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CDP 03-10; JOHANNSEN RESIDENCE; PRELIMINARY GEOTECHNICAL INVESTIGATION; 2004-05-18
;, i •. ',;-. ," •" :/ I ~ ,·. •,· -...... ,·- ... :--: \ .-;:· t-.·i:t...- ·, :,,)-,' :.-~.'~, , . ' . ~ ' '' . '•., - V t • ~-.. ~ ' ' . '< ~ -:: . ~,;-.·. ' ,· '~ ... :''·" ·,' !' 'i, . , .. ,. RECEIVED • ~HJ' 1 U HtU4 . ~~iNE~R\NG Geotechnical • t~iRiSlffil,t'2tlvironmental 5741 Palmer Way • Carlsbad, California 92008 • (760) 438-3155 • FAX (760) 931-0915 Mr. Lance Johannsen P.O. Box300 San Jacinto, California 92581 May 18, 2004 , W.O. 4340-A-SC Subject: Preliminary Geotechnical Evaluation, Vacant Lot Located in 5400 Block of Carlsbad Boulevard, City of Carlsbad, San Diego County, Califo.rnia Dear Mr. Johannsen: In accordance with your request, GeoSoils, Inc. (GSI) has performed a preliminary geotechnical evaluation of ttw subject site. The purpose of the study was to evaluate the onsite soils and geologic conditions and _their effects on the proposed site development from a geotechnical viewpoint. EXECUTIVE SUMMARY - Based on our review of the available data (see Appendix A), field exploration, laboratory testing,. ano geologic analysis, residential development of the property appears to be feasible fro_m a geotec;:hnical viewpoint, provided the recommendations presented in the text of this report are properly incorporated into the design and construction of the project. The most significal)t elements of this study are summarized below: • The proposed development will consist of a two-story, s_ingle-family residence, as well as underground utility improvements. • The . foundation system should be completely embedded into competent unweathered terrace deposits. In general, uns·uitable surficial soils are on the order of ± 1' foot. However, _localized deeper removals to mitigate potentially compressible soils cannot be precluded. • The expansion potential of tested onsite soils is generally very low. Conventional founoations may likely be utilizep for these soil conditions; however, based on field mapping in the vicinity of the site, the presence of numerous paleoliquefaction features ("sand blows,-'' liquefaction craters, sand filled fissures and injection dikes, sand vents, etc.), may exist within the site. Potential liquefaction of such areas in the future that may impact surface improvements is considered very low, provided 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 any of the undersigned. DG/JPF/DWS/jk Distribution: (3) Address~e Mr. Lance Johannsen Fife:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.O. 4340-A-SC Page Three TABLE OF CONTENTS SCOPE OF SERVICES .................................................... 1 SITE CONDITIONS/PROPOSED DEVELOPMENT .............................. 1 . FIELD STUDIES ......................................................... 1 ~ . . ' . REGIONAL GEOLOGY ...... .-............................................ 4 EARTH MATERIALS .... : ................ : ................................ 4 Topsoil/Colluvium .... .-............................................. 4 Terrace Deposits ... : .-............................................. 4 MASS WASTING ................... -...................................... 5 FAULTING AND REGIONAL SEISMICITY .............. _ ....................... 5 ·Faulting ........... · ............................................... 5 Seismicity ..... , ............. -... , ................................... 5 Seismic Shaking Parameters .....•.................. -................. 7 Seismic Hazards .......................... , .......................... 8 . GROUNDWATER ... , .. : .................................................. 8 LIQUEFACTION POTENTIAL ..................... ; ......................... 9 LABORATORY TESTING ................................................. ·10 General ......................................................... 10 Moisture-Density R~lations . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 o Shear Testing·· ............. · ......... -................................ 1 O Expansion Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 o -Corrosion Testing· .............. , .................................. 11 ' . CONCLUSIONS .............. -......................... ~ ................ 11 EARTHWORK CONSTRUCTION RECOMMENDATIONS ....................... 11 General ...... , ....... · .......... ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Site Preparatio·n . · .............. ; .................................. 11 Removals {Unsuitable Surficial Mat~rials) .............................. 11 Fill Placement .. : .. , . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Transitions/Overexcavation , ........................ _. ................ 12 RECOMMENDATIONS-FOUNDATIONS~ ................................... 12 Preliminary Foundation Design ...................................... 12 Bearing Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Lateral Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 · Foundation Settlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 . GeoSoils, lne. Footing Setbacks . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Construction .................................. -. . . . . . . . . . . . . . . . . . . 14 Very Low Expansion Potential (E.I. Oto 20) ............................ 14 POST-TENSIONED SLAB SYSTEMS ....................................... 15 Post-Tensioning Institute Method .................................... 16 .UTILITIES ............ · .... , .............. : .............................. 17 WALL DESIGN PARAMETERS ............................................ 17 Conventional Retaining Walls ............... : . . . . . . . . . . . . . . . . . . . . . . . 17 Restrained Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Cantilevered Walls ..............• .-.................................. 18 Retaining Wall Backfill and Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Wall/Retaining Wall Footing Transitions ............................... 22 . . , TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS .......................... 22 · Slope Cre~p ...................................................... 22 Top of Slope Walls/Fences ........... : ............................. 23 DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS : ...................... 24 DEVELOPMENT CRITERIA .......... _ ................. · .................... 26 Slope Deformation ................................................ 26 Slope Maintenance and Planting .... ~ _. ................................. 27 Drainage ................... · .. · ......... · .......................... 27 Erosion Control .................................................... 28 Landscape Ma:imenance · ................... · .......................... 28 Gutters and Downspouts ........ ~ ................................ '. . 28 Subsurface and Surface Water •........... ; ... · ...................... 28 Site Improvements ......... · ....................................... 29 Tile Flooring ............... : .. · ..................................... 29 Additional Grading ....... · ......................................... 29 Footing Trench Excavation ......................................... 29 Trenching ........................... · ............................ 30 Utility Trench Backfill ............ · ............ · ...................... 30 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING ................ · ........................................ 30 OTHER DESIGN PROFESSIONALS/CONSULTANTS .................... : ..... 31 . . LIMITATIONS ................... , ....................................... 32 Mi'. Lance Johannsen File:e:\wp9\4300\4340a.pge · GeoSoils, lne. Table of Contents Page ii FIGURES: Figure 1 -Site Location Map .... · ..................................... 2 Figure 2 -: Boring Location ·Map . · ...................................... 3 Figure 3 -California Fault Map ........................................ 6 Detail 1 -Typical Retaining Wall backfill and Drainage Detail .............. 19 Detail 2 -Retainin_g Wa~I Backfill and Subdrain detail Geotextile Drain ....... 20 Detail 3-Retaining _Wall and Subdrain Detail Clean Sand Backfill ........... 21 · ATTACHMENTS: Appendix A-References · . .-................................. Rear of Text Appendix B -Hand Auger Boring Logs ........................ Rear of Text Appendix C -!=QFAULT, EQSEARCH, and FRISKSP ............ Rear of Text Appendix D.:. General Earthwork and Grading Guidelines ......... Rear of Text Mr. Lance Johannsen File:e:\wp9\4300\4340a.pge GeoSoils, lne. Table of Contents Page iii PRELIMINARY GEOTECHNICAL EVALUATION VACANT LOT LOCATED IN 5400 BLOCK OF CARLSBAD BOULEVARD C/1Y OF CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA - SCOPE OF -SERVICES The scop.e of our services has included the following: 1. Review of the available geologic literature for the site and vicinity (see Appendix A). 4. Subsurfac_e exploration consisting of excavation of three exploratory hand auger borings for geotechnical logging and sampling (see Appendix B). 3. Laboratory testing_ of representative soil samples collected during our subsurface exploration program. 4. General areal seismicity evaluation (see Appendix C). 5. Appropriate engineering and geologic analysis of data collected and preparation of this report. · SITE CONDITIONS/PROPOSED DEVELOPMENT The site consists of a roughly rectangular, vacant lot located on the east side of Carlsbad Boulevard in the City of Carlsbad, ·california (see Figure 1, Site Location Map). The site is surrounded on the remaining sides by residential property. Topographically, the site slopes very gently to the west and elevation at the site is approximately 60 feet Mean Sea Level (MSL). Drainag.e appears to _be directed westward toward Carlsbad Boul~vard. Proposed site development is anticipated to consist of construction of a two-story, _ single-family residence, as well as underground utility improvements. It is anticipated that the planned building will use continuous footings and slab-on-grade floors with wood-frame and/or masonry block construction. -Building loads are assumed to be typical · for this type of relatively light structure. It is also our understanding that sewage disposal is proposed to be accommodated by tying into the regional municipal system. FIELD ·sTUDl"ES Field studies conducted by GSI consisted of -geologic mapping of the site, and the excavation of three exploratory hand auger borings for evaluation of near-surface soil and geologic conditions. The borings were logged by a geologist from our firm, who collected representative bulk and undisturb.ed samples from the borings for appropriate laboratory testing. The logs of the borings are presented in Appendix B. The locations of the borings are presented on Figure 2 .. · GeoSoils, Ine. 3-D TopoQuads Copyright© 1999 DtLonne Yannouth, ME 04096 \:. ,, \\ ,, \\ \I I' ~! ' \\ ,. Base Map: San Luis Rey a·uadrangle; California--San Diego Co., 7 .5 Minute Series (Topographic), 1968, by USGS, 1·~:2000' PA IFIC LEGOW/0 FAMILY PARK Bas.e Map: The Thomas Guide, San Diego County · Street Guide and Directory, 2004 Edition, by Thomas Bros. Maps, page 1126, .1":1/2 mile · Reproduced with ·11ermiasion_granted ~ Thomas Bro•, Maps. . Thia map la copyrighted by Thomae Bro,. Maps. It la unlawful to copr, or reproduce an· or any ,.. thereof, whether ·tor per•onal uae 9r resale, without permission. All tights reserved. N w.o. 4340-A-SC SITE LOCATION MAP Figure 1 -. -, "B-1 \ -,e-3-II.I ~ a: Q II.I C, ,, c( '-' B-2 . B-4 ...I ...I " > Q c( m (I) I, ...I .. a: Ji c( 0 , I LEGEND Not to scale - "B-4 Approximate location of ~H-RIVERSIDE CO. ORANGE CO. exploratory boring SAN DIEGO CO. ,, ..... BORING LOCATION MAP Fig~r_e 2 All locations are approximate. •• > "_;,enema ... W.O. 4340-A-SC DATE 5/04 ·SCAL@ra~lng . 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 nofthwesterly: 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 and terrestrial 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 co~stal and beach areas. The site is generally underlain by terrace deposits. EARTH MATERIALS Earth materials onsite consist of topsoil/colluvium and Pleistocene-age terrace deposits. A description of each material type is presented in the following discussion. Topsoil/Colluvium · Topsoil/colluvium underlies the site to a depth of approximately 1 foot below existing ground surface. The topsoil/colluvial materials encountered onsite consist of light brown, silty sand. The materials generally were dry, loose, and porous, These materials are considered unsuitable for the support of settlement-sensitive improvements in their existing state. , Terrace Deposits Pleistocene-age terrace deposits underlie the site at shallow depth. Where encountered, these materials are typically orange brown, dry to moist, and medium dense to dense. Unweathered dense terrace deposits are considered suitable for structural support. Based on our site exploration, terrace deposits appear relatively massive. Elsewhere in the yicinity, it has been our experience that bedding structures within terrace deposits are relatively _flat lying and therefore a~verse bedding conditions are not anticipated. Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.O. 4340-A-SC May 18, 2004 Page4 MASS WASTING No evidence of any significant pre-existing mass wasting features were indicated or observed during field exploration or during a review of available publications. FAULTING AND REGIONAL SEISMICITY Faulting The site is situated. in a region of active· as well as potentially-active faults. Our review indioates that there are no known active faults crossing the site within the areas proposed for development (Jennings, 1994), and the site is not within an Earthquake Fault Zone (Hart and Bryant, 1997). There are a number of faults in the southern California area that are considered active and would have an effect on the site in the form of ground shaking should they be the source of an earthquak.e. These faults include, but are not limited to: the San Andreas fault; the San Jacinto fault; the E:lsinore fault; the Coronado Bank fault zone; and the Newport-Inglewood -Rose Canyon fault zone. The location of these, and other major faults relative to the site, are indicated on Figure 3 (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. The following table lists the major faults and fault zones in southern California that should have a significant effect on the site should they experience significant activity. Rose Canyon 4.3 (7.0) Newport-Inglewood-Offshore 6.3 (10.2) ·Coronado Bank-Agua Blanca 20.1 (32.3) Elsinore-Temecula 25.2 (40.6) San Jacinto-Anza 47.9 77.1 Seismicity The acceleration-attenuation relations of Sadigh, et al. (1997) Horizontal Soil, Bozorgnia, Campbell, and Niazi (1999) Horizontal-Soil-Correlation, and Campbell and Bozorgnia (1997 Rev.) Soft Rock have been incorporated into EQFAULT (Blake, 2000a). For this study, Mr. Lance Johannsen 5400 Block of Carlsbac;:I Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. W.O. 4340-A-SC May 18, 2004 Page5 CALIFORNIA FAULT MAP Johannsen 1000 900 800 700 600 · 500 400 300 200 100 0 -100 -+--"__.__......_+-'-.......... -'--1-.......... __.__---t-.._._ .......... -t-'-,---'-i,--.--......... ""--t-_._._ .......... ___ ......_~-.--..._._._---'-t~.._._-'-t -400--300 . -200 · -100 0-100 200 300 400 500 600 w.o. 4340-A-SC Figure 3 GeoSoils, Inc. peak horizontal ground accelerations anticipated at the site were determined based on the random mean plus 1 -sigma attenuation curve and mean attenuation curve developed by Joyner and Boore (1981, 1982a, 1982b, 1988, 1990), Bozorgnia, Campbell, and Niazi (1999), and Campbell and Bozorgnia (1997). EQFAULT is a computer program by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using up to 150 digitized California faults as earthquake sources. The program estimates the closest distance between each fault and a given site. If a fault is found tobe within a user-selected. radius, the program estimates peak horizontal ground acc_eleration that may occur at the site from an upper bound ("maximum credible") earthquake on that fault. Site acceleration (g) is computed by one of many user-selected · acceleration-attenuation relations that are contained in EQFAUL T. Based on the EQFAULT program, peak horizontal ground accelerations from an upper bound event at the site may be on the order of 0.62g to 0.71 g. · Historical site· seismicity was evaluated with the acceleration-attenuation relations of Campbell and Bozorgnia (1.997 Rev.) Soft Rock and the computer program EQSEARCH (Blake, 2000b). This program performs a search of the historical earthquake records for magnitude 5.o· to 9.0 seismic events within a 100-mile radius, between the years 1800 through · December · 2003. . 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 2003 was 0.34g. Site specific probability of exceeding various peak horizontal ground accelerations and a · seismic recurrence curve are also estimated/generated from the historical data. Computer printouts of pertinent portions of the EQSEARCH program are presented in Appendix C. A probabilistic seismic hazards analyses w~s performed using FRISKSP (Blake, 2000c), which models earth_quake sources as three-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 these data, and considering the relative .seismic activity of the southern California region, a peak horizontal ground acceleration of 0.35g was calculated. This value was chosen as it corresponds to a 1 O percent probability of exceedance in 50 years (or a 475-year return period). Seismic Shaking Parameters .. Based on the site conditions, Chapter 16 of the Uniform Building Code ([USC], International Conference of Building .'Officials [ICBO], 1997), the following seismic parameters are provided: Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.0. 4340-A-SC May 18, 2004 Page? Seismic zone (per Figure 16-2*) 4 Seismic Zone Factor (per Table 16-1*) 0.40 Soil Profile Type (per Table 16-J*) -So Seismic Coefficient Ca (per Table 16-Q*) 0.44 Na Seismic Coefficient Cv (per Table 16-R*). 0.64 NV .Near Source Factor Na (per.Table 16-S*) 1.10 Near Source Factor Nv (per Table 16-T*) 1.33 Seismic Source Type (per Table 16-U*) B Distance to Seismic Source 4.3 mi (7.0 km) Upper Bound Earthquake (Rose Canyon) Mw6.9 ·* Figure and table references from Chapter 16 of the UBC (ICBO, 1997). 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 completely mitigated as a result of site location, soil characteristics, and typical site development procedures: · · · • • . . • Tsunami -Dynamic Settlement Surface Fault Rupture Ground Lurching or _Shallow Ground Rupture It is important to keep_ in perspective that in the event of a maximum probable or 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. This potential would be no greater than that for other existing structures and improvements _in the immediate vicinity. GROUNDWATER Subsurface water w_as not encountered within the property during field work performed in preparation of this report. _Subsurface water is not anticipated to adversely affect site development, provided thatthe 'recommendations contained in this report are incorporated into final design and construction. These observations reflect site conditions at the time . ' Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard . File:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.0. 4340-A-SC May 18, 2004 Page a of our investigation and do not preclude future changes in local groundwater conditions from excessive irrigation, precipitation, or that were not obvious,. at the time of our investigation. Regional groundwater is estimated to be at least 50 feet in depth, below the site. Seeps, springs, or other indi'cations· of a high groundwater level were not noted on the subject property during the time of our field investigation. However, seepage may occur locally (as the result of heavy precipitation or irrigation) in areas where any fill soils overlie terrace deposits or impermeable soils. Such conditions may occur during grading or after the site is developed, and should be anticipated. 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 of loose sediments, and other damaging deformations. 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. Ttie condition of liquefaction has two principal effects. One is the consolidation 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. No such loading conditions exist onsite. Liquefaction susceptibility is related to numerous factors and the following conditions should be concurrently present for liquefaction to occur: 1) 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·. Since at least one or two of the five required concurrent conditions discussed above do not have the potential to _affect the .site, and evidence of paleoliquefaction features was not observed, 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. The site conditions will also-be improved by removal and recompaction of low qensity near-surface soils, and if evidence for paleoliquefaction is encountered during grading, the use of post-tension slabs. Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSofls, Ine. W.O. 4340-A-SC May 18, 2004 Page9 LABORATORY TESTING General Laboratory tests were performed on a representative sample of the onsite earth materials in order to evaluate their physical and engineering characteristics. The test procedures used and results obtained are presented below. Moisture-Density Relations The laboratory maximum dry density and optimum moisture content for representative site soils was qetermined according to test method ASTM D-1557. A maximum dry-density of 127.0 pcf at an optimum_ moisture-content of 9:5 percent was determined for a bulk composite sample obtained from the site. Field moisture and density determinations were also performed. The results of these determinations are presented on the Boring Logs in Appendix 8. · · · · · Shear Testing Shear testing was performed on a repres·entative, remolded sample of sit~ soil, in general accordance with ASTM Test Method D-3080, in a Direct Shear Machine of the strain control type. The shear test results are summarized below: Expansion Potential Expansion testing was performed on a representative samples of site soil in accordance with UBC Standard 18-2. The results of expansion testing are presented in the following table. Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge 0 GeoSoils, lne. Very Low W.O. 4340-A-SC May 18, 2004 Page 10 Corrosion Testing Laboratory_ test results for soluble sulfates, pH, and corrosion to metals have not been received as of the date of this report. Testing will be presented as an addendum upon receipt of the results. Additional testing of site materials is recommended when proposed grading is complete, to further evaluat~ the findings. CONCLUSIONS Based upon our site reconnaissance test results, it is our opinion that the subject site appears suitable for the proposed residential development. The following recommendations should be incorporated into the construction details. EARTHWORK CONSTRUCTION RECOMMENDATIONS ·General · All grading should conform to the guidelines presented in Appendix Chapter A33 of the UBC, the requirements of the City, and the Grading Guidelines presented in Appendix D, except wher~ specifically_superceded in the text of this report. Prior to grading, a GSI represef'.ltative sho~ld 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, and the Construction Safety Act should be met. Site Preparation Debris, vegetation, existing structures, and other delet_erious material should be removed from the building area prior to the startof construction. Sloping areas to receive fill should be· properly benched in accordance with current industry standards of practice and guidelines specified in the UBC. Removals {Unsuitable Surficial Mate~i~ls) Due to the relatively loose condition of topsoil and weathered terrace deposits, these materials should be removed and recompacted in areas proposed for settlement-sensitive Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.O. 4340-A-SC May 18, 2004 Page 11 structures or areas to receive compacted fill. At this time, removal depths on the order of 1.foot (including topsoil and weathered terrace deposits) below existing grade should be anticipated-throughout a majority of the site; however, locally deeper removals cannot be precluded. Due to the relatively loose and porous condition of the topsoil/colluvial, these materials should be rem·oved, moisture conditioned, and recompacted and/or processed in place. Removals should be completed below a 1 : 1 projection down and away from the edge of any settlement-sensitive improvements and/or limits of proposed fill. Once removals are completed, the exposed bottom should be reprocessed and compacted to 90 percent relative compacti.on. · · Fill Placement Subsequer:it to ground preparation, onsite soils may be placed in thin (±6-inch) lifts, cleaned of vegetation and debris, brought to a least optimum moisture content, and compacted to. achieve a minimum .relative compaction of 90 percent. If soil importation is planned, a sample of the soil import should be evaluated by this office prior to importing, in order to assure compatibility with the onsite site soils and the recommendations presented in this report. Import soils for a fill cap should be very low expansive (Expansion Index [E.I.] less than 20). The use ·of subdrains at the bottom of the fill cap may be necessary, and subsequently recommended based on compatibility with onsite soils and proximity and/or suitability of an outlet. Transitions/Ov~rexcavation Cut portions of cut/fill transition pads should be overexcavated a minimum 3 feet below pad grade. Areas with planned fills less than 3 feet should be overexcavated in order to provide a minimum fill thickness of 3 feet, or 2 feet below the foundation, whichever is greater. Where the ratio of maximum to minimum fill thickness below a given structure exceeds 3:1, overexcavation should be completed to reduce this ratio to 3:1, or less. RECOMMENDATIONS -FOUNDATIONS Preliminary Foundation Design In the event that the informa,tion concerning the proposed development plans are not correct, or any changes in the design, location, or loading conditions of the proposed structures are made, the conclusions and recommendations contained in this report are for the subject site only and shall not be considered valid unless the changes are reviewed and conclusions 9f this report are modified or approved in writing by this office. The information and recommendations presented in this section are considered minimums and are not meant to supercede design(s) by the project structural engineer or civil engineer specializing in structural design. Upon request, GSI could provide additional Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. W.0. 4340-A-SC May 18, 2004 Page 12 consultation regarding ·soil parameters; as related to foundation design. They are considered preliminary recommendations for proposed construction, in consideration of our field investigation, and laboratory testing and engineering analysis. Our review, field work, a~d recent and previous laboratory testing indicates that onsite soils have a very low expansion potential range (E.I. Oto 20). Preliminary recommendations for foundation design a~d construction are presented below. Final foundation recommendations should be provided at the conclusion of grading based on laboratory testing of fill materials exposed at finish grade. _Bearing Value 1 . The foundation systems should be designed and constructed in accordance with guidelines presented in the latest edition of the USC. 2. · An allowable bearing value of 1,500 pounds per square foot (psf) may be used for design of continuous footings 12 inches wide and 12 inches deep and for design of isolated pad footings 24 inches square and 18 inches deep founded entirely into compacted fill' or competent formationaf material and connected by grade beam or tie beam in at least one direction. This value may be increased by 20 percent for each additional 12 inches in depth to a maximum value of 2,500 psf. The above values ma,y be incr{3ased by one-third when considering short duration seismic or wind loads. No increase in bearing for footing width is recommended. Lateral Pressure 1. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. 2. Passive earth pressure may be computed as an.equivalent fluid having a density of 250 pounds per cubic foot {pcf), With a maximum earth pressure of 2,500 psf. 3.-When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Foundation Settlement Foundations systems should be. design-ed to accommodate a worst case differential settlement of 1 inch in a 40-foot span. Footing Setbacks. . . ' All footings should maintain a minimum 7-foot horizontal setback from the base of the footing to any descending slope. This distance is measured from the footing face at the Mr. lance Johannsen '5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. W.0. 4340-A-SC May 18, 2004 Page 13' bearing elevation. Footings should maintain a minimum horizontal setback of H/3 . (H=slope height) from the base of the footing to the descending slope face, and no less than 7 feet nor need to be greater than 40 feet. Footings adjacent to unlined drainage swales should be deepened to a minimum of 6 inches below the invert of the adjacent unlined swale. Footings for structur~s adjacent to retafning 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 109-ds from buildings 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 soils expansion potentials are generally very low (E.1. Oto 20}. Recommendations for very low expansive soil conditions are ·presented herein. · Recommendations by the project's design-structural engineer or architect, which may · exceed the soils engine.er1s recommendations, should take precedence over the following minimum requirements. final foundation design will be provided based on the expansion potential of the near surface soils encountered during grading. · Very Low Expansion Pot.ential _ (E.I. o to 20) t. Exterior and interior footings should be founded at a minimum depth of 12 inches -for one-story floor loads, 18 inches for two-story floor loads, and 24 inches for three-story floor loads below the lowest adjacent ground surface. Isolated column and panel pads, or wall footings, should be founded at a minimum depth of 24 inches. All footings should be reinforced with two No. 4 reinforcing bars, one placed nearthe top and one placed ~ear the bottom of the footing. Footing widths should be as indicated in the UBC (ICBO, 1997); width of 12 inches for one-story loads, ·15 inches for two-story loads, and 18 inches for three-story loads. 2. · A grade be.am, reinforced as above, and at least 12 inches wide 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. Residential concrete slabs, where moisture condensation is undesirable, should be underlain with a vapor barrier consisting of a minimum of 1 o mil polyvinyl chloride or equivalent membrane with all laps sealed. This membrane should be covered above and below with a minimum :of 2 inch,es of sand (total of 4 inches) to-aid in uniform curing of the concrete and to protect the membrane from puncture. Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.O. 4340-A-SC May 18, 2004 Page 14 -4. Residential concrete slabs should be a minimum of 4 inches thick, and should be 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 ac~eptable method of positioning the reinforcement. 5. Residential garage slabs should be a minimum of 5 inches thick and should be reinf9rced as above. and poured separately from the structural footings and quartered with expansion joints or saw cut$. A positive separation from the footings should be maintained with expansion joint material to permit relative movement. 6. Specific pre$aturation is not required for these soil conditions; however, GSI recommends that-the moisture content of the subgrade soils should be equal to or greater than optimum moisture content to a depth of 12 inches in the slab areas prior to the placement of visqueen. POST-TENSIONED SLAB SYSTEMS Post-tension foundati~ns are spe_cifically recommended if paleoliquefaction features ("sand blows," liquefaction craters, sand filled.fissures and injection dikes, sand vents, etc.) are encountered during grading. 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 design. 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 e):(pansiori/shrinkage standpoint, a common contributing factor to distress of structures using post-tension$d slabs is fluctuation· of moisture in soils underlying the perimeter of the slab, compared to the center, causing a "dishing" or "arching" of the slabs. To mitigate this possibility, a combination of soil presaturation and construction of a perimeter cut off waU should be employed. Perimeter cut-off walls should be a minimum of (18 inches deep for medium expansive . . soils. The cut-off walls may be integrated into the slab design or independent of the slab. The concrete slab should be a minimum of 6 inches thick. Slab underlayment should consist of 4 inches of washed sand with a vapor barrier consisting of 10-mil polyvinyl chloride-or ~quivalent placed mid-depth within the sand. Mr. Lance.Johannsen 5400 Block of Carlsbad Boulevard File:e:\Wp9\4300\4340a.pge GeoSoils, lne. W.O. 4340-A-SC May 18, 2004 Page 15 Post-Tensioning Institute ~ethod Post-tensfoned slabs should have sufficient stiffness to resist excessive bending due to. · non-uniform swell and shrinkage of subgrade soils. The differential movement can occur at the corner, edge, or center of the slab. The potential for differential uplift can be evaluated using the 1997 UBC, Section l816, based on design specifications of the Post-Tensioning Institute. The following table presents suggested minimum coefficients to be used in the Post-Tensioning Institute design method. Thornthwaite Moisture Index -20 inches/year Correction Factor for Irrigation 20 inches/year Depth to Constant Soil Suction ?feet .. Constant soil Suction (pf) 3.6 Modulus of. Subgrade Reaction (pci) 75 Moisture. Velocity o. 7 inches/month .. Th_e coefficients are considered minimums and may not be adequate to represent worst case conditions such as adverse drp.inage and/or improper landscaping and maintenance. ' The above parameters are· applicable provided structures have positive drainage that is maintained away from structures. Therefore, it is important that information regarding drainage, site maintenance, settlements, and effects of expansive soils be passed on to future owners. Based on the above-parameters, the follovying values were obtained from figures or tables of the 1997 UBC Section, 1 a·1 s. The values may not be appropriate to account for possible differential s~ttlement of the slab due to other factors. If a stiffer slab is desired, higher values of Ym rnay be warranted . . em center lift 5.0 feet em edge lift 2.5 feet · y m center lift 1.0 inch 0.3 inch Deepened footings/edges around the slab· perimeter must be used to m1n1m1ze non-uniform surface moisture mi~ration (from an outside source) beneath the slab. An Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. W.O. 4340-A-SC May 18, 2004 · Page 16 edge depth of 12 inches should be considered a minimum. The bottom of the deepened footing/edge should be designed to resist tension, using cable or reinforcement per the structural engineer. Other applicable recommendations presented under conventional foundation and the California Foundation Slab Method should be adhered to during the . ·design and construction phase. of the project. UTILITIES . . Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and any potentially expansive soil conditions. Due to the potential for differential settlement, air conditioning (A/C) 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 waterlines should be d~ained to a suitable outlet. WALL DESIGN PARAMETERS Conventional Retaining Walls The design parameters provided below assume that either non expansive soils (Class 2 per.meable filter material or Class 3 aggregate base) or native materials (up to and including an E.I. of 65) are used to backfill any r,etaining walls. The type of backfill (i.e., select or native), should be specified .bY the wall designer, and clearly shown on the plans. Buflding walls, below grade, should be water-proofed or damp-proofed, depending on the degree ofmoisture protection desired. 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 1-8 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·fQr specialty walls (i.e., crib, earthstone, geogrid, etc;) can be provided upon request, and would be based on site specific conditions: Restrained Walls Any retaining walls that will be restrained prior to placing and compacting backfill material or that have re-entrant or male corners, 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 corners, the restrained wall des_ign should extend a minimum distance of twice the height of the wall (2H) late_rally from the corner. Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge -GeoSoils, Ine. W.O. 4340-A-SC May 18, 2004 Page 17 Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 1 o feet high_-Design parameters for walls less than 3 feet in height may be superseded by City and/or County standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from mino'r 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 co~ditions. When wall configurations are finalized; the appropriate loading conditions for superimposed loads can be provided upon request. Level* 2to 1 35 !50 45 60 * Level backfill behind a retaining wall is defined as compacted earth materials, ro erl drained, without a slo e for a distance of 2H behind the wall. Ret~ining Wall Backfill and Drainage Positive drainage must be provided bet,indall 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 back drainage options discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either"Class 2 permeable filter material or ½-inch to ¾-inch gravel wrapped in approved filter fabric (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 medium e~pansion potential, continuous Class 2 permeable drain· materials should be used behind the wall. This material should be continuous (i.e:, full height) behind the wall, and it should be con~tructed in accordance with "the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an E.I. potential of greater than 65 should not be used as backfill for retaining walls. For more onerous expansive situations, backfill and drainage behind the retaining wall sho~!d conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). · ' Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. W.0. 4340-A-SC May 18, 2004 Page 18 Provide Surface Dralnage CDwaterproofing Membrane (optional) ®weep Hole Firiishect· Surface .:!:12" DETAILS N . T . S . 2 Native Backfill Slope or Level Native Backfill -+- Native.Backfill . . @ WATERPROOFING MEMBRANE (optional): Liquid boot or a_ppr?ved equivalent. @ ROCK: 3/4 to 1-U2" (inches) rock. @ FILTER FABRIC-: Mirafi 140N or approved equivalent; place fabric flap behind core. @ PIPE: - 4" {inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1 % gradient to proper outlet point. @WEEP HOLE: .Minimum 2" (inches) diameter' placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep h9les for basement "'{alls.) • TYPICAL RETAINING WALL BACKFILL AND DRAINAGE DETAIL DETAIL 1 Geotechnical • Geologic • Environmental DETAILS N . T. s,. 2 Native Backfill Provide Surface Drainage Slope or Level Native Backfill ®waterpr~ofing Membrane (optional) ® weep Hole @ Filter Fabric Finished Surface @ Pipe @ WATERPROOFING MEMBRANE (optional}: Liquid boot or approved equivalent. @·DRAIN: Miradrain 6000 or J-drain 200 or equivalent for non-waterproofed walls. · ·Miradrain 6200 or J-drain 200 or equivalent for waterproofed walls. @ i:=ILTER FABRIC: Mirafi 140N or approved equivalent; place fabric flap behind care. @ PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1 % gradient to proper outlet point. . . @ WEEP ·HOLE: M[nimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep :holes for basement walls.) RETAINING WALL BACKFILL AND SUBDRAIN DETAIL GEOTEXTILE DRAIN , DETAIL 2 Geotechnical e1 Geologic • Environmental H DETAILS N . T . S 2 Native Backfill Provide Surface Drainage .±12" ®weep Hole Finished Surface H/2 min . (D, Waterproofing _ Membrane (optional) @ Filter Fabric : @ Roe Heel Width G) WATERPROOFING MEMBRANE (optional): Liquid po6t or approved equivaient. @ CLEAN .SAND BACKFILL: _ Must have sand dequivalent value of 30 or .greater; can be densified by water jetting. @ FILTER FABRIC: Mirafi 140N or approved equivalent. @ ROCK: 1 cubic foot per linear feet of pipe or 3/4 to 1-1/2" (inches) tock. @ PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1 % gradient to proper outlet point. · , @WEEP HOLE: Minimum _2" {inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) • , , RETAINING WALL AND SUBDRAIN DETAIL CLEAN SAND BACKFILL DETAIL 3 Geotectmical • Geologic • Environmental 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 in walls higher than 2.feet should not be considered. ·The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (E.I. <90). 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 Tra!1sitions . 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 des_igner may specify either: . a) A_ minimum of a 2-foot overexcavation 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 sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational material (i.e., deepened footings). If transition$ 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 nan {above) and until such transition is between 45 a,:td 90 degrees to the wall alig_nment. ... TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS Slope Creep Soils at the site may be expansive and ther~fore, may become desiccated when allowed to dry. Such soils are susceptible to surficial slope creep, especially with seasonal chang~s in moisture content. Typfcally in southern California, during the hot and dry summer period, these soils become desiccated and shrink, thereby developing surface cracks. The extent and depth of these shrinkage cracks depend on many factors such as- ·the nature and expansivity of the soils, temperature and humidity, and extraction of moisture from surface soils by plants and roots. When seasonal rains occur, water percolates into the cracks and· fissures, causing slope surfaces to expand, with a correspondi_ng loss in soil density and shear strength near the slope surface. With the · passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials Mr. Lance Johannsen · 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. W.O. 4340-A-SC May 18, 2004 Page 22 experience a very slow, but progressive, outward and downward movement, known as slope creep. For slope heights greater than 1 0 feet, this.creep related soil movement will .typically impact atr rear yard -flatwork and other secondary improvements that are located within about 15 feet from.the top of slopes, such as. swimming pools, concrete flatwork, · etc.; and in particular top ·of slope fences/walls. This influence is normally in the form of detrimental settlement, and tilting of the proposed improvements. The dessication/swelling and creep discussed above continues over the life of the improvements, and generally becomes progressively worse. Accordingly, the developer should provide this information · to any homeowners and homeowners association. · Top of Slope Walls/Fences Due to the potential for slope creep for slopes higher than about 1 0 feet, some settlement and tilting of the Walls/fence with the corresponding distresses, should be expected. To · mitigate the tilting of top· of slope walls/fences, we recommend that the walls/fences be constructed on deepened founda:tions without any consideratiori for creep forces, where the E.I. of the materials comprising the outer 15 feet of the slope is less than 50, or a combination of grade beam and caisson foundations, for expansion indices greater than 50 comprisir:,g the slope, with creep forces taken into account. The grade beam should be at a minimum of 12 inches by 12 inches in cross section·, supported by drilled caissons, 12 in·ches minimur:n in diameter, placed at a maximum spacing of fffeet on center, and with a minimum erpbedment length of 7 feet _below the bottom of the grade beam. The strength .of the concrete and grout should be evaluated by the structural engineer of record. The proper ASTM tests for the concrete and mortar should be provided along with the slump quantities. The concrete used should be appropriate to mitigate sulfate corrosion, as warranted. The design·ofthe grade beam and caissons should be in accordance with the recommendations of the project structural engineer, and include the utilization of the _ .following geotechnical parameters: .Creep Zone: Creep Load: Point of Fixity: Passive Resistance: Mr. Lance Johannsen 5-foot vertical zone below the slope face and projected upward parallel to the slope face. The cr~ep load projectec;I on the area of the grade beam . should be taken as an equivalent fluid approach, having a density. of 60 pcf. For the caisson, it should be taken as a uniform 900 pounds per linear foot of caisson's depth, located above the creep zone. Located a distance of 1.5 times the caisson's diameter, below the creep zone. Passive earth pressure of 300 psf per foot of depth per foot of · -caisson diameter, to a maximum value of 4,500 psf may be used to determine caisson depth and spacing, provided that 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pg·e W.O. 4340-A-SC May 18, 2004 Page 23 GeoSoils, Ine. they meet or exceed.the minimum requirements stated above. To determine the total lateral resistance, the contribution of the creep prone zone above the point of fixity, to passive resistance, should be disregarded. Allowable Axial Capacity: · Shaft capacity : 350 psf applied below the point of fixity over the surface area of the shaft. Tip capacity:. 4,500 psf. · DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS I The soil 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 imp~ovements. The resulting potential for distress to . improvemen1s may be reduced, but nottotally eliminated. To that end, it is recommended that the developer should notify any homeowners or homeowners association of this 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 percentage points above (or 125 percent of) the soils' optimum moisture content, to a depth of 18 inches below subgrade elevation. If very low expansive soils are present, only optimum moisture content, or great~r, is required and specific presoaking is not warranted. The.moisture content of the subgrade should be verified 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 ~and 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. Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.O. 4340-A-SC May 18, 2004 Page 24 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. 5. 6. 7. 8. 9. 10. 11. 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. The exterior slabs should be scored or saw cut, ½ to 3/a inches deep, often enough so that no section is greater than 1 O feet by 1 o feet. For sidewalks or 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. . . . . 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 isoo psi. · Oriveway.s, sidewalks, and patio slabs adjacent to the house should be separated from the house with thick expansion joint filler material. In· areas directly adjacent to a co.ntinuo.U$ source of moisture (i.e., irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. Planters and walls should not be tied to the house. 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 Ued in one direction. Any masonry landscape ~alls 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 or doweled together. Utiliti.es should be enclosed within a closed utilidor (vault) or <;f esigned with flexible connections to accommodate differential settlement and expansive soil conditions . . Positive site ·drainage should be maintained at all times. Finish grade on the lots . should provide a minimum of 1 to 2 percent fall to the 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 n·ot . periodicaUy maintained by the homeowner or homeowners association. Mr. Lance Johannsen W.O. 4340-A-SC May 18, 2004 Page 25 5400 ~lock of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. 12. Air conditioning (A/C) 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. A/C waste water lines should be drained to a suitable non-erosive outlet. 13. Shrinkage cracks could b·ecome 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. DEVELOPMENT CRITERIA Slope ·Deformatior1 Compacted fill ~lopes designed using customary factors of safety for gross or surficial stability and constructed in general accordance with the design specifications should be expected to undergo some differential vertical heave or settlement in combination with differential lateral movement in· the out.a.of-slope direction, after grading. This post-construction movement occurs in.two forms: slope creep, and lateral fill extension (LFE). Slope creep is caused.by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the .life of the slope, and is anticipated to potentially affect improvements or structures (i.e., separations and/or cracking), placed near the top-of-slope, up to a maximum distance of approximately 15 feet from the top-of-slope, depending on the slope height. This movement generally results in rotation and differential settlement of improvements located wlthin the creep zone.. LFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. AJthough some movement should be expected, long-term movement from thi~ source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet of the fill's optimum moisture content. It is generally not practical to attempt to eliminate the effects of either slope creep or LFE. Suitable mitigative measu·res to reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per the 1997 USC and/or California Building Code), positive struct.ural separations (i.e., joints) between improvements, and stiffening and deepening. of foundations·.· All of these m_easures are recommended for design of structures and improvements. The ramifications of the above conditions, and . recommendations for mitigation, should be provided to each homeowner ·and/or any . homeowners association. Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. W.O. 4340-A-SC May 18, 2004 Page 26 Slope Maintenance and Pl,mting Water' .has been shown to weaken the inherent strength bf all earth materials. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage away from slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it can adversely affect site improvements, and cause perched groundwater conditions. Graded slopes cons.tructed utilizing onsite materials would be erosive. Eroded· debris may be minimized an_d surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after. construction. Compaction to the face offill slopes would tend to minimize short-term erosion until vegetation is established. Plants ·selected for landscaping should be light weight, deep root~d types that require little water and are capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may aid in allowing the establishment of a sparse·plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, etc., to develop. A rodent control program. to prevent burrowing should be implemented. Irrigation of natural (ungraded) slope areas is generally not recommended.· These recommendations regarding plant type, irrigation practices, and rodent control should be provided to each homeowner. Over-steepening of slopes should be avoided during building construction activities and l~ndscaping. Drainage Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, hard scape, and slopes. Surface drainage should be sufficientto prevent ponding of water anywhere on a lot, and especially near structures and tops of slopes. Lot surface drainage should. be carefully taken ir:ito consideration during fine grading, landscaping, and building construction. Therefore, care should be taken that future landscaping or construction activitie~ 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 o_r other approved area(s). Although not a geotechnical requirement, roof 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 this effect could be_ provided upon request. Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.O. 4340-A-SC May 18, 2004 Page 27 ··erosion Control Cut and fill slopes Will be subject to surficial erosion during and after grading. On site 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 Mainten~nce Only the amount of irrigation necessary ·to sustain plant _ life should be provided. Over-watering the landscape areas will 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 feet. 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 adjace·nt to structures, the sides and bottom of the .planter sho_uld be provided with a moisture barrier to prevent penetration of irrigation water into the subgrade. Provisions should be·made to drain the excess irrigation 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 previousiy discussed in the drainage section, the installation of gutters and downspouts should be considered·to collect roof water that may otherwise infilJrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or non-erosive devices that will carry the water away from the house. 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 cont~ined in this report are incorporated into final design and construction and that prudentsurface 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, arid should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide -Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:~:\wp9\4300\4340a.pge GeoSoils, Ine. W.O. 4340-A-SC May 18, 2004 Page 28 the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Site lmproveme.nts · Recomme-ndations for exterior concrete flatwork design and construction can be provided · · upon req1;1est. 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. 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. ·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 and 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_ verify that the ·excavations are made_ into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recornpaction 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. · Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge . GeoSoils, Ine. W.0. 4340-A-SC May 18, 2004 Page 29 Trenching , Consiqering the nature of the onsite soils, it should be anticipated that caving or sloughing could_ be a-factor in ~ubsurface excavations and trenching. Shoring or excavating the trench walls at the angle of repose (typically 25· to 45 degrees) may be necessary and should be anticipated. All excavations should be observed by one of our representatives and minimally conform to CAL-OSHA and local safety codes. Utility Trench Backfill 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 of the 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 verify 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 b~ compac@d 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 verify the desired results. 3. All trench excavations should conform to CAL-OSHA and local safety codes. 4. Utilities. 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 following construction stages: · · • During grading/recertification. • During significant excavation (i.e., _higher than 4 feet). • During placement of subdrains; toe drains, or other subdrainage devices, prior to · placing fill and/or backfill. · Mr. Lance Johannsen 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, lne. W.O. 4340-A-SC May 18, 2004 Page 30 • • • • • • • • After excavation of building footings, retaining wall footings, and free standing walls footings, prior to the· placement of reinfo_rcing 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 (i.e., sand, pea-gravel, etc.), or vapor barriers (i.e., visqueen, · etc.). 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. During $lope construction/repair . When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this ·report. Whe_n any developer or homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed. A report of geotechnical observation and testing should be provided at the conclusion of each· of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engine~r. post-tension designer, architect, landscape architect, wall oesigner, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. In order to mitigate potential distress, the foundation and/or improvement's designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can torerate the amount of differential settlement and/or expansion characteristics and design criteria specified herein. Mr. Lance Johannsen · 5400 Block of Carlsbad Boulevard File:e:\wp9\4300\4340a.pge GeoSoils, Ine. W.O. 4340-A-SC · May 18, 2004 Page 31 LIMITATIONS The materials encountered on the project site, and utilized in our previous laboratory study, _ are believed representative .of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. GSI assumes no responsibility or liability for work, testing, or recommendations performed or provided by oth~rs. Tt-Je scope of work was performed within the limits of a budget. Inasmuch as our study i$ based upon the site materials observed, selective laboratory testing and· engineering analysis, the conclusions and recommendations are professional opinions. These opinions have been. derived in accordance with current standards of practice, and no warranty is expressed or implied. Standards of practice are subject to change with ·time. 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X.i>):,t,(< r'\:' /!'.:: :; ,, ' ' .. ;.·:;; ,:::, <. · .. , .. , ·•>::\_:~}}'.}.::'. ·'. ·: ,: ' :t; -,;·.•_',\ ,.:r,-._... :-\· .-.~-/:._ :/,'.: ~:, •. ,,.~.--,, . ' . ;_,,:. ,_:··,.f:\ ... '. , .. ::·>"::·) :,, :_:::::--;~ .. -~.:'',. ·,:;-~,_:·.:. ·:·;;;_-, • ;,, ":.<,\j::.:<,·:\:'/:<(j ," I ; ',.' :.'; \,~· ,' ,• .•,,:· ·;~,:~/',. •: ,-', ! /,,; ,:-;, ,;!',{~:~··'• •• :t '\~1 -:·;-~:~·~{,::·' ·~.' ... , .-.., ~ ,.' :;;:)}l:_::i.:r?i\,,,, . ; ::> \ \ .. • • ~ ~ ~; • ' c.·,, ·~·.~'. ' ·.: :-'~ •, : ,· J ' ·"'' • ' • I, • ~,. : :-' ; ·,, .' -~_·, -:.<:-· ,.:.·.·'·_ . .::,.-.:" ~)·· . 1'-:. ',,,\ \: .,\ ;,, ... ·,_:, ~ ' .. , .. ·: .. ' ;\1-,·, ..;.! :: ~: ·~ -: -~·-::,,i-'_<,' i' :~ ::,~ ··~ . . . '. :, ·.: ·,.· r· ~ -··::~.:,:rt-. /~~ .; /';_ ~,-~.·.:~_:_:~::·· --..: \ -·; ~~i : .. : : i. I • l : :~,_'·, {::~···f~\-.":C<.,' _ , ~.-:, .\ 1:: ·· ' j ~ ,, ·,=·:·: 1.,,,_-... '' \ ':· .... ,,' • '\ .:,: ' i , ' ,, '. 1~·,_ ~ .. , ,, ... ~ .. ,, ,,;-.:.:- , ....... _ ·;••,., __ -. ...... ' .--~ "< .~~\~ :~4:"., ,. .~· ,:. ·, \ ·:\ 4~~ ~ ·:-: .. -'~··::;·:-~;:_;. __ ·~~,J ·. ,',. ·:. .. :_' -• ::> ~'' • .. APPENDIX A REFERENCES Blake, T.F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. _. _, 2000b, l;QSEARCH, A computer program for the estimation of peak horizontal acceleration from California historical earthquake catalogs; 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 fmp_lications; Proceedings of the SMIP99 seminar on utilization· of strong-motion data; S_epter:nber, 15, Oakland, pp. 23-49. Campbell, .K.W. and Bozorgnia, Y. 1997, Attenuation relations for soft rock conditions; in EQFAULT, A computer program for the estimation of. peak horizontal acceleration from 3-D fault sources; Windows 95/98 version, Blake, 2000a. · __ , Y., 1994, Near-source attenuation of peak horizontal-acceleration from worldwide accelrog_rams recorded f~om 1957 to 1993; Proceedings, Fifth U.S. National Conference on Earthquaf(e Engineering, _Volume Ill, Earthquake Engineering Research Institute, pp 292-29~. Hart, E.W. and Bryant, W.A. 1997, Fault-rupture 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. International Conference of Building Officials, 1997, Uniform building code: Whittier, Califo_rnia, vol. 1, 2, and 3. Jennings, C.W., 1994, 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 of response-spectral values as functions of magnitude, distance and site con·ditions, in eds., Johnson, J.A., Campbell, K.W., and Blake, T.F.: AEG Short Course, Seismic Hazard Analysis, June 18, 1994. . . . __ , 1982b, Prediction of earthquake response spectra, U.S. Geological Survey Open- . File Report 82-977, 16p. GeoSoils, 'Ine. Parker, Claude 8., Geotechnical Consultant, Preliminary geotechnical report for proposed residential structure, 5480 Carlsbad Boulevard, Carlsbad, County of San Diego, California, Job no .. 82-471 P, dated August 22, 1982. Sadigh, K., Egan, J., and Youngs, R., 1987, Predictive ground motion equations reported in Joyner, W.B., and Soore, D.M., 1988, 111'v1easurement, characterization, and · prediction of strong ground motion,11 in Earthquake Engineering and Soil Dynamics II, Recent Advances in Ground Motion Evaluation, Von Thun, J.L., ed.: American Society of Civil Enginee~s Geotechnical Special Publication No. 20, pp. 43-102. Treiman, J.A., 1993, The Rose Canyon fault zone, ·southern California: California Division of Mines and Geology, Open File report OFR 93-02. __ -, 1991, Rose Canyon fault zorie, San Diego county, California: California division of Mines and Geology, _ fault Evaluation Report FER-216, July 1 o, revised January 25, 1991, 14p. Weber, F.H.;-1982, Geologic map of north-central coastal area of San Diego County, California showing recentslope failures and pre-development landslides: California Department of Conservati~n, Division of Mines and Geology, OFR 82-12 LA.· Wilson, K.L., 1972, Eocene and related ge9logy of a portion of the San Luis Rey and Encinltas quadrangies, San Diego County, California: unpublished masters thesis, University of California, Riverside. Mr. Lance Johannsen File:e:\wp9\4300\4340a.pg~ ·. GeoSoils, lne. · Appendix A Page2 '.. 't.' '~ .. )J -: • -~ .. ,>" (~· " .. ~ -._,., .. ~ :;_:l .. :,-t ':.:/=_<11..·.·:_,., , ll :-:;,:-,.,.-~ • .-,,_\ \ • I _:.~ ·,; ~-:::, ~ . ''• .. -~.{ ..... ~-:. ,, . / , ' .. ~ :',; >,·,'~'/, ',• . ·,~· ",_ ' ' ;} ; , I •. .' , • '.-. ;,< , . .:-\ .A<,_ '" ")''"': ,..o 'I > Ge·oSoils, Inc. PROJECT: LANCE JOHANNSEN . 5400 Block of Carlsbad_Blvd. Sample ;I ~ ~'6 Cl) 0 :!:: C. t -~i c- .><: ~ OE :::> -C,c ~ Gl :i C ._ Cl)·>, Q al ;::,~ ii'i . ::) (/) Cl SM .SM 5 , 5400 Block of Carlsbad Blvd. BORING LOG W.O. 4340-A-SC BORING B-1 SHEET 1 OF_1_ DATE EXCAVATED 5-6-04 SAMPLE METHOD: _H_A_N_D_A_U_G_E_R ______________ _ .""(".· .:..r-..' -~·. :.~.·1 -~-· -~· '.,_i-:,.', -~-· -~· . . .......,.._ ............. . :..,:...· -~-. . ""'("".· ,:....,-:...· -~·: :0:-. ""·. -~·-1 -~·. ,Y"'",' .:...,..:...· ·,.;,-:,,·. _'-("'"_· .:..,:,.,· ' '-:,Y;-,' • . . :,, .. :. Standard Penetration Test 'SJ. Groundwater Undisturbed, Ring Sample Description of Material . COLLUVIUM/TOPSOIL: @ 0-½' SIL TY SAND, light brown, dry, loose; porous. TERRACE DEPOSITS: @ ½-4' SIL TY SAND, orange brown, dry to damp, medium dense to dense w/depth. Total Depth = 4' No Groundwater/Caving Encountered Backfilled 5-6-2004 GeoSoils, Inc. PLATE B-1 - 5- - ,_ - GeoSoils, Inc. PROJECT: LANCE JOHANNSEN . 5400 Block of Carlsbad Blvd, Sample ~ _o· ~] Cl) [ Ill . :::i· Cl) SM SM 5400 Block of Carlsbad Blvd. ' . BORING LOG BORING B-2 DATE EXCAVATED W. 0. 4340-A-SC SHEET_1_ OF_1_ 5-6-04 SAMPLEMETHOD: _H_A_N_D_A_U_G_E_R ______________ _ .'-'('.· -~-· -~·. ·..;..:..·. ''""·' '':'1":'". ·.;.,,:,.·, ,"'(',· _ _,..._. ·~·: ·..;..:..· . ........... -~-: -~-- ."-(",' -~-- ·,.;,-:,.·. :0:-,:...,.,-...· -~-. . . ._. Standard Penetration Test "5l.-Groundwater Undisturbed, Ring Sample Description of Material COLLUVIUM/TOPSOIL: @ 0-1' SIL TY SAND, light brown to reddish brown, dry, loose; porous. TERRACE DEPOSITS: @ 1-3' SILTY SAND, orange brown, dry to damp, medium dense to dense w/depth. Total Depth= 3' No Groundwater/Caving Encountered Backfilled 5-6-2004 / GeoSoils, Inc. PLATE B-2 GeoSoils, lhc. PROJECT: LANCE JOHANNSEN 5400 Block of Carlsbad Blvd. ·sampl~ ·- E E ~'6 en o ~ C. .!!l~ c:-§. "' :J .>c: 3: (.) .a -0,c en [ ~ Q) -:3 C: .... 0 Cl CJ.l :J.;:! ii:i :J Cl) Cl SM SM 7 - - 5- - - - 5400 Block of Carlsbad Blvd. C: 0 e .a m Cl) BORING LOG BORING B-3 DATE EXCAVATED W.O. __ 4_3_4_0-_A_-S_C __ SHEET_1_ OF_1_ 5-6-04 $AMPLE METHOD: _H_A_N_D_A_U_G_E_R ______________ _ ,"("'.· ,;,,,.r.,· :;._.,.:...: -~--.:..r-.· -~-. ·0:,- 1.:..i':· :;.,,:.., . ....;:-·. ;'-(' .. ' .:...,... .. :0·_.-·0:-·-,,:...,,,..· -~--..:,n.· . . :..r-.· -~-~ ·...;,-,.·. .l..f'." 0-: ·0·, "'-:'; . . -:...r-.· ·:,.:,:-·. ·..:.,.:·. Standard Penetration Test ¥ Groundwater Undisturbed, Ring Sample Description of Material COLLUVIUMITOPSOIL: @ 0-½' SIL TY SAND, light brown, dry, loose; porous. TERRACE DEPOSITS: @ ½-4' SIL TY SAND, orange brown, dry to moist, medium dense to dense. _Total Depth= 4' No ~roundwater/Caving Encountered Backfilled 5-6-2004 GeoSoils, Inc. PLATE B-3 GeoSoils, Inc. PROJECT: LANCE JOHANNSEN 5400,819ck of Carlsbad Blvd. Sample --~'ff ~ 5-1 en o ~ C. e :[ ch "ti c:-.a .x ·-Q) (.) .Q ::> .!!! °O.Q en E ~ Cl) :l C: ... 0 0 Ill ::> .a ai ::> ~ 0 :E SM SM - - 5- - - - - 5400 Block of Carlsbad Blvd. BORING LOG BORING 8-4 DATE EXCAVATED W.O. 4340-A-SC SHEET_1_ OF_1_ 5-6-04 , SAMPLE METHOD: _H_A_N_D_A_U_G_E_R ______________ _ ·.~.· ,:...,,-,· ':--"':"". .'-("'.· .:...,:...· ':--"':"', . 0:-. ·'--"·' --~-: ·...r.--·, .:...r--.· 10.·: ·...;,,:-·. . "'-{"' ~. -~-- ':-Y:"', :0:• ,:...,-,,.· -~·. ·....,r,-1, .:....r-.· .:....,.:...· . : . ·:,,.:r.,-·. ,'-(°",' .·:...,:...· ':-J":"'. -~-- Standard Penetration Test :l Groundwater 'Undisturbed, Ring Sample Description of Material COLLUVIUM/TOPSOIL: @0-½' SILTY SAND, light brown, dry, loose; porous. TERRACE DEPOSITS: @ ½-4' SIL TY SAND, orange brown, dry to moist, medium dense to dense w/depth . Total Depth= 4' No Groundwater/Caving Encountered Backfilled 5-6-2004 GeoSoils, Inc. PLATE B-4 · ..... : .,,. I... ro Q) >---· z -Cl) ..... C Q) > w ..... 0 I... Q) .c E :::, z Q) > +:i ro :::s E E :::, (.) EARTHQUAKE·RECURRENCE CURVE 100 10 1. .1 .01 .001 Johannsen ~ 1\ r ' '· ,> . " ' .. '-. :1 --' ----......... l ........ ...... ~ --..... ; 0 . . .. " ; I . I I I I I I I I i I I I I 11 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I . . ' •>' 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 · 7.5 8.0 8.5 9.0 Magnitude (M) -W .0. 4340-A-SC Plate C-1 L -,""---~-- . . - RETURN PERIOD vs. ACCELERATION =e, 9 ~ c,., ~ o. I )> I u, O· 100000 ..-... ·Cl) s.... ~ 100010 ..__.. ·"'C 0 ·-s.... a, Cl. C 1000 s.... ::J +-' a, ~ 100 ,::, iii' .... CD 0 I I\) CAMP~ & _BOZ. (1 __ 997 Rev.) SR 1 ,,_ / -.. .-/ / .. '/' / V ---., / j~ :/ ' -. / -' _, _. _., , . _/ / / V --- ~ / ./ . /' /' / , , I - I I I I I I I I I I I I -I I I I I I I I I I I I I 0.00 0.25 0.50 0.75 1.00 1.25 1.50 , Acceleration (Q) · -PROBABILITY OF EXCEEDANCE CAMP. & B_OZ. (1997 Rev.) SR 1 I • ·1 I A I 25~ra 50yra I.• I I T I 75 rs 100 rs 1-00 --------.--~---r-----.-------.--..-----, 90 --fffi---t---t---"--t-"---+---J:----+---1 ~ 80 ----------------. ?f2. .._..._ >, 70 -,-+-_ ----'--,----,+-,-----t------t----i-------t--1 ...., ·--..c 60 _ _...._ ____________________ _ co ..c e · so -+-t--+,-t-l~~---1----+-------t----+------ir----i a,; , ~ 40 .....,_. -------...a.+--------t------t---t----+-,--i C: ~ -30 -------'--~----------©· . ~ 20· -~~------------->< UJ 10 ~-----~~~---t-~--r--i---i--; 0 -t=LJ_j_W-JLLJ....c?:~ ....... ...u...w....1.....1&..-1.-LLLJ_.wJ 0.00 0.25 0.50 0.75 1.00 1.25 t.50 Acceleration· (Q) . W.0.4340-A-SC Plate C-3 t-\ ~ !~:./\(;( >-:.: . ;.,~·' \ . :' "• --. (',>;Int?t}·;._,, ,,_,. ;.:':t/\::itt .. .... • ,_·.·_;_:(,_.:_-_-_·:,:: ___ ;: __ '..~~_-: ·.;':,' .. :_:,,;·:·;·' __ ;-._,_:_~_-.·_:_:_:_-_;:~-;:>: ;' ·': ·:i,: >.\:\ .:, --~)'f\ :::._/~ .7 > •.. '-. ·>. ·. ,:.\ :?-,/·::.-.-'~{:._/_)'i':'\. '.:·/ ·: . . _--.,.t __ :,:_-_--_: __ -__ :: .. _,.·_:·,·:_:_:·_· ___ ,_-.;_.·:_~_._, __ -:::_;._t_-_.-/, .. _.~----_· __ :_:_:_·::··_:_·_-_'._: __ ·_:._!_--.·\\/:>I.~~"-·-~·; ____ ·- -: . '' -.. :-'·_,,· -·· --:_,:\'_.: __ y_::_•_\:_:_~\s':_;~{~ • ·: ;(·::: ~-:.:·,:· ~· ~ ·.~· ~ ~ _1: • 1 ' ·,.", ___ ':_-··,.·:,: '.-;_-,r'.i·_:_.·_:;:·_ ... '-~_::.;_.)~_.·.:;.::·_;;,~"-_//_:~_L-~\~\):' .. :· -\!'.[:<\ ::,--t:: ... :\/:; -,;. -".,,·::_:_:_., .. ___ ,. ·._ \.\?-:._!. ·.1?PC:;.· -~·:~~·?:-~<[ \: ... ,; ~· ~ -r" -',-, ~. :·:,-(•, __ .. ·, ~~::;(::.·-~ ·::.'\:.i.~(.\~:! ···1:\?L:{.'.\\s. /,,,,....... -~·.t··· .;:'- ' .' . ·~., · '?GEwERAv EARr,HWOfikANii6Mli>lfii6'. Goi~EtiM~S · ; .;1: .{?/ . :: ,, ' • ~ •., • • ~ • 1-r •' :.• J: .. ,:,~·:~t~--~ •\. ._._;;/,:,-.-· '/•: .' -..,~·-· ...... , ;~1· · ... -~}~-, -1 • , _;, .r, ,-:-· ·:-= :::::/:'.·· .. ·:. ·:-_,,:. ,. ;_ r ~~<:.-D-_-l·_:,.:::)( ·_·, ·, _t.:\.-\-.:::·:~::_, ___ 3}--- 1· .. , ", .-.,.. ,,' • ·,. -r , ., .:,. ,• ,~ •• ',._ --:~,,.~~~-.-.·.--.. · .~;.-.,. .... ,.:-'; .: -, -~·°',·· ; ... ~· .. ~-··l,·,1 • '. ·-' . -., > ..... '.,·i:',' '', ,, -. . . ::. ... ' . , . . . :_,_: ,'..,·.'. :_., __ -~----,,·.·.·,·.. . -\ .. ~;~-~ ~ ' .. ~~.:--~:··.-~·-·:;~:,~--ti:'.:.: ... · -~~· " •• -'1'<"{ -... • ;~ ~: -_:} '.J', ~, :..,•;;; GENERAL EARTHWORK AND GRADING GUIDELINES General · These guidelines present general procedures and requirements for earthwork arid grading as shown on· the· approved grading plans, including preparation of areas to filled, placement of fill, -installation of subdrains and excavations. The recommendations · contained in the geotechnical report are part of the earthwork and grading guidelines and would supercede the provisions contained hereafter in the case of conflict. Evaluations performed by the consultant cturing· the course of grading may result in new recommendations which could supersede these guidelines or the recommendations contained in the geotechnical report. · The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions of the. project plans and specifications.· The project soil engineer and engineering geologist (geotechnical consultant) 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 consl!ltant (soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations of the geo~echnical report, the approved grading plans, and applicable grading codes and ordinances. · · The geotect,nical, consultant-should provide testing and observation so that determination may be made that the 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 clean-outs, prepared ground to receive fill, key excavations, and subdrains should be observed and documented by the project engineering geologist and/or soil engineer prior to placing.and fill. It is the contractors1s· responsibility to notify the engineering geologist · and soil _engineer when such areas are ready for observation. Laboratory and Field Tests Maximum dry density tests to determine the degree of compactiqn should be performed in accordance with American Standard Testing Materials test method ASTM designation D-1557-78._Random field compaction tests should be performed in accordance with test method ASTM desig_nation D-1556-82, D-2937 or D-2922 and D-3017, at intervals of approximately 2 feet of fill height or every 100 cubic yards of fill placed. These criteria GeoSoils, Ine. would vary depending on the soii conditions and the size of the project. The location and frequency of testing would be at the discretion·ot the geotechnical consultant. Contractor•s Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted -by the contractor, with observation by geotechnical consultants 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 soil engineer, and to place, spread, moisture condition, mix and co·mpact the fill in accordance with the recommenda1ions of the soil engineer. The contractor should also remove all major non- earth material considered unsatisfactory by the soil engineer. It is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the earthwork in accordance with applicable grading guidelines, codes or agency ordinances, and approved grading plans. Sufficient watering apparatus and compaction equipment should be provided by the contractor with due consideration for the fill material, rate of placement, and clima,tic 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, an_d the contractor is expected to rectify the conditions, and if nec.essary, stop work until conditions are satisfactory. During construction, the contractor shall properly grade all surfaces to maintain good drainage and pr.event ponding of water. lhe 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. Existing fill, soil, alluvium, colluvium, or rock materials · determined by the soil engineer or engineering geologist as being unsuitable in-place should be removed prior to fill placement. Depending upon the soil conditions, these mate.rials may b_e reu_sed as compacted fills. · Any materials incorporated as part of the compacted fills should be approved by the soil engineer. Any underground structures such as cesspobls, 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 soil engineer. Soft, dry, spongy, highly fractured,. or :otherwise unsuitable ground extending to such a depth that surface proc_essing cannot aqequately improve the condition should be overexcavated down to "Mr. Lance Johannsen File:e:\wp9\4300\4340a.pge GeoSoils, lne. . . Appendix D Page2 firm ground and approved by the soil engineer 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 to a minimum depth of 6 inches or· as directed by the soil engineer. After the scarified ground is brought to optimum moisture content or greater and mixed, the materials should be compacted as specified herein. If the scarified zone is grater that 6 inches in depth, it may be necessaryto remove the excess and place the material in lifts restricted to about s·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 soils engineer and/or engin·eering geologist. Scarification, disc harrowing, or other acceptable form 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, hollow, hummocks, 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), the ground should be stepped or benched. The lowest bench, which will act as a key, . should be a ~lnin:ium of 1 ~ feet wide and should be at least 2 feet deep into firm material, and approved by the soil engineer and/or engineering geologist. In fill over cut slope conditions, the recommended minimum width of the lowest 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 Soil Engineer, the minimum width of fill keys should be approximately equal to ½ the height of the slope. Standard benching is gen_erally 4 feet (minimum) vertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials, although it is understood that the-verticaJ height of the bench may exceed 4 feet. Pre-stripping may be considered for uns~itable materials i.n _excess .of 4 feet in thickness. All areas to-receive fill, including processed areas, removal areas, and the toe of fill benches should be observed and approved by the soil engineer and/or engineering _ geologist prior to placement offill. Fills may then be properly placed and compacted until design grades (elevations) are attained. · COMPACTED FILLS ~Any earth materials imported or excavated on the property may be utilized in the fill provided that each material has been determined to be suitable by the soil engineer. These materials should be free of roots, tree branches, other organic matter or other Mr. Lance Johannsen File:e:\wp9\4300\4340a.pge GeoSoils, Jne. Appendix D Page3 ------------------------ deleterious materials. All unsuitable materials should be removed from the fill as directed by the soil engineer. Soils of poor gradation, undesirable expansion potential, or substandard strengtt, charaQteristics may be designated by the consultant as unsuitable and may require blending with other-soils to serve as a satisfactory fill material. Fill' materials· derived from benching operations should be dispersed throughout the fill area and blended with ·other bedrock derived 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 dim~nsion 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 soil engineer. Oversized material shouid be taken Off-site or placed in accordance with recommendations of the soil engineer in areas designated as suitable for rock disposal. Oversized material should not be placed within 1 0 feet vertically of finish grade (elevation) or within 20 feet horizontally of slope faces. To facilitate future trenching,· rock should not be placed within.the range of foundation excavations, future utilities, or underground construction unless specifically approved by the soil engineer and/or the developers 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 soil engineer to determine its physical properties. If any material other than that previously tested is encountered during grading, an appropriate analysis of this material should be conducted by the soil engineer as soon as possible. Approved fill material should be placed in areas prepared to receive fill in near horizontal layers that when compacted should hot exceed 6 inches in thickness. The soil engine~r 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 Qf material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mixed, and wet fill layers should be aerated by ·scarification or should be blended with drier material. Moisture condition, 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 maximum density as determined by ASTM test designation, D-1557-78, or as otherwise recommended by the soil engineer. 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. Mr. Lance Johannsen File:e:\wp9\4300\4340a.pge GeoSoils, lne. Appendix D Page4 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 of fill has been tested and found to meet the density and moisture requirements, and is approved by the soil engineer. · _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 determination offill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed stee.per than 2: 1 (horizontal to vertical), specific material types, a higher minimum relative compaction, · and . special grading procedures, may be recommended.· If an alternative to over-building and cutting back the compacted fill slopes is selected, theA 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 heayy 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 9f 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~rofling. 3. Field compaction tests will be made jn the outer (hdrizontal) 2 to 8 feet of the slope at appropriate vertical intervals, subsequent to compaction operations. 4. After completion of the slope,· the slope face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compaction to-near the slope face. Subsequent to testing to verify compaction, the slopes should be grid-rolled to achieve compaction to the slope face. Final testing should be used to confirm compaction after grid_rolling. 5.. Where testing indicates less than 9-dequate compaction, the contractor will be responsible to rip, water, mix and re-compact the slope material as necessary to achieve c_ompaction. Additional testing should be performed to verify compaction. Mr. Lance Johannsen · File:e:\wp9\4300\4340a.pge OeoSoils, lne. Appendix D Page5 6. Erosion control and drainage devices should be designed by the project civil _engineer in compliance with ordinances of the controlling governmental agencies, and/or in accordance with the recomme_ndation of the soil engineer or engineering .geologist. 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 should not be changed· or modified without ·approval of the geotechnical consultant. The soil engineer and/or engineering geologist may recommend and direct changes . in subdrain line, grade and drain material in the field, pending exposed conditions. The location of constructed subdrains should be recorded by the project civil engineer. EXCAVATIONS _Excavations and cut slopes should be examined during grading by the engineering · geologist. If directed by the eng_ineering geologist, further excavations or overexcavation and re-filling 9f cut areas. should be performed and/or remedial grading of 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 engineering geologist prior to placement of materials for construction of the fill portion of the slope. The engineering geologist should-observe all cut slopes and should be-notified by the contractor when cut slopes are started. If, during the course of grading., unforeseen adverse or potential adverse geologic conditions are encountered, the engineering geologist and soil engineer should investigate, evaluate and make recommendations to treat these problems. The need for-cut slope buttressing or stabilizing should be based on in-grading eval~ation by the: engineerin§ geologist, whether anticipated or not. Unless otherwise specified in soil and geological rep.arts, 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 contractors 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 soil engineer or engineering geologist. Mr. Lance Johannsen File:e:\wp9\4300\4340a.pge GeoSoils, Ine. Appendix D Page6 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 filled areas are graded in accordance with the app(dved project specifications. After completion of grading and after the soil engineer and engineering geologist have finished their observations of the work, final reports-should be submitted subjectto review by the controlling governmental agencies; No further excavation or filling should be undertaken without prior notification of the soil engineer and/or engineering geologist. ,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 GeoSoils, Inc. (GSI) getting the job done s~fely 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 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. · lh 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 contractors regularly scheduled and documented safety meetings. -Safety Vests: Safety Flags: Mr. Lance Johannsen File:e:\wp9\4300\4340a.pge Safety vests are provided for and are to be worn by GSI personnel at all times when they are working in the field. Two safety 'flags are provided to GSI field technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits. GeoSoils, Ine. Appendix D Page7 -- . , Flashing Lights: All vehicles stationary in the_grading area shall use rotating or flashing amber beacon, 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 ~vent that the contractor's 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; Orientation and Clearance Tlietechnician is responsible for selecting test pit locations. A primary concern should be the technicians1s safety. Efforts will be made to coordinate locations with the grading contractors authorized representative, and to select locations following or behind the establi~hed traffic pattern, preferably outside of current traffic. The contractors authorized representative (dump man, operator, supervisor, grade checker, etc.) should direct excavation of the pit and safety during the test period. Of paramount concern should be the soil technicians safety and ob~aining eriough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away form 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 decreased test results. 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 contractor's representative should effectively keep all equipment at a safe operation 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, well 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 ~ccess and site safety. In the event that the technicians safety i$ jeopardized or compromised as a result of the contractors failure to comply with any of the above, the technician is required, by company policy, to immediately withdraw and -notify his/her supervisor. The grading contractors representative will eventually be contac~ed in an effort to effect a solution. However, in the Mr. Lance Johannsen File:e:\wp9\4300\4340a.pge GeoSoils, Ine. Appendix D Page a interim, no further testing will be performed until the._situation is rectified. Any fill place 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 brings this to his/her attention and notify this office. Effective communication and coordination between the contractors representative and the soils technician rs strongly encouraged in order to implement the above safety pl·an. 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 to enter any excavation or vertical cut which: 1) 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) d!splays 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 an~ local standards. Our personnel are directed not to enter any trench by being lowered or "riding· down11 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 contractors representative will eventually be contacted in an effort to effect a solution. All backfill not tested due to safety concerns or other reasons could be. subject to reprocessing and/or removal · ' If 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 awrier/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 authorities. Mr. Lance Johannsen File:e:\wp9\4300\4340a.pge .GeoSoils, Ine. Appendix D Page9 --· . TEST PIT SAFETY DIAGRAM 50 FEET SPOIL P1LE SlOE VIEW ( NOT TO SCALE ) TOP VIEW 100 FEET ... ttl u. .o . In APPROXIMAlE !EN$ / CF iEST PIT ... ttl LL 0 In 50 FEET VEHICLE FLAG {. NOT TO SCALE ) PLATE EG-16