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Home My WebLink AboutTract Map 3929 Lot 133 Subsurface Soils Feasibility , ~ -... . ~~'l L<<\~!!> . ,LIJ 01- O,fo 6 e., -77(3'"7,;).9/lr /3 3 Mr. Karl Lowery 9550 Hermitage Ln Riverside, CA 92503 April 24 2001 W.O. 00486 WAC GEDTECHNICAL -INC. Subject: Subsurface Soils Engineering Feasibility Investigation for Proposed Residential Building Construction and Foundation Evaluation for the Property Located South of the Intersection of Via Cielito and Avenida Del Sol, Tract 3929, Lot 133, Temecula, County of Riverside, California A.P.N.921-130-007 Gentlemen: Presented herein, per your request, are the results of our subsurface soils engineering feasibility investigation for proposed residential development for the property located south of the intersection of Via Cielito and Avenida Del Sol, Tract 3929, Lot 133, Temecula, County of Riverside, California, A.P.N. 921-130-007 (see Figure I, site vicinity map). The results of our investigation indicate that the soils underlying the proposed building area are comprised of alluvial materials consisting of clayey/silty fine to coarse-grained sand in a moist, loose to medium dense state, in turn, underlain by weathered granitic bedrock. Based upon information supplied to this office, it is proposed to construct a split level residential structure on . the subject property. At the time of this investigation, a grading plan, prepared by Aguirre & Associates, dated April, 200 I, at a scale of one inch equals ten feet (reduced for report). Programmed grading is on the order of approximately 400 cubic yards of cut and 750 cubic yards ,offill for the subject project (approximately 7 feet of cut and 4 feet offill maximum). Removals to competent bearing alluvial subgrade materials are on the order of approximately 3.0 feet (for support offoundations and or compacted fill). I It is proposed to construct conventional spread footings for slab-on-grade residential building. It , is our opinion that the site should be considered suitable for the planned development, provided . the recommendations presented herein are incorporated into design and in construction. . Adequately constructed spread footings founded into competent, field approved dense compacted fill materials are expected to provide necessary support for the planned residential structure. This report has been prepared in accordance with the generally accepted engineering standards . considered necessary for the proposed development. iThank you for the opportunity to be of service on your project. Should you have any questions regarding this report, please call the undersigned at your convenience. ~-=-- w:o GL'b[ Respectful~(,i:!,~~~ WAC Geo:!tyn . ~\ ~ ~i1t&rt~ 1~ f} CEG 130l\E~~1~-J RCE 14568, Exp. 00<8I/76A ~~i:~Ci""J'i..~ 354 . 38210 North Share Dr. . Fawaskla, ca 92333 ~67) BBB-3337 . (SOS) 878.3337 . Fall (S09) 878.3347 " .... '" C> I 4 1<( ~ I I i t)I.\.\.'t. ?\"'" . . '" .~,,~~' \\' ':} ,'0 \~ ,.' ....,~ ~ ~ ;J. ~ %; ~ ~. ~ z :I , sdew 'SOJE! sewoq.L L661@ , RD I c, '--" /~?;. '(l\t1. '" .. Site Vicinity Map Figure 1 "" ..., 00 '" 0> 1:) 'i:: QJ '" Q) Ol a: r'-: Q Q , Q "" ~ , ~ C\j 0> <:' Q ..: "" "" ~ '0 --J 0>' C\j 0> "" t; ~ I-- (3 2- . · .A,P.N.921-130-007 . . W.O. 00486 1.0 Introduction This report presents the results of our subsurface soils engineering feasibility investigation for ,proposed residential development for the property located south of the intersection of Via Cielito and Avenida Del Sol, Tract 3929, Lot 133, Temecula, County of Riverside, California, A.P.N. 921-130-007 (see Figure I, site vicinity map). The purpose of this evaluation is to determine the nature and engineering properties of the subsurface soils, and to provide necessary geotechnical recommendations for foundation design, site grading, utility trench backfill, and field review during construction. Our evaluation included subsurface exploration, soil sampling, laboratory testing, engineering analyses and preparation of this report, The recommendations contained herein reflect our professional opinions for the subsurface soil conditions encountered during field investigation. 1.1 Proposed Development Based on the information supplied to this office, it is proposed construct a split level, slab-on-grade residential building for the subject lot. Conventional spread footings are proposed for the building pad area. It is the understanding of this office that the property will be served by a leach line system. It is our opinion that the site should be considered suitable for the planned development, provided the recommendations presented herein are incorporated into design and in construction, Adequately constructed spread footings founded into competent, field approved compacted fill materials, are expected to provide necessary support for the planned residential structure, 1.2 Site Description The subject proposed residential pad area is located within a 0.40 :!: acre, gentle in gradient area ranging from approximately 6: I to 20: I (horizontal to vertical) draining via sheet flow to the southeast/south. The property is south of the intersection of Via Cielito and Avenida Del Sol (fronting Via Cielito on the west side of the property and fronting Avenida Del Solon the east side of the property). The property is mantled with grass and weed vegetation. 2.0 Scope of Work Geotechnical investigation for the subject site included subsurface exploration utilizing a truck mounted B-34 auger drill rig, soil sampling, laboratory testing, engineering analyses and preparation of this report. In general, scope of work included the following tasks: o Three exploratory borings were excavated using a B-34 drill rig, advanced to a maximum depth of 15 feet below the existing grade (see Plate I & Boring Logs, Appendix Section). During exploration, encountered subsurface soils were PAGE 3 WAC Geotechnical, Inc. .3 . 'A.P.N.921-130,007 . . W.O. 00486 . logged based upon visual and tactile methods with bulk samples obtained at subsurface zones at or near programmed pad grade. Collected samples were transferred to our laboratory for testing and analyses. Descriptions of encountered subsurface soils are provided on the Boring Logs in Appendix Section. Approximate locations of test borings are shown on Plate I. o Laboratory testing conducted on selected bulk and remolded samples were programmed according to the project requirements. The laboratory testing included determinations of Maximum Dry Density and Optimum Moisture content, soil Shear Strength, Consolidation characteristics (based upon remolded samples) under anticipated structural loadings and expansion testing. Descriptions of the test procedures used and test results are provided in Appendix Section. o Based upon obtained data resulting from our field investigation, laboratory testing and engineering analyses, this report presents this firms recommendations for foundation design, site preparation, grading and field reviews necessary during site construction. 3.0 Site Conditions The subject proposed residential pad area is located within a 0.40 :!: acre, gentle in gradient area ranging from approximately 6: I to 20: I (horizontal to vertical) draining via sheet flow to the southeast/south. The property is south of the intersection of Via Cielito and Avenida Del Sol (fronting Via Cielito on the west side of the property and fronting Avenida Del Solon the east side of the property). The property is mantled with grass and weed vegetation. 3.1 Subsurface Conditions Our evaluation of the site subsoil conditions are based upon subsurface soil exploration and noted laboratory testing. For the depths explored, the encountered 0-3 :!: feet of subsoils, consist of loose to medium dense clayey/silty fine to coarse-grained sand classified as alluvium. Based upon our field investigation, soil sampling and subsequent laboratory and engineering analyses, the following characteristics for the site soils are observed: In general, the upper 0 to 3.0 :!: feet of the site soils are loose and compressible for the residential pad area. These subsoils, will require removal to competent bearing subgrade for fill and foundation support, In-place and approved competent dense alluvial materials should be considered to be suitable for structural fill and foundation support of planned construction. At time of construction, actual field exposures will dictate site suitability based upon field review by the project engineering geologist or soils engineering consultant. PAGE 4 WAC Geotechnical, Inc. "\ A.P.N.92I-130-007 . . W,O.00486 Laboratory shear tests conducted on the upper bulk samples remolded to 90 percent of the laboratory determined Maximum Dry Density indicate moderate shear strengths under increased moisture conditions, Results of the laboratory shear tests are provided in Plate A-I in Appendix Section. Consolidation tests conducted on remolded samples at depths of 0-5 feet, indicate low potential for compressibility under anticipated structural loadings. Results of the laboratory determined soils consolidation potential are shown on Plate B-1, Appendix Section. Expansion testing (EI) was conducted on the bulk sample. The resulting expansion index, EI is 181. Site soils are classified as very high for potential expansion. 3.2 Excavatibility Considering the state of the non-lithified alluvial soil underlying current surface grade, it is our opinion that grading and excavation required for the project may be accomplished using conventional construction equipment to proposed design grades and recommended removal depths. 3.3 Groundwater Encountered subsoils at depths of 15 feet were in a slightly moist state. Groundwater was not encountered during our subsurface drilling excavation to depths up to 15 feet. Ground water is not expected to be a problem during site grading to anticipated grading depths. 3.4 Subsurface Variations Based upon the results of our subsurface investigation and on past experience, it is the opinion of this firm that variations in the continuity, depths of subsoil deposits may be expected. Due to the nature and characteristics of the soils underlying the subject site, care should be exercised in interpolating or extrapolating the conditions and properties of the subsoils beyond the boring locations, 3.5 Liquefaction Liquefaction is caused by the build up of excess hydrostatic pressure in saturated cohesionless soils due to cyclic stress generated by ground shaking during an earthquake. The significant factors on which liquefaction potential of a soil deposit depends, among others include, soil type, relative soil density, intensity of earthquake, duration of ground shaking, and depth of ground water. Ground water was not encountered in our subsurface exploration program. Underlying in-place alluvial soil materials are underlain by no water bearing dense granitic bedrock materials. Based upon available information from this investigation, it is the opinion of this firm that the potential for liquefaction is minimal for the subject property. PAGE 5 WAC Geotechnical, Inc. -s' . A.P.N.921-130-007 . . W.O. 00486 3.6 Potential Seismic Hazards Seismic Design Parameters Based upon 1997 UBC The seismic design fault for the subject property is the Elsinore Fault, Glen Ivy segment which is located within 3.5 kilometers of the subject property. The fault type is "B." The maximum magnitude is noted by the UBC as 6,8. The slip rate is 5 mm/yr. The Near-Source Factor N" is noted as 1.15; the Near-Source Factor Nv is noted as 1.4. The dense alluvium underlying the subject site is assigned the Soil Type Profile So. The Seismic Zone Factor is 0.40. The Seismic Coefficient, C" is noted as 0.44N" the Seismic Coefficient, Cv, is noted as 0.64Nv' 4.0 Evaluations and Recommendations 4.1 General Evaluations Based on this firm's field investigation, laboratory testing and subsequent engineering analysis, it is our opinion that, from a geotechnical viewpoint, the site should be considered suitable for the planned development, provided the recommendations presented herein, are incorporated into tinal design and in construction. Site preparation and grading should be performed in accordance with the enclosed recommendations of Section 5, Earthwork/General Grading Recommendations of this report, except as modified in the main text and with the applicable portions of Appendix Chapter 33 of the current UBC or applicable local ordinance. Structural design considerations should include the probability of moderate to high peak ground accelerations from relatively active nearby earthquake faults as noted in Section 3.6. 4.1.1 SubGrade Preparations for Structural Pad Area Programmed areas for residential building/compacted fill support will require removal of current grade to produce a flat building pad. Grading depths will range from 0-7.0:!: feet for building pad development for cut areas. Cut areas will expose a cut/fill transition line in the building area. Therefore all cut areas programmed for building support will require overexcavation of 36-inches (5-feet outside building footprint) with void replacement as compacted fill to insure a uniform fill mat for building support. Prior to fill placement, removals on the order of approximately 3.0 :!: feet to competent, field approved (by project geotechnical consultants) dense alluvial materials should be anticipated. Actual depth of removals will be predicated upon exposed field conditions and approval by this office. Recommendations for field placement offill is to take the form of thin layers of soil (not to exceed 6 inches) moisture conditioned and compacted by sheepsfoot roller (or other approved compaction equipment) with 90% relative compaction as compared to the Maximum Density/Optimum Moisture value of the soil. Fill should be placed under the observation and PAGE 6 WAC Geotechnical, Inc. ~ A.P.N.921-130-007 . . W.O. 00486 testing of the project soils engineering consultant and as noted in Section 5.0 Earth ,Work/General Grading Recommendations. 14.2 Spread Foundations For adequate support, the proposed structures may be constructed on continuous and/or isolated spread footings founded exclusively into field approved, compacted fill materials, . Conventional shallow foundation system is considered suitable for planned residential and ancillary structures. Sulfate content is considered to negligible (103 ppm) for site soils. Type II cement is considered to be acceptable for the subject project. Foundations may be designed based upon the following values: Allowable Bearing: Lateral Bearing: Sliding Coefficient: 1500 Ibs./sq.ft. 252 Ibs./sq.ft. per foot of depth to a maximum of 1500 Ibs./sq.ft. 0.28 The above values may be increased as allowed by Code to resist transient loads such as wind or seismic. Building code and structural design considerations may govern depth and reinforcement requirements and should be evaluated. 2. Other Design Recommendations · FOOTING DEPTH Exterior 12-inches below lowest adjacent grade (in approved compacted fill materials) for one story and 18-inches below adjacent grade (in approved compacted fill materials) for 2-story. Interior 12-18-inches below lowest adjacent grade (in approved compacted fill materials) for one and 2-story, respectively, · FOOTING Width Exterior 12-15 inches minimum for one and 2-story, respectively. Interior 12-15 inches minimum for one and 2-story, respectively. · FOOTING REINFORCEMENT Exterior & Interior All continuous; six No, 5 bars, three near the top, three near the bottom for exterior and four No.5 bars, two near the top and two near the bottom for the interior. Concrete Slabs Slab Thickness: 6-inches nominal, reinforced with No.4 bars at 12-inches on center, each way or equivalent. Reinforcement should be installed at mid-height in the slab. IPAGE 7 WAC Geotechnical, Inc. 1 A.P.N.921-130-o07 . . W.O. 00486 · Under-Slab Treatment Living Areas- 6-mil Visqueen; cover with at least 2 inches of sand. Subgrade soils should be presoaked to contain at least optimum moisture content immediately prior to placing Visqueen and to be verified by the soils engineering consultant. The sand cover should be moistened prior to placing concrete. Grade Beam - A grade beam reinforced continuously with the garage footings should be constructed across all garage entrances, tying together the ends of the garage footings. This grade beam should be embedded at the same depth as the adjacent perimeter footings Garage Slab - Optimum moisture content in subgrade soil verified by the soils engineering consultant. . Fireplace Footings Fireplace footings shall have a minimum embeddment depth of 12-inches measured from the lowest adjacent grade and should be an integral part ofthe building foundation system. Fireplace slabs shall be treated in the same manner as the living area slabs (same as that noted in following sections for slab-on-grade construction). 'Prior to pouring footings, soils should be pre-moistened and field approved by the project soils engineering consultant or his representative. The settlement of properly designed and constructed foundations supported on approved earth materials, carrying maximum anticipated vertical loadings, are expected to be within tolerable limits, Estimated total and differential settlements are about 3/4 and 1/2-inch, respectively. 4.3 Resistance to Lateral Loads Resistance to lateral loads can be restrained by friction acting at the base of foundations and by passive earth pressure. A coefficient of friction of 0.28 may be assumed with the normal dead load forces for footing established on compacted fill. An allowable passive lateral earth resistance of 252 pounds per square foot per foot of depth, may be assumed for the sides of foundations poured against compacted fill. However, the maximum lateral passive earth pressure is recommended not to exceed 1500 pounds. For design, lateral earth pressures of local soils when used as level backfill may be estimated from the following equivalent fluid density: Active: Passive: At Rest: 42 pcf 252 pcf 63 pcf PAGE 8 WAC Geotechnical, Inc. e A.P.N.921-l30-007 . . W.O. 00486 4.5 Construction Considerations 4.5.1 Unsupported Excavation Temporary construction excavation up to a maximum depth of 5 feet may be made without any lateral support. It is recommended that no surcharge loads such as construction equipment, be allowed within a line drawn upward at 45 degree from the toe of excavation. Use of sloping for deep excavation may be applicable where plan dimensions of the excavation are not constrained by any existing structure. 4.5.2 Supported Excavations If vertical excavations exceeding 5 feet in depths become warranted, such should be achieved using shoring to support side walls. 4.6 Site Preparation Site preparations should include cut subexcavations, import soils, and placement of soils as engineered fill. Such earth work should be in accordance with the applicable grading recommendations provided in the current UBC and as recommended in Section 5.0 of this report, This office should be notified 72 hours in advance of importing soils to site for placement as compacted fill. It will be necessary for the project soils engineering consultant to sample import soils with subsequent laboratory testing to determine suitability of import soils for project construction. It is strongly recommended that import soils be similar to site soils. The use of clayey soils for pad construction is not recommended. 4.7 Soil Caving During excavations for deep utility trenches, 'some' caving may be expected. All temporary excavations should be made at a 2: I (horizontal to vertical) slope ratio or flatter, and/or as per the construction guidelines provided by CaIOSHA. 4.8 Retaining Wall Retaining structures, if planned, should be designed using the following equivalent fluid density: Slope Surface of Equivalent Fluid Density (pet) Retained Material Imported Local (horz. to vert.) Clean Sand Site Soil Level 30 42 2;1 35 63 Backdrains will be required behind all retaining walls. Only free-draining granular materials (sand or gravel)are to used as retaining wall backfill to within IS-inches of surface grade, PAGE 9 WAC Geotechnical, Inc. ~ A.P.N.921-130-o07 '. . W.O. 00486 4.9 Utility Trench Backfill Utility trench backfill within the structural pad and beyond, should be placed in accordance with the following recommendations: o Exterior trenches along a foundation or a toe of a slope and extending below a I: I imaginary line projected from the outside bottom edge of the footing or toe of the slope, should be compacted to a minimum 90 percent. o All excavated trenches should conform to the requirements and safety as specified by the CalOSHA 4.10 Pre-Construction Meeting It is recommended that no clearing of the site or any grading operation be performed without the presence of a representative of this office. An on-site pregrading meeting should be arranged between the soils engineering consultant and the grading contractor prior to any construction. 4.11 Seasonal Limitations No structural fill shall be placed, spread or rolled during unfavorable weather conditions. Where the work is interrupted by heavy rains, fill operations shall not be resumed until moisture conditions are considered favorable by the soils engineering consultant. 4.12 Planters To minimize potential differential settlement to foundations, planters requiring irrigation should be restricted from use adjacent to footings. If unavoidable, planter boxes with sealed bottoms and drain outlets to approved areas away from the foundation, should be constructed, 4.13 Landscape Maintenance/Drainage Only the amount of irrigation necessary to sustain plant life should be provided. Pad drainage should be directed towards streets and to other approved areas away from foundations. Slope areas, when applicable, should be planted with draught resistant vegetation. 4.14 Observations and Testing During Construction Recommendations provided in this report are based upon the assumption that all foundations will be placed upon field approved fill materials for structure. Excavated footings should be inspected, verified and certified by soils engineering consultant and/or engineering geologist prior to steel and concrete placement to ensure their sufficient embeddment and proper bearing on approved dense compacted fill materials. Additional inspections by soils engineering consultant and/or engineering geologist is recommended to verify footing excavations being free PAGE 10 WAC Geotechnical, Inc. \0 'A.P.N.921-130-007 . . W,Q, 00486 ofloose and disturbed material. All structural backfill should be placed and compacted under direct observations and testing by this facility. Excess soils generated from footing excavations should be removed from pad areas and such should not be allowed on subgrades as uncompacted fill for areas programmed to receive concrete slab-on-grade. :4.15 Plan Review The recommendations presented herein should be considered 'preliminary.' It is recommended that if "precise grading plans" change, then revised plans should be available to this office for review to minimize misunderstandings between the plans and recommendations presented. Further, excavated footings should be verified as recommended earlier. If during construction, conditions are observed to be different from those as described in this report, revised and/or updated recommendations will be required. 5.0 Earth Work/General Grading Recommendations Structural Backfill: During grading, excavated site soils should be considered suitable for reuse as backfill material. Loose soils, formwork and debris should be removed prior to backfilling the walls. On-site sand backfill should be placed and compacted in accordance with the recommended specifications provided below. Where space limitations do not allow conventional backfilling operations, special backfill materials and procedures may be required. Pea gravel or other select backfill can be used in limited space areas. Recommendations for placement and densification of pea gravel or other special backfill can be provided during construction. Site Drainage: Adequate positive drainage should be provided away from the structure to prevent water from ponding and to reduce percolation of water into subsoil at foundation areas. A desirable slope for surface drainage should be a minimum of 2 percent in landscape areas and I percent in paved areas. Planters and landscaped areas adjacent to building perimeter should be avoided or designed by a qualified landscape architect utilizing a sealed planter box with drains away from footings to minimize water filtration into subsoils. Utility Trenches: Buried utility conduits should be bedded and backfilled around the conduit in accordance with the project specifications. Where conduit underlies concrete slab-on-grade and pavement, the remaining trench backfill above the pipe should be placed and compacted in accordance with the following grading specifications. General Grading Recommendations: Recommended general specifications for surface preparation to receive fill and compaction for structural and utility trench backfill and others, are presented below. PAGE II WAC Geotechnical, Inc. \\ . A.P.N.921-130-007 . . W.O, 00486 ~. 1. Areas to be graded, backfilled or paved, shall be grubbed, stripped and cleaned of all buried and undetected debris, structures, concrete, vegetation and other deleterious materials prior to grading. 2. Where compacted fill is to provide vertical support for foundations, all loose, soft and other incompetent soils should be removed to full depth as approved by soils engineering consultant, or at least up to the depth as previously described in this report. The areas of such removal should extend at least 5 feet beyond the perimeter of exterior foundation limit or to the extent as approved by soils engineering consultant during grading. 3. The recommended compaction for fill to support foundations and slab-on-grade is 90% of the maximum dry density at or near optimum moisture content. To minimize any potential differential settlement for foundations and slab-on-grade straddling over cut and fill, the cut portion should be overexcavated a minimum of 36-inches and replaced as compacted fill, compacted to at least 90% of the maximum dry density as described in this report. 4. Utility trenches within building pad areas and beyond, should be backfilled with granular material and such should be compacted to at least 90% of the maximum density for the material used. 5. Compaction for all structural fills shall be determined relative to the maximum dry density as determined by ASTM D1557-90 compaction methods. All in-situ field density of compacted fill shall be determined by the ASTM D 1556 standard methods or by other approved procedures. 6, All new imported soils, ifrequired, shall be clean, granular, non-expansive material or as approved by the soils engineering consultant. 7. During grading, fill soils shall be placed as thin layers, thickness of which following compaction shall not exceed six inches, 8. No rocks over eight inches in diameter, shall be permitted to use as a grading material without prior approval of the soils engineering consultant. 9. No jetting and/or water tampering be considered for backfill compaction for utility trenches without prior approval of the soils engineering consultant. For such backfill, hand tampering with fill layers of 8 to 12 inches in thickness, or as approved by the soils engineering consultant is recommended. 10. Any and all utility trenches at depth as well as cesspool and abandoned septic tanks within building pad area and beyond, should either be completely excavated and removed from the site, or should be backfilled with gravel, slurry or by other material, as approved by soils engineering consultant. 11. Any and all import soils if required during grading, should be equivalent to the site soils or better. Such should be approved by the soils engineering consultant prior to their use, PAGE 12 WAC Geotechnical, Inc, \2- . . A.P.N.921-130-007 <. . W.O. 00486 '. . 12. Fill slopes shall be constructed upon a keyway, a minimum of 15 feet in width or 112 the slope height, whichever is greater. Key shall be sloped with a I-foot differential between toe and heel (Sloping to heel). Fill slopes, if constructed on grade, shall be backrolled at 4 foot height intervals. If slopes are overfilled, slopes should be overfilled a minimum of 3 feet and trimmed back to expose dense compacted fill slope face. ; 13. All cut slopes shall be field monitored by the project engineering geologist. Should adverse conditions such as out of slope planar zones, shears or slumping, slopes will require replacement with either a stabilization fill or a designed buttress fill section. Action field conditions will dictate the need for remedial slope action. 14, Any and all grading required for pavement, sidewalk or other facilities to be used by general public, should be constructed under direct observation of soils engineering consultant, or as required by the local public agencies, 15. A site meeting should be held between grading contractor and soils engineering consultant ,prior to actual construction. Two days of prior notice recommended for meetings. :PAGE 13 WAC Geotechnical, Inc. \~ A.P.N.921-130-007 . . W.O. 00486 6.0 Closure The conclusions and recommendations contained herein, are based on the findings and observations made at the time of the subsurface investigation. The recommendations presented, should be considered "preliminary" since they are based on soil samples only. If during construction, the subsoil conditions appear to be different from those disclosed during ,field investigation, this office should be notified to consider any possible need for modification for the geotechnical recommendations provided in this report. Recommendations provided are based on the assumptions that structural footings will be established exclusively into field approved compacted fill materials. It is recommended that final "precise grading and foundation plans" should be reviewed by this office when they become available. Site grading must be performed under review by geotechnical representatives of this office. All footing excavations should be field reviewed prior to forming, steel and concrete placement to ensure that foundations are founded into satisfactory soils and excavations are free ofloose and disturbed materials, A pre grading meeting between grading contractor and soils engineering consultant should be arranged, preferably at the site, to discuss the grading procedures to be implemented and other requirements described in this report to be fulfilled. This report has been prepared exclusively for the use of the addressee for the project referenced in context. It shall not be transferred or be used by other parties without written consent by WAC Geotechnical, Inc. We cannot be responsible for use of this report by others without review of the grading operation by our personnel. Should the project be delayed beyond one year after the date of this report, the recommendations presented shall be reviewed to consider any possible change in site conditions. The recommendations presented are based on the assumption that the necessary geotechnical observations and testing during construction will be performed by a representative of this office, The field observations are considered a continuation of the geotechnical investigation performed. If another firm is retained for geotechnical observations and testing, our professional liability and responsibility shall be limited to the extent that WAC Geotechnical, Inc. would not be the geotechnical engineering consultant of record. PAGE 14 WAC Geotechnical, Inc. \~ . A.P.N.921-130-007 '. . W.O. 00486 . 7.0 APPENDIX Section Field Exploration The field investigation for the project included site reconnaissance and subsurface exploration using a truck mounted B-34 auger drill rig. During the site reconnaissance, the surface conditions were noted and test boring locations were determined. Soils encountered during exploration were continuously logged and classified by visual observations and tactile methods in accordance with generally accepted field classification. The field descriptions were modified, where appropriate, to reflect laboratory test results. Where appropriate, representative bulk soil samples were obtained. Logs of the exploratory borings are presented in the following summary sheets, that include the description of the subsoil materials encountered. PAGE 15 WAC Geotechnical, Inc. \:s- . \. .-.., ., A.P.N.921-130-007 . PAGE 16 Boring Logs WAC Geotechnical, Inc. . Lo OI-Cf?{)C~ W,O. 00486 U :3 &j't).. 9 fi-r I c3 "3 \~ - , '. .. B-1 Depth in Feet 0.0-2.0' 2.0-10.0' B-2 Depth in Feet 0.0-0.8' 0,8-2.5' 2,5-8.0' . Boring Logs Description Alluvium (Qal): Clayey/silty fine- grained sand, It. brown, moist, loose, porous Soil Classification: SC/SP . Silty clay very fine to medium-grained sand, It. tan brown, dry to moist, medium dense to dense Soil Classification: SC/SW End of Boring @ 10.0' No water No caving Description Alluvium (Oal): Silty clay/clayey silt, tan brown, moist, loose Soil Classification: SC Silty clay/clayey silty fine to medium- grained sand, It. tan brown, moist, loose to medium dense Soil Classification: SC/SW Clayey silt, fine to coarse-grained sand, tan brown, moist, medium dense to dense Soil Classification: SC/SW End of Boring @ 8.0' No water No caving WAC Geotechnical, Inc. Sample Blows/ft. Bulk 0-5.0 ft Sample Blows/ft. \1 , B-3 Depth in Feet 0.0-3.0' 3.0-5.0' 5.0-15.0' . . Description Alluvium (Oal): Clayey/silt, silty clay, fine to medium-grained sand, It. brown,moist, porous to 18", loose to dense Soil Classification: SC/SW Silty clay/clayey silt, very fine-grained sand/sandy clay, moist, dense Soil Classification: SC/SP Silty fine to medium-grained sand, It. brown, moist, dense Soil Classification: SM/SW End of Boring @ 15.0' No water No caving WAC Geotechnical, Inc. Sample Blows/ft. \€> " A.P.N.921-130-007 I. . W.O. 00486 8.0 APPENDIX B Laboratory Test Programs Laboratory tests were conducted on representative soils for the purpose of classification and for the determination of the physical properties and engineering characteristics, The number and selection of the types of testing for a given study are based on the geotechnical conditions ofthe site. A summary ofthe various laboratory tests performed for the project is presented below, Direct Shear (ASTM 0 3080) Data obtained from this test performed at increased moisture conditions on remolded soil samples were used to evaluate soil shear strengths. Samples contained in brass sampler rings, placed directly on test apparatus are sheared at a constant strain rate under a normal load, appropriate to represent anticipated structural loadings. Shearing deformations are recorded to failure. Peak and/or residual shear strengths are obtained from the measured shearing load versus deflection curve. Test results, plotted on graphical form, are presented on Plate A-I of this section. Consolidation (ASTM 02435) Dma obtained from this test performed on remolded to 90% samples, were used to evaluate the consolidation characteristics of foundation soils under anticipated foundation loading. Preparation for this test involved trimming the sample, placing it in one inch high brass ring, and loading it into the test apparatus which contained porous stones to accommodate drainage during testing. Normal axial loads are applied at a load increment ratio, successive loads being generally twice the preceding. Soil samples are usually under light normal load conditions to accommodate seating of the apparatus. Samples were tested at the field moisture conditions at a predetermined normal load, potentially moisture sensitive soil typically demonstrate significant volume change with the introduction of free water. The results of the consolidation tests are presented in graphical forms on Plate B-1, Expansion Index ASTM 04829 The site soils are considered to have Very High expansive potential with an E118!. Laboratory Test Results Maximum Dry Density/Optimum Moisture Content Relationship Sample Location Max. Dry Density (pet) Opt. Moisture Content (%) B-1, 0-5.0 feet 123,0 9.4 (ASTM 01557-9l) PAGE 17 WAC Geotechnical, Inc. \~ .4.. '; I- o ~ rol II/: < ~ 0' m II/: rol A- m A- - :II: , rol U Z < Ii; - m (oj II/: C Z - II/: < (oj = m . . DIRECT SHEAR TESTS It) N ~ ... . --- ./' ~./' / ~ ~ ....____...-.4 ------- ,/"./' :<= 'N "l ... It) = <= o 0.5 1.5 2.0 2.5 1.0 NORMAL LOAD - KIPS PER SQUARE FOOT 'SYMBOL LOCATION DEPTH (ft) TEST CONDITION COHESION FRICTlO~ (psi) (degrees) 220 23 ~ D-1 0-8.0' Remolded to 90% Saturated & drained ,- PROJECT NO. 00486 . WAC GEOTECHNICAL, INC. P.O. BOX 354, FA WNSKIN, CA 92333 P LA TE A-I on 2P '. -..,--;;;;;;..~- .s .6 . JO 40 50 j- Il-l " ----i-j "E LOAD IN KIPS PER SOUARE . 2 J 4 6 8 0 8 15 10 , + :z :0 - I- < o - ..J o en Z o (.) I- Z W (.) a: w 0. -- -- t-- .. 1 - -- - - - ..- J - - - , 1- 4 +.. , -r- l- S .-. , - -- ..- .. .t'- - 6 c-. -.. 1...-. .-- " , :::f:: , , , , ~- f- B-l@0-8' Remold to 90% +- ~- 1 ,- - =i -,- ~=1. ..t== .. ',L -- t- 1== t.. 1-- I r~-=r-- L.'_"I' -- ----.;,- ~ "'''''E' t----~ ,-- ...- -, f' ," - =-!:~:I~' - " --~= -:-'-L-E'Y.} ;--~"I':=j- $ - - ~.F"i. ~~'''' =1.." r: . . I . . - -i-: -. . . - ..! --t - 1- _-I- =i.--'==i.:, "'__., ---i ==L'r::--L.:iE' , - ~ -t- =T-. ~- h - L -i ,-.! , , -I f=t-'-- .... I~: -+='~i'~' . -t--j~-+t:'r_:.- - '_'-. -'-I' -- :::...,C~in.;::_j~:. ' l= 1'-' _. L.. _":, ,...... ___ _--+___._..... _...._ I _ -." =:r~::'- == - "F =1--=':: -+:f~'i:-f:,.: I, ., t-. ..- ,.1=:= c-... :...~ '/ 131== -...': I..... -- -=t-.., -l=.,g.,..~ ~_ ,.' --L:._::;,::';:::.f .. ....:.--;::: n ::::1 ' -t: --- -- .., i--:,'-j'''F~~t= .. ::f:::T:..... - J=-.. ' -1- - =- ...: --+--. "r: ",. ,'-t--- 14'~I:~=I..k 111+ ,0t, I-;:=t~:~:f=~d.;:~ :=t+:~ ~_::::j~L=i~~':::'::::li:~: --0,-"'_- .._-j...... ,-=f, .--4=.l-----:..-.-I--,-t-.ul...f==-t.-=f-..-:-.--...--.--- 15 I ~' '~~.. I I il"~ ' ..- -.. ..-......, .,... 1 I' .. I"":~ I ,--- .. ..,. -- ~..+:":I : ... ::::::r-:~::::.::'n ---'-:I'._j.::::: , .:' "-j-- .. '-' .. .....1... ~ '..+:1:,.. .1.. ...1 --I','. --::.- i ..:: .- ..'.r---, 16 .. ... -- ..../ ...../ .',. -".:-.1, . "f '1 -. I I 7 1'-- '-'- "~IL~.. _ -, ., . -- .. -- 8 !=.::::; -- t"'l.-.-.. ,.--' ......... .--..-.. . 9 ,--_.f--...... ,-- 1-. ..- ... -- .... -- ... -.....- t--. ........ 10 ~-, ___ :::J::t: 11 :~, :.. :r:"Y ______mi...;... .. :. :::I:::b 11 ::- ~ :::[= ~, I 1===1 I 1= , . WATER PERMITTED TO CONTACT SAMPLE WAC GEOTECHNICAL, INC. P.O. BOX 354 FA WNSKIN, CA 92333 PROJECT HO. PLATE 00486 B-1 ~ , . ~ A.P.N.921-130-007 . . W.O. 00486 . PROFESSIONAL LIMITATIONS Our investigation was perfonned using the degree of care and skill ordinarily exercised, under similar circumstances by other reputable Soils Engineers practicing in this general or similar localities. No other warranty, expressed or implied, is made as to the conclusions and professional advise included in this report, The investigations are based on soil samples only, consequently the recommendations provided shall be considered 'preliminary'. The samples taken and used for testing and the observations made are believed representative of site conditions; however, soil and geologic conditions can vary significantly between borings. As in most major projects, conditions revealed by excavations may vary with preliminary findings, If this occurs, the changed conditions must be evaluated by the Project Soils engineering consultant and designs adjusted as required or aiterna1e design recommended, The report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the infonnation and recommendations contained herein are brought to the attention of the project architect and engineers. Appropriate recommendations should be incorporated into structural plans. The necessary steps should be taken to see that the contractor and subcontractors carry out such recommendations in field. Thc findings of this report are valid as of this present date. However, changes in the conditions of a property can occur with the passage of time, whether they due to natural process or the works of man on this or adjacenI properties. In addition, changes in applicable or appropriate standards may occur from legislation or broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by change outside of our control. Therefore, this report is subject to review and should be updated after a period of one year, RECOMMENDED SERVICES The review of grading plans and specifications, field observations and testing by the geotechnical representative is an integral part of the conclusions and recommendations made in this report, [fWAC Geotechnical, Inc. is not retained for these services, the Client agrees to assume WAC Geotechnical, Inc. responsibility for any potenIial claims that may arise during and after construction, or during the lifetime use of the structure and its appurtenant. The required 1ests, observations and consultation by 1he geotechnical consultant during construction includes, but not be limited to; a, Continuous observation and testing during site preparation and grading, and placement of engineered fill. b. Observation and inspection of footing trench prior to steel and concrete placement, c. Consultations as required during construction, or upon your request. PAGE 18 -zz,. 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