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HomeMy WebLinkAboutCT 81-46; Carlsbad Airport Center Unit 2 Lot 41; Update Geotechnical Evaluation; 1995-01-12UPDATE GEOTECHNICAL EVALUATION LOT 41, CARLSBAD AIRPORT CENTER, UNIT 2 CARLSBAD, CALIFORNIA FOR SUMITOMO BANK OF CALIFORNIA 101 SOUTH SAN PEDRO STREET, SUITE 500 LOS ANGELES, CALIFORNIA 90012 W.O. 1779-SD JANUARY 12, 1995 199? GeoSoils, Inc. SITE DESCRIPTION 1 PROPOSED DEVELOPMENT 2 FIELD EXPLORATION 2 LABORATORY TESTING 3 General 3 Field Moisture and Density 3 Laboratory Standard - Maximum Dry Density 3 Expansion Index Test 3 Shear Testing 4 Consolidation Tests 4 EARTH MATERIALS 4 Artificial Fill 4 Bedrock 5 GROUNDWATER 5 FAULTING AND REGIONAL SEISMICITY 5 Other Hazards Considered 6 CONCLUSIONS 7 EXISTING FILLS 7 Existing Slopes 8 RECOMMENDATIONS-EARTHWORK CONSTRUCTION 8 Scarification and Removals (Parking, Non-Building Areas) 8 Fill Placement 9 Earthwork Balance 9 Subdrain Systems 9 Slope Stability 9 General 9 Fill Slopes 10 Cut Slopes 10 Erosion Control 11 RECOMMENDATIONS - POST EARTHWORK CONSTRUCTION 11 Floor Slab Design 12 Foundation Settlement 13 Retaining Walls 13 General 13 Restrained Walls 13 Cantilevered Walls 13 Wall Backfill and Drainage 14 GeoSoils, Inc. POST GRADING CRITERIA 14 Graded Slope Maintenance and Planting 14 Additional Site Improvements 15 Additional Grading 15 Footing Trench Excavation 15 Trenching 15 Drainage 15 Landscape Maintenance 15 Utility Trench Backfill 16 PLAN REVIEW 16 LIMITATIONS 17 GeoSoils, Inc. '• , Geotechnical • Geologic • Environmental 5741 Palmer Way • Carlsbad, California 92008 • (619)438-3155 • FAX (619) 931-0915 January 12, 1995 W.O. 1779-SD SUMITOMO BANK OF CALIFORNIA 101 South San Pedro Street, Suite 500 Los Angeles, California 90012 Attention: Mr. Richard Hirota, Sr. Vice President & Division Mgr. Subject: Update Geotechnical Evaluation Lot 41, Carlsbad Airport Center, Unit 2 Carlsbad, California Gentlemen: In accordance with your request, GeoSoils, Inc. has performed a preliminary geotechnical study concerning proposed development at the subject site (Site Location Map, Figure 1). The purpose of our study was to evaluate the nature of earth materials underlying the site and to provide recommendations for site preparation, earthwork construction and foundation design/construction based on our findings. Selective testing of existing artificial fills/earth materials on the previously sheet-graded property was included in our evaluation. Based on discussions with your architect (Mr. Howard Anderson), the project will consist of constructing a multi-story office building with a parking lot, access ramps and retaining walls. No basement or below grade parking is planned at this time. The new building is shown on the conceptual plot plan (see Figure 2). SITE DESCRIPTION Lot 41 of the Carlsbad Airport Center (CAC) is a roughly rectangular shaped lot which consists of a relatively level pad area bounded by landscaped 2:1 slopes on the east, west, and south sides. The lot is approximately 5± acres in size and is located northeast of the intersection of Camino Vida Roble and Palomar Oaks Way, in the City of Carlsbad, California. A fill slope, approximately 23± feet in height, ascends to Lot 40 on the eastern side of the subject lot. This lot is currently undeveloped. Lot 42 (vacant) and a portion of McClellan Palomar Airport are situated along the northern site boundary. The southern and western sides of the pad consist of fill slopes which descend to Camino Vida Roble and Palomar Oaks Way, respectively. According to the "As-Built" plans prepared by Bodas Engineering, Inc., Lot 41 is sheet graded with an approximate surface gradient of 2.5% to the southwest. This results in a fa!! cf -t—VM5^**^^-^-^- f—-v~/f Ui^ l^c^y; ' '/^""Vsapf^ °" IK' ^H/-1 e- %Jj*2s;r jPci^----- ^^y *>-~-zz::^^S\MI(nKTs''s*\ I 'x" C/JRLSB/ 71 «. "l^""1 i 9>/ »•> 0*1*10 PC '" OK1*S! ^' . srk^ <feSi% ii .^5^- fe^Tfe x/JitTl wii^X'r ^5g|i5M-J|28| Sj \ ^y^P^^rW Uaa?*/ \••-^l|T|piirS>^, V \ i^|fe^^^\ ^ sL MJK^l; ^ /IN APPROXIMATE SCALE 1"=2,400' T?pr»M nmrwac North SITE LOCATION MAP GeoSofls, Inc. . *• . i *• ' i ..»_.*. DATE 12-94 W.O. Geotechnical Engineering • Engineering Geology SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 2 approximately 12 feet across the pad. Surface drainage on the lot is by sheet flow to a catch basin located near the southwest comer of the lot. Previous mass grading has resulted in the placement of up to 70± feet of fill within Lot 41 during two phases of grading. Initial grading occurred under the observation and testing services of Moore &Taber between November, 1985 and November, 1986. The second phase of earthwork was performed between November, 1989 and March, 1990 under the observation and testing of San Diego Geotechnical Consultants (later named ICG, Inc.). PROPOSED DEVELOPMENT Based on discussions with the site architect, Mr. Howard Anderson, we understand that proposed site development will consist of preparing the property for the construction of a 3 story office building with associated access driveways, parking, concrete flatwork, and landscaped areas. We anticipate that future site grading will utilize typical cut and fill grading techniques on the order of 5 feet. Driveway construction may result in somewhat greater cuts into the existing fill. It is also our assumption that any regrading of existing slopes will result in constructed slope gradients of 2:1 (horizontal to vertical) or flatter. FIELD EXPLORATION Previous exploration of subsurface conditions on Lot 41, consisting of four backhoe trenches, was performed in preparation of our 1991 report (GeoSoils, Inc., 1991). Logs of these excavations are included in Appendix I. The purpose of our previous site exploration was for a geotechnical site evaluation of Carlsbad Airport Center Unit 2 as a whole. For that evaluation, four test pits were excavated on Lot 41 for site fill evaluation and testing purposes. Density testing performed in these test pits indicated that the fill materials tested generally met or exceeded the typical industry standard of 90 percent relative compaction. However, some zones in the upper 4 to 5 feet may not be compacted to the typical 90 percent minimum relative compaction. Test results indicate that these zones are rather limited in both vertical and areal extent. Limited zones or layers of this nature may be considered typical within compacted fills of this size. For the current evaluation, subsurface site conditions were explored by excavating 3 large diameter (24± inch) borings with a bucket auger drill rig. Field exploration was performed on November 25 and 26, 1994, by a GeoSoils, Inc. project geologist, who logged the borings and obtained representative samples of the earth materials for laboratory testing. Borings ranged from 50± to 80± feet in depth. Logs of the borings and test pits are included in Appendix I. Subsurface boring and test pit locations from our field evaluation are presented on the enclosed Geotechnical Map, Plate 1. The base map adapted for this plate was at an original scale of 1"=80', as prepared by Rick Engineering Company. GeoSoils, Inc. GeoSoils, Inc. CONCEPTUAL PLOT PLAN WO Geotechnical Engineering • Engineering Geology FIGURE 2 SUMITOMO BANK OF CALIFORNIA W.O. 1779-SD JANUARY 12, 1995 PAGES Soil samples were obtained from the borings. Soil samples were collected in a 3-inch outside diameter (O.D.), and 2.5 inch diameter (I.D.) sampler, fitted with nine one-inch 2-3/8 inch I.D. brass rings. The sampler was driven by Kelly weights (approximately 3,087 pounds from 0-29 feet; 1,999 pounds from 30-49 feet, and; 1,115 pounds from 50 feet to the full depth explored), falling 12-inches. The number of blows for the 12-inches driven for each sample was recorded. The blow counts, as recorded in the field, are reported in the boring logs. LABORATORY TESTING General Laboratory tests for the current site evaluation were performed on representative samples of the onsite earth materials in order to evaluate their physical characteristics and engineering properties. The test procedures used and subsequent results are presented below. Field Moisture and Density Field moisture content and dry unit weight were determined for relatively "undisturbed" samples of earth materials obtained. The dry unit weight was determined in pounds per cubic foot (pcf) and the field moisture content was determined as a percentage of the dry weight. Water contents were measured in general accordance with ASTM D-2216. Results of this testing are summarized in Appendix II. Laboratory Standard - Maximum Dry Density To determine the compaction character of representative samples of onsite soil, laboratory testing was performed in accordance with ASTM Test Method D-1557-91. Results of this testing are summarized in the following table: BOR1NQ AND DEPTH B-1 @ 4' B-1 @ 13' B-1 @ 48' MATERIAL DESCRIPTION Olive brown clayey SAND Olive brown silty SAND Olive brown sandy CLAY MAXIMUM DRY DENSITSf (PCF> 118.0 116.5 122.0 OPTIMUM MOISTURE CONTEST 0$ / 15.5 16.5 13.5 Expansion Index Test Expansion tests were performed on representative samples of site soil. The samples were tested in general conformance with test number 29-2 of the Uniform Building Code. Expansion index numbers were recorded for the materials obtained from boring B-1 at a depth of 4 feet and boring B-2 at a depth of 7 feet. Expansion index numbers of 63 and 72 were recorded for these respective soils. These test results indicate the soil is medium in expansion potential when compared to the 0-200 (medium 51-90), UBC classification. GeoSoilsj Inc. SUMITOMO BANK OF CALIFORNIA W.O. 1779-SD JANUARY 12, 1995 PAGE 4 Atterberq Limits Liquid limit (LL), plastic iimit (PL), and plasticity index (PI) were determined for representative samples of on-site soil. Testing was performed in general conformance with ASTM Test Method D4318-84. The following table presents results of this testing: B-1 B-1 , DEPTH 13 17 19 UQtHD 41 33 17 14 Particle Size Analysis Gradation or particle size analyses was performed on representative samples of site soil. These samples were tested in general conformance with ASTM D422. The samples were evaluated as a percentage of dry weight passing a selected particle size up to 0.075mm (U.S. Std.,No. 200 Sieve). Beyond or smaller than 0.075mm the sample was prepared for clay and silt size testing in general accordance with hydrometer testing ASTM D422-63. The results of the particle size and Hydrometer analyses are presented on Plate H-1 (see Appendix II) Shear Testing Shear testing was performed on relatively undisturbed soil samples in a strain control-type direct shear machine. Testing was performed in general accordance with ASTM Test Method D-3080- 90. Results of this testing is plotted on the enclosed Shear Test Diagrams, Plates SH-1 and SH-2 (see Appendix II). Consolidation Tests Four consolidation tests were performed on relatively undisturbed soil samples in general accordance with ASTM Test Method D-2435-90. The consolidation test results are plotted on Plates C-1 through C-4 presented in Appendix II. EARTH MATERIALS Earth materials encountered onsite consist of artificial fill, and underlying Tertiary age sediments of the Santiago Formation (Weber, 1982). As previously indicated, artificial fill was placed between 1985 and 1990, and was derived from cuts made within the Carlsbad Airport Center. Artificial Fill (map symbol at) Existing fill was encountered across most of the site. Fill observed generally consisted of olive brown clayey to siity sand, with occasional sandy clay zones. This observation was consistent with that of previously reported fill descriptions (ICG, 1993). The fill was generally medium dense to dense and moist to very moist (see Appendix I). Although oversized rock was reportedly disposed of on nearby building pads (lots 39, 40, 44-46), and in non-structural fill north of Lot 41, no oversized rock was encountered in our borings. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 5 Bedrock Santiago Formation bedrock materials (Tertiary in age) observed in borings generally consist of yellow brown to light gray silty fine sandstone. Bedrock encountered was typically dry to damp and dense. While bedding orientations were not observed during this study, & southwestern regional dip was noted in the area during previous site work performed by this office (GeoSoils, Inc., 1991) and others (San Diego Geotechnical Consultants, 1988). The apparent bedrock surface was encountered at 61.5 feet in boring B-1, 48 feet in B-2, and 75 feet in B-3. This fill over bedrock thickness is consistent with thicknesses previously reported (SDGC, 1988 and ICG, 1993). Based on the boring information, the bedrock surface below the existing fill on this lot slopes to the southeast at gradients of approximately 8 to 13 percent. This surface was reportedly benched and keyed per plan (SDGC, 1988). GROUNDWATER A groundwater table was not encountered in any of our excavations and is not anticipated to adversely affect site development. The observations made reflect site conditions at the time of this geotechnical study and do not preclude changes in local groundwater conditions in the future.- Areas of seepage were observed in relatively clean sandy layers locally encountered in two (2) of the boring excavations (see Appendix I). Boring B-1 displayed seepage at 22± and 38± feet while boring B-3 encountered seepage at 38± and 60± feet in depth. The observed seepages are not anticipated to adversely affect planned site development. The need for subdrainage should be further evaluated when project grading plans are finalized, and during project earthwork. The seepage zones may be due, in part, to oversize rock disposal areas placed on adjacent lots (39,40,44-46), (ICG, 1993). Other contributing factors may be relatively clean sand lifts (i.e., more permeable material) in the fill (see Boring Logs, Appendix I), and the reported over watering of landscaped slopes (GSI, 1991). FAULTING AND REGIONAL SEISMICITY No known active or potentially active faults are shown on published maps in the vicinity of the site (Jennings, 1992). No evidence of faulting was observed in any of the exploratory borings excavated. There are a number of faults in the Southern California area which are considered active and would have an affect on the site in the form of ground shaking, should they be the source of an earthquake. These include but are not necessarily limited to the San Andreas Fault, the San Jacinto Fault, the Elsinore Fault, and the Rose Canyon Fault Zone. It should be noted, that there is no published or unpublished consensus on the relative seismic activity of the Rose Canyon Fault Zone. Studies at one location in Rose Canyon have indicated GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 6 Holocene activity along one strand of this fault zone (Lindvall, et. al., 1989). As a result of these studies, the state of California has classified portions of the fault in the City of San Diego as active. The possibility of ground acceleration, or seismic shaking, at the site may be considered as approximately similar to the Southern California region as a whole. The relationship of the site's location to major mapped faults within Southern California is indicated on the Fault Map of Southern California (Figure 3). The peak horizontal ground accelerations were determined based on the attenuation relation developed by Sadigh (1989). The largest probable and credible peak horizontal ground accelerations anticipated at the site would be 0.24g and 0.39g, respectively, produced by a magnitude 6 earthquake on the Rose Canyon Fault, approximately 6 miles west of the site (see Appendix III). The acceleration-attenuation relations of Sadigh (1989) have been incorporated into EQFAULT (Blake, 1989). EQFAULT is a computer program which produces deterministic values of horizontal accelerations from digitized California faults. The results of this computer file search and computations are enclosed in Appendix III. Dynamic Settlements Dynamic settlements due to seismic shaking were estimated to be on the order of 2.25 inches. The results of that analysis indicate that differential settlements may be approximately 1.25 inches, which would suggest that angular distortions of 1 in 550 could occur. The project structural engineer should consider this level of foundation system distortion in their structural analysis. It is important to keep in perspective that in the event of maximum probable or credible earthquakes occurring on any of the nearby major faults, intense ground shaking would occur in this general area. Potential damage to any settlement sensitive structures would likely be greatest from the vibrations and impelling force caused by the inertia of the structures mass than that from induced dynamic settlements. Considering the subsurface soil conditions and site seismicity, it is estimated that the site has a low risk associated with the potential for dynamic settlements to occur and adversely affect surface improvements developed on this site. Other Hazards Considered The following list includes other potential seismic related hazards that have been evaluated with respect to the site. In our opinion, the potential for the following list of hazards to significantly affect the site is considered low. • Tsunami • Surface fault rupture • Ground lurching or shallow ground rupture • Liquefaction GeoSoils, Inc. »• V Ji0 Modified after Friedman and Others, 1976 ^r^nO^Oi5Of*S j\l it C« FAULT MAP OF SOUTHERN CALIFORNIA HATF 12-94 W O NO 177Q-ST) Geotechnical • Geologic • EnvironmentalFIGURE 3 SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 7 CONCLUSIONS Based on our field exploration, laboratory testing, engineering and geological analyses, it is our opinion that the proposed development appears feasible from a geotechnical engineering and geologic standpoint subject to the recommendations presented herein. The recommendations should be incorporated into the final design, grading and construction phases of site development. The engineering and geologic analyses performed and the recommendations presented, have been completed using the information provided. In the event that the information concerning the proposed development is not correct, or any changes in site design as currently understood are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed, and the recommendations presented herein are modified or approved in writing by this office. The primary geologic and geotechnical conditions which affect proposed site development are summarized below: • Differential fill thickness/settlement across the planned structure. • Setback of structures, utilities and appurtenant improvements from existing sloped. • Cut/fill transition(s) along the northern edge of the lot. • In-place densities of the existing fills and their ability to support additional loading without undergoing significant consolidation. • The surficial stability of existing fill slopes. Depth of removals of existing fill. • Material bulking and/or shrinkage. • Engineering properties of onsite earth materials. • Control and mitigation measures for erosive materials. • The possibility of strong shaking to occur during a seismic event on one of the regional faults. EXISTING FILLS Field testing provided by ICG, Inc. during the majority of earthwork construction indicated that fill was consistently placed above 90% relative compaction (ICG, 1993). Based on our field observations, field resistance values during drive sampling, and laboratory analyses, the fills appear reasonably compact and moist. Field observations within the upper 2± feet of the existing fill indicates relative compaction is consistently less than 90%. This observed lower density may be due to heating, drying, water infiltration, drainage, erosion and plant growth. As the upper 2 feet of fill material will be important for support of roads, parking, shallow foundation and appurtenant improvements, a removal and recompaction of the upper 2 feet of all existing fill exposed at pad grade is warranted. Recommendations for treatment of fills within the building foundation footprint are presented in the earthwork construction section of this report. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 8 Existing Slopes Lot 41 is bounded by fill slopes. These existing slopes have been constructed at approximate gradients of 2:1 (horizontal to vertical). The west facing slope which ascends to Lot 40 on the east side of the site is up to 23± feet in height. The west to south facing slopes which descend to Palomar Oaks Way and Camino Vida Roble, on the west and south side of Lot 41 respectively, are up to 15 ± feet in height. A small (3± feet high), north facing fill slope descends to Lot 42 toward the northwest comer of Lot 41. Since placement, these fill slopes have performed well and show no significant evidence of instability. However, some minor erosion has occurred. If maintained in a moist (not saturated or dry) condition and provided an appropriate maintenance program is followed, existing site slopes should continue to perform adequately in the future. RECOMMENDATIONS-EARTHWORK CONSTRUCTION All grading should conform to the guidelines presented in Appendix Chapter A33 of the Uniform Building Code, and the requirements of the County of San Diego and City of Carlsbad, except where specifically superseded in the text of this report. During earthwork construction all removals, keyways, sub- and/or backdrains, cut slopes, fill slopes and the general grading procedures should be observed and the fill selectively tested by a representative of this office. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and if warranted, modified and/or additional recommendations will be offered. Specific guidelines and comments pertinent to the planned development are offered below. Scarification and Removals (Parking, Non-Building Areas) Prior to placing fill, all organic materials and loose surficial fills (top 2± feet), should be removed to competent underlying materials. Previously excavated backhoe test pits will also require complete removal and recompaction. A representative of GeoSoils, Inc. should observe these removals to verify the competence of underlying materials exposed prior to any fill placement. Following removals, the exposed bottom should be scarified and moisture conditioned to a depth of 12 inches and recompacted to 90 percent relative compaction. Overexcavation surfaces should be observed by a representative of GSI prior to scarification and recompaction. Over-Excavation (Building Area) As indicated, the upper 2± feet of the existing fill appeared to be less compact. Prior to constructing building foundations, Removal and recompaction of the fill underlying the proposed building should be performed. The extent of the over-excavation work should be 1 foot below the lowest (elevation) foundation element and a minimum of 3 feet from existing grade (whichever is greatest), if a shallow foundation is used. This Overexcavation should extend down outside the building footprint at a 1:1 (horizontal to vertical) projection to the full depth of the removal. Subsequent to this removal, sand cone compaction testing should be performed on the exposed removal bottom. In-place relative densities of at least 90 percent must be reported on this GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 9 material. If a minimum 90 percent relative compaction is not reported, an additional removal of two feet should be performed. This removal bottom should be scarified, moisture conditioned as needed, and compacted prior to placing fill. Rll Placement Subsequent to completing removals and ground preparation, the excavated on-site and/or import soils may be placed in thin lifts (4 to 6± inches), cleaned, brought to at least optimum moisture content and compacted to a minimum relative compaction of 90 percent of the laboratory standard. If soil is to be imported to the site for use as compacted fill, a sample should be provided to GeoSoils, Inc. with sufficient time to be evaluated by this office prior to importing. This should be accomplished to determine if the proposed import material is compatible with the existing onsite soils and their intended use. Earthwork Balance The volume change of excavated materials upon compaction as engineered fill is anticipated to vary with material type and location. However, the overall earthwork shrinkage and bulking may be approximated by using the following parameters: Existing Artificial Fills 0% to 5% shrinkage Bedrock (if encountered) 3% to 5% bulking It should be noted that the above factors are estimates only, based on preliminary data obtained. Final earthwork balance factors could vary. Subdrain Systems Based on the nature of the existing fills and existing contacts between artificial fill and bedrock, in addition to the possible location(s) of proposed site improvements, water could possibly be transmitted through the subsurface in irregular quantities. Although not anticipated, subdrain system(s) may be recommended based on field conditions observed during the grading stage of the project. Typical recommendations for the design/construction of subdrain systems are presented in Appendix IV. Subdrain systems should discharge into an existing drainage pattern or other appropriate outlet. Slope Stability General: It is assumed that existing slopes (previously approved) were constructed in accordance with the minimum requirements of the County of San Diego, the City of Carlsbad, and the (then adopted) Uniform Building Code. Fill slopes are anticipated to perform adequately in the future with respect to gross stability if the soil materials are maintained in a solid or semi-solid state. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 10 Fill Slopes The geometry of existing fill slopes is planned to remain the same after the current project is completed, with the exception of the slopes near the front entrance stairs and driveways (see Figure 2). It is our understanding that any proposed fill slopes will be constructed at gradients of 2:1 or flatter. Fill slopes to be constructed at this gradient would be considered grossly stable assuming proper construction, as recommended in the enclosed grading guidelines (Appendix IV). The existing fill slopes at the southern portion of the lot were reviewed for gross stability using irregular (JANBU) and circular (Bishop) analyses. These analyses assumed that most of the fill above the "toe" of the slope will remain in a moist, unsaturated, condition. The existing fill slopes were evaluated for static and pseudo static conditions. The results indicated a factor of safety (FOS) of > 1.5 and > 1.1, respectively. Surficial stability of the fill slopes were reviewed using an infinite slope approach. The results indicated a FOS of > 2.0. Loose surficial soils previously identified on site slope faces, probably resulting from overwatering of landscaping (GSI, 1991), will reduce performance of surficial slope stability. No remediation measures are recommended .or this condition at this time. A program of slope maintenance along with reduced watering of slopes would aid in surficial slope stability. The importance of proper fill slope compaction (i.e., 90% per ASTM D-1557) to the face of a fill slope cannot be overemphasized. In order to achieve proper compaction, one or more of the four following methods should be employed by the contractor following implementation of typical slope construction guidelines: 1) track walk the slopes at grade, 2) grid roll the slopes, 3) use a combination of sheep foot roller and track walking, or 4) overfill the slope 3 to 5 feet laterally and cut it back to grade. Random testing should be performed to verify compaction to the face of the slope, if the tests do not meet the minimum recommendation of 90 percent relative compaction, the contractor will be informed and additional compactive efforts recommended. Cut Slopes Any proposed cut slopes are anticipated to be graded at gradients of 2:1 or flatter. Such slopes are expected to expose bedrock or existing artificial fill soil and would be considered grossly stable. Cut slopes are not anticipated to require stabilization unless highly erodible or noncohesive materials are encountered. All cut slopes should be mapped by a geologist from this office, during grading, to allow for amendments to recommendations. Slope Setbacks Current layout of proposed building (Figure 2) may not comply with UBC regulations regarding setbacks from top of slopes. All footings, therefore, should maintain a minimum 7 foot horizontal setback from the base of the footings to any descending slope face (excluding the landscape surface). Slopes, pavements, mid-slope walls, utilities, etc., which do not take into consideration recommended slope setbacks are subject to possible movements. Recommendations for GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA W.O. 1779-SD JANUARY 12, 1995 PAGE 11 alternative foundation system(s) (i.e., drilled piers) can be provided, upon request, for foundation systems adjacent to, or at, the top of slopes. Overall, based on relative uniformity of underlying fill thickness, currently depicted location of the proposed building is relatively desirable from a geotechnical standpoint. Any re-location of this structure on Lot 41 would be subject to review by this office. Erosion Control Cut and fill slopes will be subject to surficial erosion. Onsite earth materials have a moderate to high erosion potential. Evaluation of cuts during grading will be necessary in order to identify any areas of loose or non-cohesive materials. Should any significant zones be encountered during earthwork construction, remedial grading (e.g., stabilization fills) may be recommended; however, no remedial measures are anticipated at this time. RECOMMENDATIONS - POST EARTHWORK CONSTRUCTION For preliminary planning purposes the following recommendations are presented. It is our understanding that the structure will be erected utilizing a tilt-up & steel frame method of construction. Column loads are not anticipated to exceed 50 kips while wall loads are not expected to exceed 3 kips per lineal foot. The preliminary recommendations presented below, have been prepared using these anticipated loads and assuming the recommendations contained herein are considered during design and planning. Presented below are vertical bearing values that incorporate the total and differential settlement values provided. f > ^ •• FOOTJHO TYPE Isolated Column Contin- uous Perimeter MIK1MUM ; FOOTIKCT DEPTH (INCHES) 24 24 MAXIMUM ; <, VERTICAL -', I BEARfNQ (PSF) 2,750 2,500 "" \ f f fff f > sS- '' "' "' : i OCHEFtfbtENT ; OFFRJCnON 0.32 0.32 PASSIVE EARTH \ ' PRESSURE : ... pcft 225' 225 MAXFMUW , / , SAW*; - PRESSURE.',;' (POF^ - ' 2,000 2,000 'May be increased to 250 if interior column footing and confined by slab. Strip footings should have a minimum width of 24 inches. Spread footings should have a minimum soil to concrete surface area of four square feet. When combining passive pressure and friction for lateral resistance, the passive component should be reduced by one third. Bearing capacity may be increased by one third for short duration loading which includes the effects of wind or seismic forces. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 12 All continuous footings should be reinforced with a minimum of four No. 5 reinforcing bars (or equivalent) two placed near the top and two placed near the bottom of footings. A grade beam should be provided across all large entrances. The base of the grade beam should be at the same elevation as the bottom of the adjoining footings and the reinforcement should be continuous. Reinforcement for spread footings should be specifically designed by the project structural engineer. The foundation soils should be kept in a moist condition prior to placement of concrete. Floor Slab Design Concrete slab on grade construction is anticipated. The following are presented as minimum design parameters for the slab, they are in no way intended to supersede design by the structural engineer. Design parameters do not account for concentrated loads (e.g., fork lifts, other machinery, etc.) and/or the use of freezers or heating boxes. The slabs in areas which will receive relatively light live loads should be a minimum of 5 inches thick and be reinforced with No. 3 reinforcing bar on 18 inches centers in two perpendicular directions. Reinforcing should be properly supported to ensure placement near the vertical midpoint of the slab. "Hooking" of the reinforcement is not considered an acceptable method of positioning the steel. The recommended compressive strength of concrete is 4,000 pounds per square inch (psi). The project structural engineer should consider the use of transverse and longitudinal control joints to help control slab cracking due to concrete shrinkage or expansion. Two of the best ways to control this movement are: 1) add a sufficient amount of reinforcing steel to increase the tensile strength of the slab; and 2) provide an adequate amount of control and/or expansion joints of accommodate anticipated concrete shrinkage and expansion. In areas where moisture condensation is undesirable (e.g., areas to have moisture sensitive floor coverings), a minimum 10 mil plastic membrane should be placed. The membrane should be sandwiched between two-inch minimum sand layers. These areas should be separate from areas not similarly protected. This separation could be provided with a concrete cut-off wall extending at least 18 inches into the subgrade soil, below the sand layer. The project structural engineer should design the slabs in areas subject to high loads (machinery, forklifts, storage racks, etc.). If requested, we will aid the structural engineer in the design of the slab. Modulus of subgrade reaction (k-value) may be used in the design of the floor slab supporting heavy truck traffic, fork lifts, machine foundations and heavy storage areas. A k-value (modulus of subgrade reaction) of 100 pounds per square inch per inch (pci) would be prudent to utilize for preliminary slab design. An R-value test and/or plate load test may be used to verify the modulus of subgrade on near surface fill soils. The subgrade material should be compacted to a minimum ninety percent of the maximum laboratory dry density. Prior to placement of concrete, the subgrade soils should be well moistened to at least optimum moisture content and verified by our field representative. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 13 Foundation Settlement Provided that the recommendations contained in this report are incorporated into the final design and construction phases of development, most (50 to 75 percent) of the anticipated foundation settlement due to new footing loads is expected to occur during construction. Settlement is not expected to exceed 1/2 inch for continuous footings, and 3/4 inch for isolated column footings given the assumed foundation loads and dimensions. Differential settlement between similar elements within 75 feet can be estimated to be on the order of 1/2 inch. Settlement of Fill The existing fill is anticipated to be approximately 45 to 70 feet thick within the "footprint1 (perimeter) of the building. The fill was placed in stages and reached maximum height on this lot around 1990 (ICG, 1993). Although the fill consists of primarily sand soil, the silty and clayey fraction of the fill will likely be subject to long term compression and subsequent settlement. Based on the overall sandy nature of the fill, settlements may be considered substantially (on the order of 90 per cent) completed within a period of 2 to 5 years, since the fill reached its maximum height. However, the fill may continue to settle due, in part, to secondary compression, new building loads and continued landscape watering at the fill surface. GSI has estimated the long term fill settlement to induce a total settlement of on the order of two (2) inches and differential settlement of 1 to 1-1/2 inches on the building pad within the limits of the proposed building. This would suggest angular distortions of 1/1000 for the longest building dimension of approximately 150 feet and 1/600 for the shortest building dimension (75 feet). Retaining Walls General: The equivalent fluid pressure parameters provided assume that low expansive granular backfill is utilized behind the proposed walls. The low expansive granular backfill, should be provided behind the wall at a 1:1 projection from the heal of the wall footing. Foundation systems for any proposed retaining walls should be designed in accordance with the recommendations presented in the Foundation Design section of this report. Building walls, below grade, should be water-proofed or damp-proofed, depending on the degree of moisture protection desired. The below recommendations are preliminary and should be modified if onsite materials are not as anticipated. Wall footings are not anticipated to cross cut/fill transitions. If this condition is exposed during construction, additional recommendations and modifications to footings may be required. Restrained Walls: Any retaining walls that will be restrained prior to placing fill soil (backfill) or that have male or rsentrant comers, should be designed for at-rest equivalent fluid pressures of 65 pcf, plus any applicable surcharge loading. For areas of male or reentrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall laterally from the comer. Cantilevered Walls: The recommendations presented belcv; are for cantilevered retaining walls up to 10 feet high. Active earth pressure may be used for retaining wall design, provided the top of the wall is not GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 14 restrained from minor deflections. An empirical equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions such as traffic, structures, seismic events or adverse geologic conditions. When wall configurations are known, the appropriate loading conditions from any superimposed loads can be provided. SURFACE SLOPE OF EQUIVALENT RETAINED MATERIAL FLUID WEIGHT HORIZONTAL TO VERTICAL P.C.F. Level 45 2 to 1 60 Wall Backfill and Drainage: All retaining walls should be provided with an adequate pipe and gravel backdrain system (minimum two outlets), to prevent buildup of hydrostatic pressures. In addition, gravel used in backdrain systems should be a minimum of thickness of 12 inches, utilizing 3/8 to 3/4 inch clean crushed rock wrapped in filter fabric. Where the void to be filled is confined, the use of panel drains is recommended, but should be reviewed and approved by the project geotechnical engineer prior to implementation. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil. Proper surface drainage should also be provided. Heavy equipment should not be used within a distance equal to the maximum height of earth material retained behind the walls. GSI recommends that compaction efforts within the area behind the walls be accomplished with hand operated equipment. Pavements For planning purposes, and based upon an assumed R-Value of 30, the following preliminary pavement section for site parking areas is presented. A pavement section of 9 inches is anticipated (3 inches of asphalt over 6 inches of Class II base). Actual recommendations should be provided based on R-Value testing of representative materials collected at final pavement subgrade elevations. POST GRADING CRITERIA Graded Slope Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage away from graded slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Overwatering should be avoided. Graded slopes constructed within and utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a GeoSolls, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 15 suitable vegetation cover soon after construction. Compaction to the face of fill slopes would tend to minimize short term erosion until vegetation is established. Plants selected for landscaping should be light weight, deep rooted types which require little water and are capable of surviving the prevailing climate. Additional Site Improvements Recommendations for exterior concrete flatwork design and construction can be provided upon request. If in the future, any additional improvements are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. Additional Grading This office should be notified in advance of any additional fill placement, regrading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench and/or retaining wall backfills. Footing Trench Excavation All footing trench excavations should be observed by a representative of this office pn'or to placing reinforcement. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent if not removed from the site. Trenching Considering the nature of the onsite soils, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls at the angle of repose (typically 25 to 45 degrees) may be necessary and should be anticipated. All excavations should be observed by one of our representatives and conform to CAL-OSHA and local safety codes. Drainage Positive site drainage should be maintained at all times. Drainage should not be allowed to flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. Pad drainage should be directed toward the street or other approved area. Roof gutters and down spouts should be considered to control roof drainage. Down spouts should outlet a minimum of five feet from the proposed structure or into a subsurface drainage system. Due to the nature of onsite soils, combined with the hardness and permeability of the bedrock materials on site, local areas of seepage may develop due to irrigation or heavy rainfall. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over watering the landscape areas could adversely affect proposed site improvements. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 16 We would recommend that any proposed open bottom planters adjacent to proposed structures be eliminated for a minimum distance of 10 feet. As an alternative, closed bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. From a geotechnical standpoint leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of addition amendments they should be recompacted to 90% compaction. The soil materials should be maintained in a solid to semi- solid state. The slope areas should be planted with drought resistant vegetation. Consideration should be given to the type vegetation chosen and their potential effect upon surface improvements (e.g., some trees will have an affect on concrete flatwork with their extensive root systems). Utility Trench Backfill 1. All interior utility trench backfill should be brought to near optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. No jetting or flooding of trenches should be performed on this site. 2. Exterior trenches in structural areas, beneath hardscape features and in slopes, should be compacted to a minimum of 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used adjacent to perimeter footings or in trenches on slopes. Compaction testing and observation, along with probing, should be performed to verify the desired results. 3. All trench excavations should minimally conform to CAL-OSHA and local safety codes. 4. Trench dimensions, bedding requirements and structural setbacks should adhere to UBC, local ordinances, standards of the City of Carlsbad, County of San Diego or the controlling utility company/authority, whichever is more stringent. Corrosive Potential Corrosivity testing of site soils was not performed for this study. Such testing can be performed preferably subsequent to final site grading, at the client's request. PLAN REVIEW Specific grading and foundation plans should be submitted to this office for review and comment as they become available, to minimize any misunderstandings between the plans and recommendations presented herein. In addition, foundation excavations and earthwork construction performed on the site should be observed and tested by this office. If conditions are found to differ substantially from those stated, appropriate recommendations would be offered at that time. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA W.O. 1779-SD JANUARY 12, 1995 PAGE 17 LIMITATIONS The materials encountered on the project site and utilized in our laboratory study are believed to be representative of the total area. However, variations from the anticipated conditions and actual field conditions should be expected. Test excavations are reflective of the soil and rock materials only at the specific location explored. Site conditions may vary due to seasonal changes or other factors. GeoSoils, Inc. assumes no responsibility or liability for work or testing performed by others. Since our study is based on the site materials observed, selective laboratory testing and engineering analyses, the conclusions and recommendations are professional opinions based upon those parameters. These opinions have been derived in accordance with the current standards of practice and no warranty is expressed or implied. Standards of practice are subject to change in time. Overall, the enclosed results represent our professional opinions and evaluations which were performed within the constraints of a budget. If you should have any questions regarding this report, please do not hesitate to contact this office. Respectfully submitted, GeoSoils, Inc. Edward H. LaMont Senior Project Geologist Principal Geologl8iU Andrew T. Guatelli, RCE 47 Principal Engineer EHL/PLM/ATG/mb Enclosures: Reference List Appendix I, Boring Logs and 1991 Test Pit Logs Appendix II, Laboratory Testing Appendix III, EQFAULT Appendix IV, Grading Guidelines Plate 1, Geotechnical Map xc: (4) Addressee GeoSoils, Inc. REFERENCES Blake, Thomas F., 1989, EQFAULT Computer Program for the Deterministic Prediction of Horizontal Accelerations from Digitized California Faults. Geotechnical Site Evaluation, Carlsbad Airport Center, Unit II, Carlsbad, California, by GeoSoils, Inc., dated March 21, 1991, W.O. 1260-SD. Geotechnical Report of Rough Grading, Airport Business Center, Unit 2, Carlsbad, California, dated April 21, 1993, by ICG Incorporated. Jennings, Charles W., 1982, Preliminary Fault Activity Map of California; Calif. Div. of Mines and Geology, Geologic Data Map series No. 1, to 750,000 scale. Lindvall, S., Rockwell, T. and Lindvall, E., 1989, The Seismic Hazard of San Diego Revised: New Evidence for Magnitude 6+ Holocene Earthquakes on the Rose Canyon Fault Zone, in Roquemore et. al. eds., Proceedings from a Workshop on The Seismic Risk in the San Diego Region: Special Focus on the Rose Canyon Fault System, 106 pp. Sadigh, K., Egan, J., and Youngs, R. (1987), Predictive Ground Motion Equations Reported in: Joyner, W.B. and Boone, D.M. (1988), Measurement, Characterization, and Prediction of Strong Ground Motion, in Von Thun, J.L, ed., Earthquake Engineering and Soil Dynamics II. Recent Advances in Ground Motion Evaluation. American Society of Civil Engineers Geotechnical Special Publication No. 20, pp. 43-102. Supplemental Geotechnical Investigation Carlsbad Airport Center, Unit 2, and Off-Site Fill Area Carlsbad, California, Job No. 05-4879-011-00-00, dated July 29, 1988, by San Diego Geotechnical Consultants, Inc. Weber, Harold F., 1992, Geologic Map of the Central-North Coastal Area of San Diego County, California, Showing Recent Slope Failures & Pre-Development Landslides. APPENDIX I BORING LOGS AND 1991 TEST PIT LOGS GEOSOILS, INC. BORING LOG CLIENT SUMITOMO BANK WORK ORDER NO.1779-SD LOT 41, CARLSBAD AIRPORT CENTER DATE EXCAVATED 11-25-94 SAMPLE METHOD KELLY HEIGHTS BORING NO. B-l SHEET 1 OF 2 1-29' 3089 LBS 50'- 1115 IBS 30-49* 1999 LBS 4- r4-a a " 1 5- n r\ _-LU ; 15- ^.0 O C ^D - •? r\-o u 35- - S, 3 B • • AM]Undis-turbedP W/: . ^ ^ '////. ?LE Blou»/6"P/l for +V1 2/ 1 4/ 4/ 1 3/ 1 7/ 1 4/ 1 usesSumbo 1SC 8" SM SM/ SC jl La 101.3 96.0 101.3 108.0 110.4 ft 113.3 107.5 106.8 r \~ • * 0 19.4 18.9 17.9 15.6 18.0 ^ 13.2 15.5 15.5 •I '/, II I // Ii i DESCRIPTION OF MATERIAL 0-11 '+/- ARTIFICIAL FILL: Mottled gray brown clayey SAND (SC) to sandy CLAY, medium dense to firm, moist to very moist. 1 ii i i 11 '-30' Becomes predominantly gray brown silty SAND (SM) , medium dense, moist to very : moist. i i I §22' Fill seeping slightly. I 31 '-61. 5' Intermixed zones of dark gray to ?ray brown sandy CLAY with silt (SC) in ight brown silty SAND (SM) , medium dense, moist to very moist, occasional root fragments . @32' Hole bells slightly. \ @387 Slight seepage.i FORM 88/9 GEOSOILS, INC. BORING LOG CLIENT SUMITOMO BANK WORK ORDER NO.1779-SD LOT 41, CARLSBAD AIRPORT CENTER DATE EXCAVATED 11-25-94 SAMPLE METHOD EFI I Y UTTCMTS 1-29' 3089 LBS 3n-49' iqqq LBS 50'- BORING NO. 1115 LBS B-l SHEET _2_ OF 2 4» •f r Q. a - A K -43 SAMPLE y* —3 ffl y 1 TJgl • — • J3 TJ L C 3 3*- ^ P^ 50H \777-,. m " 55- - 60- 65- — - 70- 75- - - Ws, % ^ U3 \ 30 0) 5/ 1 V1 ll/1 7/ 1 13/ 1 20/ 1 «oM JOU EM 3a M 3 4- C 7"D nUL 3 w La 105.9 106.6 108.3 104.5 112.7 98.0 L3 v 4- gl —0n 19.2 21.3 16.1 19.7 16.9 2.1 DESCRIPTION OF MATERIAL %i \ \fy y w \ \ \ \ \ \W L-=J :.•=: ^=Z= 1 ARTIFICTAT. FTT.T.t rnntirmeri a<? above. I @47' Some rootlets. @61.5 '-6 6' BEDROCK - SANTIAGO FORMATION:Very light gray fine SANDSTONE with silt, dense, dry, massive. Clean, even contact with artificial fill above. Total depth= 66 feet Seepages at 22 and 38 feet Slight caving at 32 feet Hole backfilled *P= PUSH ! iIi i FORM 88/9 GEOSOILS, INC BORING LOG CLIENT SUMITOMO BANK WORK ORDER NO.1779-SD LOT 41, CARLSBAD AIRPORT CENTER DATE EXCAVATED 11-25-94 SAHPUE METHOD tf\ 1 Y HETCHTS 1-29' 3089 IBS 30-49' 1999 IBS 50' - BORING NO. 1115 IBS B-2 SHEET 1 OF 2 4- £ Q. a 5 _ -J 10- T c;-1D 20- ~ *"* -3 0 ~ 35- _ S. •aa h AMI I Tl •a L C 3D-t- W </// '£& w, % W' m =LE a 3/ 1 4/ 1 4/1 5/ 1 6/ 1 1 6/1 usesSumbo 1SC CM /on/ SC jl La 103.0 106.7 107.5 116.4 111.1 110.0 103.8 L 3 X+- c 0i: 19.1 \ 9 Q. y 12.9 12.6 9.6 9.0 13.0 19.1 \% S-'/W \ I i \ \ \ P I DESCRIPTION OF MATERIAL 0-7'+/- ARTIFICIAL FILL; Medium olive brown mottled sandy CLAY with silt (SC) , overall firm (top 2+/~ feet soft to firm) j moist to very moist. 1 5 '-7' Dark brown sandy CLAY (SC) , "topsoil" derived material) , Iirm, moist to _V^T*V TOO 1st ^-i 7 /-48/ Becomes predominantly light yellow brown silty SAND (SM) , moist, sharp horizontal contact with fill above. Occasional intermixed zones of light to dark brown sandy CLAY (SC) , firm, moist to very : moist. : 1 i FORM 88/9 GEOSOILS, INC. BORING LOG CLIENT SUMITOMO BANK WORK ORDER NO.1779-8D LOT 41, CARLSBAD AIRPORT CENTER DATE EXCAVATED 11-25-94 SAMPLE METHOD EFI I V MFTKHTS BORING NO. B-2 SHEET 2 OF_2_ 1-29' 3089 IBS 30-49' 1999 IBS 50'- 1115 LBS +•<*• r 0. a 45- 50- _ 55- - 60- 65- 70- 75- SAMPLE ^ —3ffi 1 TJ0 ( — It•0 Lc a 3+- '%% w, m u>\ 30 (0 6/ 1 6/1 20/ 8 HoM aU ECl 33 (/) 4- ^ ^3 MQ. 3 ^^ (^a 112.7 100.0 122.4 L3 C +- ^g. 0r 15.7 20.5 11.5 DESCRIPTION OF MATERIAL % \iii 9 i ^ ARTIFICIAL FILL: Continued as above. @46' Some rootlets, intermixed. 48 '-51' BEDROCK- SANTIAGO FORMATION: Liaht yellow brown and orange (oxidized) clayey SANDSTONE, dense, slightly moist. i Total depth^ 51 feet No groundwater Hole backfilled 1I FORM 88/9 GEOSOILS, INC BORING LOG CLIENT SUMITOMO BANK WORK ORDER HO. 1779-SD LOT 41, CARLSBAD AIRPORT CENTER DATE EXCAVATED 11-26-94 SAHPLE METHOD ITFI I T IffTOfTS BORING NO. 1-29' 3089 LBS 50'- 1115 LBS 30-49' 1999 LBS B-3 SHEET 1 OF 3 +-tt. r & a 5 _ T n-xu i c?- - 20- - 30- •J C- - - S 3 CO AM]Undlm-turb«d^ ^^ ^^ ^ ^^ PLE z (0 3O ffi 6/1 5/ 1 6/ 1 6/ 1 5/ 1 oco no sCO 3 3 CO SM SC SM SC/ SM SM +- ^ C y3 a La 112.2 114.9 111.5 114.5 103.5 L 3 0E 14.8 15.1 12.4 11.0 22.0 \ I 1 I DESCRIPTION OF MATERIAL 0-5'V ARTIFICIAL FILL; Medium brown gray mottled silty SAND with clay (SM) , medium dense, moist to very moist. |i 1 5' -18' Becomes predominantly light yellow \ brown silty SAND (SM) , medium dense, moist, j i , i ! 18 '-2 2' Zone of dark brown to medium olive green CLAY (SC) , firm, moist, some ; intermixed rootlets and twigs. 22/-28/ Becomes predominantly light yellow ! brown silty SAND (SM) , medium dense, moist. 28 '-3 3' Becomes predominantly light yellow green gray silty SAND to SAND with silt (SM) , medium dense, moist. 33 '-38' Zones of dark gray brown sandy CLAY (SC) , firm, moist. @38' Small seepage, slight belling of hole. 38 '-73' Becomes predominantly light yellow FORM 88/9 GEOSOILS, INC. BORING LOG CLIENT SUMITOMO BANK UORK ORDER NO.1779-8D LOT 41, CARLSBAD AIRPORT CENTER DATE EXCAVATED 11-26-94 SAMPLE METHOD IfFl I Y MFTBHTS BORING NO.B-3 SHEET 2 OF 3 1-29' 3089 LBS 50'- 1115 LBS 30-49' 1999 IBS +- w £+-a. a - 45- - 50- K K-DO - 60- f C _DO - 70- -J "7 C/ O SI ^« 30) ^MI i -a0 0-.0•o L C 33 +• P ^ •^% //// '/// >LE U)\ 0 3 O fi 5/1 13/ 1 7 / 1 _ o M J3 U EVt 3 3 Vt SC * C*a « 3 La 112.1 107.6 £ 106.2 iin i , 3 0+•n« OC 16.8 17.9 ^ 17.0 17 T ::: ;; 'i -— s DESCRIPTION OF MATERIAL green gray silty SAND to SAND with silt (SM) , medium dense, moist. @60' Some seepage, slight belling of hole. 1 73/-75/ Medium green gray mottled clayey SAND (SC) , medium dense, moist, occasional \rootieu. / @75'-80' BEDROCK - SANTIAGO FORMATION: Medium brown silty SANDSTONE, dense, slightly moist. FORM 88/9 GEOSOILS, INC. BORING LOG CLIENT SUMITOMO BANK WORK ORDER NO.1779-8D LOT 41, CARLSBAD AIRPORT CENTER DATE EXCAVATED 11-26-94 SAHPLE METHOD tFI I Y HEIGHTS BORING NO.B-3 SHEET 3 OF 3 1-29' 3089 LBS 50'- 1115 LBS 30-49 1999 LBS •4-H- r 0. a 85- - 90- 95- - 00- 05- 10- 15- SAMPLE •a 0)Undf •-turbcdBlouB/6"usesSumbo 1it La l~ 0c DESCRIPTION OF MATERIAL 1 Total depth= 80 feet ! Minor caving at 38 and 60 feet Slight seepages at 38 and 60 feet Hole backfilled i i i I i FORM 88/9 MAJOR DIVISIONS COARSE GRAINED SOILS MORE THAN 50% Of MATERIAL IS LARGER THAN NO.700 sieve SIZE FINE GRAINED SOILS MORE THAN W» Of MATERIAL IS SMALLER THAN NO. 2OO SIEVE SIZE CRAVIL AND uRAVELLV SOILS UORE THAN SO» Of COARSE FRAC- TION RETAINED ON NO. 4 SIEVE SAND AND SANOV SOILS MORE THAN 5O% OF COARSE FRAC- TION PASSING NO. 4 SIEVE SILTS AND CLAYS cut SY* r«*.! 4*• CLEAN GRAVELS ' • •«•• FINES! *y «-«•• •• GRAVELS WITH FINIS ' i '(APPRECIABLE 1 AMOUNT OF FINES! 7*fa %• • f • • CLEAN SANO *', • • • • ILITTLEORNO " ' * FINES! -v'-s -^w.\ SANDS WITH FINES ' (APPRECIABLE . AMOUNT OF FINES) 77% %?/ %% ™T LIQUID LIMIT yyy/ LESSTHANSO %A> !i!:1111it IIS!V.T? L1OUIO LIMIT ^H CLAYS GREATER THAN SO HB 1%%%'/Mm'/V% 'i//s•Wt HIGHLY ORGANIC SOILS r— - LPMIC LETTER •SOU SYMBOL *«;; -• , »::::::h:; GP «::i i i CM, m % " 'i\ **•*.• »•%•£.^ "• i SM 1 I i i % *fffr ML I-l'l'II If OLI II '" RH MH ^1 CH yyy\ lagA OHwwvzz. TYPICAL DESCRIPTIONS WELL-CRAOEO GRAVELS. GRAVEL- SAND MIXTURES. LITTLE OR NO rlNES FOORLY^RAOEO GRAVELS.GRAVEL-SANO MIXTURES. LITTLE OR NO FINES SILTY GRAVELS. GRAVEL-SAND- SILT MIXTURES CLAYEY GRAVELS. GRAVEL-SANO-CLAY MIXTURES WELL-GRADED SANDS. GRAVELLY SANDS. LITTLE OR NO FINES POORLY -GRADED SANOS. GRAVEL- LY SANDS. LITTLE OR NO FINES SILTY SANOS. SAND-SILT MIXTURES CLAYEY SANOS. SAND-CLAY MIXTURES INORGANIC SILTS AND VERY FINESANOS. ROCK FLOUR. SILTY ORCLAYEY FINE SANOS OR CLAYEYSILTS WITH SLIGHT PLASTICITY INORGANIC CLAYS OF LOW TOMEDIUM PLASTICITY. GRAVELLYCLAYS. SANDY CLAYS. SILTY CLAYS. LEAN CLAYS ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY INORGANIC SILTS. MICACEOUS OR DIATOMACEOUS FINE SANO OR SILTY SOILS INORGANIC CLAYS OF HIGH PLASTICITY. FAT CLAYS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY. ORGANIC SILTS PEAT. HUMUS. SWAMP SOILS WITH HIGH ORGANIC CONTENTS NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS UNIFIED SOIL CLASSIFICATION SYSTEM NOTE: GRAPHIC SYMBOLS HEREIN DO NOT RESEMBLE GRAPHIC SYMBOLS UTILIZED ON BORING LOGS. CENTRE DEVELOPMENT W.O. 1260-SD MARCH 21, 1991 TEST PIT LOG Test Pit Depth (ft.)Material Description TP-31 0-3.5 ARTIFICIAL FILL: Gray brown, dry, dense, silty fine SAND. §.5' Becomes yellow brown, moist, dense fine sandy SILT to silty SAND. 3.5' Blue gray volcanic rock fragments in red brown CLAY matrix (rock fill). Total Depth= 3.5 feet TP-32 0-10 ARTIFICIAL FILL: Yellow brown, dry, medium dense silty fine SAND. @1.5' Becomes interlayered brown, moist, dense silty to clayey fine SAND and dark to light gray dense SAND. @2' Yellow brown moist, dense clayey to silty SAND brown moist dense sandy CLAY and dark gray to blocky clayey SAND and red brown, dry, sandy SILT. Few stems and twigs, musty organic odor. Occurs as thin layer 0.5 to 1 foot thick. @5' Red brown and dark gray brown, moist dense clayey SAND and yellow brown moist dense silty fine SAND. As thin layers .5 to 1 foot thick. Total Depth= 10 feet. -10- GeoSoils, Inc. CENTRE DEVELOPMENT MARCH 21, 1991 W.O. 1260-SD TEST PIT LOG Test: Pit Depth (ft.) Material Description TP-33 0-10 ARTIFICTAT, FTT.T.- Yellow brown, moist, dense, silty fine SAND, moist, dense, dark gray, clayey SAND and brown sandy CLAY. Total Depth= 10 feet TP-34 0-10 ARTIFICIAL FILL: Yellow brown, moist, dense, silty fine SAND, moist, dense, dark gray, clayey SAND and brown sandy CLAY. 10-10.5 BEDROCK - SANTIAGO FORMATION: Pale yellow and orange brown, dry, dense, massive silty SANDSTONE. Total Depth= 10.5 feet TP-35 SEE GRAPHIC LOG TP-35 TP-36 0-10 ARTIFICIAL FILL; Yellow brown, moist, dense, silty fine SAND, moist, dense, dark gray, clayey SAND and brown sandy CLAY. Total Depth: 10 feet TP-37 SEE GRAPHIC LOG TP-36 TP-38 SEE GRAPHIC LOG TP-38 -11- GeoSoils, Inc. APPENDIX II LABORATORY TESTING SUMITOMO BANK APPENDIX II BORING TEST DATA RESULTS "BCWI»JaAHOOa«TH -. •• •-..•• ;• -. B-1 @ 2' B-1 @6' B-1 @ 10' B-1 @ 15' B-1 @ 20' B-1 @ 25' B-1 @ 30' B-1 @ 35' B-1 @ 40' 8-1 @ 45' B-1 @ 50' B-1 @55' B-1 @ 60' B-1 @ 65' B-2@ 5' B-2 @ 7.5' B-2 @ 10' B-2 @ 15' B-2@ 20' B-2 @ 25' B-2 @ 30' B-2 @ 35' B-2 @ 40' B-2 @ 45' B-2 @ 50' B-3 @ 5' B-3 @ 10' B-3 @ 15' B-3 @ 25' B-3 @ 35' B-3 @ 45' B-3 @ 55' B-3@ 65' B-3 @ 75' ^, ^ ,.,-; - f ^''* MATEffiAL£KSCH9nbi< , " Pale brown dayey SAND Pale brown sandy CLAY Yellow brown sandy CLAY Yellow brown sifty SAND Yellow brown sitty SAND YeUow Brown sifty SAND Yellow brown sitty SAND Yellow brown sitty SAND Pale brown sandy CLAY dive gray sandy CLAY Olive gray sandy CLAY Pale brown sandy CLAY Brown sandy CLAY White sitty SAND Brown sandy CLAY Yellow brown sitty SAND Yellow brown sitty SAND White silty SAND Pale brown sitty SAND White silty SAND White silty SAND OUve gray sandy CLAY Yellow brown dayey SAND Yellow brown dayey SAND Orange brown sandy CLAY Yellow brown dayey SAND Gray brown sitty SAND Yellow brown sitty SAND White sifty SAND Olive sandy CLAY Yellow Clay Pale brown sandy CLAY Olive sandy CLAY Olive sandy CLAY - Y> *'&Kf "-"- ": DBWITYfPCF):'- 101.3 96.0 101.3 106.0 110.4 113.3 107.5 106.8 105.9 106.6 106.3 104.5 112.7 96.0 103.0 109.7 106.7 107.5 116.4 111.1 110.0 103.8 112.7 100.0 122.4 112.2 114.9 111.5 114.5 103.5 112.1 107.6 106.2 110.1 ~ K»«tt»^X .COKTEtif £Q "- 19.4 18.9 17.9 15.6 18.0 13.2 15.5 15.5 19.2 21.3 16.1 19.7 16.9 2.1 19.1 9.9 12.9 12.6 9.6 9.0 13.0 19.1 15.7 20.5 11.5 14.8 15.1 12.4 11.0 22.0 16.8 17.9 17.0 17.3 100" 90 80 r- I ID ' U £ >- e m a Ul !z LL f- < Z UIu K ; Ula. * ro >o 50 »o JO >o 10 j SIEVE ANALYSIS SIZE OF OPENING IN INCHES j NUMBER OF MESH PER INCH. U S STANDARD <0 *T IO CJ _ _ Jl I 1 I I 1 1 1 — 1 *#*£*? o ^ - — 1 §" O O O O Q Q O °O O CD ID ^ i*> <M ~~(M — SAMPLE NO. B-l COBBLES DEPTH --FT. 10' COARSE LLL LICO U> FINE GRAVEL I [ 1 1 ~— — I I •) o o 9j <r »o 2 s^*^ ,^*< I I.LI 1 \\\ 1 I \ » \\ \ \ \ ^ HYDROMETER ANALYSIS GRAIN SIZE IN MM O eo »o 5 Q *^ aO<C'*''r>M —Oo'-'OO CCMOOOO QQQQQQ C f) ^,\ 1 \ \ \ \ \ II ^lOCM — CD U> f . IO CM -: GRAIN SIZE IN MILLIMETERS COARSE MEDIUM 103Q FINE SAND CLASSIFICATION Yellow brown clayey SAND (SO NAT. w. c.LL PL PI - -- _ v - - - — - S - — ^^'^i.^s ^->,^ Qi^v i. \ -- •, ^ — K - «»-•»C »^^ ^"^"^^o § S. 3S q§§§§8 < FINES , <a CB •>|O>wiASj'Ko c3'N"|oooooooo°PER CENT COARSER BY WEIGHTi GRADATION CURVES BORING B-l 6 10' W.O. 1779-SD GeoSotls, Inc. H-1 3.0 2.5 2.0 a.COxiX HI<r CO a UJ X CO 1.5 1.0 0.5 0 0.5 1.0 1.5 2.0 NORMAL PRESSURE-KSF EXPLANATION O RESHEAR - AT SATURATED MOISTURE CONTENT • PEAK - AT SATURATED MOISTURE CONTENT 2.5 3.0 DIRECT SHEAR REMOLDED TO 90%RELATIVE DENSITY; THEN SATURATED PCF % MOISTURE % SATURATED MOISTURE CONTENT UNDISTURBED NATURAL SHEAR SATURATED 23.5 SATURATED MOISTURE CONTENT GeoSoils, Inc. SHEAR TEST DIAGRAM BORING B-l § 10' DATE 12"94 W.O.1779-SD Soil Mechanics • Geology • Foundation Engineering FORM 87/8-2A CI4-*f 3.0 2.5 2.0 u. CO XI t-oz UJ CO oz UJz CO 1.5 1.0 0.5 0 0.5 1.0 1.5 2.0 NORMAL PRESSURE-KSF EXPLANATION O RESHEAR - AT SATURATED MOISTURE CONTENT • PEAK - AT SATURATED MOISTURE CONTENT 2.5 3.0 DIRECT SHEAR REMOLDED TO 90%RELATIVE DENSITY; THEN SATURATED PCF % MOISTURE % SATURATED MOISTURE CONTENT UNDISTURBED NATURAL SHEAR SATURATED 22.3 % SATURATED MOISTURE CONTENT GeoSoils, Inc. SHEAR TEST DIAGRAM BORING B-2 § 5' DATE 12-94 n Mft 1779-SD Soil Mechanics • Geology • Foundation Engineering FORM S7/8-2A 3 GEOSOILS, INC. » CONSOLIDATION TEST .. CLIEN'_ SUMITOMO BANK BORING SAMPLE DEPTH WATER CONTENT. % HEIGHT OIA. FEET BEFORE AFTER INCHES INCHES _6 CLASSIFICATION WORK ORDER NO L1779-SD DATE-J;/9S . 0.01 0.12 346678* 2 3 11 STRESS IN KIPS/SQ. FT .4 8 e_LjV*°. 2 34 6 6 7 8 C-1 •nO QEOSOILS, INC. CONSOLIDATION TEST CLIEN'_ SUMITOMO BANK BORING SAMPLE DEPTH WATER CONTENT, % HEIQHT DIA. FEET BEFORE AFTER INCHES INCHES R-2 & 40 FT- CLASSIFICATION WORK ORDER NO. 0.01 2 rSD DATE 1/95-STRESS IN KIPS/SQ. FT. 4 6 678 9 ' 2 346678 z O O COz OO Ooc UJ •nOac QEOSOILS, INC. CONSOLIDATION TEST CLIEN'_ SUMITOMO BANK BORING SAMPLE DEPTH WATER CONTENT, % HEIGHT OIA. FEET BEFORE AFTER INCHES INCHES .B-3 g 35 FT. CLASSIFICATION WORK ORDER NO 1.779-.SB , DATE 0.01 0.12 3 4 68 ._T_| • 2 0 STRESS IN KIPS/SQ. FT. 4 6 8789' 2 3 46878 o 0)zoo LJ O K 3 QEOSOILS, INC. » CONSOLIDATION TEST CHEN'_ SUMITOMO BANK : i I • i : • BORINQ SAMPLE DEPTH WATER CONTENT, % HEIGHT OIA. FEET 1EFORE AFTER INCHES INCHES B-3 £ 65 JET. CLASSIFICATION WORK ORDER NO. _J_iia=SD PATg 0.01 0.1 STRESS IN KIPS/SQ.FT. 4 6 e._7_8_«_* 2 4 8 6 7 B • APPENDIX III EQFAULT REPORT )A.TE. Wednesday. December 7. 1994 (Estimation of Peak Horizontal AcceTeraf prom Digitized California Faults) SEARCH PERFORMED FOR; Sumitomo .08 NUMBER. 1779 OB NAME. Sumitomo SITE COORDINATES: LATITUDE. 33.125 N LONGITUDE: 117.29 W SEARCH RADIUS; 50 mi ...TTENUATION RELATION: '13} Sad-San et a 1 . (1989) Horiz. •••• Rock UNCERTAINTY CM=Mean. S=Mean *• 1 -Sigma ): M SCOND: 0 COMPUTE PEAK. HORIZONTAL ACCELERATION FAULT-DATA FILE USED: CALIFLT.DAT •OURCE OF DEPTH VALUES (A=Attenuat i OP. File. F = Fau1t Data File): A DETERMINISTIC SITE 1 ABBREVIATED 1 FAULT NAME !i! — ,..__..__ j 3ASA LCMA-CLARK. ( S . Jacin . ) ! J ;ATALINA ESCARPMENT ! :HIN.C !_ . . ._ -. _ _ ii :OYOTE CREEK. (San Jaclnto)! „_..._...... ' ELSINORE ! _ ! _A N AC I ON I _„ _ _i 4EWPORT-INGLEWOOO-OFFSHORE | — _.— *. | ^.ALOS VERD-CORON .B . -A.BLAN ! i }CSE CANYON '. .__ _ — ... ™ „ _ _ J 3 AN DIEGO TRGH . -3AHIA SOL.! i WITTIER - NORTH ELSINORE |_ 1 11 APPROX. . ! DISTANCE ! mi (km} • ! 47 38 49 50 24 21 10 22 5 32 47 I ( 751 ! — 1 ( si)! C 78) ! | ( 80V,. i ( 38)1 1 ( 34) ! . | ( 1 R > ! i ( 35): _ 1 ( ? ) !i ( 51)! ( 75) i M.AX . MAX. . CRED. MAG. 7 .00 7 .00 7 .00 7 .00 7.50 5.50 7 nn 7 . 50 7 .00 7 .50 7.50 CREDIBLE EVENT! ! _..-_- i ' ! PEAK ! SITE ! ACC . g I ! 0.039 I _ 1 0.054 1 ! 0.044I! ! 0.035 i . _ ! 0.143 1 ! 0.103 l ! 0.251 | 0.159i ! 0.388 ! 0 . 102I . _ ! 0.058 i <^TTF i i INTENSI I MM i !i | V ! ii i VI ! ! ! 1 VI ! !i | V ! 1 _ i | VIII ', !i i! 1 VII ! ! _ i i IX. ! !i i VIII i ! 11* * X ! i 1 | VII ! !_ | i VI | ! ! I M.AX. . MAX. . PROB . MAG . 6.75 5 .25 5.50 5.75 5.75 4.25 5.75 5.75 5 .00 5.25 5.00 PROBABLE i PEAK. ! ! SITE ! ! ACC . g I i - i ! 0 . 0 3 1 ; 1 . 11 1 ! 0.029; 1 1 1 o o 1 n 1'_• . U i t i 1 1 ! 0.012! l i i 0.0871 i _ _ _ ' ! 0.015! 1 i ! 0.1181 ' . i. .. — | ! 0.099! I 0 . 2 3 S ! i - l ! 0 .039 I 1 - ! I 0.016! l i EVENT SITE INTENS MM V y T T T1 i i_ _ T T T1^1 VI I IV VII VI I IX. V IV — _ 1 ZND OF SEARCH,-FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. <E ROSE CANYON FAULT IS CLOSEST TO THE SITE. r IS ABOUT 5.8 MILES AWAY. vRGEST MAXIMUM-CREDIBLE SITE ACCELERATION: 0.388 c ARGEST MAXIMUM-PROBABLE SITE ACCELERATION: 0.235 g APPENDIX IV GRADING GUIDELINES GRADING GUIDELINES Grading should be performed to at least the minimum requirements of the governing agencies, Chapter 70 of the Uniform Building Code and the guidelines presented below: Site Clearing Trees, dense vegetation, and other deleterious materials should be removed from the site. Non- organic debris or concrete may be placed in deeper fill arsas under direction of the Soils Engineer. Light, dry grasses may be thinly scattered and incorporated into the fill under direction of the Soils Engineer, provided concentrations of organics are not developed. Subdrainage 1. Subdrainage systems should be provided in all canyon bottoms and within buttress and stabilization fills prior to placing fill. Subdrains should conform to schematic diagrams GS-1, GS-3, and GS-4, approved by the Soils Engineer. For canyon subdrains, runs less than 500 feet may use six inch pipe. Runs in excess of 500 feet should have the lower end as eight inch minimum. 2. Filter material should be Class 2 permeable filter material per California Department of Transportation Standards tested by the Soils Engineer to verify its suitability. A sample of the material should be provided to the Soils Engineer by the contractor at least two working days before it is delivered to the site. The filter should be clean with a wide range of sizes. As an alternative to the Class 2 filter, the material may be a 50/50 mix of pea gravel and clean concrete sand which is well mixed, or clean gravel wrapped in a suitable filter fabric. 3. An exact delineation of anticipated subdrain locations may be determined at 40 scale plan review stage. During grading, the Engineering Geologist should evaluate the necessity of placing additional drains. 4. All subdrainage systems should be observed by the Engineering Geologist and Soils Engineer during construction and prior to covering with compacted fill. 5. Consideration should be given to having subdrains located by the project surveyors. Outlets should be located and protected. Treatment of Existing Ground 1. All heavy vegetation, rubbish and other deleterious materials should be disposed of off site. 2. All surficial deposits of alluvium and colluvium should be removed (see Plate GS-1) unless otherwise indicated in the text of this report. Groundwater existing in the alluvial areas may make excavation difficult. Deeper removals than indicated in the text of the report may be necessary due to saturation during winter months. 3. Subsequent to removals, the natural ground should be processed to a depth of six inches, moistened to near optimum moisture conditions and compacted to fill standards. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 2 GRADING GUIDELINES Fill Placement 1. All site soil and bedrock may be reused for compacted fill; however, some special processing or handling may be required (see report). 2. Material used in the compacting process should be evenly spread, moisture conditioned, processed, and compacted in thin lifts not to exceed six inches in thickness to obtain a uniformly dense layer. The fill should be placed and compacted on a horizontal plane, unless otherwise found acceptable by the Soils Engineer. 3. If the moisture content or relative density varies from that acceptable to the Soils Engineer, the Contractor should rework the fill until it is in accordance with the following: a) Moisture content of the fill should be at or above optimum moisture. Moisture should be evenly distributed without wet and dry pockets. Pre-watering of cut or removal areas should be considered in addition to watering during fill placement, particularly in clay or dry surficial soils. b) Each six inch layer should be compacted to at least 90 percent of the maximum density in compliance with the testing method specified by the controlling governmental agency. In this case, the testing method is ASTM Test Designation D-1557-91. 4. Side-hill fills should have an equipment-width key at their toe excavated through all surficial soil and into competent material and tilted back into the hill (GS-2, GS-6). As the fill is elevated, it should be benched through surficial soil and slopewash, and into competent bedrock or other material deemed suitable by the Soils Engineer. 5. Rock fragments less than eight inches in diameter may be utilized in the fill, provided: a) They are not placed in concentrated pockets; b) There is a sufficient percentage of fine-grained material to surround the rocks; c) The distribution of the rocks is supervised by the Soils Engineer. 6. Rocks greater than eight inches in diameter should be taken off site, or placed in accordance with the recommendations of the Soils Engineer in areas designated as suitable for rock disposal (See GS-5). 7. In clay soil large chunks or blocks are common; if in excess of eight (8) inches minimum dimension then they are considered as oversized. Sheepsfoot compactors or other suitable methods should be used to break the up blocks. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 3 GRADING GUIDELINES 8. The Contractor should be required to obtain a minimum relative compaction of 90 percent out to the finished slope face of fill slopes. This may be achieved by either overbuilding the slope and cutting back to the compacted core, or by direct compaction of the slope face with suitable equipment. If fill slopes are built "at grade" using direct compaction methods then the slope construction should be performed so that a constant gradient is maintained throughout construction. Soil should not be "spilled" over the slope face nor should slopes be "pushed out" to obtain grades. Compaction equipment should compact each lift along the immediate top of slope. Slopes should be back rolled approximately every 4 feet vertically as the slope is built. Density tests should be taken periodically during grading on the flat surface of the fill three to five feet horizontally from the face of the slope. In addition, if a method other than over building and cutting back to the compacted core is to be employed, slope compaction testing during construction should include testing the outer six inches to three feet in the slope face to determine if the required compaction is being achieved. Finish grade testing of the slope should be performed after construction is complete. Each day the Contractor should receive a copy of the Soils Engineer's "Daily Field Engineering Report" which would indicate the results of field density tests that day. 9. Fill over cut slopes should be constructed in the following manner: a) All surficial soils and weathered rock materials should be removed at the cut-fill interface. b) A key at least 1 equipment width wide and tipped at least 1 foot into slope should be excavated into competent materials and observed by the soils engineer or his representative. c) The cut portion of the slope should be constructed prior to fill placement to evaluate if stabilization is necessary, the contractor should be responsible for any additional earthwork created by placing fill prior to cut excavation. 10. Transition lots (cut and fill) and lots above stabilization fills should be capped with a three foot thick compacted fill blanket. 11. Cut pads should be observed by the Engineering Geologist to evaluate the need for overexcavation and replacement with fill. This may be necessary to reduce water infiltration into highly fractured bedrock or other permeable zones,and/or due to differing expansive potential of materials beneath a structure. The overexcavation should be at least three feet. Deeper overexcavation may be recommended in some cases. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 4 GRADING GUIDELINES 12. Exploratory backhoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located. Grading Observation and Testing 1. Observation of the fill placement should be provided by the Soils Engineer during the progress of grading. 2. In general, density tests would be made at intervals not exceeding two feet of fill height or every 1,000 cubic yards of fill placed. This criteria will vary depending on soil conditions and the size of the fill. In any event, an adequate number of field density tests should be made to evaluate if the required compaction and moisture content is generally being obtained. 3. Density tests may be made on the surface material to receive fill, as required by the Soils Engineer. 4. Cleanouts, processed ground to receive fill, key excavations.subdrains and rock disposal should be observed by the Soils Engineer prior to placing any fill. It will be the Contractor's responsibility to notify the Soils Engineer when such areas are ready for observation. 5. An Engineering Geologist should observe subdrain construction. 6. An Engineering Geologist should observe benching prior to and during placement of fill. Utility Trench Backfill Utility trench backfill should be placed to the following standards: 1. Ninety percent of the laboratory standard if native material is used as backfill. 2. As an alternative, clean sand may be utilized and flooded into place. No specific relative compaction would be required; however, observation, probing, and if deemed necessary, testing may be required. 3. Exterior trenches, paralleling a footing and extending below a 1:1 plane projected from the outside bottom edge of the footing, should be compacted to 90 percent of the laboratory standard. Sand backfill, until it is similar to the inplace fill, should not be allowed in these trench backfill areas. Density testing along with probing should be accomplished to verify the desired results. GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 5 GRADING GUIDELINES JOB SAFETY General: At GeoSoils, Inc., getting the job done safely is of primary concern. The following is the company's safety considerations for use by all employees on multi-employer construction sites. On ground personnel are at highest risk of injury and possible fatality on grading construction projects. The company recognizes that construction activities will vary on each site and that job site safety is the contractor's responsibility. However, it is, imperative that all personnel be safety conscious to avoid accidents and potential injury. In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of our field personnel on grading and construction projects. 1. Safety Meetings: Our field personnel are directed to attend the contractor's regularly scheduled safety meetings. 2. Safety Vests: Safety vests are provided for and are to be worn by our personnel where warranted. 3. Safety Flags: Two safety flags are provided to our field technician; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits. In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location, Orientation and Clearance: The technician is responsible for selecting test pit locations. The primary concern is the technician's safety. However, it is necessary to take sufficient tests at various location to obtain a representative sampling of the fill. As such, efforts will be made to coordinate locations with the grading contractors authorized representatives (e.g. dump man, operator, supervisor, grade checker, etc.), and to select locations following or behind the established traffic pattern, preferable outside of current traffic. The contractors authorized representative should direct excavation of the pit and safety during the test period. Again, safety is the paramount concern. Test pits should be excavated so that the spoil pile is placed away from oncoming traffic. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates that the fill be maintained in a driveable condition. Alternatively, the contractor may opt to park a piece of equipment in front of the test pits, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits (see Plate GS-7). No grading equipment should enter this zone during the test procedure. The zone should extend approximately 50 feet outward from the center of the test pit. This zone is established both for safety and to avoid excessive ground vibration which typically decreases test results. When taking slope tests, the technician should park their vehicle directly above or below the test GeoSoils, Inc. SUMITOMO BANK OF CALIFORNIA JANUARY 12, 1995 W.O. 1779-SD PAGE 6 GRADING GUIDELINES location on the slope. The contractor's representative should effectively keep all equipment at a safe operation distance (e.g. 50 feet) away from the slope during testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location. In the event that the technician's safety is jeopardized or compromised as a result of the contractor's failure to comply with any of the above, the technician is directed to inform both the developer's and contractor's representatives. If the condition is not rectified, the technician is required, by company policy, to immediately withdraw and notify their supervisor. The grading contractors representative will then be contacted in an effort to effect a solution. No further testing will be performed until the situation is rectified. Any fill placed in the interim can be considered unacceptable and subject to reprocessing, recompaction or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor brings this to technicians attention and notify our the project manager or office. Effectre communication and coordination between the contractors' representative and the field technician(s) is strongly encouraged in order to implement the above safety program and safety in general. The safety procedures outlined above should be discussed at the contractor's safety meetings. This will serve to inform and remind the equipment operators of these safety procedures particularly the zone of non-encroachment. Trench Safety: It is the contractor's responsibility to provide safe access into trenches where compaction testing is needed. Our personnel are directed not to enter any excavation which 1) is 5 feet or deeper unless shored or laid back, 2) displays any evidence of instability, has any loose rock or other debris which could fall into the trench, or 3) displays any other evidence of any unsafe conditions regardless of depth. All utility trench excavations in excess of 5 feet deep, which a person enters, are to be shored or laid back. Trench access should be provided in accordance with OSHA standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment. If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify their supervisor. The contractors representative will then be contacted in an effort to effect a solution. All backfill not tested due to safety concerns or other reasons could be subject to reprocessing and/or removal. GeoSoils, Inc. Final Grade Original ground Loose Surface Deposits Suitable Material Bench where slope exceeds 5:l Suitable Material Subdrain (See Plate GS-3) GeoSoils, Inc. TYPICAL TREATMENT OF NATURAL GROUND DATE 1/95 W.O.1779-SD Geotechnical Engineering * Engineering Geology ,TOE SHOWN ON GRADING PLAN PROJECTED I '/2 ' I NATURAL SLOPE - N^.- - 'lO' Typical — ^-> 1 IN 4 '1,/ Typicfcl BEDROCK OR FIRM FORMATION MATERIAL Note: Where natural slope gradient is 5=1 or less, benching is not necessary unless stripping did not remove all compressible material. GeoSoils, Inc. TYPICAL FILL OVER NATURAL SLOP DATE 1/95 W.O. NO 1779-SD Geotechnical Engineering • Engineering Geology ALTERNATE 1 SOIL - SLOPEWASH ALLUVIUM REMOVED BEDROCK Canyon subdrain : 6" perforated pipe with 9 cu. ft. gravel per ft. of drain wraped with filter fabric. ALTERNATE 2 6" perforated pipe with 9 cu. ft. gravel per ft. of drain wraped with filter fabric. GeoSofls, Inc. CANYON SUBDRAIN DESIGN AND CONSTRUCTION HATP 1/95 W0 Nrt 1779-SD Geotechnical Engineering « Engineering Geology 36" THICK FILL CAP. FINISHED SURFACE COMPACTED ' FILL ' D (See drain detail) A. Buttress slope to have a bench at every 20 to 30 feet. B. Buttress key depth varies, (see preliminary reports) C. Buttress key width varies, (see preliminary reports) D. Backdrains and lateral drains located at elevation of every bench drain. First drain at elevation just above lower lot grade. Additional drains may be required at discretion of GeoSoils, Inc. 4"perforated pipe (or approved equivalent) placed in I cu. ft. per linear ft. of graded . filter material.* Pipe to extend ' ' full length of buttress. nonperforated pipe lateral to slope face at t IOO1 intervals .Pipe I "above, bench Graded filter material to conform to State of Call.. Dept- Public Works standard specifications for Class 2permeable material GeoSoils, Inc. TYPICAL BUTTRESS SECTION DATE 1/95 W.O. Mn 177Q-SD Geotechnical Engineering • Engineering Geology FILL SLOPE A CLEAR ZONE t^EQUIPMENT WIDTH -^ Soil shall be pushedover rocks and floodec into voids. Compact around and over each windrow. \ Stack boulders end to end. Do not pile upon each other. •* : MO' Typical FILL SLOPE /^Stagger rows ^s^_ __ _^^ <•—»*• O O O ^ ^ 3* mi n i mum ' ' FIRM GROUND , v^ G^oSoflsf Inc. ROCK DISPOSAL DETAIL DATE W.O. MO 1779-SD Geotechnical Engineering • Engineering Geology REMOVE ALL TOPSOIL, COLLUVIUM AND CREEP MATERIAL FROM TRANSITION -I51 Minimum BEDROCK OR FIRM FORMATION MATERIAL GeoSoils, Inc. TYPICAL FILL OVER CUT SLOPE 1/95 /r> KIO 1779-SD Geotechnical Engineering • Engineering Geology TEST PIT SAFETY DIAGRAM SIDE VIEW TEST PVT-m&** ( NOT TO SCALE ) TOP VIEW 100 FEET APPROXIMATE OF TEST PIT GeoSoiIs, Inc.\. ' ™ *- (K TT TH 1/95 W.O. Mf> 1779-SD Geotechnical Engineering • Engineering Geology PLATE I GEOTECHN1CAL MAP B-lS TP-34Q ARTIFICIAL FILL BORING LOCATION TEST PTT LOCATION ALL LOCATIONS ARE APPROXIMATE. NORTH Approximate scale 1":80' GeoSoils, Inc. GEOTECHNICAL MAP DATE 12-94 w.O.1779-SD Geotechnical Engineering • Engineering Geology