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1988-8091 G/H/N/P/R/U Street Address ~ /lð I 02 ~/:?3 Serial # Category T P /1/1 Z?-(Ja? I Description Name Year Plan ck. # recdescv ! ,'.',,""',"~ . CON S& U en 0 N 1ESTIN G &IEN GINEERIN G, INC. SAN DIEGO, CA . RIVERSIDE, CA . VENTURA, CA 2414 Vineyard Ave. 490 E. Princeland Ct. 1645 Pacific Ave. Sutit G Suite 7 Suite 105 Escondldo, CA Corona, CA 91719 Oxnard, CA 93033 (760) 746-4955 (909) 371.1890 (661) 486-6475 (760) 746-9806 FAX (909) 371.2168 FAX (661) 486-9016 FAX --' ...- . , . TRACY, tp¡ ¡ ,~ r~~~ERW4 ~ r~) i 242 W. Leith, .~ --.. .QI&6.ÌOOis..-w-.- ....... , ! , SuiteF ' UBit K " , Tracey, CA9S37fi LancastelJLC~' (209) 83902890 (661)72~7P"'1..-.J . (209) 83902895 lIAX (661) 726-%7fi FAX UPDATED GEOTECHNICAL INVESTIGATION PROPOSED 4-UNIT RESIDENTIAL SUBDIVISION TPM 87-008 ENCINIT AS, CALIFORNIA Prepared for: MR. STEVE GARDALITY 1115 RANCHO ENCINIT AS DRIVE ENCINIT AS, CALIFORNIA 92024 Prepared by: CONSTRUCTION TESTING & ENGINEERING, INC. 2414 VINEYARD AVENUE, SUITE G ESCONDIDO, CA 92029 CTE JOB NO.1 0-3582 August 3, 1999 GEOTECHNICAL AND CONSTRUCTION ENGINEERING TESTING AND INSPECTION " " . \. . J . CO NS' U CTI 0 N 1ESTIN G & ~N G INEERIN G, INC. SAN DIEGO, CA 2414 Vmeyard Ave. SutitG Escondido, CA (760) 746-4955 (760) 746-9806 FAX . RIVERSIDE, CA 490 E. Princeland Ct. Suite 7 Corona, CA 91719 (909) 371.1890 (909) 371.2168 FAX VENTURA, CA 1645 Pacific Ave. Suite 105 Oxnard, CA 93033 (661) 486-6475 (661) 486-9016 FAX . TRACY, CA 242 W. Larch SuiteF Tracey, CA95376 (209) 83902890 (209) 83902895 FAX . LANCASTER, CA 42156 10th St. W. UnitK Lancaster, CA 93534 (661) 726-%76 (661) 726-%76 FAX August 3, 1999 CTE Job No.1 0-3582 Mr. Steve Gardality 1115 Rancho Encinitas Drive Encinitas, California 92024 Subject: Updated Geotechnical Investigation Proposed 4-unit R~idential Subdivision TPM 87-008 Encinitas, California Mr. Gardality: At your request, we have performed an updated investigation of the referenced site. The attached report discusses the findings of our investigation activities and provides geotechnical recommendations for use during project design and construction. The project is considered feasible if the recommendations presented in this report are carried out. If you have any questions regarding our findings or recommendations, please do not hesitate to contact this office. The opportunity to be of service is appreciated. Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. a an oodmacher, CEG #2136 S ior Engineering Geologist GEOTECHNICAL AND, CONSTRUCTION ENGINEERING TESTING AND INSPECTION , , I J 8 8 TABLE OF CONTENTS 1.0 INTRODUCTION AND SCOPE OF SERVICES ................................................................... 1 1.1 Introduction.......................................................... ..... .......................... ....... ................... 1 1.2 Scope of Services.................. ......... ........................................ ............... ...... ...."............ 1 2.0 SITE DESCRIPTION........ ................................. .... ............... ......,............. ....... ....... ..,........ ...... 2 3.0 FIELD AND LABORATORY INVESTIGATIONS ............................................................... 2 3.1 Previous Field and Laboratory Investigations .............................................................. 2 3.2 Reconnaissance Investigations........ .............. ........... ........... .......... ....... ....... .........., ....... 3 4.0 GEOLOGY............... ..................... ......... ........... .......".... .."... ............... .................. .................. 3 4.1 General Setting........................ ........ .....,.... .................... .........,.... .......... .................. ...... 3 4.2 Geologic Conditions ....... ..................... .................. ...................... ....... .......... .......... ..oo.. 3 4.3 Groundwater Conditions...............................................................................................3 4.4 Geologic Hazards... ........ ..."........... .......... ........ ................... ...... ................ ............... ..... 4 4.4.1 General Geologic Hazards Observation................................................................ 4 4.4.2 Local and Regional Faulting ................................................................................. 4 4.4.3 Earthquake Accelerations..................................... ................................................. 4 4.4.4 Liquefaction Evaluation............................................................ ..................... ....... 5 4.4.5 Seismic Settlement Evaluation........................ .......oo.................. .............. ............. 5 4.4.6 Tsunamis and Seiche Evaluation .......................................................................... 6 4.4.7 Landsliding........................ ............................ .......... .................. .................... ........ 6 4.4.8 Compressible and Expansive Soils ....................................................................... 6 4.4.9 Potentially Corrosive Soils........... ....,............. ..... ................. ........ ......................... 7 5.0 CONCLUSIONS AND RECOMMENDATIONS ................................................................... 7 5.1 General......................... ......".... .........".... ................... .............. ...... .................... ...... ..... 7 5.2 Grading and Earthwork... ........................ ....."... ......... ................ ......... ...,.. ...... ..".. ........ 7 5.3 Site Preparation...................... ................ ..................... ...."............... ........... .................. 8 5.4 Site Excavation................. ................ ........ ................. ..,... ..".... ..".. ......".... ...."............. 8 5.5 Fill Placement and Compaction............ ........... ........... ............ ...... ................................ 9 5.6 Fill Materials.................................................................................... ......, ...................... 9 5.7 Temporary Construction Slopes ................................................................................. 10. 5.8 Foundations and Slab Recommendations .........................oo................oo...................... 10 5.8.1 Foundations.............. .......................................... ..oooo....................... .................... 11 5.8.2 Foundation Settlement............. ..... ..................... .................... ............ ................. 11 5.8.3 Foundation Setback.......................................... ............... ..... ..,..................... ..oo... 12 5.8.4 Interior Concrete Slabs................. ...................... .oo............ ...... ..oo......... .......... ..... 12 5.9 Lateral Resistance and Earth Pressures....................................................................... 12 5.10 Exterior Flatwork........ .."..... ........ ........................... .............. .................... "oo'" ......... 13 5.11 Drainage .................. .............. ........... ....... .".... ."...... ............... ........... ....... ................. 14 5.12 Vehicular Pavements ........................... ...... ..... ..."................ ....".... ................. ...... .... 14 5.12.1 Asphalt Pavement.. .............. ............................ ............. ......................... ............ 14 5.12.2 Portland Cement Concrete Pavements .............................................................. 15 5.13 Slopes................................................. ..................... .............. .......... .................. ........ 16 5.14 Construction Observation........................................ ...".......... ..... .............. ...... ......... 16 5.15 Plan Review............................................................ ........................... ....................... 17 6.0 LIMITATIONS OF INVESTIGATION ................................................................................. 17 " " . " I, FI GURES FIGURE 1 APPENDICES APPENDIX A 8 TABLE OF CONTENTS (continued) SITE INDEX MAP REFERENCES CITED 8 " '. ,I, " 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 1 CTE Job No.1 0-3582 1.0 INTRODUCTION AND SCOPE OF SERVICES 1.1 Introduction This report presents the results of our updated investigation and provides conclusions and geotechnical engineering criteria for the proposed development. It is our understanding that the site is to be developed by constructing four, conventional, single-family residences and associated improvements (e.g., utilities, landscaping, drive, and parking areas). Figure 1 is an index map showing the general site location. Specific recommendations for excavations, fill placement, and foundation design for the proposed structures are presented in this report. The investigation for this report included field exploration, laboratory testing, geologic hazard evaluation, and engineering analysis. Appendix A contains a list of references cited in this report. 1.2 Scope of Services The scope of services provided included: . Review of a previous geotechnical report pertinent to the site (San Marcos Engineering, Inc. [San Marcos], 1988) Reconnaissance geologic observations of the site and surrounding area. Define the general geology and evaluate the potential geologic hazards at the site. Soil engineering design criteria for the proposed improvements. Preparation of this summary report (with geotechnical construction recommendations). . . . . F:\I 0-3S82\Updatc Gcotcch Rptdoc " . I 8 8 I. Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 2 CTE Job No.1 0-3582 2.0 SITE DESCRIPTION The roughly, triangular-shaped parcel is at the southeastern comer of the intersection of Rancho Santa Fe Road and 13th Street in the Olivenhain area of Encinitas, California. Currently, the proposed 4-unit residential subdivision site consists generally of "raw" (undeveloped) land. The site is covered with "weeds" and some shrubs and trees. In addition, some minor amounts of construction debris (minor volumes of fill soil and concrete truck cleanouts) and yard waste are present at the site. Site elevations range from approximately 145 to 190 feet above mean sea level (msl). Topographically, the site slopes down to the southwest from the highest elevation on 13th Street. Developed land in the site area is used for residential purposes. Undeveloped land in the area has been used for farming. 3.0 FIELD AND LABORATORY INVESTIGATIONS 3.1 Previous Field and Laboratory Investigations Field explorations for this and the adjacent parcel were conducted in 1988 (San Marcos, 1988). Their scope of work included site reconnaissance and the excavation of four exploratory test pits. San Marcos conducted laboratory tests on representative soil samples for classification purposes and to evaluate physical properties and engineering characteristics. Their laboratory testing program F:\1O-3S82\Updatc Gcotcch Rpt.doc I , '.' I '. 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 3 CTE Job No. 10-3582 included direct shear, Modified Proctor, particle size, Atterberg limits determination, and expansion index tests. 3.2 Reconnaissance Investigations A senior geologist from this firm conducted field reconnaissance observations of the site and surrounding area in August 1999. It appears, based on our observations, that site conditions are essentially similar to those existing at the time of the previous study. 4.0 GEOLOGY 4.1 General Setting The site lies at the edge of the coastal mesa and upland portions of the San Diego coastal area. Topographically, the area consists generally of rolling hills dissected by intermittent streams. 4.2 Geologic Conditions As mapped by San Marcos (1988) and based on our observations, surface and near-surface soils at the site consist of units of the Eocene Torrey Sandstone and Del Mar Formation. Based on their' report and our observations, a layer of topsoil up to approximately two Y2 feet thick overlies these units. The Torrey Sandstone and Del Mar Formation materials consist of hard, dry to moist, claystone or dense, dry to moist, silty sandstone or sandy siltstone. 4.3 Groundwater Conditions San Marcos (1988) apparently did not encounter groundwater in any of their explorations at this site to the maximum depth explored of 13 feet below grade. Although groundwater levels will likely F:\10-3582\Update Geotcch Rpt.doc . " I '. 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 4 CTE Job No.1 0-3582 fluctuate during periods of precipitation, groundwater is not expected to affect the proposed development if recommendations regarding drainage are carried out during construction. 4.4 Geologic Hazards 4.4.1 General Geologic Hazards Observation From our investigation it appears that geologic hazards at the site are primarily limited to those caused by violent shaking from earthquake generated ground motion waves. The potential for damage from displacement or fault movement beneath the proposed structures should be considered low. 4.4.2 Local and Regional Faulting Based on our site reconnaissance, evidence from exploratory soil borings and test pits, and a review of appropriate geologic literature, it is our opinion that the site is not on known fault traces. The Rose Canyon Fault, approximately 10 miles to the west, is the closest zoned active fault (Jennings, 1987). Other principal active regional faults include the Coronado Banks, San Clemente, Elsinore, San Jacinto, and San Andreas faults. According to the . California Division of Mines and Geology, a fault is zoned active ifit displays evidence of activity in the last 11,000 years (Hart, 1994). 4.4.3 Earthquake Accelerations We have analyzed possible bedrock accelerations at the site using the computer software program EQF AUL T (Blake, 1996). The program uses the attenuation relationship developed by Campbell and Bozorgnia (1994) for soft rock conditions. Based on this analysis, the maximum credible acceleration was generated by a 6.9 magnitude earthquake on the Rose F:\I 0-3582\Update Gcotcch RpLdoc , " 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 5 CTE Job No.1 0-3582 Canyon Fault. This event is predicted to produce estimated peak ground acceleration at the site of 0.360g. In accordance with the Uniform Building Code 1997 Volume 2, the site is located within Zone 4 and therefore has a zone factor Z = 0.40. The nearest active fault the Rose Canyon is considered a Class B seismic source type. Based on the distance ITom the Rose Canyon Fault, the near source factor N" = 1.0 and Na = 1.0. Based on our field investigation, the site subsurface soils have a soil profile type of So, a seismic coefficient Cy = 0.40 and Ca = 0.44. 4.4.4 Liquefaction Evaluation Liquefaction occurs when saturated fine-grained sands or silts lose their physical strengths during earthquake induced shaking and behave as a liquid. This is due to loss of point-to-point grain contact and transfer of normal stress to the pore water. Liquefaction potential varies with water level, soil type, material gradation, relative density, and probable intensity and duration of ground shaking. It is our opinion that the liquefaction potential in all areas of the project is very low. This is based on the generally dense to locally very dense nature of the soils and because there apparently is no permanent shallow groundwater. 4.4.5 Seismic Settlement Evaluation Seismic settlement occurs when loose to medium dense granular soils become denser during seismic events. However, because the underlying site soils consist of generally fine F:\IO-3582\Update Gcotech Rpt.doc . " . '. " 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 6 CTE Job No.1 0-3582 materials and are generally medium dense to locally very dense, it is our opinion that the potential for seismic settlement should be considered low in all areas of the project. 4.4.6 Tsunamis and Seiche Evaluation The potential for tsunami damage at the site is very low due to the distance from the ocean (several miles) and elevation (greater than 150 feet above msl). Damage caused by oscillatory waves (seiche) is considered unlikely, as the site is not near any significant bodies of water. 4.4.7 Landsliding Although the site is in an area of San Diego County deemed moderately susceptible to landsliding (Tan and Giffen, 1995), the potential for landsliding or rocksliding to affect the site is considered remote. We did not encounter active landslides or rockslides at the site. Active landslides or rockslides have not been mapped in the immediate area of the site (Tan and Giffen, 1995). 4.4.8 Compressible and Expansive Soils Based on observations during previous investigations, site soil materials generally consist of clayey or silty sandstone or sandy siltstone or claystones. These materials are expected to have low compressibility characteristics and are suitable for support of the proposed structures. F:\IO-3582\Update Gcotech Rpt.doc '. " . '. 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 7 CTE Job No.1 0-3582 According to San Marcos (1988), site soils range from very low to highly expansive (Per UBC Table 18-I-B). Ifpossible building pads should be selectively graded and capped with the least expansive materials. 4.4.9 Potentially Corrosive Soils We recommend that samples of soils used during the grading process be tested to evaluate their resistivity and pH. Based on the resistivity measurements, special protection for buried metal pipes and metal water lines may be required for their long-term performance. Additionally, recommendations regarding the type of cement used in building slabs will be based on the results of sulfate analyses. 5.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 General We conclude that the proposed construction on the site is feasible from a geoteclmical standpoint, provided the recommendations in this report are incorporated into the design of the project: Recommendations for the design and construction of the proposed structure are included below. 5.2 Gradin~ and Earthwork Upon commencement of construction, personnel from CTE should rontinuously observe the grading and earthwork operations for this project. Such observations are essential to identify field conditions that differ from those predicted by this investigation, to adjust designs to actual field conditions, and to ensure that the grading is in overall accordance with the recommendations of this report. Our F:\IO-3S82\Update Geotech Rpt.doc . " . '. 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 8 CTE Job No.1 0-3582 personnel should perform adequate observation and sufficient testing of fills during grading to our professional opinion regarding compliance with compaction requirements and specifications contained herein. 5.3 Site Preparation Before grading, the site should be cleared of any existing debris and deleterious materials. Based on our observations, the average removal depth is expected to be about two feet. However, based on our experience at similar sites, deeper removals may be expected in some areas of undocumented fills or loose topsoil. Organic and other deleterious materials not suitable for structural backfill should be disposed of at a legal off-site disposal location. 5.4 Site Excavation Excavations in site materials should generally be accomplished with heavy-duty construction equipment under normal CQnditions. If encountered, irreducible materials greater than six inches . . . encountered should not be used in fills on the site. As discussed elsewhere in this report, transitional conditions (changes from cut to fill) are to be avoided beneath structures. On transitional lots, we recommend overexcavating the cut portions of the site to create more uniform bearing conditions. These overexcavations are intended to create a minimum of 18 inches of compacted beneath all building footings. Overexcavations should also extend a minimum of five feet beyond the limits of the proposed improvements. F:\IO-3582\Update Gcotecb Rpt.doc '. " . '. '. 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 9 CTE Job No.1 0-3582 5.5 Fill Placement and Compaction An engineer or geologist from CTE should verify that the proper site preparation has occurred before fill placement occurs. Following removal ofloose, disturbed soils, areas to receive fills or concrete slabs on grade should be scarified nine inches, moisture conditioned to above optimum moisture content, and properly compacted. Fill and backfill should be compacted to a minimum relative compaction of90 percent as evaluated by ASTM D 1557 at a minimum moisture content of between 2 and 4 percent above the laboratory determined optimum. The optimum lift thickness for backfill soil will be dependent on the type of compaction equipment used. Generally, backfill should be placed in uniform lifts not exceeding 8-inches in loose thickness. Backfill placement and compaction should be done in overall conformance with geotechnical recommendations and local ordinances. 5.6 Fill Materials Low or moderately expansive soils derived from on-site materials are considered suitable for reuse on the site as compacted fill. If used, these materials must be screened of organic materials and materials greater than six inches in a maximum dimension. Clayey native soils may be blended with granular soils and reused in non-structural fill areas. Imported fill placed beneath structures, pavements and walks should have an expansion index less than or equal to 30 (per UBC 18-I-B). Additionally, less than 35 percent of this fill should pass a F:\1O-3S82\Update Geotech Rpldoc , . , , . . " 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 10 CTE Job No. 10-3582 Number 200 sieve. Imported fill soils for use in structural or slope areas should be evaluated by the soils engineer to detennine strength characteristics before placement on the site. 5.7 Temporary Construction Slopes Sloping recommendations for unshored temporary excavations are provided. The recommended slopes should be relatively stable against deep-seated failure, but may experience localized sloughing. On site native soils are considered Type A soils with recommended slope ratios as set forth in Table 1 below. SOIL TYPE TABLE I RECOMMENDED TEMPORARY SLOPE RATIOS SLOPE RATIO (Horizontal: vertical) MAXIMUM HEIGHT A (Native fonnational soils) ~: 1 (MAXIMUM) 10 FEET According to Cal-OSHA regulations, a "competent person" must verify actual field conditions and soil type designations. Additionally, the above sloping recommendations do not allow for surcharge loading at the top of slopes by vehicular traffic, equipment or materials. Appropriate surcharge setbacks must be maintained from the top of all unshored slopes. Shoring may be used in lieu of sloped excavations. Specific recommendations and geotechnical parameters for shoring design will be provided upon request. 5.8 Foundations and Slab Recommendations The following recommendations are for preliminary planning purposes only. These foundation recommendations should be reviewed after completion of earthwork and testing of surface soils. F:\1O-3582\Update Geotech Rpt.doc . " 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 11 CTE Job No.1 0-3582 5.8.1 Foundations Continuous and isolated spread footings are suitable for use at this site. However, as stated footings should not straddle cutlfill interfaces. We anticipate all building footings will be founded entirely in Engineered Fill or entirely in native formational soil materials. Foundation dimensions and reinforcement should be based on allowable bearing values of 2,000 pounds per square foot (pst). The allowable bearing value may be increased by one third for short duration loading which includes the effects of wind or seismic forces. For continuous and isolated spread footings, the minimum width should be at least 18 inches. All footings should be installed at least 24 inches below the lowest adjacent subgrade. Footing reinforcement for continuous footings should consist of four #4 reinforcing bars; two placed near the top and two placed near the bottom. The structural engineer should design isolated footing reinforcement. However, at the completion of grading expansion index tests of the surficial soils should be made. The foundation recommendations presented above may require revision pending the laboratory analysis. 5.8.2 Foundation Settlement In general, for the anticipated construction the maximum post-construction compression settlement is expected to be about 1.0 inch. Maximum differential settlement of continuous footings across the buildings is expected to be about 0.5 inches. F:\lO-3582\Update Geotech Rpt.doc '. '. " '. 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 12 CTE Job No.1 0-3582 5.8.3 Foundation Setback Footings for structures should be designed such that the minimum horizontal distance from the face of adjacent slopes to the outer edge of the footing is a minimum of 10 feet. 5.8.4 Interior Concrete Slabs Lightly loaded concrete slabs should be a minimum of 4 inches thick. Minimum slab reinforcement should consist of #3 reinforcing bars or # 4 reinforcing bars placed on 18-inch or 24-inch centers, respectively, each way at mid-slab height. A vapor barrier of ten-mil visqueen overlying a three-inch layer of compacted, clean sand should be installed beneath moisture sensitive slab areas. At a minimum, a one-inch layer of clean sand should be placed above the visqueen to protect the membrane during steel and concrete placement. Slab areas subject to heavy loads or vehicular traffic may require increased thickness and reinforcement. This office should be contacted to provide additional recommendations. 5.9 Lateral Resistance and Earth Pressures The following recommendätions may be used for shallow footings on the site. Foundations placed in firm, engineered fill materials may be designed using a coefficient of friction of 0.35 (total frictional resistance equals coefficient of friction times the dead load). A design passive resistance value of 300 pounds per square foot per foot of depth (with a maximum value of 1200 pounds per square foot) may be used. The allowable lateral resistance can be taken as the sum of the frictional resistance and the passive resistance, provided the passive resistance does not exceed two-thirds of the total allowable resistance. F:\lO-3582\Update Geotech Rptdoc - , '" .' . 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 13 CTE Job No.1 0-3582 Retaining walls up to ten feet high and backfilled using generally granular soils may be designed using the equivalent fluid weights given in Table 2 below. TABLE 2 EQUIVALENT FLUID UNIT WEIGHTS (pounds per cubic foot) WALL TYPE LEVEL BACKFILL SLOPE BACKFILL 2: 1 (HORIZONTAL: VERTICAL) CANTILEVER WALL 38 60 (YIELDING) RESTRAINED WALL 58 90 The values above assume non-expansive backfill and free draining conditions. Measures should be taken to prevent a moisture buildup behind all retaining walls. Drainage measures should include free draining backfill materials and perforated drains. 5.10 Exterior Flatwork Based on the results of expansion index testing we recommend that flatwork be installed with crack-. control joints at appropriate spacing as designed by the project architect. Flatwork, which should be installed with crack control joints, includes driveways, sidewalks, and architectural features. All subgrade should be prepared according to the earthwork recommendations previously given before placing concrete. Positive drainage should be established and maintained next to all flatwork. F:\IO-3S82\Update Geotech Rpt.doc '. " 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 14 CTE Job No. 10-3582 5.11 Drainage Surface runoff should be collected and directed away from improvements by means of appropriate erosion reducing devices and positive drainage should be established around the proposed improvements. Positive drainage should be directed away from improvements at a gradient of at least 2 percent for a distance of at least five feet. The project civil engineers should evaluate the on- site drainage and make necessary provisions to keep surface water from affecting the site. 5.12 Vehicular Pavements Preliminary pavement sections presented below are based on Resistance "R"-Value testing of representative soil materials at similar sites nearby. The upper one-foot of sub grade soils should be moisture conditioned and compacted to a minimum of95% of the laboratory determined maximum density. 5.12.1 Asphalt Pavement The asphalt pavement design is based on extensive laboratory testing of surficial soils in the business park, California Department of Transportation Highway Manual and on traffic indexes as indicated in Table 3 below. Upon completion of finish grading, "R" Value sampling and testing of subgrade soils should occur and the pavement section modified if necessary. F:\IO-3582\Update Geotech Rpt.doc , , 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 15 CTE Job No.1 0-3582 Traffic Area Traffic Index Assumed AC Class II Subgrade Thickness Aggregate Base Thickness UR" Value (inches) (inches) Truck Drivel Loading Areas 6.0 25 4.0 7.0 Auto Parking Areas 4.5 25 3.5 4.0 5.12.2 Portland Cement Concrete Pavements We understand that parking and drive areas may be paved with concrete pavements. The recommended concrete pavement sections for drive areas have been designed assuming traffic loads of single axles of 15 kips, 10 repetitions per day. Corresponding pavement designs presented in the table below may not be adequate for larger axle loads and traffic volume. Concrete used for pavement areas should possess a minimum 600-psi modulus of rupture. Pavements should be constructed according to industry standards. TABLE 4 CONCRETE PA VEMENTDESIGN Traffic Area Average PCC Thickness (inches) Subgrade R-Value Truck Drivel 25 6.5 Loading Areas Auto Parking Areas 25 6.0 F:\IO-3582\Update Gcotech Rptdoc '. " 8 8 . Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 16 CTE Job No.1 0-3582 5.13 Slopes Based on anticipated soil strength characteristics, fill slopes should be constructed at slope ratios of 2: 1 (horizontal: vertical) or flatter. These fill slope inclinations should exhibit factors of safety greater than 1.5. Although graded and existing slopes on this site should be grossly stable, the soils will be somewhat erodible. Therefore, runoff water should not be pennitted to drain over the edges of slopes unless that water is confined to properly designed and constructed drainage facilities. Erosion resistant vegetation should be maintained on the face of all slopes. Typically, soils along the top portion of a fill slope face will tend to creep laterally. We do not recommend distress sensitive hardscape improvements be constructed within five feet of slope crests in fill areas. 5.14 Construction Observation Recommendations provided in this report are based on preliminary design infonnation for the proposed construction and the subsurface conditions documented. The interpolated subsurface conditions should be checked in the field during construction to verify that conditions are as anticipated. F:\lO-3582\Update Geotech Rpt.doc . " " " 8 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 Page 17 CTE Job No.1 0-3582 Recommendations provided in this report are based on the understanding and assumption that CTE will provide the observation and testing services for the project. All earthworks should be observed and tested to verify that grading activity has been performed according to the recommendations contained within this report. Before placement of reinforcing steel reinforcing the project engineer should evaluate footing trenches. 5.15 Plan Review CTE should review the project foundation plans and grading plans before commencement of earthwork to identify potential conflicts with the recommendations contained in this report. 6.0 LIMITATIONS OF INVESTIGATION The field evaluation, laboratory testing and geotechnical analysis presented in this report have been conducted according to current engineering practice and the standard of care exercised by reputable geotechnical consultants performing similar tasks in this area. No other warranty, expressed or' implied, is made regarding the conclusions, recommendations and opinions expressed in this report. Variations may exist and conditions not observed or described in this report may be encountered during construction. Our conclusions and recommendations are based on an analysis of the observed conditions. If conditions different from those described in this report are encountered, our office should be notified and additional recommendations, if required, will be provided upon request. We appreciate this F:\IO-3S82\Update Geotech Rpt.doc - . I '. 8 Updated Geotechnical Investigation Proposed 4-unit Residential Subdivision TPM 87-008, Encinitas, California August 3, 1999 8 Page 18 CTE Job No.1 0-3582 opportunity to be of service on this project. If you have any questions regarding this report, please do not hesitate to contact the undersigned. Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. ~~~t~33¥Ç Geotechnical Engineering Manager .- a an Goodmacher, CEG #2136 Se ior Engineering Geologist F:\IO-3S82\Update Gcotech RpLdoc , ., " 0 I 0 8 8 . \ " ~--:-~~~~ ~ ~. ~",'~~ ~!ø~i~~¡;-;~O' r\1;""-¡ g >~ :; '\ ~;;>~ ~~T;.:;";' j~ ~ V'Ç:;;I' ~..J t\.."!!i~ "1<:1 l!i"í w::t ¡.,¡ ~.f! 2ff.T":; \1- \"..Ik1 - \ >sU~~. +----~l ~-~'7~-1 ; V6 ----> ~ 13, ': 11 ¡ -~~-""';;;~,v.Y--l~...ai~ I \ \~ 1 ! ",,-' 1 - ~ - -IO=U~ CIV ~~ì. I - - --1 \ "~'Ia : -J- ----p,;1'1~ ~ 11.JL-j \ "t ".." "~~r--;-- ! .~L~.;'~~""""""" ~~ .~~~ \ J~-~~~ ,......,,! \ ~ ~ ~"'L Ô.~~-~r~~~ I \ " ~~J,,~llb~~'.' .,f'~~~;.,\ ~, rti-;~" E=-~'~'~ :'i¿-~')(; r/Jrf:RLV:;;:<} L'-- - \"'. \ ~~: "., ::...Y'"I l.1:..- """Ij.-:to:. ~ \~ ' ,~, .. JIOI!!!!!- Iiì-J ROii"""'" Q. ""'" u 11 " '\. '-~ \~----f I~~H" -:k ;':Þ-J' ~4 ---"" \\ ,!f:'",' {:;:,c.;' .. ~~ i!L..., ! ~ --Y-7~' ry.:... ~ ~\.r. -r-.';,.."; I ¡----\ : '.' ,~\ ~~ ~"'.ç f> t"""~ ! ; I ; ~ ~ .Ú~-'~'~ ~ i \ ' :, jh~~~~~l~~ ~l~-j.t;'.'~ ¡ _L______-;'. . . "- i_li i ....¿ ~'í.~"C -""~. ti. 115,' "" i¡":iEl.,~. ! I' , -- ::~ ~-- ,~~ ~ki !':~ -- 'I -,: II ~~-~ ;:~t'- ,,'~~~.-k , - .L--',~.. t.:;'" . ::: :!;t¥. :' ---d ~ i \ 1:.,;,~ ~~ I.i..~ !fi~." ¡¡II ,,1~ ~iill .' . ~ro:ìr \JII ,,~~,øÞ- ~ ~^j~':' f~ ~'~~ ~~_r .~. .,' ST___'~~~\.-rr_~\.' . ~~~ ~U: "Ii~ L -~f-- J=~;'; Jí ~..~ ~:~..:k~ t ~ ~ w' r f<r~ ~ ~~~-;4~<- 01 .' ~~ iL- \.i'" ~ ~. ~~:;7d ~ ~" ~~ A t ~ "~.~" ~ :T~I'-~." r~-:;~ ~œiv~:::lAS/~~ '¡;;Ij¡ r}.~ "~~~ ~;'. ~ 1 !!!Ir lO;~j . ':.. i~~"" ¡¡ III¡-..-!!-r- I ~~f,.~ \J \," ¡¡ i-'.~!, ""-r "':8114 ~/ DR rdrct I .!UJ.-' :ii a. ~ ~\~~-- ~ ~ jn~ '. ... I~ ;;- ~ ~)'" ~"r"'" ..,,-~... ~~ ~ ' ~":" S& !....~.. rz:t .~tf-g,' I --'-..;'o"~'iii~ tì i 1/4 I 1320 1/2 I 2640 I Mll.ES I 5280 FEET ~1;, CO~STRUCTION TESTING & ENGINEERING, INC. -.,. GEOTECHN1c.~ AND CONSTRUCTION ENGINEERING TESTING AND INSPECTION 2414 VlNEYARD\VENVE. STE G ESCONDIDO CA, Q2029 (760) 746-49SS SITE INDEX MAP .t-L~IT RESIDENTIAL SUBDIVISION DiCINITAS, C-\LIFORNl-\ 10-3582 SaURCF.' THOMAS BROTHERS MAPS 1996 SAN DIEGO EDmaN DATE: 8/99 ,,"'.Þ u"""o nnn""............,n "n~\..m"v... n ...". ~ '. ".' '. 8 . ~ APPENDIX A REFERENCES CITED . '. ." .~ . . 8 . ... i REFEREN CES CITED 1. California Division of Mines and Geology Website, January 15, 1997, California Fault Parameters. 2. Jennings, Charles W., revised 1987, "Fault Map of California with Locations of Volcanoes, Thermal Springs and Thermal Wells." 3. San Marcos Engineering, Inc., 1988, "Preliminary Soils Investigation Report ofTPM 87-008 and TPM 18962" [consultant report]. 4. Tan, S.S. and Giffen, D.G., 1995, "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California," Landslide Hazard Identification Map No. 35, California Division of Mines and Geology, Open File Report 95-04. '.....""""""nO&OIECHUT.)()(' '-"-"-.GEOCRID (TYP) ----.- HAND TAMPED - SOIL WIfHIN UNITS HAND TAMPED - SOIL WITHIN UNITS' -'-~GEOGRD (TYP) ,- 12" WIDTH OF CRUSHED ROCK 6" THICK BY 30'" WIDE CRUSHED ROCK LEVElING PAD t 6" THICK BY 30" WIDE CRUSHED ROCK LEVELING PAD 2-#4 REBAR 6" THICK BY 30" WIDE CONCRETE LEVELING PAD SEGMENTAL WALL LOW HEIGHT NO S~lE SEGMENTAL WALL MEDIUM HEIGHT flO SCIILE SEGMENTAL WALL HIGH HEIGHT ... ,~..........., flO S~lE ;:, "",' iJ'; f........-, Ì\,""..... ¡!¡ ~?I . " ,~ ;¡¡1.....~~,! 8l}TE: TUAL HEIGHTS FOR THE OPTIONS SHOWN iLL VARY DEPENDING UPON SOIL CONDITIONS ACTUAL 8URIAL PER SOILS ENGINEER. WIfH ,. MINIMUM REQUIRED. ", -, I~ :¡: '; SOUTHERN OFFICE RErrAINING f:;H CRIDLOCK W AL,L~ cu. NORTHERN OFFICE 1531 GRAND AVENUE SAN MARCOS, CA. 92069 (619) 471-2500 (300) FOR-WALL SEGMENTAL WALL SAMPLE CROSS SECTIONS 000 E. GI{ANT LINE RD. TRACY, CA. 95376 209) 032-2600