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Home My WebLink AboutCT 03-01-03; LA COSTA RESORT & SPA PHASE 3; GEOTECHNICAL UPDATE; 2006-03-28Sladden Engineering u/o^^s3</^oooi /pc^f^ ^73/ 6782 Stanton Avenue, Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 114 South Caiifomla Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 951-845-8803 39-725 Garand Lane.. Suite G, Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-3895 March 28,2006 Project No. 444-3161 06-03-308 G Companies Construction, Inc. 1107 Quail Street Newport Beach, Califomia 92660 Subject: Geotechnical Update Project: Planning Area 2 Resort Villas La Costa Resort & Spa Costa Del Mar Road Carlsbad, Califomia Ref: Geotechnical Investigation Report prepared by Sladden Engineering dated November 11,2004, Project No. 444-3161, Report No. 03-10-183. As requested, we have reviewed the referenced Geotechnical Investigation report as it relates to the design and cor\stmction of the resort villas complex proposed for Plarming Area 2 of the La Costa Resort and Spa campus. Planning area 2 is located just north of the ballroom facility at the La Costa Resort and Spa in the City of Carlsbad, Califomia. The proposed resort villas building will include a subterranean parking level. The referenced Geotechnical Investigation report includes recommendations for the design and construction of the resort residential units including subterranean paridng levels. Based upon our review of the referenced report, our involvement throughout the grading and construction of the adjacent La Costa facilities and our recent site observations, it is our opinion that the reconmiendations included in the above referenced report remain applicable for the proposed Planning Area 2 resort residential units. Because the excavation required to attain the subterranean parking level will result in the removal of the potentially expansive surface soil, it is our opinion that foundations may be designed in accordance with "very low" expansion category design criteria. Footings should extend at least 18 inches beneath lowest adjacent grade. Isolated square or rectangular footings at least 2 feet square may be designed using an allowable bearing value of 2500 poimds per square foot. Continuous footings at least 12 inches wide may be designed using an allowable bearing value of 2000 pounds per square foot. Allowable increases of 200 psf for each additional 1 foot of width and 250 psf for each additional 6 inches of depth may be utilized if desired. The maximum allowable bearing pressure should be 3000 psf. The allowable bearing pressures are for dead and frequently applied live loads and may be increased by 1/3 to resist wind, seismic or other transient loading. March 31,2006 -2- Project No. 444-3161 06-03-308 The recommendations made in the preceding paragraph are based on the assumption that all footings will be supported by properly compacted soils. Prior to the placement of the reinforcing steel and concrete, we recommend that the footing excavations be inspected in order to verify that they extend into the firm compacted soils and are free of loose and disturbed materials. Settlements may result from the antidpated foundation loads. These estimated ultimate settlements are calculated to be a maximum of 1 inch when using the recommended bearing values. As a practical matter, differential settlements between footings can be assumed as one- half of the total settlement. These elastic settlements are expected to occur during constiruction. Proper compaction of die backfill soil adjacent to basement walls will be critical to limit potential differential settlement of foundatior\s and slabs constructed adjacent to basement walls. Resistance to lateral loads may be provided by a combination of friction acting at the base of the slabs or foundations and passive earth pressure along tiie sides of tiie foundations. A coefficient of friction of 0.40 between soil and concrete may be used for dead load forces only. A passive earth pressure of 250 pounds per square foot, per foot of deptii, may be used along tiie sides of footings that are poured against properly compacted native or approved import soils. Basement walls and retaining walls will be required to accomplish tiie proposed constmction. Cantilever retaining walls may be designed using "active" pressures. Active pressures may be estimated using an equivalent fluid weight of 40 pcf for native backfill soils witii level free- draining backfill conditions. For walls tiiat are resfarained, "at rest" pressures should be utilized in design. At rest pressures may be estimated using an equivalent fluid weight of 60 pcf. Walls should be provided with adequate waterproofing and drainage. It is our opinion that the remedial grading recommended in tiie referenced report remains appropriate. The remedial grading should include over-excavation of the surface soils and the primary foundation bearing soil within the building areas. The foundation areas should be cleared of any surface vegetation prior to grading. In order to provide for firm and uniform fovmdation support, we recommend over-excavation and recompaction. The foundation areas should be over-excavated to a depth of at least 3 feet below existing grade or 2 feet below tiie bottom of tiie footings, whichever is deeper. The exposed surface should then be scarified, moisture conditioned and compacted to a minimum of 90 percent relative compaction. The previously removed soils and fill material may then be placed in thin lifts and compacted to at least 90 percent relative compaction. It should be noted that the site is located witiiin a seismically active area of Southem Califomia and it is likely tiiat the proposed stmctures will experience strong ground shaking as a result of an earthquake event along one of the faults in the region during tiie expected life of tiie development. As a minimum, stmctures should be designed based upon Seismic Zone 4 design criteria included in tiie Uniform Building Code (UBC). The potential for liquefaction or otiier geologic/seismic hazards occurring at the site is considered to be negligible. Sladden Engineering March 31,2006 -3-Project No. 444-3161 06-03-308 We appreciate the opporhanity to provide service to you on tiiis project, if you have any questions regarding tiiis letter or the referenced reports please contact tiie undersigned. Respectfully submitted, SLADDENENGINEERING Brett L. Anderson Principal Engineer SER/pc Copies: 4/G Companies Constmction, Inc. Sladden Engineering March 31, 2006 -4-Project No. 444-3161 06-03-308 1997 UNIFORM BUILDING CODE INFORMATION The Intemational Conference of Building Officials 1997 Uniform Building Code contains substantial revisions and additions to the earthquake engineering section in Chapter 16. Concepts contained in the updated code that will be relevant to construction of the proposed stmctures are summarized below. Ground shaking is expected to be the primary hazard most likely to affect the site, based upon proximity to significant faults capable of generating large earthquakes. Major fault zones considered to be most likely to create strong groimd shaking at the site are listed below. Fault Zone Approximate Distance From Site Fault Type (1997 UBC) Newport - Inglewood 16.8 km B Rose Canyon Fault 8.8 km B Based on our field observations and understanding of local geologic conditions, the soil profile type judged applicable to tiiis site is SD, generally described as stiff or dense soil. The site is located within UBC Seismic Zone 4. The following table presents additional coefficients and factors relevant to seismic mitigation for new constmction upon adoption of the 1997 code. Seismic Source Near-Source Acceleration Factor, Na Near-Source Velocity Factor, Nv Seismic Coefficient Ca Seismic Coefficient Cv Newport Inglewood 1.0 1.0 0.44 Na 0.64 Nv Rose Canyon Fault 1.0 1.05 0.44 Na 0.64 Nv Sladden Engineering GEOTECHNICAL INVESTIGATION PROPOSED RESORT VILLAS LA COSTA RESORT & SPA COSTA DEL MAR ROAD CAKLSBAD, CALIFORNIA -Prepared By- Sladden Engineering 39-725 Garand Lane, Suite G Palm Desert, California 92211 (760)772-3893 Sladden Engineering 6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 39-725 Garand Ln., Suite G, Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-3895 November 11, 2003 ProjectNo. 444-3161 03-10-183 La Costa Resort and Spa KSL Development Corporation 2100 Costa Del Mar Road Carlsbad, California 92009 Attention: Mr. Chevis Hosea Project: Proposed Resort Villas La Costa Resort & Spa 2100 Costa Del Mar Road Carlsbad, California Subject: Geotechnical Investigation Presented herewith is the report of our Geotechnical Investigation prepared for the new resort villas proposed for the La Costa Resort & Spa complex located at 2100 Costa Del Mar Road in the City of Carlsbad, California. The preliminary plans indicate that the proposed resort villas will consist of 2 or 3 story structures with subterranean parking levels. This report was prepared in order to pro-vide recommendations for design and construction of the proposed building foundations. This report presents the results of our field investigation and laboratory testing along with conclusions and recommendations for design and construction. This report completes our agreed upon scope of services as described in our proposal dated July 30, 2003. We appreciate the opportunity to provide service to you on this project. If you have any questions regarding this report, please contact the vmdersigned Respectfiilly submitted, SLADDEN ENGI Copies: 6/La Costa Resort and Spa GEOTECHNICAL INVESTIGATION PROPOSED RESORT VILLAS LA COSTA RESORT & SPA COSTA DEL MAR ROAD CARLSBAD. CALIFORNIA November 11, 2003 TABLE OF CONTENTS INTRODUCTION 1 SCOPE OF WORK 1 PROJECT DESCRIPTION "' ' 1 REGIONAL SEISMICITY 2 LIQUEFACTION 2 SUBSURFACE CONDITIONS 2 CONCLUSIONS AND RECOMMENDATIONS '"Z". 3 Foundation Design 4 Settlements 4 Lateral Design 4 Retaining Walls 4 Expansive Soils 4 Concrete Slabs-on-Grade 5 Soluble Sulfates 5 Tentative Pavement Design 5 Shrinkage and Subsidence 6 General Site Grading 6 1. Clearing and Demohtion 6 2. Preparation of Building and Foundation Areas 6 3. Placement of Compacted Fill 6 4. Preparation of Slab and Pavement Areas 7 5. Testing and Inspection 7 GENERAL ZZ^ZZZZZ^Z. 7 APPENDIX A - Site Plan & Boring Logs Field Exploration APPENDIX B - Laboratory Testing Laboratory Test Results APPENDIX C - 1997 UBC Seismic Design Criteria Sladden Engineering November 11, 2003 -1- Project No. 444-3161 03-10-183 INTRODUCTION This report presents the results of a Geotechnical Investigation performed in order to provide recommendations for the design and construction of the proposed resort -villas and the various associated site improvements. The La Costa Resort & Spa is located on the northeast corner of El Camino Real and Costa Del Mar Road in the City of Carlsbad, California. It is proposed to construct several multi-unit resort/residential buildings within the central portion of the La Costa Resort and Spa complex. It is our understanding that the proposed resort villas will consist of 2 or 3 story structures with subterranean parking levels. The plans indicate that the project wiU include reconfigured driveways, walkways and parking areas and other related site improvements. A preliminary site plan provided by the KSL Development Corporation was used during our investigation. SCOPE OF WORK The purpose of our investigation was to determine certain engineering characteristics of the near surface soils on the site in order to develop recommendations for foundation design and site preparation. Our investigation included field exploration, laboratory testing, Hterature review, engineering analysis and the preparation of this report. Evaluation of hazardous wastes was not within the scope of services provided. Our investigation was performed in accordance with contemporary geotechnical engineering principles and practice. We make no other warranty, either express or impUed. PROJECT DESCRIPTION The La Costa Resort and Spa complex is located on the northeast corner of El Camino Real and Costa Del Mar Road in the City of Carlsbad, CaUfornia. The proposed project wiU include the construction of 11 resort/residential buildings along with various associated site improvements. The associated improvements wiU include reconfigured walkways, driveways and parking areas, landscaped areas and underground utiUties. It is our understanding that the proposed resort/residential buildings will be of relatively Ughtweight wood-frame and/or steel frame construction and wiU include subterranean parking levels. The proposed resort/residential buildings will be supported by conventional shaUow spread footings and concrete slabs on grade. Based upon preliminary foundation loading information pro-vided by KSL, we assumed isolated column loads of up to 100 kips and waU loads of up to 5.0 kips per Unear foot for the resort -viUas buildings. We also assumed isolated column loads of up to 50 kips and wall loads of up to 3.0 kips per Unear foot for the proposed spa building. Grading is assumed to include excavation for the proposed subterranean parking levels along with cutting and filUng of the surface soils to construct level building pads and to provide for proper site drainage. The proposed resort viUas wiU be constructed within the central portion of the La Costa Resort and Spa complex in the vicinity of the new spa and ballroom buildings. The majority of the proposed resort -viUas locations are concentrated within existing landscape areas but some existing structures and improvements wUl be removed to accommodate the new buildings. The proposed building sites and adjacent areas slope gently downward towards the south but some areas include irregular topography related to pre-vious grading and landscaping. There are several existing buildings in the area including the new baUroom and spa buildings as well as several older structures. There are numerous underground utiUties servicing the existing buildings and transecting the new building areas. OI_JJ 17 ! November IL 2003 -2- Project No. 444-3161 03-10-183 REGIONAL SEISMICITY A computer program was utiUzed to compile data related to earthquake fault zones in the region and related seismic acti-vity that may affect the site. E.Q. Fault Version 3.00 (Blake 2000) provides a compilation of data related to earthquake faults in the region. The program searches available databases and provides both distances to causitive faults and the corresponding accelerations that may be experienced on the site due to earthquake activity along these faults. The attenuation relationship utilized for this project was based upon Boore (1997) attenuation curves. The output data from this program is included in Appendix C. The information generated was utiUzed in our liquefaction evaluation As indicated on the summary page ofthe E.Q. Fault output data, the Rose Canyon fault is the closest to the site (approximately 8.8 kilometers). The Newport-Inglewood (offshore) fault is located approximately 16.8 kilometers west of the site. The maximum site acceleration is estimated to be 0.332g. This acceleration is based upon a maximum event of magnitude 6.9. LIQUEFACTION Liquefaction occurs with sudden loss of soil strength due to rapid increases in pore pressures within cohesionless soils as a restdt of repeated cycUc loading during seismic events. Several conditions must be present for Uquefaction to occur including! the presence of relatively shaUow groundwater, generaUy loose soils conditions, the susceptibiUty of soils to Uquefaction based upon grain-size characteristics and the generation of significant and repeated seismicaUy induced ground accelerations. Liquefaction affects primarily loose, uniform grained cohesionless sands with low relative densities. As previously indicated the soils underlying the site consist primarily of a thin layer of sUty clays and clayey sUts overlying dense sUty sands. Grovmdwater was encountered at varying depths within several of our borings. The variable groundwater depths suggest that the water encountered perched may be perched groundwater concentrated within more permeable silty sand and silt layers . Based upon the prominence of non-Uquefiable sUts and clays and the dense conditions of the silty sand layers, it is our opinion that the potential for Uquefaction occurring beneath the site is neghgible. SUBSURFACE CONDITIONS The site soUs consist primarUy of a surface layer of sUty clays and clayey sands overlying native silty sands, sandy sUts, sUty clays and clayey sUts. Silty clays and clayey sands were encountered within the upper 5 to 10 feet within the majority of ovu: borings. The near surface sUty clay layers were underlain primarUy by dense sUty sand, sandy sUt and sUty clay layers. The site soUs appeared fairly consistent in composition but very iaconsistent in stratigraphy due to the varying grades across the site. The native soUs underlying the site were found to be firm throughout the depth of each of our borings. The relatively undisturbed samples obtained indicated dry density varying from 93 to 123 pcf. Sampler penetration resistance indicates that density within the underlying native soUs generaUy mcreases with depth. The soUs were found to be moist throughout the depth of our borings but some nearly saturated soils were encountered. Laboratory testing indicates moisture content varying from 1.0 to 37.0 percent. cr» IJ c : November 11, 2003 -3- Project No. 444-3161 03-10-183 Laboratory testing indicates that the surface soUs consist primarily of sUty clays that were found to be moderately expansive. Expansion testing indicates an expansion index of 81 for the silty clays that faUs within the "medium" expansion category in accordance with the Uniform BuUding Code classification system. ConsoUdation testing indicates that the majority of the site soils are susceptible to only minor consolidation and/or compression related settlements. Groundwater was encountered within several of our borings at depths as shallow as 9 feet below the existing groimd surface. The lack of groundwater within several of our borings suggests that the groundwater encountered was perched groundwater concentrated within more permeable layers. The possible presence of groundwater should be considered in foundation design and may impact construction. CONCLUSIONS AND RECOMMENDATIONS Based upon our field investigation and laboratory testing, it is our opinion that the proposed resort residential vUlas are feasible from a soil mechanic's standpoint provided that the recommendations included in this report are considered in buUding foundation design and site preparation. Due to the somewhat inconsistent condition of the near surface soUs and the possibUity of cut/fiU transitions in some of the proposed buUding areas, remedial grading including overexcavation and recompaction of the primary foundation bearing soUs is recommended. It is our opinion that remedial grading within the proposed building areas should include the removal and recompaction of any compressible surface soUs as weU as the primary foundation bearing soUs. Specific recommendations for site preparation are presented in the Site Grading section of this report. Groundwater was encountered within several of our borings at depths as shaUow as 9 feet below the existing ground surface. Due to the dense condition of the sandy soUs underljdng the site, the potential for Uquefaction affecting the site is considered to be neghgible. In our opinion, Uquefaction related mitigation measures in addition to the site grading and foundation design recommendations included in this report should not be necessary. The site is located in a seismicaUy active area as is aU of Southern California. Design professionals should be aware of the site setting and the potential for earthquake activity during the anticipated life of the structure should be acknowledged. The accelerations that may be experienced on the site (as previously discussed) should be considered in design. Seismic design parameters as outhned in the 1997 UBC are summarized in Appendix C. Caving did not occur within our borings but the potential for ca-ving should be considered within deeper excavations. AU excavations should be constructed in accordance with the normal CalOSHA excavation criteria. On the basis of our observations of the materials encountered, we anticipate that the near surface clayey sUts and sUty sands wiU be classified by CalOSHA as Type B and Type C soUs, respectively. Soil conditions should be verified in the field by a "Competent person" employed by the Contractor. The surface soils encountered during our investigation were found to be moderately expansive. Laboratory testing indicated an Expansion Index of 81 for the near surface sUty clays and clayey sUts which corresponds with the "medium" expansion category in accordance with UBC Standard 18- 2. Special expansive soU design criteria as outUned in the Uiuform BuUding Code should not be the controlling factor m the design of foundations and slabs on grade for this project but should be considered in design. Ct^AJ^... TP November 11, 2003 -4- Project No. 444-3161 03-10-183 The foUowing recommendations present more detaUed design criteria that have been developed on the basis of our field and laboratory investigation. Foundation Design: The results of our investigation indicate that either conventional shaUow continuous footings or isolated pad footings that are supported upon properly recompacted soUs, may be expected to provide satisfactory support for the proposed residential structure foundations. Footings should extend at least 18 inches beneath lowest adjacent grade. Isolated square or rectangular footings at least 2 feet square may be designed using an aUowable bearing pressure of 2500 pounds per square foot. Continuous footings at least 12 inches wide may be designed using an aUowable bearing value of 2000 pounds per square foot. The allowable bearing pressures may be increased by 200 psf for each additional one foot of width and 250 psf for each additional 6 inches of depth, if desired. The maximum aUowable bearing pressure should be 3000 psf. The aUowable bearing pressures are for dead and frequently appUed Uve loads and may be increased by 1/3 to resist wind, seismic or other transient loading. Drainage firom the buUding area should be rapid and complete. The recommendations pro-vided in the preceding paragraph are based on the assumption that all footings wUl be supported upon properly compacted soU. All grading should be performed under the testing and inspection of the SoUs Engineer or his representative. Prior to the placement of concrete, we recommend that the footing excavations be inspected in order to verify that they extend into compacted soU and are free of loose and disturbed materials. Settlements: Settlements resulting from the anticipated foundation loads and fUl placement are expected to be mimmal. We estimate that ultimate settlements should be less than one inch when using the recommended foundation bearing values. As a practical matter, differential settlements between footings can be assumed as one-half of the total settlement. Lateral Design: Resistance to lateral loads can be pro-vided by a combination of friction acting at the base of the slabs or foundations and passive earth pressure along the sides of the foundations. A coefficient of friction of 0.40 between soU and concrete may be used with dead load forces only. A passive earth pressure of 250 pounds per square foot, per foot of depth, may be used for the sides of footings that Eire poured against properly compacted native soUs. Passive earth pressure should be ignored within the upper 1 foot except where confined (such as beneath a floor slab). Retaining WaUs: Retaining waUs wUl be necessary to accompUsh the proposed construction. Lateral pressures for use in cantUever retaining waU design may be estimated using an equivalent fluid weight of 40 pcf for level drained native backfill conditions. For waUs that are to be restrained at the top (such as the subterranean parking level waUs), the equivalent fluid weight should be increased to 60 pcf for level drained native backfiU conditions. Backdrains should be provided for the fuU height of the waUs. The recommended lateral pressures should also be appUcable for use in the design of temporary shoring systems, if required Expansive Soils: Due to the presence of "medium" expansion category soUs near the surface throughout the majority of the site, special expansive soU design criteria should be considered in the design of foundations and concrete slabs-on-grade. Due to the somewhat variable conditions, expansion potential should be reevaluated after grading. OJ t J ?— ! November 11, 2003 -5- Project No. 444-3161 03-10-183 Concrete Slabs-on-Grade: AU surfaces to receive concrete slabs-on-grade should be underlain by a minimum compacted fill thickness of 12 inches, placed as described in the Site Grading Section of this report. Where slabs are to receive moisture sensitive floor coverings or where dampness of the floor slab is not desired, we recommend the use of an appropriate vapor barrier or an adequate capiUary break. Vapor barriers should be protected by sand in order to reduce the possibUity of puncture and to aid in obtaining uniform concrete curing. Reinforcement of slabs-on-grade in order to resist expansive soil pressures wUl lUcely be necessary. Slab reinforcement wUl also have a beneficial effect in containing cracking due to concrete shrinkage. Temperature and shrinkage related cracking should be anticipated in all concrete slabs-on-grade. Slab reinforcement and the spacing of control joints should be determined by the Structural Engineer based upon post-grading expansion test results. Soluble Sulfates: The soluble sulfate concentrations of the surface soils were determined to be 774 and 1832 parts per milUon (ppm) which is considered potentiaUy corrosive with respect to concrete. The use of Type V cement and specialized sulfate resistant concrete mix designs may be necessary. The soluble sulfate content of the surface soUs should be reevaluated after grading and appropriate concrete mix designs should be determined based upon post-grading test results. Tentative Pavement Design: AU paving should be underlain by a minimum compacted fill thickness of 12 inches (excluding aggregate base). This may be performed as described in the Site Grading Section of this report. Based upon the surface soU conditions observed, an R- Value of approximately 30 is expected. Based upon a design R-Value of 30, a preliminary pavement design section of 3.0 inches of asphalt on 6.0 inches of Class 2 base material is recommended for parking areas and areas Umited to auto and Ught truck traffic (Traffic Index = 5.0). In driveway areas and areas where hea-vy truck traffic is expected (Traffic Index = 6.5), the pavement section should be increased to 4.0 inches of asphalt on 6.0 inches of base material. Pavement should be confined by curbs. Subgrade should be compacted to at least 90 percent and base material should be compacted to at least 95 percent of maximum density. Final design for asphalt pavement should be based upon R-Value testing performed after rough grading. Aggregate base should conform to the requirements for Class 2 Aggregate Base in Section 26 of CalTrans Standard Specifications, January, 1992. Asphaltic concrete should conform to Section 39 of the CalTrans Standard Specifications. The recommended sections should be provided with a uniformly compacted subgrade and precise control of thickness and elevations during placement. Drainage from paved areas should be rapid and complete. It should be noted that the pavement sections recommended above are minimum sections, if heavfly loaded vehicles are expected to cross automobUe parking and dri-ving areas, thicker pavement sections should be considered in these locations. Pavement design sections are tentative and should be confirmed at the completion of site grading when the subgrade soUs are in-place. This wiU include sampUng and testing of the actual subgrade sofls and an analysis based upon the specific use. November 11, 2003 -6- Project No. 444-3161 03-10-183 Shrinkage and Subsidence: Volumetric shrinkage of the material that is excavated and replaced as controUed compacted fill should be anticipated. We expect that the shriiUcage could vary from 10 to 15 percent. Subsidence of the surfaces that are scarified and compacted should be between 1 and 2 tenths of a foot. This wUl vary depending upon the type of equipment used, the moisture content ofthe soU at the time of grading and the actual degree of compaction attained durmg grading. These values for shrmkage and subsidence are exclusive of losses that wiU occur due to the site clearing, buUding demoUtion and the removal of unsuitable materials. General Site Grading: All grading should be performed in accordance with the grading ordinance of the City of Carlsbad, CaUfornia. The foUowing recommendations have been developed on the basis of our field and laboratory testing: 1. Clearing and DemoUtion: Proper clearing wUl be very important. AU previous pavements, slabs, foundations, trees and the associated root systems should be removed from the buUding areas. Underground utUities should also be removed from the buUdmg areas. SoUs that are disturbed during site clearing and demohtion operations should be removed and replaced as controUed compacted fill under the direction of the SoUs Engineer. 2. Preparation of Building and Foimdation Areas: The remedial grading recommended should include the overexcavation and recompaction of any compressible surface soUs as weU as the primary foundation bearing sofls in order to pro-vide uniform foundation support. Removals within the buUding areas should extend to a minimum depth of 3 feet below existing grade or 3 feet below the bottom of the footings, whichever ia deeper. Subsequent to excavation, the exposed sofls should be scarified to a depth of 1-foot, moisture conditioned and recompacted to at least 90 percent relative compaction! Once cleaned of unsuitable material, the excavated sofls may then be replaced as controUed compacted fiU. 3. Placement of Compacted FUl: PiU materials consisting of on-site soUs or approved import soUs should be spread in shaUow Ufts at near optunum moisture content and compacted to a mmimum of 90 percent relative compaction. Imported fiU material shaU be of equal or greater quaUty than the native surface soils. The contractor shaU notify the SoUs Engineer at least 48 hours in advance of importuig soUs in order to provide sufficient time for the evaluation of proposed import materials. The contractor shaU be responsible for deUvering material to the site that complies with the project specifications. Approval by the SoUs Engineer wUl be based upon material deUvered to the site and not the preUminary evaluation of import sources. Our observations of the material encountered during our investigation indicate that compaction wUl be most readUy obtauied by means of heavy rubber tu-ed grading equipment and sheepsfoot compactors. A uniform and near optimum moisture content should be maintained during fiU placement and compaction. November 11, 2003 -7- Project No. 444-3161 03-10-183 4. Preparation of Slab and Paving Areas: AU surfaces to receive asphalt or concrete paving and exterior concrete slabs-on-grade should be underlain by a mimmum compacted fUl thickness of 12 inches. This may be accompUshed by a combination of overexcavation, scarification and recompaction of the surface soUs, and the placement of the excavated material as compacted enguieered fiU. Compaction of the concrete slab areas should be to a minimum of 90 percent relative compaction Compaction within the proposed pavement areas should be to a minimum of 95 percent relative compaction. 5. Testing and Inspection: During grading tests and observations should be performed by the SoUs Engineer or his representative in order to verify that the grading is being performed in accordance with the project specifications. Field density testing shaU be performed in accordance with applicable ASTM test standards. The minimum acceptable degree of compaction shall be 90 percent of the maximum dry density as obtained by the ASTM D1557-91 test method. Where testing indicates insufficient density, additional compactive effort shall be appUed untU retesting indicates satisfactory compaction. GENERAL The fmdings and recommendations presented in this report are based upon an mterpolation of the soU conditions between boruig locations and extrapolation of these conditions throughout the proposed buUding area. Should conditions encountered during grading appear different than those indicated in this report, this office should be notified. This report is considered to be appUcable for use by La Costa Resort and Spa for the specific site and project described herein. The use of this report by other parties or for other projects is not authorized. The recommendations of this report are contingent upon monitoring of the grading operations by a representative of Sladden Engineermg. AU recommendations are considered to be tentative pending our review of the graduig operations and additional testing, if indicated. If others are employed to perform any soU testmg, this office should be notified prior to such testing in order to coordmate any required site visits by our representative and to assure indemnification of Sladden Engineering. We recommend that a pre-job conference be held on the site prior to the initiation of site grading The purpose of this meeting wfll be to assure a complete understanding of the recommendations presented m this report as they apply to the actual grading performed. APPENDIXA Site Plan Borings Logs Sladden Engineering APPENDIXA FIELD EXPLORATION For our field investigation, 11 exploratory borings were excavated on September 3 and 4, 2003, using a truck mounted hoUow stem auger rig (Mobile B6l). The approximate boring locations are indicated on the site plan included in this appendix. Continuous logs of the materials encountered were prepared during drUUng by a representative of Sladden Engineering. Boring logs are included in this appendix. Representative undisturbed samples were obtained within our borings by driving a thin-waUed steel penetration sampler (CaUfornia spUt spoon sampler) or a Standard Penetration Test (SPT) sampler with a 140-pound hammer dropping approximately 30 inches (ASTM D1586). The number of blows required to drive the samplers 18 inches was recorded in 6-inch increments and blowcounts are indicated on the boring logs. The California samplers are 3.0 inches in diameter, carrying brass sample rings having inner diameters of 2.5 inches. The standard penetration samplers are 2.0 inches in diameter with an inner diameter of 1.5 inches. Undisturbed samples were removed from the sampler and placed in moisture sealed containers in order to preserve the natural soil moisture content. Bulk samples were obtained from the excavation spoUs and samples were then transported to our laboratory for further observations and testing. Samples were then transported to our laboratory for further observations and testing. Sladden Engineering LA COSTA RESORT - TENTATIVE TRACT MAP cmr OF CARLSBAD, STA-TE OF (iALFORMA ,0T4_^; y C O • 1—4 •a O o l-l • f—. o PQ -o as O Oj I-. ca 4) CO t; ca o c ca O cJ ro o c ll u u c 'Bb a W c u CO •a Q C o ta o o ao .fl 'C o CQ u a • 1—4 X O IH o IU La Costa Resort N.E.C. EI Camino Real & Costa Del Mar Road / Carlsbad, California Date; 9-3-03 Boring No. 1 - Lot 10 Job No.: 444-3161 ft'" a r 10 15 20 25 30 O B an o s 10/13/19 8/26/37 i-15/16/21 h 35 40 45 1^ 50 55 21/35/38 11/22/25 10/14/20 DESCRIPTION Siity Clay: Brown, slightly sandy Silty Clay: Brown with interbedded siity clayey sand layers Silty Clay: Brown, slightiy sandy Silty Clay: Brown with interbedded siity clayey sand layers Clayey Sand: Brown, slightly silty, fine grained Silty Clay: Brown with very silty sand layer 4" thick 6/9/13 9/11/16 12/14/15 H 'S c/1 CL CL 118 118 CL CL SC CL Silty Clay: Brown Silty Clay: Brown, slightly sandy 11/13/21 Silty Ciay: Brown 116 105 CL CL CL ^1 Recovered Sample I I I Standard Penetration Sample 01 'o IS 13 14 23 25 28 21 30 CJ Oi a ^6 REMARKS 82% passing #200 82% passing #200 86% passing #200 85% passing #200 39% passing #200 91% passing #200 Note: The stratification lines represent the approximate boundai-ies between the soil types; the transitions may be graduaL 88% passing #200 87% passing #200 89% passing #200 95% passing #200 Total Depth = 51.5' No Bedrock No Groundwater La Costa Resort N.E.C. El Camlno Real & Costa Del Mar Road / Carlsbad, California Date: 9-3-03 Boring No. 2 - Lot ll Job No.: 444-3161 10 15 20 25 30 35 40 45 50 o B CO VO 12/17/20 13/40/45 11 21/33/30 17/20/36 55 I 15/27/36 15/22/35 DESCRIPTION Clayey Sand: Brown, slightiy silty, fme grained H *o (Zl SC Silty Clay: Brown, sandy Clayey Sand: Brown, slightly silty Sand: Grey brown, fine grained trace silt, trace clay RecQvered Sample [ [ I Standard Penetration Sample CL SC SP 123 121 115 103 S 11 REMARKS 44% passing #200 79% passing #200 38% passing #200 26% passing #200 14% passing #200 16% passing #200 Total Depth = 31.5' No Bedrock No Groundwater Note: The stratification lines represent the approximate boundaries between the soil types; the transitions may be gradual. La Costa Resort N.E.C. El Camino Real & Costa Del Mar Road / Carlsbad, California Date: 9-3-03 a PC 10 15 20 25 30 35 40 O S 1/1 i O s i- 12/13/17 14/20/27 Boring No. 3 - Lot 15 DESCRIPTION Silty Clay: Brown, slightly sandy eu H o 00 CL r 23/33/37 7/23/24 11/19/26 16/50-5" 45 50 55 Silty Clay: Brown, sandy Clayey Sand: Brown, very clayey, silty, fine grained Silty Sand: Grey brown, fine grained Sand: Grey brown, fine grained IfH Recovered Sample \y<C\ Unrecovered Sample I [ I Standard Penetration Sample CL SC SM SP .-SO a y <u 3 •H •<-' 112 120 115 17 12 15 Job No.: 444-3161 REMARKS Scattered tree roots 83% passing #200 86% passing #200 46% passing #200 21% passing #200 6% passing #200 Total Depth = 31.5' No Bedrock No Groundwater Note: The stratification lines represent the approximate boundaries between the soii types; the transitions may be graduaL La Costa Resort N.E.C. EI Camino Real & Costa Del Mar Road / Carlsbad, California Pate: 9-3-03 Boring N o. 4 - Lot 14 Job No.: 444-3161 il 10 15 20 25 30 35 40 45 O Xi B u o U vo CO O mm Cf? 5/10/16 9/13/18 I 14/20/27 14/24/30 15/26/26 7/15/16 DESCRIPTION Silty Clay: Brown with interbedded silty clayey sand layers Silty Clay: Brown, slightly sandy a H '3 CO CL Clayey Silt: Brown, sandy Silty Sand: Grey brown, fine grained Sand: Grey brown, fine grained Silty Sand: Grey brown, fine grained CL ML Q <u S o 112 SM SP SM 107 115 94 IU Cu 05 e 19 21 15 12 REMARKS 73% passing #200 84% passing #200 78% passing #200 19% passing #200 6% passing #200 26% passing #200 Recovered Sample I [ I Standard Penetration Sample so 55 Total Depth = 31.5' No Bedrock No Groundwater Note: The stratification lines represent the approximate boundaries between the soil types; the transitions may be graduaL La Costa Resort N.E.C. EI Camino Real & Costa Del Mar Road / Carlsbad, California Pate: 9-3-03 Boring No. 5 - Lot 8 Job No.: 444-3161 o Xi B CO e vo GO o i-30/31/26 10 15 20 25 30 35 y 126/50-5 19/30/37 15/15/15 r 40 45 50 7/10/13 7/9/9 8/9/8 8/17/19 8/7/17 7/14/19 DESCRIPTION Clayey Sand: Brown, slightly silty, fine grained Clayey Sand: Brown, fine to coarse grained, silty Sand: Brown, slightly silty, slightly clayey, fine grained Sand: Grey brown, fine grained Silty Sand: Grey brown, fine grained Silty Clay: Brown u Cu >. H o CO SC SC SP/SM .ac D 3 SP SM CL Silty Clay: Brown with very silty fine grained sand layer 2" thick Silty Clay: Brown, stiff Silty Clay: Brown with very silty fine grained sand layer 2" thick Silty Clay: Brown, stiff CL CL CL 102 102 100 102 a " « E 22 CL 37 37 22 17 22 21 REMARKS 23% passing #200 11% passing #200 3% passing #200 26% passing #200 91% passing #200 92% passing #200 \/ Groundwater @ 33' 78% passing #200 93% passing #200 71% passing #200 92% passing #200 55 I Recovered Sample [ I Standard Penetration Sample Note: The stratification lines represent the approximate boundaries between the soil types; the transitions may be graduaL Total Depth = 51.5' No Bedrock La Costa Resort N.E.C. EI Camino Real & Costa Del Mar Road / Carlsbad, California Pate: 9-3-03 Boring No. 6 - Lot 12 Job No.: 444-3161 a*" QC CO u o o fi vo cn DESCRIPTION a E- O CO u Q .ac t3 3 4> s •p" a " REMARKS Silty Clay: Brown, sandy CL r 9/13/23 108 16 10 15 20 25 30 35 40 45 50 55 19/12/16 16/35/43 Clayey Silt: Brown with thin interbedded silty fine to coarse grained sand layers ML 99 20 I 8/13/17 Silty Clay: Brown, sandy CL 20/34/50 Silty Clay: Brown, stiff CL Clayey Silt: Brown with clayey, silty fine grained sand layer 6" thick ML 9/16/17 Silty Sand: Grey brown, fine grained SM im Recovered Sample I J I Standard Penetration Sample 114 16 115 17 14 82% passing #200 67% passing #200 85% passing #200 91% passing #200 51% passing #200 19% passing #200 Total Depth = 31.5' No Bedrock No Groundwater Note: The stratification lines represent the approximate boundaries between the soil types; the transitions may be gradual. La Costa Resort N.E.C. EI Camino Real & Costa Del Mar Road / Carlsbad, California Pate: 9-4-03 Boring No. 7 - Lot 16 Job No.: 444-3161 cu"** « fi Qc o x: B CO 10 15 20 25 30 35 40 45 50 i •FN VO CO 9/10/12 10/15/19 11 31/50-5" 15/18/18 19/25/25 50-4" DESCRIPTION Clayey Sand: Brown, slightly silty, fine grained Clayey Sand: Brovm, fine to coarse grained, silty Sand: Brown, slightly silty, slightly clayey, fine grained Sand: Brown, slightly silty, slightly clayey, fine to coarse grained with gravel 0) '3 SC SC SP/SM SP/SM .-ac- P 3 108 118 121 <u a o 10 10 10 a " 107 16 13 REMARKS 22% passing #200 24% passing #200 Groundwater @ 14' \7 14% passing #200 19% passing #200 13% passing #200 Unrecovered sample Recovered Sample I [ I Standard Penetration Sample i 55 Total Depth = 31.5' No Bedrock Note: The stratification lines represent the approximate boundaries between the soil types; the transitions may be gradual. La Costa Resort N.E.C. El Camino Real & Costa Del Mar Road / Carlsbad, California Pate: 9-4-03 a*" QC 10 15 20 25 30 35 40 45 |1 ^^•5/7/8 50 55 O B CO 0) u o U vo cn O CQ 16/17/8 11 9/9/12 6/10/11 i %/T 6/10/10 6/11/13 4/6/6 7/8/10 5/6/6 Boring No. 8 - Lot 17 DESCRIPTION Clayey Silt: Brown (U o c/3 ML Silty Clay: Brown with slightly silty, slightly clayey sand layer layer 6" thick Silty Clay: Brown, slightly sandy Silty Clay: Brown CL CL CL u Q .-ac D 3 100 108 114 111 Silty Clay: Brown, sandy I Recovered Sample I J I Standard Penetration Sample u 3 21 16 .EH *J a (U Cu Pi B ^6 16 CL 17 18 19 16 21 23 Job No.: 444-3161 REMARKS Note: The stratification lines represent the apfiroximate boundaries between the soil types; the transitions may be graduaL 85% passing #200 \/ Groundwater @ 9' 71% passing #200 87% passing #200 93% passing #200 94% passing #200 91% passing #200 89% passing #200 94% passing #200 87% passing #200 83% passing #200 Total Depth = 51.5' No Bedrock La Costa Resort N.E.C. El Camino Real & Costa Del Mar Road / Carlsbad, California Pate: 9-4-03 Boring No. 9 - Lot 11 Job No.: 444-3161 Q^ o B CO o fl vo O DESCRIPTION CU >. H *3 CO La Q .-ac P 3 s o X3 u D. O U REMARKS Silty Clay: Brown, sandy CL 10 15 20 25 30 35 40 45 50 55 ii 6/9/13 8/12/12 118 111 13 12 10/13/15 Silty Clay: Brown with interbedded silty clayey sand layers CL 10:5 20/50-5" Clayey Sand: Brown, slightly silty, fine grained SC 98 19/24/24 Sand: Grey brown, slightly silty, fine grained SP/SM 25/50-5" Recovered Sample I J I Standai'd Penetration Sample Asphalt 3" thick 82% passing #200 80% passing #200 68% passing #200 32% passing #200 10% passing #200 11% passing #200 Total Depth = 31.5' No Bedrock No Groundwater Note: The stratification lines represent the approximate boundaries between the soil types; the transitions may be gradual. La Costa Resort N.E.C. EI Camino Real & Costa Del Mar Road / Carlsbad, California Pate: 9-4-03 Boring No. 10 - Lot 7 Job No.: 444-3161 (U fi QC o xa B >, CO vo cn & o s DESCRIPTION 0) cu >. H mm 'o C/3 .ac P 3 3 9 a V Cll ^ B ^6 REMARKS I /yvpi6/9/i3 10 10/17/26 11 16/19/29 20 25 30 35 40 45 50 55 |1 20/17/21 ^j5/6/8 5/8/8 Silty Clay: Dark grey CL 115 15 Silty Clay: Brown, sandy CL 116 14 Silty Clay: Brown CL 96 25 Silty Clay: Dark grey CL 94 26 Silty Clay: Brown CL 29 29 86% passing #200 75% passing #200 93% passing #200 97% passing #200 95% passing #200 Groundwater @ 27' \/ 88% passing #200 Recovered Sample I Standard Penetration Sample Total Depth = 31.5' No Bedrock Note: The stratification lines represent the approximate boundaries between the soil types; the transitions may be gradual. La Costa Resort N.E.C. EI Camino Real & Costa Del Mar Road / Carlsbad, California Date: 9-4-03 Boring No. 11 - Lot 5 Job No.: 444-3161 « fi QC o e tZ! I a vo en O DESCRIPTION a Cu >> H o CO Q .-ac-ts y P 3 ll s a 0) cu Pi a REMARKS r 8/11/15 10 15 20 25 30 35 40 45 50 10/35/30 17/24/30 121/24/30 55 7/9/22 7/9/9 Silty Clay: Brown CL 108 17 Sand: Brown, slightly silty, slightly clayey, fine grained SP/SM 119 Sand: Grey brown, slightly silty, fine grained SP/SM 93 Sand: Grey brown, fine grained SP 97 Silty Clay: Brown, stiff Silty Clay: Brown, sandy m Recovered Sample I [ I Standard Penetration Sample CL 29 CL 87% passing #200 15% passing #200 11% passing #200 4% passing #200 91% passing #200 Groundwater @ 27' -S^ 82% passing #200 Total Depth = 31.5' No Bedrock Note: The stratification lines represent the approximate boundaries between the soil types; the transitions may be gradual. APPENDIX B Laboratory Testing Laboratory Test Results .C/n A it att 17 wt frf M aatn wt rt APPENDIX B LABORATORY TESTING Representative bulk and relatively imcUsturbed sod samples were obtained in the field and returned to our laboratory for additional observations and testing. Laboratory testing was generally performed in two phases. The first phase consisted of testing in order to determine the compaction of the existing natural soU and the general engineering classifications of the soUs underlying the site This testing was performed in order to estimate the engineering characteristics of the soil and to serve as a basis for selecting samples for the second phase of testing. The second phase consisted of soU mechanics testing. This testing including consoUdation, shear strength and expansion testing was performed in order to provide a means of developing specific design recommendations based on the mechanical properties of the soU. CLASSIFICATION AND COMPACTIONTESTING Unit Weight and Moisture Content Determinations: Each uncUsturbed sample was weighed and measiu'ed in order to determine its unit weight. A smaU portion of each sample was then subjected to testing in order to determine its moisture content. This was used in order to determine the dry density of the sofl in its natural condition. The results ofthis testing are shown on the Boring Logs. Maximum Density-Optimum Moisture Determinations: Representative soU types were selected for maximum density determinations. This testing was performed in accordance with the ASTM Standard D1557-91, Test Method A. The results of this testing are presented graphicaUy in this appendix. The maximum densities are compared to the field densities of the soU in order to determine the existing relative compaction to the sofl. This is shown on the Boring Logs, and is useful in estimating the strength and compressibihty ofthe soU. Classification Testing: SoU samples were selected for classification testing. This testing consists of mechanical grain size analyses and Atterberg Limits determinations. These pro-vide information for developing classifications for the soU in accordance with the Unified Classification System. This classification system categorizes the soU into groups ha-ving simUar engineering characteristics. The results of this testing are very useful in detecting variations in the soUs and in selecting samples for further testing. SOIL MECHANIC'S TESTING Direct Shear Testing: Three bulk samples were selected for Direct Shear Testing. This testing measures the shear strength of the soU under various normal pressures and is used in developing parameters for foundation design and lateral design. Testing was performed using recompacted test specimens, which were saturated prior to testing. Testing was performed using a stram controUed test apparatus with normal pressures ranging from 800 to 2300 pounds per square foot. Expansion Testing: Three bulk samples were selected for Expansion testing. Expansion testing was performed in accordance with the UBC Standard 18-2. This testing consists of remolding 4-inch diameter by l-inch thick test specimens to a moisture content and dry density corresponding to approximately 50 percent saturation. The samples are subjected to a surcharge of 144 pounds per square foot and aUowed to reach equiUbrium. At that point the specimens are inundated with distiUed water. The linear expansion is then measured untfl complete. ConsoUdation Testing: Eight relatively undisturbed samples were selected for consoUdation testing. For this testing one-inch thick test specimens are subjected to vertical loads varying from 575 psf to 11520 psf appUed progressively. The consoUdation at each load increment was recorded prior to placement of each subsequent load. The specimens were saturated at the 575 psf or 720 psf load increment. Sladden Eneineerine Maximum Density/Optimum Moisture Project Number: ProjectName: Lab ID Number: Sample Location: Description: Maximuin Density: Optimum Moisture ASTM D698/D1557 444-3161 La Costa Villas Bulk 1 @ 15-20' Sandy Silt with Traces of Clay 123 pcf 9% October 3, 2003 ASTMD-1557 A Rammer Type: Machine Sieve Size % Retained 3/4" 3/8" #4 10 15 Moisture Content, % X4».. r. Cl I _ J .1 T-. Project Niunber: ProjectName: Lab ID Number: Sample Location: Description: Maximum Density: Optimum Moisture Maximum Density/Optimum Moisture ASTM D698/DI557 444-3161 La Costa Villas Bulk 3 @ 25-30' Sand 107 pcf 8% October 3, 2003 ASTMD-1557 A Rammer Type: Machine Sieve Size % Retained 3/4" 3/8" #4 Maximum Density/Optimum Moisture ASTM D698/D1557 Project Number: 444-3161 La Costa Villas Project Name: Lab ID Number: Sample Location: Bulk 1 @ 1-5' Description: Maximum Density: Optimum Moisture Silty Sand with Traces of Clay 116 pcf 12% October 3, 2003 ASTMD-1557 A Rammer Type: Machine Sieve Size % Retained 3/4" 3/8" #4 Direct Shear ASTM D 3080-90 (modified for unconsolidated, undrained conditions) Job Number 444-3161 October 3, 2003 Job Name La Costa Villas Lab ID No. Sample ID Bulk 1 @ 0-5' Classification Sandy Silt with Traces of Clay Sample Type Remolded @ 90% of Maximum Density Initial Dry Density: 112.0 pcf Initial Mosture Content: 9.0 % Peak Friction Angle (0): 34° Cohesion (c): 90 psf Test Results 1 2 3 4 Average Moisture Content, % 16.5 16.5 16.5 16.5 16.5 Saturation, % 88.5 88.5 88.5 88.5 88.5 Normal Stress, kips 0.151 0.301 0.603 1.206 Peak Stress, kips 0.135 0.351 0.504 0.891 • Peak Stress Linear (Peak Stress) 1-2 • 1.0 - 1-2 • 1.0 - 4 1-2 • 1.0 - 4 0.8 - 4 0.8 - 4 V) V) a> ? 0.6- 4 V) V) a> ? 0.6- 4 la V JS CO 0.4 - 4 la V JS CO 0.4 -1 4 0.2 - < 1 4 0.2 - 4 • • 4 0.0 - 4 0.0 0.2 0. 4 0. r 6 0. 'formal Stress 8 1. 0 1. 2 1. 4 Direct Shear ASTM D 3080-90 (modified for unconsolidated, undrained conditions) Job Number 444-3161 October 3, 2003 Job Name La Costa Villas Lab ID No. Sample ID Bulk 3 @ 25-30 Classification Sand Sample Type Remolded @ 90% of Maximum Density Initial Dry Density: 95.1 pcf Initial Mosture Content: 8.0 % Peak Friction Angle (0): 37° Cohesion (c): 130 psf Test Results 1 2 3 4 Average Moisture Content, % 26.6 26.6 26.6 26.6 26.6 Saturation, % 93.1 93.1 93.1 93.1 93.1 Normal Stress, kips 0.151 0.301 0.603 1.206 Peak Stress, kips 0.099 0.405 0.765 0.954 1.2 1.0 0.8 u CO 0.6 0.4 0.2 0.0 0.0 Peak Stress —— Linear (Peak Stress) 0.2 0.4 0.6 0.8 Normal Stress 1.0 » i ( % 1.2 1.4 Direct Shear ASTM D 3080-90 (modified for unconsolidated, undrained conditions) Job Number 444-3161 October 3, 2003 Job Name La Costa Villas Lab ID No. Sample ID Bulk 7 @ 0-5' Classification Silty Sand with Traces of Clay Sample Type Remolded @ 90% of Maximum Density Initial Dry Density: 102.3 pcf Initial Mosture Content: 12.0% Peak Friction Angle (0): 26° Cohesion (c): 80 psf Test Results 1 2 3 4 Average Moisture Content, % 24.4 24.4 24.4 24.4 24.4 Saturation, % 101.5 101.5 101.5 101.5 101.5 Normal Stress, kips 0.151 0.301 0.603 1.206 Peak Stress, kips 0.162 0.207 0.396 0.675 1.2 1.0 0.8 ^ 0.6 Ol 0.4 0.2 0.0 0.0 • Peak Stress Linear (Peak Stress) 4- 0.2 0.4 0.6 0.8 Normal Stress 1.0 1.2 1.4 One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 1 (g 15' Soil Description: Sandy Silt October 3, 2003 Initial Dry Density, pcf: 114.5 Initial Moisture, %: 14 Initial. Void Ratio: 0.456 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram —«—Before Saturation A • After Saturation O • Rebound —•— Hydro Consolidation One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 1 @ 20' Soil Description: Silty Sand October 3, 2003 Initial Dry Density, pcf: 105.1 Initial Moisture, %: 9 Initial Void Rafio: 0.587 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram 0 Before Saturation A After Saturation 0 Rebound —•—Hydro Consolidation -4 -5 -6 -7 -8 -9 -10 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 One Dimensional Consolidation ASTM D2435 &. D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 2 @ 5' Soil Description: Silty Sand October 3, 2003 Initial Dry Density, pcf: 122.8 Initial Moisture, %>: 9 Inifial Void Ratio: 0.357 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram -10 0.0 • Before Saturation • Rebound 0.5 1.0 1.5 2.0 • After Saturation •Hydro Consolidation 2.5 3.0 3.5 4.0 4.5 5.0 One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 2 @ 10' Soil Description: Silty Sand October 3, 2003 Inifial Dry Density, pcf: 116.8 Initial Moisture, %; 11 Inifial Void Rafio: 0.427 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram -3 -6 -7 -10 -•— Before Saturation -o— Rebound • After Saturation • Hydro Consolidation 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 3 @ 15' Soil Description: Silty Sand October 3, 2003 Initial Dry Density, pcf: 120.3 Initial Moisture, %: 12 Initial Void Ratio: 0.386 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram -10 0.0 Before Saturation Rebound -ir— After Saturation -•—Hydro Consolidation 1.0 2.0 3.0 4.0 5.0 6.0 7.0 One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 3 @ 20' Soil Description: Sandy Silt October 3, 2003 Initial Dry Density, pcf: 113.5 Initial Moisture, %>: 15 Initial Void Ratio: 0.469 Specific Gravity: 2.67 % Change In Height vs Normal Presssure Diagram -5 -6 -10 0.0 1.0 Before Saturation Rebound 2.0 3.0 • After Saturation • Hydro Consolidation \ 4.0 5.0 6.0 7.0 One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 8 (g 15' Soil Description: Silty Sand October 3, 2003 Initial Dry Density, pcf: 108.2 Initial Moisture, %: 16 Initial Void Ratio: 0.541 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram -3 -5 -6 -7 -8 -10 Before Saturation Rebound •After Saturation -Hydro Consolidation 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 8 @ 20' Soil Description: Silty Sand October 3,2003 Initial Dry Density, pcf: 110.6 Initial Moisture, %: 18 Initial Void Ratio: 0.507 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram -4 -6 -7 -8 -9 •10 • Before Saturation • Rebound -A— After Saturation -•— Hydro Consolidation 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 One Dimensional Consolidation ASTM D2435 & 053 3 3 Job Number: 444-3161 October 3, 2003 Job Name: La Costa Villas Sample ID: Boring 10 @ 15' Soil Description: Silty Clay Initial Dry Density, pcf: 94.3 Initial Moisture, %: 25 Initial Void Ratio: 0.767 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram • Before Saturation •Rebound After Saturation Hydro Consolidation One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 10 (§ 20' Soil Description: Silty Clay October 3, 2003 Initial Dry Density, pcf: 92.2 Initial Moisture, %: 26 Initial Void Ratio: 0.807 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram • Before Saturation •Rebound • After Saturation • Hydro Consolidation One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 11 @ 5' Soil Description: Sandy Silt October 3, 2003 Initial Dry Density, pcf: 105.1 Initial Moisture, %: 17 Initial Void Ratio: 0.586 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram • Before Saturation •Rebound -After Saturation . •Hydro Consolidation 0-5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 One Dimensional Consolidation ASTM D2435 & D5333 Job Number: 444-3161 Job Name: La Costa Villas Sample ID: Boring 11 @ 10' Soil Description: Silty Sand October 3, 2003 Initial Dry Density, pcf: 118.0 Initial Moisture, %: 7 Initial Void Ratio: 0.412 Specific Gravity: 2.67 % Change in Height vs Normal Presssure Diagram -d— Before Saturation -&— Rebound •Ar— After Saturation -•— Hydro Consolidation 00 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Gradation ASTMC117&C136 Project Number: Project Name: 444-3161 La Costa Villas Sample ID: Bulk 1 @ 15-20' Sieve Sieve Percent Size,in Size, mm Passing 1" 25.4 100 3/4" 19.1 100 1/2" 12.7 100 3/8" 9.53 100 #4 4.75 100 #8 2.36 100 #16 1.18 100 #30 0.60 100 #50 0.30 97 #100 0.15 84 #200 0.074 58 Project Number: Project Name: Sample ID: 444-3161 La Costa Villas Bulk 3 (5) 25-30' Gradation ASTMC117&C136 Sieve Sieve Percent Size, in Size, mm Passing 1" 25.4 100 3/4" 19.1 100 1/2" 12.7 100 3/8" 9.53 100 #4 4.75 100 #8 2.36 100 #16 1.18 100 #30 0.60 100 #50 0.30 100 #100 0.15 48 #200 0.074 9 100 90 80 70 60 .s "c/i cn cij 50 40 30 20 10 0 • • • It 100.0 10.0 1.0 0.1 Sieve Size, mm 0.0 0.0 Gradation ASTMC117&C136 Project Number: Project Nai-ne: 444-3161 La Costa Villas Sample ID: Bulk 7 @ 1-5' Sieve Sieve Percent Size, in Size, mm Passing 1" 25.4 100 3/4" 19.1 100 1/2" 12.7 100 3/8" 9.53 100 #4 4.75 97 #8 2.36 96 #16 1.18 93 #30 0.60 88 #50 0.30 78 #100 0.15 63 #200 0.074 48 Gradation ASTMC117&C136 Project Number: ProjectName: 444-3161 La Costa Villas Sample ID: Boring 7 @ 5' Sieve Sieve Percent Size, in Size, mm Passing 1" 25.4 100 3/4" 19.1 100 1/2" 12.7 100 3/8" 9.53 100 #4 4.75 98 #8 2.36 93 #16 1.18 86 #30 0.60 75 #50 0.30 54 #100 0.15 31 #200 0.074 22 Expansion Index ASTM D 4829/UBC 29-2 Job Number: Job Name: Lab ID: Sample ID: Soil Description: 444-3161 La Costa Villas Date: Tech: 10/3/03 Jake Bulk 1 @ 0-5' Sandy Silt vdth Traces of Clay WtofSoil + Ring: 595.0 Weight of Ring: 179.0 WtofWet Soil: 416.0 Percent Moisture: 8% Wet Density, pcf: 126.0 Dry Denstiy, pcf: 116.7 % Saturation: 48.7 Expansion Rack # Date/Time 10/7/03 11:50 a.m. Initial Reading 0.500 Final Reading 0.581 Expansion Index (Final - Initial) X 1000 81 EI Sladden Engineering Revised 12/10/02 Expansion Index ASTM D 4829/UBC 29-2 Job Number: Job Name: Lab ID: Sample ID: Soil Description: 444-3161 La Costa Villas Bulk 3 (al 25-30' Sand Date: Tech: 10/3/03 Jake WtofSoil + Ring: 620.0 Weight of Ring: 179.0 WtofWet Soil: 441.0 Percent Moisture: 6% Wet Density, pcf: 133.6 Dry Denstiy, pcf: 126.1 % Saturation: 48.1 Expansion Rack# Date/Time 10/6/03 8:00 a.m. Initial Reading 0.500 Final Reading 0.501 Expansion Index (Final - Initial) x 1000 El Sladden Engineering Revised 12/10/02 Expansion Index ASTM D 4829/UBC 29-2 Job Number: Job Name: Lab ID: Sample ID: Soil Description: 444-3161 La Costa Villas Date: Tech: 10/3/03 Jake Bulk 7 (fli 0-5' Silty Sand with Traces of Clay WtofSoil + Ring: 565.0 Weight of Ring: 179.0 WtofWet Soil: 386.0 Percent Moisture: 11% Wet Density, pcf: 117.0 Dry Denstiy, pcf: 105.4 1% Saturation: 49.6 1 Expansion Rack # Date/Time 10/9/03 7:30 a.m. Initial Reading 0.500 Final Reading 0.542 Expansion Index (Final - Initial) X 1000 42 EI Sladden Engineering Revised 12/10/02 ANAHEIM TEST LABORATORY 3008 S. ORANGE A-VEKUE SANTA ANA. CALIFORNIA 92707 PHONE (714) 549-7267 TO. SLADDEM ENGINEERING: 6782 STANTON AVE, SUITE A BUENA PARK, CA. 90621 ATTN: BRETT/DAVE DATE: 9/22/03 P.O. No. Chain of Custody Shipper No. LQl3.No. A-3815 1-2 Soeclflcalion: Material: SOIL PROJECT: #444-3161 ANALYTICAL REPORT CORROSION SERIES SUMMARY OF DATA pH SOLUBLE SULFATES per CA. 417 ppra SOLUBLE CHLORIDES MIN. RESISTIVITY per CA. 422 per CA. 643 ppm ohm-cm #1 B-7 e 1'-5' 6.5 774 #2 B-1 @ 15'-20' 6.6 1,832 304 364 600 max 600 max APPENDIX C 1997 UBC Seismic Design Criteria mwt iron ttn I I 1997 UNIFORM BUILDING CODE SEISMIC DESIGN INFORMATION The Intemational Conference of Building Officials 1997 Uniform Building Code contains substantial revisions and additions to the earthquake engineering section in Chapter 16. Concepts contained in the 1997 code that wiU be relevant to construction of the proposed structures are summarized below. Ground shaking is expected to be the primary hazard most likely to affect the site, based upon proximity to significant faults capable of generating large earthquakes. Major fault zones considered to be most likely to create strong ground shaking at the site are listed below. Fault Zone Approximate Distance From Site Fault Type (1997 UBC) Newport - Inglewood 16.8 km B Rose Canyon Fault 8.8 km B Based on our field observations and understanding of local geologic conditions, the soil profile type judged appUcable to this site is SD, generally described as stiff or dense soil. The site is located within UBC Seismic Zone 4. The following table presents additional coefficients and factors relevant to seismic mitigation for design is accordance with the 1997 code. Near-Source Near-Source Seismic Seismic Seismic Acceleration Velocity Coefficient Coefficient Source Factor, Na Factor, Nv Ca Cv Ne-wport 1.0 1.0 0.44 Na 0.64 Nv Inglewood Rose Canyon Fault 1.0 1.05 0.44 Na 0.64 Nv Sladden Eneineerine *********************** * * * EQFAULT * * * •> Version 3.00 * * * *********************** DETERMINISTIC ESTIMATION OF PEAK ACCELERATION FROM DIGITIZED FAULTS JOB NUMBER: 544-2063 DATE: 06-23-2002 JOB NAME: Costa Del Mar Road / Carlsbad CALCULATION NAME: Test Run Analysis FAULT-DATA-FILE NAME: CDMGFLTE.DAT SITE COORDINATES: SITE LATITUDE: 33.0889 SITE LONGITUDE: 117.2678 SEARCH RADIUS: 100 mi ATTENUATION RELATION: 5) Boore et al. (1997) Horiz. - SOIL (310) UNCERTAINTY (M=.Median, S=Sigma) : M Number of Sigmas: 0.0 DISTANCE MEASURE: cd_2drp SCOND: 0 Basement Depth: 5.00 km Campbell SSR: Campbell SHR: COMPUTE PEAK HORIZONTAL ACCELERATION FAULT-DATA FILE USED: CDMGFLTE.DAT MINIMUM DEPTH VALUE (km): 0.0 EQFAULT SUMMARY DETERMINISTIC SITE PARAMETERS Page ESTIMATED MAX. EARTHQUAKE EVENT APPROXIMATE ABBREVIATED DISTANCE MAXIMUM 1 PEAK EST. SITE FAULT NAME mi (km) EARTHQUAKE 1 SITE INTENSITY MAG . (Mw) 1 ACCEL, g MOD.MERC. ROSE CANYON 5. 5 ( 8. 8) 6 . 9 1 0 .332 IX NEWPORT-INGLEWOOD (Offshore) 10. 4 ( 16. 8) 6 . 9 1 0 .220 IX CORONADO BANK 20. 6 ( 33. 2) 7 . 4 1 0 . 173 VIII ELSINORE-TEMECULA 24 . 8 { 39. 9) 6 . 8 1 0 .110 VII ELSINORE-JULIAN 24 . 8 ( 39. 9) 7 . 1 1 0 . 129 VIII ELSINORE-GLEN IVY 38. 6 ( 62. 1) 6 .8 1 0 . 078 VII EARTHQUAKE VALLEY 40. 3 { 64 . 8) 6 .5 1 0 .065 VI PALOS VERDES 41. 1 { 66. 1) 7 . 1 1 0 .087 VII SAN JACINTO-ANZA 47. 7 ( 76. 7) 7 .2 1 0 .082 VII SAN JACINTO-SAN JACINTO VALLEY 49. 3 ( 79. 4 ) 6 . 9 1 0 .068 VI SAN JACINTO-COYOTE CREEK 50. 8 ( 81. 8) 6 . 8 1 0 .063 VI NEWPORT-INGLEWOOD (L.A.Basin) 52. 2 ( 84 . 0) 6 . 9 i 0 . 065 VI CHINO-CENTRAL AVE. (Elsinore) 52. 8 ( 84 . 9) 6 . 7 1 0 .071 VI ELSINORE-COYOTE MOUNTAIN 53. 1 { 85. 5) 6 . 8 1 0 .061 VI WHITTIER 57 . 0 ( 91. 8) 6 . 8 1 0 .058 VI COMPTON THRUST 61. 8 ( 99. 5 ) 6 .8 1 0 .066 VI SAN JACINTO - BORREGO 62. 6 ( 100. 8) 6 . 6 1 0 .048 VI SAN JACINTO-SAN BERNARDINO 64. 1 ( 103. 2) 6 .7 1 0 .050 VI ELYSIAN PARK THRUST 64. 5 ( 103. 8) 6 . 7 i 0 .061 VI SAN ANDREAS - San Bernardino 67. 4 ( 108. 4) 7 .3 1 0 .066 VI SAN ANDREAS - Southern 67 . 4 ( 108 . 4) 7 . 4 1 0 .070 VI SAN JOSE 73. 8 ( 118. 8) 6 .5 1 0 .049 VI SAN ANDREAS - Coachella 73. 8 ( 118. 8) 7 . 1 1 0 .055 VI PINTO MOUNTAIN 74. 0 ( 119. 1) 7 .0 1 0 .052 VI CUCAMONGA 76. 2 ( 122. 7) 7 0 1 0 . 062 VI SIERRA MADRE 76. 5 ( 123. 1) 7 . 0 1 0 .062 VI SUPERSTITION MTN. (San Jacinto) 78 . 2 ( 125. 8) 6 . 6 1 0 .041 V BURNT MTN. 78. 5 ( 126. 3) 6 . 4 1 0 .037 V NORTH FRONTAL FAULT ZONE (West) 79. 5( 128. 0) 7 .0 1 0 .060 VI EUREKA PEAK 81. 2 ( 130. 7) 6 . 4 1 0 .036 V ELMORE RANCH .81. 9 ( 131. B) 6 6 1 0 .039 V CLEGHORN •81. 9{ 131. 8) 6 5 1 0 .037 V NORTH FRONTAL FAULT ZONE (East) 82. 7 ( 133. 1) 6 .7 1 0 .050 VI SUPERSTITION HILLS (San Jacinto) 83. 0 ( 133. 5) 6 . 6 1 0 .039 V LAGUNA SALADA 84 . 1 ( 135. 3) 7 0 1 0 .048 VI SAN ANDREAS - 1857 Rupture 85. 7 ( 138. 0) 7 .8 1 0 .071 VI SAN ANDREAS - Mojave 85. 7 ( 138. 0) 7 . 1 1 0 . 049 VI RAYMOND 85. 9( 138. 2) 6 . 5 1 0 .044 VI CLAMSHELL-SAWPIT 86. 1 ( 138. 5) 6 .5 1 0 .044 VI VERDUGO 88. 4 ( 142 . 3) 6 . 7 1 0 .047 VI DETERMINISTIC SITE PARAMETERS Page ABBREVIATED FAULT NAME LANDERS HOLLYWOOD HELENDALE - S. LOCKHARDT BRAWLEY SEISMIC ZONE LENWOOD-LOCKHART-OLD WOMA SANTA MONICA EMERSON So. - COPPER MTN. JOHNSON VALLEY (Northern) MALIBU COAST IMPERIAL 1 1 ESTIMATED t-^AX. EARTHQUAKE EVENT 1 APPROXIMATE 1 DISTANCE 1 APPROXIMATE 1 DISTANCE 1 MAXIMUM 1 PEAK EST. SITE 1 mi (km) EARTHQUAKE 1 SITE INTENSITY 1 MAG.(Mw) 1 ACCEL, g MOD.MERC. ===== 1 ============== ========== 1 ========== ========= 1 89.1( 143.4) 7.3 1 0.053 VI I 90.4{ 145.5) 6.4 1 0.040 j V 1 91.5( 147,3) 7 . 1 1 0.047 1 VI 1 92.1( 148.2) 6.4 1 0.032 1 V SPRGSI 94.8( 152.5) 7.3 i 0.051 1 VI 1 95.2( 153.2) 6.6 1 0.043 1 VI 1 96.8( 155.8) 6.9 1 0.040 1 V 1 97.3 ( 156.6) 1 6.7 0.036 1 V I 97.9( 157.6)1 6.7 0.044 1 VI I 99.2 ( 159.6) 1 7.0 0.042 1 yj ******************************.^**i,j,*^,.i,^^^j^^. -END OF SEARCH- 50 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. THE ROSE CANYON FAULT IS CLOSEST TO THE SITE. IT IS ABOUT 5.5 MILES (8.8 km) AWAY. LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.3317 g 1100 1000 900 800 -- 700 -- 600 500 400 -- 300 200 100 -- CALIFORNIA FAULT MAP Costa Del Mar Road / Carlsbad -100 -400 -300 -200 -100 100 200 300 400 500 600 STRIKE-SLIP FAULTS 5) Boore et al. (1997) Horiz. - SOIL (310) M=5 M=6 M=7 M=8 v2 c o '-4—« CO CD o o < ,001 10 100 Distance fadistl (km) DIP-SLIP FAULTS 5) Boore et al. (1997) Horiz. - SOIL (310) M=5 W\=6 W\=7 M=8 c o CO 0 CD o o < 1 .1 ,01 -= ,001 -k 10 100 Distance fadistl (km) BLIND-THRUST FAULTS 5) Boore et al. (1997) Horiz. - SOIL (310) iVI=5 IV1=6 M=7 M=8 c q '•*-> CO 0) 0 o o < ,001 10 100 Distance fadistl (km) MAXIMUM EARTHQUAKES Costa Del Mar Road / Carlsbad c o CO i_ 0 0 o o < 1 -= 1 01 -= .001 4t 1 10 Distance (mi) 100 EARTHQUAKE MAGNITUDES «& DISTANCES Costa Del Mar Road / Carlsbad 1 10 Distance (mi) 100 Sladden Engineering 77-725 Enfield Lane, Suite 100, Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-3895 6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 15438 Cholame Road, Suite A, Victorville, CA 92392 (760)962-1868 Fax (760) 962-1878 September 11, 2006 P'-oje^* No. 444-3161 *^ 06-09-892 G Companies Construction, Inc. 1107 Quail Street RECEIVED New^port Beach, California 92660 FEB 0 2 2007 Subject: Geotechnical Addendum/Update ENGINEERING Project: Planning Area 2 Resort Villas DEPARTMENT La Costa Resort & Spa Costa Del Mar Road Carlsbad, California Ref: Geotechnical hivestigation Report prepared by Sladden Engineering dated November 11, 2003, Project No. 444-3161, Report No. 03-10-183. As requested, -we have reviewed the referenced Geotechnical Investigation report as it relates to the design and construction of the resort villas complex proposed for Planning Area 2 of the La Costa Resort and Spa campus. Planning Area 2 is located just north of the existing ballroom facility at the La Costa Resort and Spa in the City of Carlsbad, California. The proposed Planning Area 2 Resort Villas project will consist of 2 or 3 story wood-frame struchires with slab on grade construction. The referenced Geotechnical Investigation report includes recommendations for the design and construction of similar resort residential units. Based upon our review of the referenced report, our involvement throughout the grading and conshniction of the adjacent La Costa facilities, our recent site observations and our understanding of the proposed project, it is our opinion that the recommendations included in the above referenced report remain applicable for the proposed Planning Area 2 resort residential units. Because the proposed use of slab on grade construction, it is likely that potentially expansive surface soil will be encountered at the planned elevation. Because the recommended remedial Ji* grading will result in significant mixing and blending of the surface soil, it is our opinion that \J foundahons should be designed based upon post-grading expansion test results. For preliminary QJ design purposes, footings should extend at least 18 inches beneath lowest adjacent grade. «^ Isolated square or rectangular footings at least 2 feet square may be designed using an allowable ^ bearing value of 2500 pounds per square foot. Continuous footings at least 12 inches wide may W be designed using an allowable bearing value of 2000 pounds per square foot. 3 September 11, 2006 -2- Project No. 444-3161 ^ 06-09-892 Allowable increases of 200 psf for each additional 1 foot of width and 250 psf for each additional 6 inches of depth may be utilized if desired. The maximum allowable bearing pressure should be 3000 psf. The allowable bearing pressures are for dead and frequently applied live loads and may be increased by 1/3 to resist wind, seismic or other transient loading. The recommendations made in the preceding paragraph are based on the assumption that all footings will be supported by properly compacted soils. Prior to the placement of the reinforcing steel and concrete, we recommend that the footing excavations be inspected in order to verify that they extend into the firm compacted soils and are free of loose and disturbed materials. Settlements may result from the anticipated foundation loads. These estimated ultimate settlements are calculated to be a maximum of 1 inch when using the recommended bearing values. As a practical matter, differential settlements between footings can be assumed as one- half of the total settlement. These elastic settlements are expected to occur during conshuction. Resistance to lateral loads may be provided by a combination of friction acting at the base of the slabs or foundations and passive earth pressure along the sides of the foundations. A coeffident of friction of 0.40 between soil and concrete may be used for dead load forces only. A passive earth pressure of 250 pounds per square foot, per foot of depth, may be used along the sides of footings that are poured against properly compacted native or approved import soils. Retaining walls may be required to accomplish the proposed construction. Cantilever retaining walls may be designed using "active" pressures. Active pressures may be estimated using an equivalent fluid weight of 40 pcf for native backfill soil with level free-draining backfill conditions. For walls that are resti-ained, "at rest" pressures should be utilized in design. At rest pressures may be estimated using an equivalent fluid weight of 60 pcf. Walls should be provided with adequate waterproofing and drainage. It is our opinion that the remedial grading recommended in the referenced report remains appropriate. The remedial grading should include over-excavation of the surface soil and the primary foundation bearing soil within the building areas. The foundation areas should be cleared of any surface vegetation prior to grading. In order to provide for firm and uniform foundation support, we recommend over-excavation and recompaction. The foundation areas should be over-excavated to a depth of at least 3 feet below existing grade or 2 feet below the bottom of the footings, whichever is deeper. The exposed surface should then be scarified, moishare conditioned and compacted to a minimum of 90 percent relative compaction. The previously removed soils and fill material may then be placed in thin lifts and compacted to at least 90 percent relative compaction. Sladden Engineering September 11, 2006 Project No. 444-3161 06-09-892 It should be noted that the site is located within a seismically active area of Southern Califomia and it is likely that the proposed structures will experience strong ground shaking as a result of an earthquake event along one of the faults in the region during the expected life of the development. As a minimum, structures should be designed based upon Seismic Zone 4 design criteria included in the Uniform Building Code (UBC). The potential for liquefaction or other geologic/seismic hazards occurring at the site is considered to be negligible. We appreciate the opportunity to provide service to you on this project, if you have any questions regarding this letter or the referenced report please contact the undersigned. Respectfully submitted, SLADDEN ENGINEERING Brett L. Anc Principal Engineer SER/pc Copies: 2/G Companies Construction, Inc. 1/Gin Wong Associates Iff ohn A. Martin & Associates Sladden Engineering September 11, 2006 -4- P^ojectJVo.444.3jgj 06-09-892 Groundshaking,-,,, ' ^° ^construction Proximity to IgniZT ^"'"ary hazard — F^iili. / Anr»».«.—"T^ ^ • • _FroinSite J6£]an _a997UBQ B -?2HiL?one J!!:[evvport - Tn^i LfeCanyonFau]^ ^ ^ 2;0Jan / Seismic —^Source Newport I ^°^f Canyon ' Fault ^fear-Source Acceleration 1.0 Near-Source Velocity Seismic Coefficient Ca Seismic Coefficient Cv