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Home My WebLink AboutCDP 14-07; PRYOR RESIDENCE; UPDATED GEOTECHNICAL LETTER & PRELIMINARY GEOTECH INVESTIGATION; 2014-08-06Construction Testing & Engineering, Inc. Inspection I Testing I Geotechnical I Environmental & Construction Engineering I Civil Engineeng I Surveying CTE Project No. 10-12145G Mr. Jeff Pryor 5243 Shore Drive Via Email: jeff2pryorproducts.com Carlsbad, California 92008 Subject: Update Geotechnical Letter - Response to City Review Comments Proposed Improvements to Pryor Residence 5243 Shore Drive Carlsbad, California 92008 References: First Review for CDP 14-07 - Pryor Residence City of Carlsbad Coastal Development Permit Application No CDP 14-07 Dated May 12, 2014 Preliminary Geotechnical Investigation Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California CTE Job No. 10-8356G, Dated June 2, 2006 (Attached) Mr. Pryor: As requested and required, CTE has provided the following update geotechnical letter which includes responses to the City of Carlsbad's plan review comments dated May 12, 2014. Our work has been performed in general accordance with our agreement (CTE Proposal No. G- 3112B, revised July 22, 2014). Once available, CTE should perform a detailed review of the project grading and foundations plans. 1.0 GENERAL PROPOSED PROJECT INFORMATION Proposed site development at this time consists of the construction of a new two-story, wood- frame residential building and associated improvements. Associated improvements may include minor parking and drive areas, utilities, and landscaping areas. Based on our original 2006 investigation, soils beneath the site consist of topsoil/fill soils overlying Quaternary Terrace Deposits. Site conditions at the time of the original CTE investigation appear relatively unchanged and the CTE Geotechnical Report (2006) referenced above is still considered valid, except for the portions specifically modified in this document. 1441 Montiel Road Suite 115 1 Escondido CA 92026 I Ph (760) 746-4955 J Fax(760)746-9806 I www.c.t,e-inc.net I I I I I I Update Geotechnical Letter - Response to City Review Comments Page 2 I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California I August 61 2014 CTEJobNo.: 10-12145G 2.0 RESPONSE TO CITY OF CARLSBAD REVIEW COMMENTS Planning: Comment 4: As requested, the referenced 2006 CTE report is attached herewith. The referenced report (2006) is considered valid without revision, except as amended or detailed herein. Updates and modifications to the project plans for the proposed residential building and associated improvements have been made such that the proposed improvements to the stair access to the beach will not occur. As a result, the proposed improvements should not modify or adversely impact the stability of the bluff. Additional information regarding the bluff conditions are presented in Section 4.0 of this document and in the referenced report. Engineering: Comment 7: As stated, the site conditions have not been appreciably modified since issuance of our previous report (2006) and the conclusions and recommendations provided therein remain appropriate without modification, except as specifically provided herein. Where insufficient distance is present adjacent to the proposed building limits, it is acceptable to have less than five feet of positive drainage away from the improvements. I However, proposed grades and/or improvements should ensure positive drainage away from the building and away from the top of the adjacent bluff, to the degree feasible, and in no instance should surface drainage flow toward the building structure or toward/over I the top of bluff. We understand that the access ramp extending between the building pad and beach is no longer proposed in the current scope of development. In addition, we understand that no I modifications to the beach or to the water side of the top of bluff are proposed at this time. In addition, proper Storm Water Pollution Prevention Plan (SWPPP), maintaining positive drainage away from top of bluff, is anticipated to provide adequate erosion control during project construction. - 3.0 UPDATE SEISMIC PARAMETERS The seismic parameter evaluation provided in the original report (CTE 2006) was not performed in accordance with the current 2013 CBC and ASTM 7-10 standards. Therefore, we have performed an updated seismic evaluation based on the peak ground acceleration determined in accordance with ASCE 7-10 and 2013 CBC requirements. The following table presents the seismic coeficients that are anticipated to be suitable for use during project design and construction: I I \\Esc_server\projects\10- 12 145G\Ltr_Response to City Comms.doc I Update Geotechnical Letter - Response to City Review Comments Page 3 I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California - August 6,2014 CTEJobNo.: 10-12145G I\13l l I SLISi\IIC (il<Ol f N ) M( )1 l()N VA LL IS CBC PARAMETER CBC REFERENCE (2013) 2013 Site Class D ASCE 7, Chapter 20 Mapped Spectral Response 1.177g Figure 1613.3.1(1) Acceleration Parameter, Mapped Spectral Response 0.453g Figure 1613.3.1(2) Acceleration Parameter, S, Seismic Coefficient, Fa 1.029 Table 1613.3.3(l) Seismic Coefficient, F 1.547 Table 1613.3.3(2) MCE Spectral Response Acceleration Parameter, SMS 1.211g Section 1613.5.3 MCE Spectral Response Acceleration Parameter, 5M1 0.700g Section 16 13.3.3 Design Spectral Response Acceleration, Parameter SDS 0.808g Section 1613.3.4 Design Spectral Response 0.467g Section 1613.3.4 Acceleration, Parameter SDI 4.0 ADDITIONAL BLUFF RECOMMENDATIONS As stated in referenced original geotechnical report (CTE 2006), section 5.4.9, due to the current moderate layback of the bluff slope, the site is not anticipated to be significantly impacted by the widespread coastal bluff erosion that typically results in relatively fast-paced coastline collapse and/or recession in the northern areas of San Diego County. The toe of bluff has been protected from wave erosion by the placement of shotcrete materials that appear to provide significant additional ocean wave protection to the site, especially during significant storm and/or associated storm-surge. Although the construction information for this shotcrete wall is not available, it appears to be performing well and remains structurally intact. Nevertheless, erosion of all coastal areas and shoreline retreat is inevitable, especially over extended periods of time. The bluff slope may also undergo surficial erosion and sloughing over an extended period of time. If excessive surficial slough does occur over time, it may become necessary to replace the bluff slope sand. \\Esc_server\projects\10-I2145G\Ltr Response to City Comms.doc Update Geotechnical Letter - Response to City Review Comments Page 4 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California August 6.2014 CTEJobNo.: 10-12145G 5.0 LIMITATIONS CTE should review the project grading and foundation plans as they become available. The recommendations provided in this report are based on the anticipated construction and the subsurface conditions found in the previous explorations. The shallow interpolated subsurface conditions should be checked in the field during construction to verify that conditions are as anticipated. I Recommendations provided in this report are based on the understanding and assumption that CTE will provide the observation and testing services for the project. All earthworks should be observed and tested to verify that grading activity has been performed according to the I recommendations contained within our reports. The project engineer should evaluate all footing trenches before reinforcing steel placement. I The evaluation and geotechnical analysis presented in our reports have been conducted according to current engineering practice and the standard of care exercised by reputable geotechnical consultants performing similar tasks in this area, and in accordance with our limited approved I scope of services. No warranty, expressed or implied, is made regarding the conclusions, recommendations and opinions expressed in this report. Variations may exist and conditions not observed or described in this report may be encountered during construction. I We appreciate the opportunity to be of service on this project. Should you have any questions, please contact our office. Sincerely, .I CONSTRUCTION TESTING AND ENGINEERING, INC. i Dan T. Math, GE# 2665 Martin E. Siem, CEG# 2311 Principal Engineer T. Certified Engineering Geologist Z3 6 No-2665 T OF CA GEOLOGIST Attachment 1: Up. 6/30/16 OF Preliminary Geotechmcal Investigation I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California CTE Job No. 10-8356G, Dated June 2, 2006 I \\Esc_server\projects\10- 12 145G\Ltr_Response to City Comms.doc ATTACHMENT 1 PRELIMINARY GEOTECHNICAL INVESTIGATION I PROPOSED IMPROVEMENTS TO PRYOR RESIDENCE 5243 SHORE DRIVE, CARLSBAD, CALIFORNIA CTE JOB NO. 10-8356G, DATED JUNE 2, 2006 1 I, CONSTRUCTION TESTING & ENGINEERING, INC. 1441 M.ONTIEt RUAX, SUITE 115 1 ESCONOIDO, CA 92026 1760.746.4955 1 FAX 760;1489806 PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED IMPROVEMENTS TO PRYOR RESIDENCE 5243 SHORE DRIVE CARLSBAD, CALIFORNIA PREPARED FOR: MR. JEFF PRYOR 5243 SHORE DRIVE CARLSBAD, CALIFORNIA, 92008 I1EiDi:Y CONSTRUCTION TESTING & ENGINEERING, INC. 1441 MONTIEL ROAD, SUITE 115 ESCONDIDO, CALIFORNIA 92026 CTE JOB NO. 10-8356G JUNE 2, 2006 GEGTECHNICAI. I ENVIRONMENTAL J CONSTRUCTION INSPECTION AND TESTING I CIVIL ENGINEERING I SURVEYING TABLE OF CONTENTS Section Page 1.0 EXECUTIVE SUMMARY .......................................................................................................1 2.0 INTRODUCTION AND SCOPE OF SERVICES ....................................................................2 2.1 Introduction....................................................................................................................2 2.2 Scope of Services...........................................................................................................2 3.0 BACKGROUND INFORMATION ..........................................................................................2 3.1 Site Location and Description........................................................................................2 3.2 Proposed Improvements..................................................................................................3 4.0 FIELD AND, LABORATORY INVESTIGATION ..................................................................3 4.1 Field Investigations........................................................................................................3 4.2 Laboratory Investigation.................................................................................................4 5.0 GEOLOGY................................................................................................................................4 5.1 General Physiographic Setting.......................................................................................4 5.2 Geologic Conditions ......................................................................................................4 5.2.1 Topsoil/Fill Soils...................................................................................................5 5.2.2 Quaternary Terrace Deposits .................................................................................5 5.3 Groundwater Conditions................................................................................................5 5.4 Geologic Hazards...........................................................................................................6 5.4.1 Local and Regional Faulting.................................................................................6 5.4.2 Site Near Source Factors and Seismic Coefficients .............................................. 6 5.4.3 Tsunami and Seiche Damage................................................................................7 5.4.4 Landsliding or Rocksliding...................................................................................7 5.4.5 Compressible and Expansive Soils.......................................................................7 5.4.6 Liquefaction Evaluation........................................................................................8 5.4.7 Seismic Settlement Evaluation.............................................................................8 5.4.8 Corrosive Soils......................................................................................................9 5.4.9 Bluff Erosion and Setbacks...................................................................................9 6.0 CONCLUSIONS AND RECOMMENDATIONS ..................................................................10 6.1 General ......................................................................................................................... 10 6.2 Site Preparation............................................................................................................10 6.2.1 General ................................................................................................................. 10 6.2.2 Site Excavations..................................................................................................11 6.2.3 Fill Placement and Compaction..........................................................................12 6.2.4 Fill Materials.......................................................................................................12 6.3 Temporary Construction Slopes ..................................................................................13 6.4 Foundations and Slab Recommendations....................................................................13 6.4.1 General................................................................................................................13 6.4.2 Spread Foundations and Slabs-on-Grade ............................................................ 14 6.4.3 Foundation Settlement........................................................................................15 6.5 Lateral Resistance and Earth Pressures........................................................................15 6.6 Exterior Flatwork.........................................................................................................16 6.7 Vehicular Pavements ...................................................................................................17 6.8 Drainage.......................................................................................................................18 6.9 Slopes...........................................................................................................................18 6. 10 Construction Observation . 6.11 Plan Review........................................................................................................ 7.0 LIMITATIONS OF INVESTIGATION .......................................................................... FIGURES FIGURE 1 INDEX MAP FIGURE 2 EXPLORATION LOCATION I GEOLOGIC MAP FIGURE 3 CROSS SECTION A-A' FEW 9:0103140 APPENDIX A REFERENCES CITED APPENDIX B EXPLORATION LOGS APPENDIX C LABORATORY METHODS AND RESULTS APPENDIX D STANDARD SPECIFICATIONS FOR GRADING Preliminary Geotechnical Investigation Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 Page 1 CTE Job No. 10-8356G 1.0 EXECUTIVE SUMMARY I Our investigations were performed to provide site-specific geotechnical information for the construction of the proposed improvements to the Pryor Residence on the west side of Shore Drive, in Carlsbad, California. The proposed development is considered feasible from a geotechnical viewpoint provided that recommendations in our report are implemented during design and construction. Based on our observations and reference review, soils beneath the site consist of topsoil/fill soils I overlying Quaternary Terrace Deposits. Our explorations show that there is approximately four feet of topsoil/fill on the west side of the site and one foot of topsoil/fill on the east side of the site overlying Quaternary Terrace Deposits. Groundwater was not encountered at this site during our investigation. During seasonal weather changes, areas of local saturation may be encountered. However, from a review of preliminary I project plans, we do not anticipate that groundwater will affect the proposed development, provided appropriate surface drainage is maintained. I - Based on the geologic findings and referenced review, no active surface faults are known to exist at the site. In general, the results of our review indicate that the proposed project can be constructed as planned provided the recommendations presented in this report are followed. I I Preliminary Geotechnical Investigation Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 Page 2 CTE Job No. 10-8356G 2.0 INTRODUCTION AND SCOPE OF SERVICES 2.1 Introduction Construction Testing and Engineering, Incorporated ("CTE") has prepared this geotechnical engineering report for the proposed improvements to the Pryor Residence. The site is on the west side of Shore Drive, in Carlsbad, California. Figure 1 is a map showing the general location of the site. 2.2 Scope of Services Our scope of services included: Review of readily available geologic reports pertinent to the site and adjacent areas (Appendix A contains a list of cited references). Explorations to determine subsurface conditions to the depths influenced by the proposed construction. Laboratory testing of representative soil samples to provide data to evaluate the geotechnical design characteristics of the site foundation soils. Definition of the general geology and evaluation of potential geologic hazards at the site. Preparation of this report detailing the investigation performed and providing conclusions and geotechnical engineering recommendations for design and construction. 3.0 BACKGROUND INFORMATION 3.1 Site Location and Description The site is located on the west side of Shore Drive, approximately 0.5 mile west of the Interstate 5 Freeway. Figure 2 shows the approximate configuration of the site and existing improvements. The site is roughly rectangular in shape and slopes down slightly to the west. The site is situated at an elevation of approximately 40 feet above mean sea level (msl), overlooking the Pacific Ocean to the immediate west. A small patio exists at the rear of the house with a slope Preliminary Geotechnical Investigation Page 3 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G descending down approximately 35 feet to the beach below. As detailed further herein, the site and immediate vicinity do not appear to be significantly affected by typical bluff erosion. Land use near the site consists of residential properties. The north and south sides of the site are bound by existing residences, the west side by the Pacific Ocean, and the east side by Shore Drive and the residences along it. 3.2 Proposed Improvements We understand that the proposed development/project will include the demolition of most or all existing improvements and the subsequent construction of a new two-story, wood-frame residential building and associated improvements. Associated improvements may include parking and drive areas, utilities, and landscaping areas. We understand the proposed improvements will be located in the same general area of the existing improvements and will cover the majority of the site. 4.0 FIELD AND LABORATORY INVESTIGATION 4.1 Field Investigations Field investigations at this site, performed April 27, 2006, included site reconnaissance and excavation of two soil borings. Soils were logged and visually classified in the field by a geologist using the Unified Soil Classification System. The field descriptions have been modified, where appropriate, to reflect laboratory test results. Excavation logs including descriptions of the soil, in situ field-testing data, and supplementary laboratory data are included in Appendix B. Figure 2 is a map showing the approximate locations of the explorations conducted by this firm. Preliminary Geotechnical Investigation Page 4 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G 4.2 Laboratory Investigation Specific laboratory tests conducted for this investigation included: grain size analysis, In-Place Moisture and Density, Consolidation and Chemical Analysis. Test method descriptions and laboratory results are presented in Appendix C. 5.0 GEOLOGY 5.1 General Physio graphic Setting San Diego is located with the Peninsular Ranges physiographic province, which is characterized by its northwest-trending mountain ranges, intervening valleys, and predominantly northwest trending active regional faults. The San Diego Region can be further subdivided into the coastal plain area, a central mountain-valley area and the eastern mountain valley area. The site is located within the costal plain sub-province along the Carlsbad coastline. The costal plain sub- province ranges in elevation from approximately sea level to 1200 feet above mean sea level and is characterized by Cretaceous and Tertiary sedimentary deposits that onlap an eroded basement surface consisting of Jurassic and Cretaceous crystalline rocks. In addition, this area is characterized by uplifted marine terraces that roughly parallel the present day coastline. The terraces have been dissected by intermittent streams forming deep canyons in response to the on going uplift. Uplift has been accommodated primarily along northwest and subsidiary northeast trending faults associated with Rose Canyon Fault System. 5.2 Geologic Conditions Based on mapping compiled by Tan and Kennedy (1996), surface soils in the site vicinity consist of Quaternary Terrace Deposits and Tertiary Santiago Formation. Based on our explorations, surface and near surface soils consist of topsoil/fill soils overlying Quaternary Terrace Deposits. Preliminary Geotechnical Investigation Page 5 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G It is anticipated that units of the Tertiary Santiago Formation underlie the Terrace Deposits at depths beyond those explored. The soil descriptions below are based on qualitative and quantitative attributes of the soils at the site. 5.2.1 Topsoil/Fill Soils Fill soils were encountered in the boring at the rear of the residence (B-i) to a maximum depth of approximately four feet below existing grade. Fill soils appear to be relatively well compacted. These materials were observed to consist primarily of medium dense, slightly moist, brown to red brown, silty, fine-grained SAND, with old cobble-cement debris. Fills will require mitigative grading prior to construction of the proposed improvements as recommended herein. 5.2.2 Quaternary Terrace Deposits Quaternary terrace deposits were observed beneath site fill soils to the maximum depth explored. These materials generally consist of medium dense to very dense, slightly moist, orange to yellow brown poorly graded or silty, medium- to coarse-grained SAND. These native materials are suitable for support of the proposed improvements as recommended herein. 5.3 Groundwater Conditions Groundwater was not encountered during our explorations to the maximum depth of 20 fbg at the site. We anticipate groundwater is located at an approximate elevation of zero feet msl, and may vary with tidal fluctuations. Although groundwater levels may fluctuate, groundwater is not expected to affect the proposed improvements if proper drainage is maintained. I Preliminary Geotechnical Investigation Page 6 I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California I June 2, 2006 CTE Job No. 10-8356G 5.4 Geologic Hazards I From our investigation it appears that geologic hazards at the site are primarily limited to those I caused by violent shaking from earthquake generated ground motion waves. The potential for damage from displacement or fault movement beneath the proposed structures should be considered low. The site is not within a State of California-designated Alquist-Priolo Special Studies Zone for earthquake faults. 5.4.1 Local and Regional Faulting ' Based on our site reconnaissance, evidence from our explorations, and a review of appropriate geologic literature, it is our opinion that the site is not on known active fault traces. According to the California Division of Mines and Geology, a fault is active if it displays evidence of activity in the last 11,000 years (Hart and Bryant, 1997). The Rose Canyon Fault Zone, approximately five kilometers to the west, is the closest I known active fault (Jennings, 1987). Other principal active regional faults include: The Coronado Banks, San Jacinto, Palos Verdes, San Andreas, and Elsinore Faults. 5.4.2 Site Near Source Factors and Seismic Coefficients I In accordance with the 2001 California Building Code, Volume 2, Figure 16-2, the referenced site is located within seismic zone 4 and has a seismic zone factor of Z0.4. I The nearest active fault, the Rose Canyon Fault Zone, is approximately five kilometers to I the west and is considered a Type B seismic source. Based on the distance from the site to the Rose Canyon Fault Zone, near source factors of Nv=1.2 and Nal.O are appropriate. Based on the shallow subsurface explorations and our knowledge of the I H I Preliminary Geotechnical Investigation Page 7 I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G area, the site has a soil profile type of SD and seismic coefficients of C=0.77 and I I 5.4.3 Tsunami and Seiche Damage The potential for tsunami damage at the can not be precluded, based on the site's I elevation (approximately 35 to 40 feet above sea level) and distance from the ocean. However, according to McCullough (1985) the potential for 100 and 500 years tsunami I events is four and six feet. This suggests that there is a very low probability of site damage due to the elevation of the building pad of the site (approximately 41 feet above msl). Seismically induced seiche (oscillatory waves) damage is also considered unlikely I for the reasons stated above. I 5.4.4 Landsliding or Rocksliding According to Tan and Giffen (1995), the site area is generally susceptible to landsliding. However, we did not observe active landslides or rockslides at the site. Landslides have I not been mapped near the site area (Tan and Kennedy, 1996). We anticipate that the potential for landsliding or rocksliding to affect the site during its design life is I negligible. I 5.4.5 Compressible and Expansive Soils Based on geologic observation and laboratory testing of onsite soils, the fill materials generally exhibit low to moderate compressibility and low expansive characteristics (El I less than 30). Compressible fill materials will be mitigated via overexcavation and recompaction. Underlying native materials are generally non-compressible and non- I expansive. Furthermore, native materials do not appear to be subject to significant I I Preliminary Geotechnical Investigation Page 8 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G seismic settlement; therefore, these materials are considered suitable for support of proposed improvements. 5.4.6 Liquefaction Evaluation Liquefaction occurs when saturated fine-grained sands or silts lose their physical strength during earthquake-induced shaking and behave as a liquid. This is due to loss of point- to-point grain contact and transfer of normal stress to the pore water. Liquefaction potential varies with groundwater level, soil type, material gradation, relative density, and the intensity and duration of ground shaking. The potential for damage to the site from liquefaction of site soils is considered low. This is based on the depth to groundwater and the generally medium dense or better nature of underlying native soils in the area. 5.4.7 Seismic Settlement Evaluation Seismic settlement occurs when loose to medium dense granular soils densify during seismic events. We anticipate that topsoils and/or loose or soft surficial soils will be mitigated during site grading. The upper 10 to 15 feet of native materials at the site were generally found to be medium dense, but may experience very minor seismic settlement. Based on our evaluation, the building pad area of the site could experience considerably less than 0.5 inches of total settlement as a result of seismic settlement of dry sands. The recommended uniform layer of engineered fill beneath the site and the foundation recommendations herein will adequately mitigate adverse effects of differential Preliminary Geotechnical Investigation Page 9 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G settlement of deeper native soils in the unlikely event of a major earthquake in the immediate vicinity of the site. Therefore, in our opinion, the potential for seismic settlement resulting in damage to site improvements should be considered low. 5.4.8 Corrosive Soils Chemical tests were conducted from select soil samples to evaluate the soil corrosivitity. Based on the results the potential for severe corrosion of ferrious metals is indicated from the high chloride concentrations and low resistivity values of the analyzed soils. Sulfate concentrations indicate a low potential for corrosion of concrete. However, CTE does not practice corrosion engineering, and a corrosion specialist should be consulted if additional investigation and/or evaluation are deemed necessary by the project architect or structural engineer. 5.4.9 Bluff Erosion and Setbacks As previously indicated, due to the low site elevation (approximately 35 to 40 feet msl) and the current moderate layback of the bluff slope, the site is not anticipated to be significantly impacted by the widespread coastal bluff erosion that typically results in relatively fast-paced coastline collapse and/or recession in the northern areas of San Diego County. The toe of bluff has been protected from wave erosion by the placement of shotcrete materials which appears to provide significant additional ocean wave protection to the site, especially during significant storm and/or associated storm-surge. Although the construction information for this shotcrete wall is not available, it appears to be performing well and remains structurally intact. Nevertheless, erosion of all coastal areas and shoreline retreat is inevitable, especially over extended periods of time. Preliminary Geotechnical Investigation Page 10 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G Based on the information provided above, as well as our understanding of the proposed improvements, it is our opinion that proposed building improvements need not be excessively setback from the existing "top of bluff' location. However, foundations shall have adequate setback/embedment as recommended in the subsequent sections of this report. 6.0 CONCLUSIONS AND RECOMMENDATIONS 6.1 General We conclude that the proposed construction on the site is feasible from a geotechnical standpoint, provided the recommendations in this report are incorporated into the design and construction of the project. Based on our subsurface investigation and engineering analysis, the proposed improvements can be supported on spread foundations designed and constructed as recommended herein. However, preparatory site grading will be required. Specific recommendations for the design and construction of improvements at the subject site are included in the subsequent sections of this report. 6.2 Site Preparation 6.2.1 General The site should be cleared of any debris and other deleterious materials. In areas to receive engineered fill, structures or distress-sensitive improvements, expansive, surficial eroded, desiccated, burrowed, or otherwise loose or disturbed soils should be removed to I the depth of competent native material and to a minimum depth of four feet below I I I Preliminary Geotechnical Investigation Page 11 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G existing or proposed building pad elevations, whichever is deeper. Based on our onsite explorations, we anticipate uniform removals of four feet below existing grades will generally be adequate. However, localized areas of deeper removals may be required. In addition, any materials disturbed during demolition of existing site improvements shall be completely removed and replaced as engineered fill. The recommended removals shall also result in placement of a minimum 24 inches of engineered fill beneath all footings. However, all footings may also be deepened to bear entirely on native materials if the proposed grades make this treatment more viable. Organic and other deleterious materials not suitable for structural backfill should be disposed of offsite at a legal disposal site. Prior to placing any engineered fill, exposed subgrade shall be scarified, moisture conditioned to near optimum moisture content, and properly recompacted. General engineered fill shall be compacted to a minimum 90% relative compaction (per ASTM D 1557) at the near optimum moisture contents. 6.2.2 Site Excavations Site excavations can generally be accomplished using heavy-duty construction equipment. Design recommendations for temporary construction slopes are provided in a subsequent section of this report. Site excavations should be observed by CTE. Such observations are essential to identify field conditions that differ from those identified during our subsurface investigation and to adjust designs to actual field conditions encountered. I Preliminary Geotechnical Investigation I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California - June 2, 2006 Page 12 CTE Job No. 10-8356G 6.2.3 Fill Placement and Compaction As stated, an engineer or geologist from CTE should be called upon to verify that the proper site preparation has occurred before fill placement begins. As stated, following the recommended removals, areas to receive fills or improvements should be scarified, moisture conditioned near optimum moisture content, and properly recompacted. General fill and backfill should be compacted to a minimum relative compaction of 90% as evaluated by ASTM D-1557 (except in pavement areas) at moisture contents near optimum (generally within two percent). The optimum lift thickness for backfill soil will be dependent on the type of compaction equipment used. Generally, backfill should be placed in uniform lifts not exceeding eight inches in loose thickness. If proposed, sloping backfill shall be properly keyed and benched. Backfill placement and compaction should be done in overall conformance with geotechnical recommendations and local ordinances. All grading shall be performed in accordance with the regulations of the governing authorities. 6.2.4 Fill Materials Soils derived from on-site materials are considered suitable for reuse on the site as fill, provided they are screened of significant organic materials and materials greater than three inches in maximum dimension, if encountered.' Imported fill beneath structures, pavements and walks should have an expansion index less than or equal to 30 (per UBC 18-I-B) with less than 35% passing the no. 200 sieve. Preliminary Geotechnical Investigation Page 13 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G Imported fill soils for use in structural or slope areas should be evaluated by the soils engineer to determine strength characteristics before placement on the site. 6.3 Temporary Construction Slopes Sloping recommendations for unshored temporary excavations are provided herein. The recommended slopes should be relatively stable against deep-seated failure, but may experience localized sloughing. Recommended slope ratios are set forth in Table 1. TABLE 1 REC01\tENDED TEMPORARY SLOPE RATIOS SOILS TYPE SLOPE RATIO MAXIMUM HEIGHT (Horizontal: Vertical) B (Quaternary Terrace Deposits) 1:1 (MAXIMUM) 8 FEET Actual field conditions and soil type designations must be verified by a "competent person" while excavations exist according to Cal-OSHA regulations. In addition, the above sloping recommendations do not allow for potential water seepage, or surcharge loading at the top of slopes by vehicular traffic, equipment or materials. Appropriate surcharge setbacks must be maintained from the top of all unshored slopes. Excavations shall not encroach within a 1:1 plane extended down from adjacent foundations or improvements to remain. 6.4 Foundations and Slab Recommendations 6.4.1 General The following recommendations are for preliminary planning purposes only. These foundation recommendations should be reviewed after completion of earthwork and testing of surface soils. Preliminary Geotechnical Investigation Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2 2006 Page 14 CTE Job No. 10-8356G We anticipate all foundations for proposed structures will be either founded entirely in properly compacted engineered fill materials or entirely upon competent native materials. Foundations should not straddle transitional conditions (changes from cut to fill soils). 6.4.2 Spread Foundations and Slabs-on-Grade Continuous and isolated spread footings are suitable for use at this site. We anticipate that all building footings will be founded either entirely in properly compacted fills or entirely upon competent native materials as recommended herein. Foundation dimensions and reinforcement should be based on allowable bearing values of 2,500 pounds per square foot (psf) for footings embedded a minimum of 18 inches. The allowable bearing value may be increased by one third for short duration loading which includes the effects of wind or seismic forces. Minimum footing reinforcement for continuous footings should consist of four No. 4 reinforcing bars; two placed near the top and two placed near the bottom or as per the project structural engineer. The structural engineer should design isolated footing reinforcement. It is recommended that isolated footings be connected to each other or adjacent continuous foundations via minimum 12-inch by 12-inch tie beams with minimum reinforcing steel percentages. As a precautionary measure, it is generally recommended that all foundations attain a minimum 15-foot horizontal distance to daylight. Deepening of locally affected foundations may be a suitable means of attaining the prescribed foundation setbacks. Preliminary Geotechnical Investigation Page 15 I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G I Lightly loaded concrete slabs should be a minimum of five inches thick. Minimum slab reinforcement should consist of #4 reinforcing bars placed at maximum 24-inch centers, each way, at mid-slab height. Moisture sensitive floor areas shall be underlain by a minimum 10-mil visqueen layer, with all laps sealed or taped. Slabs subjected to heavier loads may require thicker slab sections and/or increased reinforcement. 6.4.3 Foundation Settlement Based on the preliminary plans as well as the conditions observed at the site, the maximum total static settlement is expected to be less than 1.0 inches and the maximum differential static settlement is expected to be less than 0.5 inches. Total and differential dynamic settlements are anticipated to be less than 0.5 inches, and will not likely affect the proposed improvements. 6.5 Lateral Resistance and Earth Pressures Foundations placed in firm, well-compacted fill material may be designed using a coefficient of friction of 0.35 (total frictional resistance equals the coefficient of friction times the dead load). A design passive resistance value of 250 pounds per square foot per foot of depth (with a maximum value of 1,000 pounds per square foot) may be used. The allowable lateral resistance can be taken as the sum of the frictional resistance and the passive resistance, provided the passive resistance does not exceed two-thirds of the total allowable resistance. Walls below grade up to ten feet high and backfilled using granular soils may be designed using the equivalent fluid weights given in Table 2 below. If segmental block walls are proposed at the I Preliminary Geotechnical Investigation Page 16 I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G I site, our office shall be contacted and additional design and construction recommendations will be provided upon request. TABLE 2 EQUIVALENT FLUID UNIT WEIGHTS (pounds_ per _cubic _foot) WALL TYPE LEVEL BACKFILL SLOPE BACKFILL 2:1 (HORIZONTAL: VERTICAL) CANTILEVER WALL 35 55 (YIELDING) RESTRAINED WALL 55 85 The above values assume non-expansive backfill and free draining conditions. Measures should be taken to prevent a moisture buildup behind all walls below grade. Drainage measures should include free draining backfill materials and perforated drains. Drains should discharge to an appropriate offsite location. We recommend that walls below grade be backfilled with soils having an expansion index of 20 or less. The backfill area should include the zone defined by a 1:1 sloping plane, extended back from the base of the wall. Wall backfill should be compacted to at least 90 percent relative I compaction, based on ASTM D1557-91. Backfill should not be placed until walls have achieved adequate structural strength. Heavy compactors, which could cause distress to walls, should not be used. 6.6 Exterior Flatwork To reduce the potential for distress to exterior flatwork caused by minor settlement of foundation I soils, we recommend that such flatwork be reinforced and installed with crack-control joints at I I Preliminary Geotechnical Investigation Page 17 I Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California - June 2, 2006 CTE Job No. 10-8356G appropriate spacing as designed by the project architect. The upper 12 inches of subgrade should 1 be properly recompacted before placing concrete. Flatwork shall be a minimum four inches I thick. We recommend flatwork be reinforced with minimum #3 rebar spaced at maximum 18 inches, on center, both ways. Reinforcing shall be located near mid-height of the concrete I section. I 6.7 Vehicular Pavements The proposed development may include the construction of pavement areas. Presented in Table 3 below are recommended pavement sections. Two options are presented. Option 1 is for construction of asphalted concrete pavements; Option 2 is for construction of full-depth concrete pavements. The pavement sections presented are based on estimated traffic indices and the design value for the Resistance "R"- Value of onsite materials. The upper 12 inches of subgrade and all base I materials shall be compacted to 95% of laboratory determined maximum dry density, as per i ASTM D1557, at moisture contents near optimum. TABLE 3 PRELIMINARY RECOMMENDED V\\ I MEN I I I IICKNESS Option 1: Option 2: Preliminary Asphalt Pavements Full Traffic Area Assumed Traffic Subgrade Depth AC Class II Index "R"-Value Thickness Aggregate Base Concrete (inches) Thickness Pavements (inches) (inches) Drive and 4.5 25+ 2.5 4.0 5.5 Parking Areas or or 4.0 0.0 Li Preliminary Geotechnical Investigation Page 18 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G At the owner's option, upon completion of preparatory grading in the proposed pavement areas, additional subgrade sampling and testing for "R" Value determination can be conducted. This additional testing will enable us to modify the pavement sections based on the as-graded conditions, if necessary. 6.8 Drainage Surface runoff should be collected and directed away from improvements by means of appropriate erosion reducing devices and positive drainage should be established around the proposed improvements. Positive drainage should be directed away from improvements at a gradient of at least two percent for a distance of at least five feet. Surficial contours within the area should keep water from affecting the foundations provided planter areas are not over watered. The project civil engineer should evaluate the on-site drainage and make necessary provisions to keep surface water from affecting the site. 6.9 Slopes Graded slopes should be constructed at 2:1 (horizontal: vertical) or flatter. Although graded slopes on this site will be grossly stable (i.e., factor of safety greater than 1.5), the soils will be somewhat erodible. Therefore, runoff water should not be permitted to drain over the edges of slopes unless that water is confined to properly designed and constructed drainage facilities. Erosion resistant vegetation should be maintained on the face of all slopes. As previously stated, all graded slopes shall be properly keyed and benched. Preliminary Geotechnical Investigation Page 19 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G Typically, soils along the top portion of a fill slope face will tend to creep laterally. We do not recommend that distress sensitive landscape improvements be constructed within five feet of slope crests in fill areas. 6.10 Construction Observation The recommendations provided in this report are based on preliminary design information for the proposed construction and the subsurface conditions found in the exploratory boring locations. The interpolated subsurface conditions should be checked in the field during construction to verify that conditions are as anticipated. Recommendations provided in this report are based on the understanding and assumption that CTE will provide the observation and testing services for the project. All earthwork should be observed and tested to verify that grading activity has been performed according to the recommendations contained within this report. All foundation excavations shall be evaluated by the project engineer before reinforcing steel placement. 6.11 Plan Review CTE should review all project grading and foundation plans before the start of earthworks to identify potential conflicts with the recommendations contained in this report. 7.0 LIMITATIONS OF INVESTIGATION The recommendations provided in this report are based on the anticipated construction and the subsurface conditions found in our explorations. The interpolated subsurface conditions should be checked in the field during construction to verify that conditions are as anticipated. Preliminary Geotechnical Investigation Page 20 Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 CTE Job No. 10-8356G Recommendations provided in this report are based on the understanding and assumption that CTE will provide the observation and testing services for the project. All earthworks should be observed and tested to verify that grading activity has been performed according to the recommendations contained within this report. The project engineer should evaluate all footing trenches before reinforcing steel placement. The field field evaluation, laboratory testing and geotechnical analysis presented in this report have been conducted according to current engineering practice and the standard of care exercised by reputable geotechnical consultants performing similar tasks in this area. No other warranty, expressed or implied, is made regarding the conclusions, recommendations and opinions expressed in this report. Variations may exist and conditions not observed or described in this report may be encountered during construction. Our conclusions and recommendations are based on an analysis of the observed conditions. If conditions different from those described in this report are encountered, our office should be notified and additional recommendations, if required, will be provided upon request. We appreciate this opportunity to be of service on this project. If you have any questions regarding this report, please do not hesitate to contact the undersigned. 1 • E5 (c:3 No-2665 :L EXP.12/31/14 jfl Preliminary Geotechnical Investigation Proposed Improvements to Pryor Residence 5243 Shore Drive, Carlsbad, California June 2, 2006 Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. Dan T. Math, GE #2665 Principal Engineer Dennis A. Kilian Staff Geologist Page 21 CTE Job No. 10-8356G No 23,11 GEOLOGIST Exp. 6/30/16 Martin Siem, CEG #2311 °' CM Certified Engineering Geologist U _- - - - - - - - - - - - - - - - - - - ELEVA TIOAI (FT) 155 I / I / I / BEACH SAND CROSS SECTION A- A' (EXISTING FLOOR/ GROUND ELEVATION SHOWN) A A' APPENDIX A REFERENCES CITED I REFERENCES CITED I 1. Hart, Earl W. and Bryant, W.A., 1997, "Fault-Rupture Hazard Zones in California, I Aiquist-Priolo Earthquake Fault Zoning Act with Index to Earthquake Fault Zones Maps," California Division of Mines and Geology, Special Publication 42. I 2. Jennings, C. W., 1987, "Fault Map of California with Locations of Volcanoes, Thermal Springs and Thermal Wells." 3. Tan, S. S., and Giffen, D.G., 1995, "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California: Landslide Hazard Identification Map", California Department of Conservation, Division of Mines and Geology, Open- File Report 95-04, State of California, Division of Mines and Geology, Sacramento, California. I 4. LiquifyPro, Version 4, Civiltech Corporation, 2003, "Computer Program for Evaluation of Liquefaction Potential and Calculations of Settlement of Soil Deposits Due to Seismic Loads per NCEER Workshop and SP 117 Implementation." I 5. McCulloch, D.S., 1985, "Evaluating Tsunami Potential" in Ziony, J.I., ed., Evaluation Earthquake Hazards in Los Angeles Region - An Earth-Science Perspective, U.S. 1 Geological Survey Professional Paper 1360 6. Tan, S. S., and Kennedy M., 1996, "Geological Map of the Oceanside and San Marcos I 7.5' Quadrangles", Geological Maps of the Northwestern Part of San Diego County, California, California Department of Conservation, Division of Mines and Geology. I 7. Uniform Building Code, 1997, Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada. I I I I I I APPENDIX B EXPLORATION LOGS I ' CONSTRUCTION TESTING & ENGINEERING, INC. GEOTECHIlICAt I CONSTRUCTION EN ATTAINS TESIING AND IHAFAClISH III MaNila HEAD. SUITE 115 I ESCDNDITO, CA 1209 1160340,4955 DEFINITION OF TERMS PRIMARY DIVISIONS SYMBOLS SECONDARY DIVISIONS GRAVELS CLEAN GW WELL GRADED GRAVELS, GRAVEL-SAND MIXTURES z HALF MORETHAN GRAVELS -LITFLEORNO FINES POORLY GRADED GRAVELS OR GRAVEL SAND MIXTURES, OF COARSE <5% FINE P LITTLE OF NO FINES GRAVELS SILTY GRAVELS, GRAVEL-SAND-SILT MIXTURES, N FRACTION IS -' —J W W W LARGER THAN WITH FINE NON-PLASTIC FINES *t4 CLAYEY GRAVELS, GRAVEL-SAND-CLAY MIXTURES, Z5 W NO. 4 SIEVE C PLASTIC FINES SANDS CLEAN w : WELL GRADED SANDS, GRAVELLY SANDS, LITFLE OR NO z> ..jo W MORE THAN HALF OF SANDS <5%FINES ______ FINES SP POORLY GRADED SANDS, GRAVELLY SANDS, LITTLE OR COARSE NO FINES SILTY SANDS, SAND-SILT MIXTURES, NON-PLASTIC FINES FRACTION IS SMALLER THAN NO. 4 SIEVE SANDS WITH FINES CLAYEY SANDS, SAND-CLAY MIXTURES, PLASTIC FINES i L INORGANIC SILTS, VERY FINE SANDS, ROCK FLOUR, SILTY SILTS AND CLAYS OR CLAYEY FINE SANDS, SLIGHTLY PLASTIC CLAYEY SILTS __________ 2 o LIQUID LIMIT IS ' [> INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, -j < > LESS THAN 50 GRAVELLY, SANDY, SILTS OR LEAN CLAYS "-'---- 0 L I ORGANIC SILTS AND ORGANIC CLAYS OF LOW PLASTICITY I zZS2c, MH i INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE 0 SILTS AND CLAYS SANDY OR SILTY SOILS, ELASTIC SILTS 4.++4) INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS Z Wr Uj ZOZ LIQUID LIMIT IS I— GREATER THAN 50 64 ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTY CLAYS HIGHLY ORGANIC SOILS PEAT AND OTHER HIGHLY ORGANIC SOILS GRAIN SIZES GRAVEL I SAND I I BOULDERS COBBLES SILTS AND CLAYS COARSE I FINE I COARSE I MEDIUM I FINE I 12" 3" 3/4" 4 10 40 200 CLEAR SQUARE SIEVE OPENING U.S. STANDARD SIEVE SIZE ADDITIONAL TESTS (OTHER THAN TEST PIT AND BORING LOG COLUMN HEADINGS) MAX- Maximum Dry Density PM- Permeability PP- Pocket Penetrometer GS- Grain Size Distribution SG- Specific Gravity WA- Wash Analysis SE- Sand Equivalent HA- Hydrometer Analysis DS- Direct Shear El- Expansion Index AL- Atterberg Limits UC- Unconfined Compression CHM- Sulfate and Chloride RV- R-Value MD- Moisture/Density Content , pH, Resistivity CN- Consolidation M- Moisture COR - Corrosivity CP- Collapse Potential SC- Swell Compression SD- Sample Disturbed HC- Hydrocollapse 01- Organic Impurities REM- Remolded FIGURE:I BL1 CONSTRUCTION TESTING & ENGINEERING, INC. GEGEECEINICAL CONSTRUCTION ENGINEERING TESTING AND INSPECTION RE RG 145 1955 TE MON SET ROAD, SUIT EElS I ESCONGITE CE STEEN 1 160.140,495 5 PROJECT: DRILLER: SHEET: of CTE JOB NO: DRILL METHOD: DRILLING DATE: LOGGED BY: SAMPLE METHOD: ELEVATION: - - - I BORING LEGEND Laboratory Tests Cu Q. C1 - a Cl? DESCRIPTION - - - - Block or Chunk Sample - X --- - Bulk Sample - - - 5- - - - - - Standard Penetration Test 10 - - / -a-- - Modified Split-Barrel Drive Sampler (Cal Sampler) - - - I - - Thin Walled Army Corp. of Engineers Sample - - 15- - - Groundwater Table - - Soil Type or Classification Change - Formation Change 1(Approximate boundaries queried (?)1 - "SM' Quotes are placed around classifications where the soils 25 exist in situ as bedrock FIGURE: I BL2 CONSTRUCTION TESTING & ENGINEERING, INC. 6E-01ECHSSAt I CONSTRUCTION 5555 N.5RIMG 15555555 5550 INSPECTION 'N. 1455 MOHIIIS ROAD, SUITE 115 1 5550555100, 54 51526 1 002464955 PROJECT: PRYOR RESIDENCE DRILLER: PAC DRILLING SHEET: 1 of CTE JOB NO: 10-8356G DRILL METHOD: TRIPOD-6" DRILLING DATE: 4/27/2006 LOGGED BY: DK SAMPLE METHOD: BULK, RING, SPT ELEVATION: -a. 0. .0 F BORING: B-i Laboratory Tests 0 -a .2 0 DESCRIPTION - - - - - - 0-0.25' BRICK @ 0.25' QUATERNARY ARTIFICIAL FILL (Oaf): - - SM Medium dense, slightly moist, brown to red brown silty fine SAND - (SM) with old cobble/cement debris. WA, CHEM QUATERNARY TERRACE DEPOSITS (Of): - Very dense, slightly moist, orange brown fine SAND with MD, GS, CN - - • / 66 115.7 3.5 SP-SM SILT (SP-SM). 10 @ 10' Medium dense to dense, slightly moist, tan to yellow brown 19 SP fine to coarse SAND, thin laminations with relatively flat - L orientation. 15 - SP @ 15' Dense, slightly moist, tan to yellow brown, fine to coarse - / 50/6" grained SAND with micas. 24 @ 18.5' Dense to very dense, slightly moist, light tan, silty fine - 50/6" SM SAND with medium and coarse SAND (SM). - . Total Depth 20' No Groundwater Backfilled with Spoils -2j I B-i Boring B-1 I \ CONSTRUCTION TESTING & ENGINEERING, INC. ¶t GDOTFCHN,CAL I CONSTRUCTION ENDINEENINO TESUND AND INSPECTION 1 441 MONflAL ROAD, SUITE IS I ESCSAUITD, CA ADODA 1 1110.746.4955 PROJECT: PRYOR RESIDENCE DRILLER: PAC DRILLING SHEET: 1 of CTE JOB NO: I0-8356G DRILL METHOD: TRIPOD-6" DRILLING DATE: 4/27/2006 LOGGED BY: DK SAMPLE METHOD: BULK, RING, SPT ELEVATION: '15 ' BORING: B-2 Laboratory Tests DESCRIPTION - - - - - - 0-1' TOPSOIL: Loose, dry, brown, silty SAND with organics. - - @ 1' OUATERNARY TERRACE DEPOSITS (Ot): - - SM Medium dense, slightly moist, brown to red brown silty fine SAND with trace CLAY (SM). I SM-SC @ 5' Medium dense, slightly moist, brown to red brown silty to - - 13 clayey fine SAND (SM-SC). • SM WA @ 10' Dense, slightly moist, tan to light brown fine to occasional SP medium grained SAND, trace silt and clay. GS / 54 .1 SP @ 15' Medium dense to dense, slightly moist, tan to light brown fine - 29 to occasional medium grained SAND, trace silt and clay. - @ 18.5' Dense, slightly moist, light tan, fine to medium grained / 41 SP SAND (SP) with trace coarse SAND. - Total Depth 20' No Groundwater - Backfilled with Spoils 25 APPPNDTX C LABORATORY METHODS AND RESULTS APPENDIX C LABORATORY METHODS AND RESULTS Laboratory tests were performed on representative soil samples to detect their relative I engineering properties. Tests were performed following test methods of the American Society for Testing Materials or other accepted standards. The following presents a brief description of - the various test methods used. Laboratory results are presented in the following section of this I Appendix. Classification I Soils were classified visually according to the Unified Soil Classification System. Visual classifications were supplemented by laboratory testing of selected samples according to ASTM D2487. Particle-Size Analysis I Particle-size analyses were performed on selected representative samples according to ASTM D422. In-Place Moisture/Density The in-place moisture content and dry unit weight of selected samples were determined using I relatively undisturbed chunk soil samples. Chemical Analysis Soil materials were collected with sterile sampling equipment and tested for Sulfate and Chloride content, pH, Corrosivity, and Resistivity Consolidation To assess their compressibility and volume change behavior when loaded and wetted, relatively I undisturbed samples of representative samples from the investigation were subject to consolidation tests (ASTM D2435). ¶ \ CONSTRUCTION TESTING & ENGINEERING, INC. GEOIECHNICAI. I C05S155c1104 ENS NESSINS TESTING AND INSPECTION I 441 MONIIELTOAT, SUITS 115 1 ESCONDIUT, CS 95125 1 1551454555 200 WASH ANALYSIS I LOCATION DEPTH - PERCENT PASSING CLASSIFICATION (feet) #200 SIEVE B-i 1-5 18.5 SM I B-2 6-10 14.2 SM IN-PLACE MOISTURE AND DENSITY I LOCATION DEPTH DRY DENSITY MOISTURE (feet) (pcf) (%) I B-i 5 115.7 3.5 SULFATE LOCATION DEPTH RESULTS (feet) ppm B-i 12 93.1 CHLORIDE LOCATION DEPTH RESULTS (feet) ppm B-i 12 825 CONDUCTIVITY CALIFORNIA TEST 424 LOCATION DEPTH RESULTS (feet) us/cm B-i 12 601 RESISTIVITY CALIFORNIA TEST 424 LOCATION DEPTH RESULTS (feet) ohms/cm B-i 12 1370 LABORATORY SUMMARY CTE JOB NO. 10-8356G U. S. STANDARD SIEVE SIZE u~ CD coo CD CD CD 0 C. ,- ----- ___ - 100 ------1 S 90 80 70 60 U) U) I— z w U 40 I1111_ :: liii :111 Ijii_ _ 1:HH HH HHH 100 10 1 0.1 0.01 0.001 PARTICLE SIZE (mm) - PARTICLE SIZE ANALYSIS CONSTRUCTION TESTING & ENGINEERING, INC. Sample Designation Sample Depth (feet) Symbol Liquid Limit (%) Plasticity Index Classification B-I 5 0 - - SP CTE JOB NUMBER: 10-8356G FIGURE: c-i U. S. STANDARD SIEVE SIZE 0 00 0 Q 0 - 100 ----)---•-) S --p----- . 90 80 70 11111 :111 :iii_ _ _ 60 50 I— z w 0 w 40 0. 30 10 20 L 0 100 10 1 0.1 0.01 0.001 PARTICLE SIZE (mm) PARTICLE SIZE ANALYSIS CONSTRUCTION TESTING & ENGINEERING. INC. ation Sample Depth (feet) Symbol Liquid Limit (%) Plasacey Index Classificatmn MCTE 10 - - SP JOB NUMBER: 10-8356G FIGURE: C-2 0.00%- 1.00% 2.00% 3.00% 4.00% 5.00% S 6.00% ------ 7.00% 8.00% 9.00% 0 U) U) uj 10.00% 0. 2 3 11.00% 12.00% 13.00% 14.00% 15.00% 16.00% 17.00% 18.00% 19.00% 20.00% 1000 10000 100000 VERTICAL EFFECTIVE STRESS (psf) SWELL/COMPRESSION TEST Sample Designation Depth (ft) Symbol Legend BI 5' FIELD MOISTURE SAMPLE SATURATED -REBOUND Initial Moisture (%): 3.5 Initial Dry Density (pef) 115.7 Final Moisture (%): 20.0 Final Dry Denstiy (pcf) 99.75 CTE JOB NO: 10-8356G FIGURE NO: APPENDIX D STANDARD SPECIFICATIONS FOR GRADING Appendix Page D-i Standard Grading Specifications Section 1 - General The guidelines contained herein represent Construction Testing & Engineering's standard recommendations for grading and other associated operations on construction projects. These guidelines should be considered a portion of the project specifications. Recommendations contained in the body of the previously presented soils report shall supersede the recommendations and or requirements as specified herein. The project geotechnical consultant shall interpret disputes arising out of interpretation of the recommendations contained in the soils report or specifications contained herein. Section 2 - Responsibilities of Project Personnel The geotechnical consultant should provide observation and testing services sufficient to assure that geotechnical construction is performed in general conformance with project specifications and standard grading practices. The geotechnical consultant should report any deviations to the client or his authorized representative. The Client should be chiefly responsible for all aspects of the project. He or his authorized representative has the responsibility of reviewing the findings and recommendations of the geotechnical consultant. He shall authorize or cause to have authorized the Contractor and/or other consultants to perform work and/or provide services. During grading the Client or his authorized representative should remain on-site or should remain reasonably accessible to all concerned parties in order to make decisions necessary to maintain the flow of the project. The Contractor should be responsible for the safety of the project and satisfactory completion of all grading and other associated operations on construction projects, including, but not limited to, earth work in accordance with the project plans, specifications and controlling agency requirements. Section 3 - Preconstruction Meeting A preconstruction site meeting shall be arranged by the owner and/or client and shall include the grading contractor, the design engineer, the geotechnical consultant, owner's representative and representatives of the appropriate governing authorities. Section 4 - Site Preparation The client or contractor should obtain the required approvals from the controlling authorities for the project prior, during and/or after demolition, site preparation and removals, etc. The appropriate approvals should be obtained prior to proceeding with grading operations. Clearing and grubbing should consist of the removal of vegetation such as brush, grass, woods, stumps, trees, root of trees and otherwise deleterious natural materials from the areas to be graded. Clearing and grubbing should extend to the outside of all proposed excavation and fill areas. Demolition should include removal of buildings, structures, foundations, reservoirs, utilities (including underground pipelines, septic tanks, leach fields, seepage pits, cisterns, mining shafts, I tunnels, etc.) and other man-made surface and subsurface improvements from the areas to be graded. Demolition of utilities should include proper capping and/or rerouting pipelines at the project perimeter and cutoff and capping of wells in accordance with the requirements of the I governing authorities and the recommendations of the geotechnical consultant at the time of demolition. Appendix D Page D-2 Standard Grading Specifications Trees, plants or man-made improvements not planned to be removed or demolished should be protected by the contractor from damage or injury. Debris generated during clearing, grubbing and/or demolition operations should be wasted from areas to be graded and disposed off-site. Clearing, grubbing and demolition operations should be performed under the observation of the geotechnical consultant. Section 5 - Site Protection Protection of the site during the period of grading should be the responsibility of the contractor. Unless other provisions are made in writing and agreed upon among the concerned parties, completion of a portion of the project should not be considered to preclude that portion or adjacent areas from the requirements for site protection until such time as the entire project is complete as identified by the geotechnical consultant, the client and the regulating agencies. Precautions should be taken during the performance of site clearing, excavations and grading to protect the work site from flooding, ponding or inundation by poor or improper surface drainage. Temporary provisions should be made during the rainy season to adequately direct surface drainage away from and off the work site. Where low areas cannot be avoided, pumps should be kept on hand to continually remove water during periods of rainfall. Rain related damage should be considered to include, but may not be limited to, erosion, silting, saturation, swelling, structural distress and other adverse conditions as determined by the geotechnical consultant. Soil adversely affected should be classified as unsuitable materials and should be subject to overexcavation and replacement with compacted fill or other remedial grading as recommended by the geotechnical consultant. The contractor should be responsible for the stability of all temporary excavations. Recommendations by the geotechnical consultant pertaining to temporary excavations (e.g., backcuts) are made in consideration of stability of the completed project and, therefore, should not be considered to preclude the responsibilities of the contractor. Recommendations by the geotechnical consultant should not be considered to preclude requirements that are more restrictive by the regulating agencies. The contractor should provide during periods of extensive rainfall plastic sheeting to prevent unprotected slopes from becoming saturated and unstable. When deemed appropriate by the geotechnical consultant or governing agencies the contractor shall install checkdams, desilting basins, sand bags or other drainage control measures. In relatively level areas and/or slope areas, where saturated soil and/or erosion gullies exist to depths of greater than 1.0 foot; they should be overexcavated and replaced as compacted fill in accordance with the applicable specifications. Where affected materials exist to depths of 1.0 foot or less below proposed finished grade, remedial grading by moisture conditioning in-place, followed by thorough recompaction in accordance with the applicable grading guidelines herein may be attempted. If the desired results are not achieved, all affected materials should be overexcavated and replaced as compacted fill in accordance with the slope repair recommendations herein. If field conditions dictate, the geotechnical consultant may recommend other slope repair procedures. Section 6 - Excavations 1 Appendix D Page D-3 I Standard Grading Specifications 6.1 Unsuitable Materials I Materials that are unsuitable should be excavated under observation and recommendations of the geotechnical consultant. Unsuitable materials include, but may not be limited to, dry, loose, soft, wet, organic compressible natural soils and fractured, weathered, soft bedrock and I nonengineered or otherwise deleterious fill materials. Material identified by the geotechnical consultant as unsatisfactory due to its moisture conditions I should be overexcavated; moisture conditioned as needed, to a uniform at or above optimum moisture condition before placement as compacted fill. I If during the course of grading adverse geotechnical conditions are exposed which were not anticipated in the preliminary soil report as determined by the geotechnical consultant additional exploration, analysis, and treatment of these problems may be recommended. 6.2 Cut Slopes Unless otherwise recommended by the geotechnical consultant and approved by the regulating agencies, permanent cut slopes should not be steeper than 2:1 (horizontal: vertical). The geotechnical consultant should observe cut slope excavation and if these excavations expose loose cohesionless, significantly fractured or otherwise unsuitable material, the materials should be overexcavated and replaced with a compacted stabilization fill. If encountered specific cross section details should be obtained from the Geotechnical Consultant. When extensive cut slopes are excavated or these cut slopes are made in the direction of the prevailing drainage, a non-erodible diversion swale (brow ditch) should be provided at the top of the slope. 6.3 Pad Areas All lot pad areas, including side yard terrace containing both cut and fill materials, transitions, located less than 3 feet deep should be overexcavated to a depth of 3 feet and replaced with a uniform compacted fill blanket of 3 feet. Actual depth of overexcavation may vary and should be delineated by the geotechnical consultant during grading. For pad areas created above cut or natural slopes, positive drainage should be established away from the top-of-slope. This may be accomplished utilizing a berm drainage swale and/or an appropriate pad gradient. A gradient in soil areas away from the top-of-slopes of 2 percent or greater is recommended. Section 7 - Compacted Fill All fill materials should have fill quality, placement, conditioning and compaction as specified below or as approved by the geotechnical consultant. 7.1 Fill Material Ouality Excavated on-site or import materials which are acceptable to the geotechnical consultant may be utilized as compacted fill, provided trash, vegetation and other deleterious materials are removed prior to placement. All import materials anticipated for use on-site should be sampled tested and approved prior to and placement is in conformance with the requirements outlined. 1 Appendix D Page D-4 I Standard Grading Specifications Rocks 12 inches in maximum and smaller may be utilized within compacted fill provided I sufficient fill material is placed and thoroughly compacted over and around all rock to effectively fill rock voids. The amount of rock should not exceed 40 percent by dry weight passing the 3/4- inch sieve. The geotechnical consultant may vary those requirements as field conditions dictate. Where rocks greater than 12 inches but less than four feet of maximum dimension are generated during grading, or otherwise desired to be placed within an engineered fill, special handling in accordance with the recommendations below. Rocks greater than four feet should be broken down or disposed off-site. 7.2 Placement of Fill Prior to placement of fill material, the geotechnical consultant should inspect the area to receive fill. After inspection and approval, the exposed ground surface should be scarified to a depth of 6 to 8 inches. The scarified material should be conditioned (i.e. moisture added or air dried by continued discing) to achieve a moisture content at or slightly above optimum moisture conditions and compacted to a minimum of 90 percent of the maximum density or as otherwise recommended in the soils report or by appropriate government agencies. Compacted fill should then be placed in thin horizontal lifts not exceeding eight inches in loose thickness prior to compaction. Each lift should be moisture conditioned as needed, thoroughly blended to achieve a consistent moisture content at or slightly above optimum and thoroughly compacted by mechanical methods to a minimum of 90 percent of laboratory maximum dry density. Each lift should be treated in a like manner until the desired finished grades are achieved. The contractor should have suitable and sufficient mechanical compaction equipment and watering apparatus on the job site to handle the amount of fill being placed in consideration of moisture retention properties of the materials and weather conditions. When placing fill in horizontal lifts adjacent to areas sloping steeper than 5:1 (horizontal: I vertical), horizontal keys and vertical benches should be excavated into the adjacent slope area. Keying and benching should be sufficient to provide at least six-foot wide benches and a minimum of four feet of vertical bench height within the firm natural ground, firm bedrock or I engineered compacted fill. No compacted fill should be placed in an area after keying and benching until the geotechnical consultant has reviewed the area. Material generated by the benching operation should be moved sufficiently away from the bench area to allow for the I recommended review of the horizontal bench prior to placement of fill. Within a single fill area where grading procedures dictate two or more separate fills, temporary I slopes (false slopes) may be created. When placing fill adjacent to a false slope, benching should be conducted in the same manner as above described. At least a 3-foot vertical bench should be established within the firm core of adjacent approved compacted fill prior to placement of I additional fill. Benching should proceed in at least 3-foot vertical increments until the desired finished grades are achieved. I Prior to placement of additional compacted fill following an overnight or other grading delay, the exposed surface or previously compacted fill should be processed by scarification, moisture I Appendix D Page D-5 I Standard Grading Specifications conditioning as needed to at or slightly above optimum moisture content, thoroughly blended and I recompacted to a minimum of 90 percent of laboratory maximum dry density. Where unsuitable materials exist to depths of greater than one foot, the unsuitable materials should be over- excavated. I Following a period of flooding, rainfall or overwatering by other means, no additional fill should be placed until damage assessments have been made and remedial grading performed as I described herein. Rocks 12 inch in maximum dimension and smaller may be utilized in the compacted fill I provided the fill is placed and thoroughly compacted over and around all rock. No oversize material should be used within 3 feet of finished pad grade and within 1 foot of other compacted fill areas. Rocks 12 inches up to four feet maximum dimension should be placed below the I upper 5 feet of any fill and should not be closer than 11 feet to any slope face. These recommendations could vary as locations of improvements dictate. Where practical, oversized material should not be placed below areas where structures or deep utilities are proposed. i Oversized material should be placed in windrows on a clean, overexcavated or unyielding compacted fill or firm natural ground surface. Select native or imported granular soil (S.E. 30 or higher) should be placed and thoroughly flooded over and around all windrowed rock, such that voids are filled. Windrows of oversized material should be staggered so those successive strata I of oversized material are not in the same vertical plane. It may be possible to dispose of individual larger rock as field conditions dictate and as I recommended by the geotechnical consultant at the time of placement. The contractor should assist the geotechnical consultant and/or his representative by digging test I pits for removal determinations and/or for testing compacted fill. The contractor should provide this work at no additional cost to the owner or contractor's client. Fill should be tested by the geotechnical consultant for compliance with the recommended relative compaction and moisture conditions. Field density testing should conform to ASTM Method of Test D 1556-82, D 2922-81. Tests should be conducted at a minimum of two vertical feet or 1,000 cubic yards of fill placed. Actual test intervals may vary as field conditions dictate. Fill found not to be in conformance with the grading recommendations should be removed or otherwise handled as recommended by the geotechnical consultant. 7.3 Fill Slopes Unless otherwise recommended by the geotechnical consultant and approved by the regulating agencies, permanent fill slopes should not be steeper than 2:1 (horizontal: vertical). Except as specifically recommended in these grading guidelines compacted fill slopes should be over-built and cut back to grade, exposing the firm, compacted fill inner core. The actual amount of overbuilding may vary as field conditions dictate. If the desired results are not achieved, the existing slopes should be overexcavated and reconstructed under the guidelines of the geotechnical consultant. The degree of overbuilding shall be increased until the desired compacted slope surface condition is achieved. Care should be taken by the contractor to provide thorough mechanical compaction to the outer edge of the overbuilt slope surface. I Appendix D Page D-6 I Standard Grading Specifications I At the discretion of the geotechnical consultant, slope face compaction may be attempted by conventional construction procedures including backrolling. The procedure must create a firmly compacted material throughout the entire depth of the slope face to the surface of the previously i compacted firm fill intercore. During grading operations, care should be taken to extend compactive effort to the outer edge of ' the slope. Each lift should extend horizontally to the desired finished slope surface or more as needed to ultimately established desired grades. Grade during construction should not be allowed to roll off at the edge of the slope. It may be helpful to elevate slightly the outer edge of I the slope. Slough resulting from the placement of individual lifts should not be allowed to drift down over previous lifts. At intervals not exceeding four feet in vertical slope height or the capability of available equipment, whichever is less, fill slopes should be thoroughly dozer trackrolled. For pad areas above fill slopes, positive drainage should be established away from the top-of-slope. This may be accomplished using a berm and pad gradient of at least 2 percent. Section 8 - Trench Backfill Utility and/or other excavation of trench backfill should, unless otherwise recommended, be compacted by mechanical means. Unless otherwise recommended, the degree of compaction should be a minimum of 90 percent of the laboratory maximum density. Within slab areas, but outside the influence of foundations, trenches up to one foot wide and two feet deep may be backfilled with sand and consolidated by jetting, flooding or by mechanical means. If on-site materials are utilized, they should be wheel-rolled, tamped or otherwise compacted to a firm condition. For minor interior trenches, density testing may be deleted or spot testing may be elected if deemed necessary, based on review of backfill operations during construction. If utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit, the contractor may elect the utilization of light weight mechanical compaction equipment and/or shading of the conduit with clean, granular material, which should be thoroughly jetted in-place above the conduit, prior to initiating mechanical compaction procedures. Other methods of utility trench compaction may also be appropriate, upon review of the geotechnical consultant at the time of construction. In cases where clean granular materials are proposed for use in lieu of native materials or where flooding or jetting is proposed, the procedures should be considered subject to review by the geotechnical consultant. Clean granular backfill and/or bedding are not recommended in slope areas. Section 9 - Drainage Where deemed appropriate by the geotechnical consultant, canyon subdrain systems should be installed in accordance. Typical subdrains for compacted fill buttresses, slope stabilization or sidehill masses, should be installed in accordance with the specifications. I Appendix D Page D-7 I Standard Grading Specifications I Roof, pad and slope drainage should be directed away from slopes and areas of structures to suitable disposal areas via non-erodible devices (i.e., gutters, downspouts, and concrete swales). I For drainage in extensively landscaped areas near structures, (i.e., within four feet) a minimum of 5 percent gradient away from the structure should be maintained. Pad drainage of at least 2 percent should be maintained over the remainder of the site. Drainage patterns established at the time of fine grading should be maintained throughout the life of the project. Property owners should be made aware that altering drainage patterns could be detrimental to slope stability and foundation performance. Section 10 - Slope Maintenance 10.1 - Landscape Plants To enhance surficial slope stability, slope planting should be accomplished at the completion of grading. Slope planting should consist of deep-rooting vegetation requiring little watering. Plants native to the southern California area and plants relative to native plants are generally desirable. Plants native to other semi-arid and and areas may also be appropriate. A Landscape Architect should be the best party to consult regarding actual types of plants and planting configuration. 10.2 - Irrigation Irrigation pipes should be anchored to slope faces, not placed in trenches excavated into slope faces. Slope irrigation should be minimized. If automatic timing devices are utilized on irrigation systems, provisions should be made for interrupting normal irrigation during periods of rainfall. 10.3 - Repair As a precautionary measure, plastic sheeting should be readily available, or kept on hand, to protect all slope areas from saturation by periods of heavy or prolonged rainfall. This measure is strongly recommended, beginning with the period prior to landscape planting. If slope failures occur, the geotechnical consultant should be contacted for a field review of site conditions and development of recommendations for evaluation and repair. - If slope failures occur as a result of exposure to period of heavy rainfall, the failure areas and currently unaffected areas should be covered with plastic sheeting to protect against additional I saturation.