placed direclty on competent material or bedrock, provided adequate space is available for compaction. D. Orientation of windrows may vary but should be as recommended by the geotechnical engineer and/ or engineering geologist. Staggering of windrows is not necessary unless recommended. E. Clear area for utility trenches, foundations, and swimming pools; Hold-down depth as specified in text of report, subject to governing agency approval. F. All fill over and around rock windrow shall be compacted to at least 90 percent relative compaction or as recommended. G. After fill between windrows is placed and compacted, with the lift of fill covering windrow, windrow should be proof rolled with a D-9 dozer or equivalent. VIEWS ARE DIAGRAMMATIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDATIONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED OVERSIZE ROCK DISPOSAL DETAIL Plate F-13 ROCK DISPOSAL PITS Fill lifts compacted oy-er rock after embedment r------- 1 . . . . . . Granular material L _ _ _ .....:..--~:-·:.>>:::-Large Rock I I I I Compacted Fill I ------1 I Size of excavation to I be commensurate I with rock size I ROCK DISPOSAL LA YEAS Granular soil to fill voids, densified by flooding _.. __ -{ _:ompacte~fi~ _ Layer one rock high ~ )LJQCT I ,r-Proposed finish grade ,-~~ ~-~~~ .-. f L -------........._ -------- -:-Hold-down depth "-. PROFILE ALONG LA YEA -t- Oversize layer c:cxx::o -•- Compacted fill 3-foot " ........... ( • Hold-®WTI depth " minimum rill Slope l l I •• Clear zone TOP VIEW Layer one rock high • Hold-down depth or below lowest utility as specffied in text of report, subject to governing agency approval. •• Clear zone for utility trenches, foundations, and swimming pools, as specified in text of report. VIEWS ARE DIAGRAMMATIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDATIONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED IN ROCK DISPOSAL DETAIL Plate F-14 Existing grade 5-foot-high impact/debris wall METHOD 1 1 Pad grade -_J_ __ --- Existing grade 5-foot-high impact/ debris wall METHOD2 Existing grade 5-foot-wide catchment area ( 5-foot-high METHOD 3 impact/ debris wall · \\\ ~ Pad grade ~ ,; ~/,___ -- -- ----- ... :\, /' \\.\\/ ,...'~/ ,,;-\ Existing grade ~\ 2:1 (h:v) slope cence -\\),~ \ 2:1 (h:v) slope METHOD 4 ~'\ \,-.r-Pad grade ·\\\ '-_[_ ·-- ~ ,; NOTTO SCALE DEBRIS DEVICE CONTROL METHODS DETAIL Plate F-15 Rock-filled gabion basket Existing grade Filter fabric Drain rock 5--foot minimum or as recommended by geotechnical consultant Compacted fill Proposed grade Gabion impact or diversion wall should be constructed at the base of the ascending slope subject to rock fall. Walls need to be constructed with high segments that sustain impact and mitigate potential for overtopping, and low segment that provides channelization of sediments and debris to desired depositional area for subsequent clean-out. Additional subdrain may be recommended by geotechnical consultant. From GSA, 1987 ROCK FALL MITIGATION DETAIL Plate F-16 ~ .-------------------------------------------------------------------------------~ MAP VIEW NOTTO SCALE Concrete cut-off wall SEENOT,~S~~~~~~~~~------<d B I Top of slope ~ 2-inch-thick sand layer Gravity-flow, nonperforated subdrain I===-pipe (transverse) Toe of slope I 1 ---5teet Pool 4-inch perforated subdrain pipe (longitudinal) Coping A' 4-inch perforated subdrain pipe (transverse) Pool Direction of drainage B' CROSS SECTION VIEW Coping NOTTO SCALE SEE NOTES Pool encapsulated in 5-foot thickness of sand ---, 6-inch-thick gravel layer 4-inch perforated subdrain pipe B NOTES= r H Gravity-flow nonperforated subdrain pipe I I ---1 1--5 feet Coping B' 2-inch-thick sand layer Vapor retarder Perforated subdrain pipe 1. 6-inch-thick, clean gravel(% to 1~ inch) sub-base encapsulated in Mirafi 140N or equivalent, underlain by a 15-mil vapor retarder, with 4-inch-diameter perforated pipe longitudinal connected to 4-inch-diameter perforated pipe transverse. Connect transverse pipe to 4-inch-diameter nonperforated pipe at low point and outlet or to sump pump area. 2. Pools on fills thicker than 20 feet should be constructed on deep foundations; otherwise, distress (tilting, cracking, etc.) should be expected. 3. Design does not apply to infinity-edge pools/spas. TYPICAL POOL/SPA DETAIL Plate F-17 1r· --------------------------------------------------------------------------. -t- NOTES: 2-foot x 2-foot x ~-inch steel plate Standard %-inch pipe nipple welded to top of plate %-inch x 5-foot galvanized pipe, standard pipe threads top and bottom; extensions threaded on both ends and added in 5-foot increments 3-inch schedule 40 PVC pipe sleeve, add in 5-foot increments with glue joints Proposed finish grade bedding of compacted sand 1. Locations of settlement plates should be clearly marked and readily visible (red flagged) to equipment operators. 2. Contractor should maintain clearance of a 5-foot radius of plate base and withiin 5 feet (vertical) for heavy equipment. Fill within clearance area should be hand compacted to project specifications or compacted by alternative approved method by the geotechnical consultant (in writing, prior to construction). 3. After 5 feet (vertical) of fill is in place, contractor should maintain a 5-foot radius equipment clearance from riser. 4. Place and mechanically hand compact initial 2 feet of fill prior to establishing the initial reading. 5. In the event of damage to the settlement plate or extension resulting from equipment operating within the specified clearance area, contractor should immediately notify the geotechnical consultant and should be responsible for restoring the settlement plates to working order. 6. An alternate design and method of installation may be provided at the discretion of the geotechnical consultant. SETTLEMENT PLATE AND RISER DETAIL Plate F-18 .-----------------------------------------------------------------------------~ Finish grade -~ LI <J <J <J LI LI <J 3 to 6 feet LI . Lj <J LI <! .<J Lj LI LI<!. -----%-inch-diameter X 6-inch-long carriage bolt or equivalent 1 .-6-inch diameter X 3~-inch-long hole -------Concrete backfill -· - ------------ TYPICAL SURFACE SETTLEMENT MONUMENT Plate F-19 .. _. p--------------------------------------------------------------. ', .. · . ... , . · .... Flag SIDE VIEW Test pit TOP VIEW Flag Spoil pile Test pit Light Vehicle -------50 feet------------50 feet---------- ------------~100 fee,t-----------------1_.. TEST PIT SAFETY DIAGRAM Plate F-20 '8.5 j i I ' X )alo ! X / /J a:, ,r.1.,, " ii / I 1 / / ,./ X 45.2/ i ' I J / / ; I l ,; f x16.o l I XJ7/ I I J I ! 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