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HomeMy WebLinkAboutCT 05-13; LA COSTA RIDGE NEIGHBORHOOD 2.6; PROJECT GRADING REPORT; 2009-09-01CT o53 PACIFIC SOILS ENGINEERING, INC. — 7715 CONVOY COURT, SAN DIEGO, CALIFORNIA 92111 TELEPHONE: (858) 560-1713, FAX: (858) 560-0380 D.R. HORTON INC. 1021 Costa Pacifica Way #2107 Oceanside, CA 92054 September 1, 2009 Work Order 401036G Attention: Ms. Kim Molina Subject: Project Grading Report, Model Site, Lots 1 through 4, La Costa Ridge Project, Neighborhood 2.6, in the City of Carlsbad, California Reference: See Appendix A Gentlemen: Presented herein are Pacific Soils Engineering, Inc.'s (PSE) geotechnical data and test results pertaining to the completion of grading for the model site at the La Costa Ridge Project, Lots 1 through 4, in the City of Carlsbad, California. This report pertains to the grading operations that were performed in August of 2009. PSE provided geoteehnical observation and testing services during cut and fill grading operations for the subject project.; Data developed during the grading are summarized in the text of this report, on the enclosed 40-scale grading plan (Plate 1) and in Table I. Also presented herein are foundation and slab recommendations based upon field and laboratory testing of as* graded soil conditions. Cuts, fills and processing of original ground covered by this report have been completed under P SE's testing and observation. Based on the testing and observations, the grading summarized herein is considered to be in general conformance with the City of Carlsbad grading code, the 40-scale grading plan, and the referenced geotechnical reports. Slopes are considered grossly stable and should remain so under normal conditions. To reduce exposure to erosion, landscaping of graded slopes should be accomplished as soon as possible. Drainage berms and swales should be established and maintained to aid in long-term slope protection. CORPORATE HEADQUARTERS LOS ANGELES COUNTY RIVERSIDE COUNTY SOUTH ORANGE COUNTY TEL: (714) 220-0770 TEL: (310) 325-7272 or (323) 775-5771 TEL (951) 582.0170 TEL (714) 730-2122 FAX: (714) 220-9589 FAX: (114) 220-9589 FAX: (951) 582-0170 FAX: (714) 730-5191 ci 0!5-13 $9 Work Order 401036G Page 2 September 1, 2009 1.0 ENGINEERING GEOLOGY 1.1 Geologic Units The geologic unit encountered during the grading of the subject site included previously placed undocumented artificial fill, topsoil and granitic rock. Prior to the placement of compacted fill the existing undocumented fill, topsoil and highly weathered granitic rock were completely removed. 1.2 Structure Based upon review of available literature, maps and aerial photographs and PSE's geologic observation and mapping of project grading, the onsite granitic is considered to be unfaulted. Minor fractures were observed. 1.3 Corrective Grading Corrective grading in the form of stabilization fills and/or buttresses was not recommended. 1.4 Groundwater Groundwater was not encountered on Lots I through 4 during grading. 1.5 Conclusions From an engineering geologic viewpoint, the model site, Lots 1 through 4, located in the City of Carlsbad, California are suitable for their intended residential use. 2.0 PROJECT GRADING 2.1 Compaction Test Results Compaction test results are presented in Table I (Appendix B). Approximate locations are shown on the enclosed 40-scale grading plan (Plate 1). Compaction testing was conducted utilizing Campbell Pacific Nuclear Test Gauges (ASTM:D 2922 and D 3017). 2.2 Removals 2.2.1 The removal of unsuitable existing artificial fill, topsoil and highly weathered granitic rock was accomplished to competent granitic bedrock (Kgr). Prior to the placement of compacted fill, the exposed surface was scarified, moisture PACIFIC SOILS ENGINEERING. INC. Work Order 401036G Page 3 September 1, 2009 conditioned to a minimum of optimum moisture or slightly above, and compacted. 2.2.2 Removals, excavations, cleanouts and processing in preparing fill areas were observed by PSE's representatives prior to the placement of fill reported herein. 2.3 Compacted Fill Placement Fill consisting of the soil types indicated in Table I was placed in thin lifts (approximately six to eight inches), moisture conditioned to optimum moisture or slightly above and compacted to a minimum of 90 percent relative compaction (ASTM:D 1557). This was accomplished utilizing self-propelled, rubber-tired compactors, along with heavy earth moving equipment. Each succeeding fill lift was treated in a similar manner. 2.4 Fill Slope Construction The fill slopes were built to grade and were shaped and compacted by track walking. Finish slope surfaces have been probed and/or tested and are considered to satisfy the project requirements and the grading codes of the City of Carlsbad. The soil materials utilized to construct the fill slopes are subject to erosion and creep. As such, landscaping and irrigation management are important elements in the long-term performance of slopes and should be established and maintained as soon as possible and maintained through the life of the project. 2.5 Depth of Fill Compaction testing was performed approximately for each one to two feet of fill placed. The approximate maximum vertical depth of fill placed on individual lots is presented below in Table 2.1. PACIFIC SOILS ENGINEERING, INC. Work Order 401036G Page 4 September 1, 2009 3.0 PROPOSED DEVELOPMENT The subject site is proposed for single-family residential use. One- and two-story family dwellings will be constructed utilizing wood-frame and post-tensioned, slab-on-grade foundation systems 4.0 DESIGN RECOMMENDATIONS 4.1 Expansion Index Materials utilized for compacted fill ranged from "very low" to "high" in expansion potential: Sampling of the post-grading conditions was conducted for Lots 1 through 4 to determine the expansion potential per ASTM:D 4829. That evaluation revealed "medium" expansive materials on the subject lots. Soluble sulfate content was also tested (see Section 4.11). The laboratory test data are presented in Table 4.1. TABLE 4.1 Laboratory Test Data and Lot Categories OR ---- —;c .1 I IxIII 4.2 Foundation Design Criteria The following foundation design recommendations and the design parameters presented in Table 4.2 may be utilized to design the foundations for the proposed PACIFIC SOIL.B ENGINEERING, INC. Work Order 401036G Page 5 September 1, 2009 structure. The post-tensioned slab parameters presented herein are based on procedures outlined in the Design of Post-Tensioned Slabs-on-Ground, Third Edition by Post-Tensioning Institute, per the 2007 CBC. Allowable Bearing: 2000 lbs./sq.ft. (assuming a minimum embedment depth of 12-inches and a minimum width of 12 inches) Lateral Bearing: 250 lbs./sq.ft. per foot plus 125 lbs/& for each additional foot embedment to a maximum of 2000 lbs/ ft2 Sliding Coefficient: 0.35 Total Settlement: ¼-inch Differential Settlement: 3/8-inch in 20 feet. 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 should be evaluated by the Structural Engineer. PACIFIC SOILS ENGINEERING. INC. Work Order 401036G Page 6 September 1, 2009 TABLE 4.2 POST-TENSIONED FOUNDATION DESIGN CRITERIA* CENTER LIFE EDGE LIFT MINIM" All Perimeter Beam SOIL LOT EXPANSION EMBEDMENT Conditions CATEGORY NUMBERS POTENTIAL (INCHES)** Em (ft.) I Yin (in.) Em (ft.) Yin (in.) II 1-4 Medium 18 9.0 0.46 5.4 1.10 Footing/Slab Dimensions The footing width, depth and the structural slab-on-grade thickness shall be as specified by the structural engineer based upon the soil parameters provided by PSE and the requirements of the most current CBC guidelines. Under-Slab Requirements An approved moisture and vapor retarder should be placed below all slabs-on-grade within living and moisture sensitive areas as discussed in Section 4.4. Slab Subgrade Moisture Requirements Based Upon Expansion Potential I Minimum of 130 percent of optimum moisture at least 24 hours prior to Soil Category U I placing concrete to a depth of 12 inches. Footing Embedment If exterior footings adjacent to drainage swales are to exist within five (5) feet horizontally of the swale, the footing should be embedded sufficiently to assure embedment below the swale bottom is maintained. Footings adjacent to slopes should be embedded such that at least seven (7) feet are provided horizontally from edge of the footing to the face of the slope. * The values of predicted lift presented in this table are based on procedures outlines in the Design of Post-Tensioned Slabs-on-Ground, Third Edition. No corrections for vertical barriers at edge of slab or other corrections (such as tree roots under the slab or horizontal barriers) are assumed. The design parameters are based on a Constant Suction Value of 3.9 pF. **Foundations supporting multiple stories may require additional embedment. The foundation designer should verify whether additional embedment is required based on the type of structure being constructed and the requirements of the most current CBC. 4.3 Seismic Design Parameters The following seismic design parameters are presented to be code compliant to the California Building Code (2007). The subject site has been identified as "D" site class in accordance with CBC, 2007, Table 1613.5.3 (1). The site is located at Latitude 33.1058 N and Longitude 117.2266 W. Utilizing this information, the computer program USGS Earthquake Ground Motion Parameters Version 5.0.7 and ASCE 7 criterion, the seismic design category for 0.20 seconds (Ss) and 1.0 second (Si) period response accelerations can be determined (CBC, 2007 1613.5.5.1) along with the design spectral response acceleration (CBC, 2007 16 13.5.4). PACIFIC 801L9 ENGINEERING, INC. Work Order 401036(3 Page 7 September 1, 2009 4.4 Moisture Barrier A moisture and vapor retarding system should be placed below the slabs-on-grade in portions of the structure considered to be moisture sensitive. The retarder should be of suitable composition, thickness and strength, and have low permeability to effectively prevent the migration of water and reduce the transmission of water vapor to acceptable levels. Historically, a 10-mil plastic membrane, such as Visqueen, placed between one to four inches of clean sand, has been used for this purpose. The use of this system or other systems, materials or techniques can be considered, at the discretion of the designer, provided the system reduces the vapor transmission rates to acceptable levels. 4.5 Footing Excavation Observations The project soil engineer or his representative should observe footing excavations for the proposed structures prior to the placement of concrete. 4.6 Minimum Depth of Embedment For the subject site, where foundations for structures are to exist in proximity to slopes, the footings should be embedded to satisfy the requirements presented in Figure 1. PACIFIC BOILS ENGINEERING. INC. Work Order 401036G Page 8 September 1, 2009 FIGURE 1 FACE OF FOOThG TOP OF SLOPE I' fill WII I I ji H FACE Cc STRUCTURE ".1 H TOE OF I43. NO NOT EXCE4O FT. SLOPE 7 1412 MIT I NOT Ø(C 15 FT. (4.572 mm) MAX. 4.7 Backyard Improvements Future improvements such as patios, slabs, pools, and perimeter screen walls can be constructed within the setback zones; however, the design and siting of all such improvements should be reviewed by a soil engineer who is familiar with the site- specific conditions reported herein. Walls should be structurally separated at appropriate intervals. Wall footing excavations should be observed by the project soils engineer/engineering geologist. 4.8 Retaining Wall Design Retaining walls should be founded on compacted fill or bedrock. Foundations may be designed in accordance with the recommendations presented in Section 4.2. In general, conventional walls can be designed to retain select granular backfill. It should be anticipated that suitable backfill material will have to be imported or selectively produced from onsite sources, and should consist of granular "very low" to "low" expansive materials. Conventional walls constructed with select granular backfill or native soils can be designed to resist lateral pressures that are developed by a fluid as presented on Table 4.3. PACIFIC SOILS ENGINEERING, INC. Work Order 401036G Page 9 September 1, 2009 TABLE 4.3 EARTH PRESSURE COEFFICIENTS SELECT COMPACTED BACKFILL Unit weight = 130 lbs. I Cu. ft. Cohesion = 200 lbs. / sq. ft. Friction angle = 32 degrees Rankine Equivalent Fluid Level Backfill Coefficients Pressure (psfllin.fi) Coefficient of Active Pressure: K3 = 0.31 40 Coefficient of Passive Pressure: K = 3.25 423 Coefficient of At-Rest Pressure: K0 = 0.47 61 2: 1 Backfill Coefficient of Active Pressure: Ka = 0.47 61 Coefficient of Passive Pressure: Descending K (-) = 1.23 161 Coefficient of At-Rest Pressure: IC = 0.72 94 Per the 2007 CBC, presented below are seismic earth pressure coefficients that may be utilized in the design of retaining walls. TABLE 4.4 SEISMIC EARTH PRESSURE COEFFICIENTS Rankine Equivalent Fluid Level Backfill Coefficients Pressure (psf/lin.ft.) Coefficient of Active Pressure: Ka = 0.54 70 Coefficient of Passive Pressure: Kp = 3.02 393 2: 1 Backfill Coefficient of Active Pressure: K. = 0.70 91 Coefficient of Passive Pressure: K (-) = 1.0 130 Restrained retaining walls should be designed for "at-rest" conditions, utilizing K0. Retaining walls should be backfllled with a free draining material (SE'20) extending horizontally from the back of the retaining wall a minimum of one-half the height of the retaining wall to within 12 inches of grade (Figure 2). Backfill should be compacted to project specifications. Native soils shall be utilized in the upper 12 inches. Drainage systems including, as a minimum, a 4-inch diameter perforated drain line surrounded by four cubic feet per lineal foot of 3/4-inch to 1-inch crushed rock wrapped with a suitable filter fabric, should be provided to cantilever and restrained retaining walls to relieve hydrostatic pressure. PACIFIC SOILS ENGINEERING. INC. Work Order 401036G Page 10 September 1, 2009 FIGURE 2 RETAINING WALL BACKFILL N.T.S. PROVIDE DRAINAGE SWALE BACKFILL NATIVE OR SELECT•. : [ = BACKFILl. I SELECT I BACKFILL DRAIN LATERALLY, OR PROVIDE WEEP •. - HOLES -. AS REQUIRED I AND TO DRAIN SE?20 * OR AS MODIFIED BY A SPECIFIC REPORT () 4 INCH PERFORATED PVC, SCHEDULE 40, SOIl 35 OR APPROVED ALTERNATE, PLACE PERFORATIONS DOWN AND SURROUND WITH 4 CU. FT. PER FT.DF + INCH ROCK OR APPROVED ALTERNATE AND MIRAF1 140 FILTER FABRIC OR APPROVED EQUIVALENT 4.8.1 Other Design and Construction Considerations > The design loads presented in Tables 4.3 and 4.4 are to be applied on the retaining wall in a horizontal fashion. Friction between wall and retained soils should not be allowed in the retaining wall analyses. > Additional allowances should be made in the retaining wall design to account for the influence of construction loads, temporary loads and possible nearby structural footing loads. Unit weights of 125 pcf and 130 pcf may be used to model the dry and wet density of onsite compacted fill materials. > Select backfill, imported or native, should be granular, structural quality backfill with a sand equivalent of 20 or better and an ASCE Expansion Index of 20 or less. The backfill must encompass the full active wedge area. > No backfill should be placed against concrete until minimum design strengths are achieved in compression tests of cylinders. Footing excavations for retaining walls should be observed by the project soil engineer or his representative. PACIFIC BOILS ENGINEERING. INC. Work Order 401036G Page 11 September 1, 2009 Backfill should be compacted to a minimum of 90 percent of the laboratory maximum density at or slightly above optimum moisture as per ASTM:D 1557-02. > It should be noted that the bearing capacity and passive resistance values presented in Section 4.2 are based on level conditions at the toe. Modified design parameters can be presented for retaining walls with sloped conditions at the toe. 4.9 Utility Trenches 4.9.1 Excavation All utility trenches should be shored or laid back in accordance with applicable OSHA standards. Excavations in bedrock areas should be made in consideration of underlying geologic structure. Pacific Soils Engineering, Inc. should be consulted on these issues during construction. The onsite soils are classified as Soil Type B per OSHA standards. 4.9.2 Backfill Mainline and lateral utility trench backfill should be compacted to at least 90 percent of maximum dry density as determined by ASTM:D-1557-02. Onsite soils will not be suitable for use as bedding material but will be suitable for use in backfill, provided oversized materials are removed. No surcharge loads should be imposed above excavations. This includes spoil piles, lumber, concrete trucks or other construction materials and equipment. Drainage above excavations should be directed away from the banks. Care should be taken to avoid saturation of the soils. Compaction should be accomplished by mechanical means. Jetting of native soils will not be acceptable. Under-slab trenches should also be compacted to project specifications. If native soils are used, mechanical compaction is recommended. If select granular backfill (SE> 30) is used, compaction by flooding will be acceptable. The soil engineer should be notified for inspection prior to placement of the membrane and slab reinforcement. The use of a double layer of mesh across under-slab plumbing trenches is considered an acceptable alternative to compaction of sand backfill. PACIFIC SOILS ENGINEERING, INC. Work Order 401036G Page 12 September 1, 2009 4.10 Exterior Slabs and Walkways 4.10.1 Subgrade Compaction The subgrade below exterior slabs, sidewalks, driveways, patios, etc. should be compacted to a minimum of 90 percent relative compaction as determined by ASTM Test Method: D 1557-02. 4.10.2 Subgrade Moisture The subgrade below exterior slabs, sidewalks, driveways, patios, etc. should be moisture conditioned to a minimum of 120 percent of optimum moisture content prior to concrete placement. 4.10.3 Slab Thickness Concrete flatwork and driveways should be designed utilizing four-inch minimum thickness. 4.10.4 Control Joints Weakened plane joints should be installed on walkways at intervals of approximately eight feet. Exterior slabs should be designed to withstand shrinkage of the concrete. 4.10.5 Flatwork Reinforcement Consideration should be given to reinforcing any exterior flatwork. 4.10.6 Thickened Edge Consideration should be given to construct a thickened edge (scoop-footing) at the perimeter of slabs and walkways adjacent to landscape areas to minimize moisture variation below these improvements. The thickened edge (scoop-footing) should extend approximately eight inches below concrete slabs and should be a minimum of six inches wide. 4.11 Chemical Tests The results of chemical tests conducted during rough grading indicate that the soluble sulfate concentrations of the majority of the site materials tested are below 0.1. As such, soluble sulfate potential of near surface soils can be classified as "negligible", in accordance with Table 4.3.1 of ACI 318-05. PACIFIC SOILS ENGINEERING, INC. Work Order 401036G Page 13 September 1, 2009 4.12 Concrete Design As stated in Section 4.6, negligible concentrations of sulfates were detected in the onsite soils. Therefore, per ACI 318-05, the use of sulfate-resistant concrete is not required. 5.0 OTHER DESIGN AND CONSTRUCTION CONSIDERATIONS 5.1 Site Drainage Positive drainage away from structures should be provided and maintained. Roof, pad and slope drainage should be collected and directed away from the proposed structures to approved disposal areas. It is important that drainage be directed away from foundations. This is especially true in patio areas and greenbelt areas. The recommended drainage patterns should be established at the time of fine grading and maintained throughout the life of the structure. 5.2 Service Utility Trench Backfill Service utility trench backfill should be accomplished in accordance with the prevailing criteria of the City of Carlsbad. 5.3 Seismic Design Seismic design should be based on current and applicable building code requirements. 7.0 HOMEOWNER CONSTRUCTION AND MAINTENANCE RESPONSIBILITIES During and upon completion of mass grading of the subject site, representative soil samples were tested for expansive soil characteristics and soluble sulfate concentrations. The results of these tests are presented in Table 4.1 of the text. In addition, certain lots contain manufactured slopes within or adjacent to the building pad area. All of these conditions should be considered in design, construction and maintenance of homeowner improvements. The homeowners should be advised of certain responsibilities they must accept in consideration of these factors. Suggested information to educate the homeowners regarding these responsibilities is presented in Appendix C. We suggest that PACIFIC SOILS ENGINEERING, INC. Manager of Geologic Work Order 401036G Page 14 September 1, 2009 this information be provided to all homeowners as part of an information packet during the sales process. This report presents information and data relative to the mass grading and/or placement of compacted fill at the subject site. A representative(s) of this firm conducted periodic tests and observations during the progress of the construction in an effort to determine whether compliance with the project drawings, specifications and Building Code were being obtained. The presence of our personnel during the work process did not involve the direction or supervision of the contractor. Technical advice and suggestions were provided to the owner and/or his representative based upon the results of the tests and observations. Completed work under the purview of this report is considered suitable for the intended use. Conditions of the reference reports remain applicable unless specifically superseded herein. Respectfully submitted, PACIFIC SOILS ENGINEERING, INC. By: SCOTT A. GRAY, RCt 67391 Manager of Geotechnical Services Dist: (4) Addressee 0BISAGIDAM:jz400589AM, January 16.2009 A. No 67391 Exp * PACIFIC SOILS ENGINEERING, INC. APPENDIX A PACIFIC BOILS ENGINEERING, INC. Work Order 401036G Page 15 September 1, 2009 REFERENCES Pacific Soils Engineering, Inc., 2009a, Observations and Recommendations of Wet Area in Southeast Corner of the La Costa Ridge Project, City of Carlsbad, California, dated August 21, 2009 (Work Order 401036). Pacific Soils Engineering, Inc., 2009b, Supplemental Geotechnical Investigation, La Costa Ridge Project, City of Carlsbad, California, dated July 21, 2009 (Work Order 401036). Pacific Soils Engineering, Inc., 2009c, Foundation Plan Review, La Costa Ridge Project, City of Carlsbad, California, dated June 22, 2009 (Work Order 401036). Pacific Soils Engineering, Inc., 2009d, Updated Foundation Design Recommendations, La Costa Ridge Project, City of Carlsbad, California, dated February 16, 2009 (Work Order 401036). Pacific Soils Engineering, Inc. 2007a, Reinforced 1.5: 1 Fill Slope Recommendations, La Costa Ridge Neighborhood 2.6, Carlsbad, California, dated June 13, 2007 (Work Order 401036). Pacific Soils Engineering, Inc., 2007b, Response to Plan Check Review Comment, La Costa Ridge Project, in the City of Carlsbad, California, dated June 25, 2007 (Work Order 401036). Pacific Soils Engineering, Inc., 2007c, Embankment Constraints, La Costa Ridge Neighborhood 2.6, Carlsbad, California, by Pacific Soils Engineering, Inc., dated February 21, 2007 (Work Order 401036). Pacific Soils Engineering, Inc., 2007d, Updated Preliminary Geotechnical Investigation, La Costa Ridge Project, in the City of Carlsbad, California, by Pacific Soils Engineering, Inc., dated February 15, 2007 (Work Order 401036). Pacific Soils Engineering, Inc., 2006a, Suitability of Stockpile Material, La Costa Ridge 26-Acre Parcel, Located Southwest of Rancho Santa Fe Road and Melrose Drive, City of Carlsbad, CA, dated February 15, 2006 (Work Order 401036). Pacific Soils Engineering, Inc., 2006b, Supplemental Geotechnical Recommendations, La Costa Ridge Project, in the City of Carlsbad, CA, dated January 16, 2006 (Work Order 401036). Pacific Soils Engineering, Inc., 2005a, Preliminary Geotechnical Investigation, La Costa Ridge Project (Approximately 7+-Acre Parcel), in the City of Carlsbad, California, dated June 2, 2005 (Work Order 401036). Pacific Soils Engineering, Inc., 2005b, Geotechnical Summary, La Costa Ridge 2.6-Acre Parcel, Located Southwest of Rancho Santa Fe Road and Melrose Drive, City of Carlsbad, CA, dated March 29, 2005 (Work Order 401036). PACIFIC SOILS ENGINEERING, INC. APPENDIX B PACIFIC BOIIB ENGINEERING, INC. Work Order 401036G La Cosa Ridge Models September 1, 2009 TABLE I Laboratory Testing Laboratory Maximum Density ASTM:D 1557-02 (All Soil Types) Rock Corrections were calculated based on ASTM: D 4718 Optimum Maximum Moisture Dry Density Soil Type & Description (% dry wt.) (lbs./cu.ft.) B - Light Brown Sandy Silt 9.3 117.3 C - Brown Silty Sand 10.9 121.5 E - Brown Silty Sand w/Gravel 9.0 128.4 E25 - Brown Silty Sand w/Gravel (25% rock*) 7.0 135.7 E30 - Brown Silty Sand w/Gravel (30% rock*) 6.6 137.2 * percent rock was estimated based on field conditions LEGEND Non-Designated Test - Indicates test taken in compacted fill. Test Location - Indicated by street and street stationing, by. specified utility line number or stationing, or by direction from closest adjacent building, or by lot and unit number. - Indicates side of center line in direction of ascending stationing. Elevation - Indicated by approximate field elevation (feet) above mean sea level. TEST TYPE N - Indicates test by Campbell Pacific Nuclear Test Gauge (per ASTM:D 2922-05 and D 3017-05). PACIFIC SOILS ENGINEERING. INC. Work Order 401036G La Costa Ridge Models September 1, 2009 TABLE I (cont'd) Depth Test or Moisture Unit Dry Density Rel. Soil Test Proj. Date Number Test Location Elev. Opt Field Max. Field Comp. Type Type Spec. Pass/Fail 8/14/09 148 Lot 358 10.9 11.3 121.5 116.4 95 C N 90 Pass 8/14/09 149 Lot 355 10.9 11.8 121.5 117.0 96 C N 90 Pass 8/17/09 152 Lot 355 9.3 12.1 117.3 108.5 92 B N 90 Pass 8/17/09 153 Lot 357 9.3 12.8 1173 108.6 92 B N 90 Pass 8/18/09 165 Lot 358 7.0 9.8 135.7 129.6 95 E25 N 90 Pass 8/18/09 166 Lot 359 7.0 9.6 135.7 129.9 95 E25 N 90 Pass 8t24/09 195FG Lot 1 360.0 6.6 8.9 137.2 133.5 97 E30 N 90 Pass 8t24/09 196FG Lot 359.0 6.6 6.9 137.2 129.2 94 E30 N 90 Pass 8/24/09 197FG Lot 359.0 6.6 6.8 137.2 133.2 97 E30 N 90 Pass 8/24/09 198FG Lot 358.6 6.6 8.2 137.2 128.9 93 E30 N 90 Pass APPENDIX C PACIFIC BOILS ENGINEERING, INC. Work Order 400589AM Mr. Jeff O'Connor January 16, 2009 HOMEOWNER MAINTENANCE AND IMPROVEMENT CONSIDERATIONS General Homeowners and/or residents must assume a certain degree of responsibility for improvements and for maintaining conditions. Maintaining drainage patterns and minimizing the soil moisture variation below all improvements are of primary importance. Such design, construction and maintenance provisions may include: Employing contractors for improvements who design and build in recognition of local building codes and specific site soils conditions. Establishing and maintaining positive drainage away from all foundations, walkways, driveways, patios, and other hardscape improvements. Avoiding the construction of planters adjacent to structural improvements. Alternatively, planter sides/bottoms can be sealed with an impermeable membrane and drained away from the improvements via subdrains into approved disposal areas. Sealing and maintaining construction/control joints within concrete slabs and walkways to reduce the potential for moisture infiltration into the subgrade soils. Utilizing landscaping schemes with vegetation that requires minimal watering. Watering should be done in a uniform manner, as equally as possible on all sides of the foundation, keeping the soil "moist" but not allowing the soil to become saturated. Maintaining positive drainage away from structures and providing roof gutters on all structures with downspouts that are designed to carry roof runoff directly into area drains or discharged well away from the foundation areas. Avoiding the placement of trees closer to the proposed structures than a distance of one-half the mature height of the tree. Observation of the soil conditions around the perimeter of the structure during extremely hot/dry or unusually wet weather conditions so that modifications can be made in irrigation programs to maintain relatively uniform moisture conditions. PACIFIC SOILS ENGINEERING, INC. Work Order 401036G Page 17 September 1, 2009 Sulfates Homeowners should be cautioned against the import and use of certain inorganic fertilizers, soil amendments, and/or other soils from offsite sources in the absence of specific information relating to their chemical composition. Some fertilizers have been known to leach sulfate- compounds into soils otherwise containing "negligible" sulfate concentrations and increase the sulfate concentrations to potentially detrimental levels. In some cases, concrete improvements constructed in soils containing high levels of soluble sulfates may be affected by crystalline growth or mineral accumulation, which may, in the long term, result in deterioration and loss of strength. Site Drainage The owners should be made aware of the potential problems that may develop when drainage is altered through construction of retaining walls, paved walkways, patios or other hardscape improvements. Ponded water, drainage over the slope face, leaking irrigation systems, overwatering or other conditions which could lead to ground saturation must be avoided. No water should be allowed to flow over the slopes. No alteration of pad gradients should be allowed that would prevent pad and roof runoff from being directed to approved disposal areas. As part of site maintenance, all roof and pad drainage should be directed away from slopes and around structures to approved disposal areas. All berms were constructed and compacted as part of fine grading and should be maintained by the resident. Drainage patterns have been established at the time of the fine grading should be maintained throughout the life of the structure. No alterations to these drainage patterns should be made unless designed by qualified professionals in compliance with local code requirements and site-specific soils conditions. PACIFIC SOILS ENGINEERING, INC. Work Order 401036G Page 18 September 1, 2009 Slope Drainage Homeowners should be made aware of the importance of maintaining and cleaning all interceptor ditches, drainage terraces, downdrains, and any other drainage devices, which have been installed to promote slope stability. Subsurface drainage pipe outlets may protrude through slope surfaces and/or wall faces. These pipes, in conjunction with the graded features, are essential to slope and wall stability and must be protected in-place. They should not be altered or damaged in any way. Planting and Irrigation of Slopes Seeding and planting of the slopes should be planned to achieve, as rapidly as possible, a well-established and deep-rooted vegetal cover requiring minimal watering. It is the responsibility of the landscape architect to provide such plants initially and of the residents to maintain such planting. Alteration of such a planting scheme is at the resident's risk. The homeowner is responsible for proper irrigation and for maintenance and repair of properly installed irrigation systems. Leaks should be fixed immediately. Sprinklers should be adjusted to provide maximum uniform coverage with a minimum of water usage and overlap. Overwatering with consequent wasteful runoff and serious ground saturation must be avoided. If automatic sprinkler systems are installed, their use must be adjusted to account for seasonal and natural rainfall conditions. Burrowing Animals Homeowners must undertake a program to eliminate burrowing animals. This must be an ongoing program in order to promote slope stability. Owner Improvements Homeowner improvements (patio slabs, retaining walls, planters, etc.) should be designed to account for the terrain of the project, as well as expansive soil conditions and chemical characteristics. Design considerations on any given lot may need to include provisions for differential bearing materials, ascending/descending slope conditions, bedrock structure, perched (irrigation) water, PACIFIC SOILS ENGINEERING, INC. Work Order 401036G Page 19 September 1, 2009 special geologic surcharge loading conditions, expansive soil stresses, and long-term creep/settlement. All owner improvements should be designed and constructed by qualified professionals utilizing appropriate design methodologies, which account for the on-site soils and geologic conditions. Setback Zones Manufactured slopes may be subject to long-term settlement and creep that can manifest itself in the form of both horizontal and vertical movement. These movements typically are produced as a result of weathering, erosion, gravity forces, and other natural phenomenon. A setback adjacent to slopes is required by most building codes, including the California Building Code. This zone is intended to locate and support the residential structures away from these slopes and onto soils that are not subject to the potential adverse effects of these natural phenomena. The homeowner may wish to construct patios, walls, walkways, planters, etc. within this zone. Such facilities may be sensitive to settlement and creep and should not be constructed within the setback zone unless properly engineered. It is suggested that plans for such improvements be designed by a professional engineer who is familiar with hillside grading ordinances and design and construction requirements associated with hillside conditions. In addition, we recommend that the designer and contractor familiarize themselves with the site specific geologic and geotechnical conditions on the specific lot. PACIFIC SOILS ENGINEERING. INC.