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HomeMy WebLinkAbout; Single s/o 5305 Carlsbad blvd(A.P.N.210-120-31); Geotechnical Investigation and Foundation Recommendation; 1997-03-03ENGINEERING••DESIGN GROUP 810 W. Los Vallecitos, Ste A • San Marcos CA -92069 (619) 752-7010 • FAX (619) 752-7092 GEOTECHNICAL INVESTIGATION AND FOUNDATION RECOMMENDATIONS FOR A PROPOSED SINGLE FAMILY RESIDENCE TO BE LOCATED SOUTH OF 5305 CARLSBAD BOULEVARD (A.P.N. 210-120-31), CARLSBAD, CALIFORNIA Project No: 971491-1 March 3,1997 PREPARED FOR: L.D. Richards Co., Builder 1830 Oxford Avenue Cardiff, CA. 92007 TABLE OF CONTENTS Page SCOPE 3 SITE AND PROJECT DESCRIPTION 3 SITE AND SUBSURFACE OBSERVATIONS 3 SUBSOIL CONDITIONS 4 GEOLOGIC HAZARDS AND SEISMICITY 4 CONCLUSIONS AND RECOMMENDATIONS 5 GENERAL 5 EARTHWORK 5 FOUNDATIONS 6 CONCRETE SLABS ON GRADE 7 RETAINING WALLS 8 SURFACE DRAINAGE 8 CONSTRUCTION OBSERVATION AND TESTING 8 MISCELLANEOUS 9 ATTACHMENTS Site Vicinity Map Figure No. 1 Site Location Map Figure No. 2 Site Plan/Location of Exploratory Test Pits Figure No. 3 Logs of Exploratory Test Pits Figures 4 - 6 References Appendix A Grading Specifications Appendix B Laboratory Testing Procedures Appendix C Home Owners Maintenance Appendix D This report presents the results of our geotechnical investigation and evaluation for a proposed single family residence to be located south of 5305 Carlsbad Boulevard, in the City of Carlsbad, California. Please see Figure No. 1, "Site Vicinity Map", and Figure No. 2, "Site Location Map". The scope of our work, conducted on-site to date, has included a visual reconnaissance of the property and neighboring sites, subsurface observation of the property, laboratory testing, and preparation of this report presenting our findings, conclusions, and recommendations. SITE AND PROJECT DESCRIPTION The subject property consists of a rectangular shaped lot located south of 5305 Carlsbad Boulevard, in the City of Carlsbad, California. The site is bordered to the south by an undeveloped residential lot, to the east by Carlsbad Boulevard, to the north by a residential development, and to the west by the Pacific Ocean. The site is currently undeveloped. The topography of the overall site area consists of coastal bluff terrain. The site topography consists of relatively gently sloping terrain extending from Carlsbad Boulevard to the top of a bluff trending along the western portion of the property. The bluff extends to a maximum of approximately forty feet in height, with an overall slope of approximately 45 degrees. Site vegetation generally consists of iceplant and native grasses and weeds. Based on our discussions with the project owner, it is our understanding that the proposed site improvements will include a one and/or two story single family residential structure and associated improvements. It is our understanding that the structures are to be located a minimum setback distance of twenty five feet from the top of the bluff. It is anticipated that the proposed residence will utilize conventional shallow foundation systems, concrete slabs on grade and/or raised wood floors, and wood framing. SITE AND SUBSURFACE OBSERVATIONS Site and subsurface observations were conducted on January 31,1997, and consisted of a general site reconnaissance, site field measurements, observation of existing conditions on-site and on adjacent sites, and a subsurface investigation of soil conditions. Our subsurface investigation consisted of visual observation of three test pit excavations and logging of soil types encountered. Logs of the three test pits are presented in Figures 4-6 of this report. The locations of the test pits are given in Figure No. 3, "Site Plan/Location of Exploratory Test Pits". SUBSOIL CONDITIONS Job No. 971491-1 Page No. 3 Materials consisting of fill and terrace deposits were encountered during our subsurface investigation of the site. Soil types encountered in the test pit excavations are described as follows: Fill: Fill materials were encountered up to approximately four feet below existing grade at Test Pit No: 3, and generally consisted of brown, dry, loose to damp, silty fine sand with concrete and asphalt fragments and rodent burrows. Based on our field observations and laboratory testing, these materials are considered unsuitable for the support of structures or improvements in their present state, but may be used for structural fill during grading. Fill materials in excess of eight inches in diameter are not considered suitable for re-use as fill material during grading. Fill materials classify as SM according to the Unified Classification System, and based on visual observation, are generally non-expansive in nature. Terrace Deposits: Formational terrace deposits generally consisted of brown to orange brown, damp, dense, silty fine grained sand. These materials were generally weathered and contained rootlets and organics within the upper six inches. These materials are considered suitable for the support of structures and structural improvements, provided loose weathered material and organics are removed, and the recommendations of this report are followed. Formational materials classify as SM according to the Unified Classification System, and based on visual observation, are generally non-expansive in nature. GEOLOGIC HAZARDS AND SEISMICITY A review of pertinent published geologic maps, suggests that no geologic hazards such as faults, potential landslides, or areas of suspected soils liquefaction exist within the project boundaries. Based on this information, it appears that no active or potentially active fault exists at or in the immediate vicinity (250 ft.) of the site, and none were observed during our investigation. The nearest known active faults are the Rose Canyon, Coronado Bank, and Elisnore fault zones which lie approximately 4 miles and 19.5 miles to the west, and 25 miles to the northeast of the site, respectively. It is our opinion that the site could be subjected to moderate to severe ground shaking in the event of a major earthquake along any of the faults mentioned above or other faults in the Southern California region. However, the seismic risk at this site is not significantly greater than that of the surrounding developed area. We believe that the proposed development will have no more negative geologic consequence than the existing or surrounding development if the guidelines in this report are followed, and other good development techniques are used. The seismic hazard most likely to impact the site is ground shaking resulting from an earthquake on one of the major active regional faults. The adverse effects of seismic shaking can be reduced Job No. 971491-1 Page No. 4 by adhering to code requirements given in the most recent edition of the Uniform Building Code, and design parameters of the Structural Engineers Association of California. CONCLUSIONS AND RECOMMENDATIONS In general, it is our opinion that site improvements, as described, are feasible from a geotechnical standpoint, provided the recommendations of this report and generally accepted construction practices are followed. EARTHWORK It is our understanding that site earthwork and grading is proposed for the new construction. Grading should be performed in accordance with the following recommendations, pertinent county standards, and grading specifications provided in "Appendix B" of this report. 1. Site Preparation: Prior to grading, areas of proposed improvement should be cleared of existing structures, surface and subsurface debris, and stripped of vegetation. Removed vegetation and debris should be properly disposed of prior to the commencement of any fill operations. Holes resulting from the removal of debris, existing structures, or other improvements which extend below the undercut depths noted should be filled and compacted using on-site material or a non-expansive import material. 2. Removals: Fill materials and weathered deposits found to mantle the site in the exploratory test pits are not suitable for structural support of buildings or improvements in their present state, and will require removal and recompaction. Fill materials are suitable for re-use as fill material during grading, provided they are cleaned of organics, debris and oversized material in excess of 8 inches in diameter. Depths of removal below existing grade for unsuitable material in the area of proposed construction may be inferred from inspection of the test pit logs (Figures No. 4 - 6), and will likely range up to a maximum of approximately four feet in depth. To provide a uniform building "mat", the pad area should be undercut to a minimum depth of 3 ft. below finish pad grade (to be confirmed in field), to a minimum horizontal distance of 5 ft outside the footprint of proposed structure. Removal depths should be visually verified by a representative from our firm prior to the placement of fill. Any temporary removals should be observed in the field by a representative of Engineering Design Group during excavation, and as deemed necessary during construction. Job No. 971491-1 Page No. 5 3. Fills: Bottom of removals should be scarified to a minimum depth of 12 inches, moisture conditioned, and recompacted to a minimum of 90 percent relative dry density (based on ASTM D1557-78). Fill material should be cleaned of loose debris and oversized material in excess of 8 inches in diameter, moisture conditioned, and recompacted to a minimum of 90 percent relative dry density (based on ASTM D1557-78). In order to minimize erosion and sloughage, the face of any fill slopes should be compacted to 90 percent relative dry density. Fills should generally be placed in lifts not exceeding 8 inches in thickness. If importing of soil is planned, soils should be non-expansive and free of debris and organic matter. Prior to importing, soils should be visually observed, sampled and tested at the borrow pit area to evaluate soil suitability as fill. FOUNDATIONS In deriving foundation recommendations for this site, the subsoil conditions, as well as the proposed construction, were evaluated. We anticipate the foundation system for the proposed residence will utilize conventional shallow foundations. Minimum design parameters for shallow foundation systems are as follows: 1. Footings bearing in competent formational materials or properly compacted fill may be designed based on a maximum allowable soils pressure of 1500 psf. If the structural engineer is designing a building utilizing heavy point loads, our office should be notified regarding increasing the bearing value provided. 2. Bearing values may be increased by 33% when considering wind, seismic, or other short duration loadings. 3. Any loose soil found at the base of footings, when the excavation is opened, shall be removed and extended to firm undisturbed material. Job No. 971491-1 Page No. 6 4. The following parameters should be used as a minimum for designing footing width and depth below lowest adjacent grade: Depth Below Lowest Adjacent Floors Supported Width Grade 1 18 inches 18 inches 2 18 inches 18 inches 3 18 inches 24 inches 5. For footings adjacent to slopes, a minimum horizontal setback of 7 feet should be maintained, as measured horizontally from the bottom of the footing to slope daylight in formational materials or properly compacted fill. 6. All footings should be reinforced with a minimum of two #4 bars at the top and two #4 bars at the bottom (3 inches above bottom of footing excavation). Footing excavations should be visually verified in the field in order to verify competent bearing material. A letter of compliance should be obtained, as applicable. 7. All isolated spread footings should be designed utilizing the above given bearing values and footing depths, and be reinforced with a minimum of #4 bars at 12 inches o.c. in each direction (3 inches above the ground). Isolated spread footings should have a minimum width of 24 inches. 8. Grading should be performed in general accordance with the minimum specifications and design requirements as outlined within this report, applicable city and/or county standards, and attached "Appendix B". CONCRETE SLABS ON GRADE As we understand it, concrete slabs on grade will be utilized in the construction of proposed improvements. Minimum design parameters for concrete slabs on grade are as follows: 1. Concrete slabs on grade should have a minimum thickness of 4 inches (5 inches for driveway and garage slabs), and should be reinforced with a minimum of #4 bars at 18 inches o.c. placed at the midpoint of the slab. The bars provide better assurance of crack control and/or vertical movement if minor cracking does occur. Exterior slabs should be independent of foundations. 2. All required fills used to support slabs, should be placed in accordance with the grading section of this report and the attached Appendix B, and compacted to 90% Modified Proctor Density, ASTM D-1557. 3. A uniform layer of 4 inches of clean sand should be provided under concrete slabs in order to more uniformly support the slab, help distribute loads to the soils beneath the slab, and Job No. 971491-1 Page No. 7 act as a capillary break. In addition, a visqueen layer (10 mil) should be placed mid height in the sand bed to act as a vapor barrier. 4. Adequate control joints should be installed to control the unavoidable cracking of concrete that takes place when undergoing its natural shrinkage during curing. The control joints should be well located to direct unavoidable slab cracking to areas that are desirable by the designer. 5. Brittle floor slab finishes may crack if concrete is not adequately cured prior to installing the finish or if there is minor slab movement. It is the responsibility of the contractor chosen for the project, to properly place and cure all concrete. However, to minimize potential damage to movement sensitive flooring, we recommend the use of slip sheeting which allows for foundation and slab movement without transmitting this movement to the floor finishes. RETAINING WALLS Retaining walls should be designed by the project structural engineer in accordance with the following recommendations and minimum design parameters: 1. Footings bearing in competent formational materials or properly compacted fill may be designed based on a maximum allowable soils pressure of 1500 psf. 2. Bearing values may be increased by 33% when considering wind, seismic, or other short duration loadings. 3. Unrestrained cantilever retaining walls should be designed using an active equivalent fluid pressure of 35 pcf. This assumes that granular, free draining, non-expansive fill material will be used. Based on our observations, onsite materials will generally be suitable for this purpose, however material should be field verified for suitability prior to the start of backfilling. For sloping backfill, the following parameters may be utilized: Condition 2:1 Slope 1.5:1 Slope Active 50 65 Any other surcharge loadings shall be analyzed in addition to the above values. 4. If the tops of retaining walls are restrained from movement, they should be designed for an additional uniform soil pressure of 7XH psf, where H is the height of the wall in feet. 5. Passive soil resistance may be calculated using an equivalent fluid pressure of 350 pcf. This value assumes that the soil being utilized to resist passive pressures, extends horizontally 2.5 times the height of the passive pressure wedge of the soil. Where the Job No. 971491-1 Page No. 8 horizontal distance of the available passive pressure wedge is less than 2.5 times the height of the soil, the passive pressure value must be reduced by the percent reduction in available horizontal length. 6. A coefficient of friction of .35 between the soil and concrete footings may be utilized to resist lateral loads in addition to the passive earth pressures above. 7. Retaining walls over 4 ft. high should be braced and monitored during compaction. If this cannot be accomplished, the compactive effort should be included as a surcharge load when designing the wall. 8. All walls shall be provided with adequate back drainage to relieve hydrostatic pressure, and be designed in accordance with Appendix B "Retaining Wall Drainage Detail". 9. Retaining wall backfill should be placed and compacted in accordance with the "Earthwork" section of this report. SURFACE DRAINAGE Adequate drainage precautions at the site are critical. Under no circumstances should water be allowed to pond against or adjacent to foundations or settlement sensitive improvements. The ground surface surrounding proposed structures should be relatively impervious in nature, and slope to drain away from the building in all directions, with a minimum slope of 5% for a horizontal distance of 7 feet (where possible). Area drains or surface swales should then be provided to accommodate runoff and avoid any ponding of water. Drainage should be diverted away from the tops of slopes to avoid erosion. Surface and area drains should not be connected to any wall drainage or underdrain systems. Surface and subsurface drainage systems should outlet within the western portion of the property at beach level. Erosion to face of bluff caused by drainage systems should be strictly avoided. Engineering Design Group shall be provided with a set of drainage improvement plans for review prior to implementation. CONSTRUCTION OBSERVATION AND TESTING The following services should be conducted by a representative of our office during construction of the proposed improvements (if applicable): 1. Review of final project plans prior to construction. 2. Observation of bottom of removals prior to any fill placement. 3. Observation and testing of any fill placement. 4. Observation of site drainage systems including wall back drains, and surface and subsurface drainage systems during placement. 5. Observation of foundation excavations prior to placement of reinforcement. Job No. 971491-1 Page No. 9 MISCELLANEOUS It must be noted that no structure or slab should be expected to remain totally free of cracks and minor signs of cosmetic distress. The flexible nature of wood and steel structures allows them to respond to movements resulting from minor unavoidable settlement of fill or natural soils, the swelling of clay soils, or the motions induced from seismic activity. All of the above can induce movement that frequently results in cosmetic cracking of brittle wall surfaces, such as stucco, interior plaster, or interior brittle slab finishes. Data for this report was derived from surface observations at the site, knowledge of local conditions, and a visual observation of the soils exposed in the exploratory test pits. The recommendations in this report are based on our experience in conjunction with the limited soils exposed at this site and neighboring sites. We believe that this information gives an acceptable degree of reliability for anticipating the behavior of the proposed structure. However, our recommendations are professional opinions and cannot control nature, nor can they assure the soils profiles beneath or adjacent to those observed. Therefore, no warranties of the accuracy of these recommendations, beyond the limits of the obtained data, is herein expressed or implied. This report is based on the investigation at the described site and on the specific anticipated construction as stated herein. If either of these conditions is changed, the results would also most likely change. Man-made or natural changes in the conditions of a property can occur over a period of time. In addition, changes in requirements due to state of the art knowledge and/or legislation, are rapidly occurring. As a result, the findings of this report may become invalid due to these changes. Therefore, this report for the specific site, is subject to review and not considered valid after a period of one year, or if conditions as stated above are altered. It is the responsibility of the owner or his representative to insure that the information in this report be incorporated into the plans and/or specifications and construction of the project. It is advisable that a contractor familiar with construction details typically used to deal with the local subsoil and seismic conditions, be retained to build the structure. If you have any questions regarding this report, or if we can be of further service, please do not hesitate to contact us. We hope the report provides you with necessary information to continue with the development of the project. Very truly yours, ENGINEERIN Steven Norris California RGB #47672 Job No. 971491-1 Page No. 10 J J I I 1 1 I I 1 L L I I •4067O1068/P1069 itw . f^lMBIt. xrjl*j-fdB®SITE ENQINEERINQ DESIGN GROUP SITE VICINITY MAP FIGURE NO. 1 J I 1 1 i i SBAD ,. TATE -BEACH CARLSBAD ENGINEERING DESIGN GROUP SITE LOCATION MAP FIGURE NO. 2 4E I 41 12 113 a CARLSBAD BOULEVARD T TAG MARKBSACH BOUNDARY ADJUSTMENT PLAT N& 342 MM 237 NORTH NOT TO SCALE LEGEND TV 5£T *&* CX/€ W $UBM£ffC£D LAWS *-TP3 - APPROXIMATE LOCATION Or TEST PIT EXCAVATIONS APPROXIMATE CONTOURELEVATIONS (FEET) APPROXIMATE BUILDINGSETBACK FROM TOP OF SLOPE (25 FEET) ENQINEERINQ DESIGN GROUP SITE PLAN/LOCATION OF EXPLORATORY TEST PITS FIGURE NO. 3 r" P- ~ J J JJ. i i i*Jr J . 1 Equipment: HAND EXCAVATED Datum: ADJACENT GRADE Elevation: 0.00* D P t h (ft) 0 - —- —1 - —- O mi 3 - S m b o 1 1 TEST PIT LOG NO. i 1 Depth of Excavation: 3.5* Date logged: 1-31-9? Groundwater depth: Logged by: -N/A- Location: See Site Plan US CS Field description and classification: DISTURBED TERRACE DEPOSITS: BROWN, DRY TO SLIGHTLY DAMP, LOOSE TO MEDIUM DENSE, SILTY FINE SAND, WITH ROOTLETS AND ORGANICS. TERRACE DEPOSITS.*. BROWN TO ORANGE BROWN, DAMP, DENSE, SILTY FINE SAND. • TOTAL DEPTH OF EXCAVATION = 3.5FT. • NO GROUNDWATER ENCOUNTERED UC Hand penetration test ( uuCOti.Lj.iieu btjceng^n D Disturbed sample J.OC / U Undisturbed sample LL Liquid limit PL Plastic limit PI Plastic index NP Non plastic -200 % passing the £200 sieve ENGINEERING PROPERTIES U. S. C. S. SM SM Sample (Bag) Moist. (%) Den. (pcf) Job Name: PROPOSED RESIDENCE Site location: SOUTH OF 5305 OCEANSIDE BLVD. OCEANS IDE, CA. Job No: Figure No . : 4 J Equipment: HAND EXCAVATED Datum : ADJACENT GRADE .Elevation: O.OO1 J D i e • P t i h J tft* 0 -i — i - —i 1 ""1 - - I2: U: I 1 S ym b o 1 i TEST PIT LOG NO. / 2 Depth of Excavation: 3.01 Date logged: 1-31-9? Groundwater depth: Logged by: -N/A- Location: See Site Plan US CS Field description and classification: DISTURBED TERRACE DEPOSITS: BROWN, DRY TO SLIGHTLY DAMP, LOOSE TO MEDIUM DENSE, SILTY FINE SAND, WITH ROOTLETS. TERRACE DEPOSITS: BROWN TO ORANGE BROWN, DAMP, DENSE, SILTY FINE SAND. • TOTAL DEPTH OF EXCAVATION = 3. OFT. • NO GROUNDWATER ENCOUNTERED UC Hand penetration test (unconfined strength , D Disturbed sample TSF) U Undisturbed sample LL Liquid limit PL Plastic limit PI Plastic index NP Non plastic -200 % passing the #200 sieve ENGINEERING PROPERTIES U. S. C. S. SM SM Sample (Bag) Moist . (%)Den. (pcf) Job Name: PROPOSED RESIDENCE Site location: SOUTH OF 5305 OCEANSIDE BLVD. OCEANS IDE, CA. Job No: Figure No . : 5 TEST PIT LOG NO. f 3 Equipment: HAND EXCAVATED Depth of Excavation: 4.0'Date logged: 1-31-97 Datum: ADJACENT GRADE Elevation: O.OO1 Groundwater depth: -N/A- Logged by: D e Pt h (ft) Location: See Site Plan US CS Field description and classification ENGINEERING PROPERTIES U. S. C. S. Sample (Bag) Moist.Den. (pcf) 0 - 1 - 2 - 3 - 4 1 FILL; BROWN, DRY, LOOSE TO MEDIUM DENSE, SILTY FINE SAND, WITH ASPHALT AND CONCRETE DEBRIS, AND RODENT BURROWS, EXTENDING TO A MAXIMUM DEPTH OF 4FT. SM TERRACE DEPOSITS; BROWN TO ORANGE BROWN, DAMP, DENSE, SILTY FINE SAND. SM j j TOTAL DEPTH OF EXCAVATION = 4.OFT, NO GROUNDWATER ENCOUNTERED j j UC Hand penetration test (unconfined strength TSF) D Disturbed sample U Undisturbed sample LL Liquid limit PL Plastic limit PI Plastic index NP Non plastic -200 % passing the #200 sieve Job Name: PROPOSED RESIDENCE Site location: SOUTH OF 5305 OCEANSIDE BLVD OCEANSIDE, CA. Job No: Figure No.: 6 APPENDIX -A- APPENDIX A REFERENCES 1. California Department of Conservation, Division of Mines and Geology, Fault- Rupture Zones in California, Special Publication 42, Revised 1990. 2. Greensfelder, R.W., 1974, Maximum Credible Rock Acceleration from Earthquakes in California: California Division of Mines and Geology, Map Sheet 23. 3. Tan, S.S., 1995, Landslide Hazards in the Northern San Diego Metropolitan Area, California: California Division of Mines and Geology, Open File Report. 4. Engineering Design Group, Unpublished In-House Data. 5. Ploessel, M.R., and Slosson, J.E., 1974, Repeatable High Ground Acceleration from Earthquakes: California Geology, Vol. 27, No. 9, P. 195-199. 6. State of California, 1994, Fault Activity Map of California: California Division Mines and Geology, Geologic Data, Map No. 6. 7. State of California, Geologic Map of California, Map No. 2, Dated 1977. APPENDIX -B- APPENDIX B GENERAL EARTHWORK AND GRADING SPECIFICATIONS 1.0 General Intent These specifications are presented as general procedures and recommendations for grading and earthwork to be utilized in conjunction with the approved grading plans. These general earthwork and grading specifications are a part of the recommendations contained in the geotechnical report and shall be superseded by the recommendations in the geotechnical report in the case of conflict. Evaluations performed by the consultant during the course of grading may resutt in new recommendations which could supersede these specifications or the recommendations of the geotechnical report. It shall be the responsibility of the contractor to read and understand these specifications, as well as the geotechnical report and approved grading plans. 2.0 Earthwork Observation and Testing Prior to the commencement of grading, a qualified geotechnical consultant should be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations of the geotechnical report and these specifications. It shall be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes, at least 24 hours in advance, so that he may schedule his personnel accordingly. No grading operations should be performed without the knowledge of the geotechnical consultant. The contractor shall not assume that the geotechnical consultant is aware of all grading operations. It shall be the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes and agency ordinances, recommendations in the geotechnical report, and the approved grading plans not withstanding the testing and observation of the geotechnical consultant. If, in the opinion of the consultant, unsatisfactory conditions, such as unsuitable soil, poor moisture condition, inadequate compaction, adverse weather, etc., are resulting in a quality of work less than recommended in the geotechnical report and the specifications, the consultant will be empowered to reject the work and recommend that construction be stopped until the conditions are rectified. Maximum dry density tests used to evaluate the degree of compaction should be performed in general accordance with the latest version of the American Society for Testing and Materials test method ASTM D1557. APPENDIX B (Cont'd.) 3.0 Preparation of Areas to be Filled 3.1 Clearing and Grubbing: Sufficient brush, vegetation, roots and all other deleterious material should be removed or properly disposed of in a method acceptable to the owner, design engineer, governing agencies and the geotechnical consultant. The geotechnical consultant should evaluate the extent of these removals depending on specific srte conditions. In general, no more than 1 percent (by volume) of the fill material should consist of these materials and nesting of these materials should not be allowed. 3-2 Processing: The existing ground which has been evaluated by the geotechnical consultant to be satisfactory for support of fill, should be scarified to a minimum depth of 6 inches. Existing ground which is not satisfactory should be overexcavated as specified in the following section. Scarification should continue until the soils are broken down and free of large clay lumps or dods and until the working surface is reasonably uniform, flat, and free of uneven features which would inhibit uniform compaction. 3.3 Overexcavation: Soft, dry, organic-rich, spongy, highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overexcavated down to competent ground, as evaluated by the geotechnical consultant. For purposes of determining quantities of materials overexcavated, a licensed land surveyor/civil engineer should be utilized. 3.4 Moisture Conditioning: Overexcavated and processed soils should be watered, dried-back, blended, and/or mixed, as necessary to attain a uniform moisture content near optimum. 3.5 Recompaction: Overexcavated and processed soils which have been properly mixed, screened of deleterious material, and moisture-conditioned should be recompacted to a minimum relative compaction of 90 percent or as otherwise recommended by the geotechnical consultant. APPENDIX B (Cont'd.) 3.6 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical), the ground should be stepped or benched. The lowest bench should be a minimum of 15 feet wide, at least 2 feet into competent material as evaluated by the geotechnical consultant. Other benches should be excavated into competent material as evaluated by the geotechnical consultant. Ground sloping flatter than 5:1 should be benched or otherwise overexcavated when recommended by the geotechnical consultant. 3.7 Evaluation of Fill Areas: All areas to receive fill, including processed areas, removal areas, and toe-of-fill benches, should be evaluated by the geotechnical consultant prior to fill placement. 4.0 Fill Material 4-1 General: Material to be placed as fill should be sufficiently free of organic matter and other deleterious substances, and should be evaluated by the geotechnical consultant prior too placement Soils of poor gradation, expansion, or strength characteristics should be placed as recommended by the geotechnical consultant or mixed with other soils to achieve satisfactory fill material. 4.2 Oversize: Oversize material, defined as rock or other irreducible material with a maximum dimension greater than 6 inches, should not be buried or placed in fills, unless the location, materials, and disposal methods are specifically recommended by the geotechnical consultant. Oversize disposal operations should be such that nesting of oversize material does not occur, and such that the oversize material is completely surrounded by compacted or densffied fill. Oversize material should not be placed within 10 feet vertically of finish grade, within 2 feet of future utilities or underground construction, or within 15 feet horizontally of slope faces, in accordance with the attached detail. APPENDIX B (Cont'd.) 4.3 Import: If importing of fill material is required for grading, the import material should meet the requirements of Section 4.1. Sufficient time should be given to allow the geotechnical consultant to observe (and test, ff necessary) the proposed import materials. 5-0 Fill Placement and Compaction 5.1 Fill Lifts: Fill material should be placed in areas prepared and previously evaluated to receive fill, in near-horizontal layers approximately 6 inches in compacted thickness. Each layer should be spread evenly and thoroughly mixed to attain uniformity of material and moisture throughout. 5.2 Moisture Conditioning: Fill soils should be watered, dried-back, blended, and/or mixed, as necessary to attain a uniform moisture content near optimum. 5.3 Compaction of Fill: After each layer has been evenly spread, moisture- conditioned, and mixed, it should be uniformly compacted to not less than 90 percent of maximum dry density (unless otherwise specified). Compaction equipment should be adequately sized and be either specifically designed for soil compaction or of proven reliability, to efficiently achieve the specified degree and uniformity of compaction. 5.4 Fill Slopes: Compacting of slopes should be accomplished, in addition to normal compacting procedures, by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation gain, or by other methods producing satisfactory results. At the completion of grading, the relative compaction of the fill out to the slope face would be at least 90 percent. APPENDIX B (Cont'd.) 5.5 Compaction Testing: Reid tests of the moisture content and degree of compaction of the fill soils should be performed at the consultant's discretion based on field conditions encountered. In general, the tests should be taken at approximate intervals of 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils. In addition, on slope faces, as a guideline approximately one test should be taken for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope. 6.0 Subdrain Installation Subdrain systems, if recommended, should be installed in areas previously evaluated for suitability by the geotechnical consultant, to conform to the approximate alignment and details shown on the plans or herein. The subdrain location or materials should not be changed or modified unless recommended by the geotechnical consultant. The consultant, however, may recommend changes in subdrain line or grade depending on conditions encountered. All subdrains should be surveyed by a licensed land surveyor/civil engineer for line and grade after installation. Sufficient time shall be allowed for the survey, prior to commencement of filling over the subdrains. 7.0 Excavation Excavations and cut slopes should be evaluated by a representative of the geotechnical consultant (as necessary) during grading. If directed by the geotechnical consultant, further excavation, overexcavation, and refilling of cut areas and/or remedial grading of cut slopes (i.e., stability fills or slope buttresses) may be recommended. 8.0 Quantity Determination For purposes of determining quantities of materials excavated during grading and/or determining the limits of overexcavation, a licensed land surveyor/civil engineer should be utilized. RETAINING WALL DRAINAGE DETAIL L L L L 1 1 1 JL 1 i i SOIL BACKFILL. COMPACTED TO 90 PERCENT RELATIVE COMPACTION* RETAINING WALL ^^^ WALL WATERPROOFING PER ARCHITECT'S SPECIFICATIONS _^^^ FINISH GRADE — ^ -—I-^^KiCOMP ACTED FILLS^Sisi; WALL FOOTING <S ^_ X o H« ojo* o'a* MIN. <» OVERLAP• 1' MIN. ' °J3^0 *• * 0 * , I^U* ° f [ =s^ If ii IIS\\ S^-5S55S-"" •_r-3-2- -FILTER FABRIC E (MIRAFI 140N OF EQUIVALENT)** -3y4*-1-1/2* CLEAI .4* (MIN.) DIAMET PVC PIPE (3CHE EQUIVALENT) Wl ORIENTED DOWN MINIMUM 1 PERC TO SUITABLE OUT NOT TO SCALE SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size 1" 3/4" 3/8" No. 4 No. 8 No. 30 Passing 100 90-100 40-100 25-40 18-33 5-15 Sand Equ1valent>75 COMPETENT BEDROCK OR MATERIAL AS EVALUATED BY THE CONSULTANT * BASED ON ASTM 01557 **IF CALTRANS CLASS 2 PERMEABLE MATERIAL (SEE GRADATION TO LEFT) IS USED IN PLACE OF 3/4'-1-1/2* GRAVEL, FILTER FABRIC MAY BE DELETED. CALTRANS CLASS 2 PERMEABLE MATERIAL SHOULD BE COMPACTED TO 90 PERCENT RELATIVE COMPACTION* NOTECOMPOSITE DRAINAGE PRODUCTS SUCH AS MIRADRAIN OR J-DRAIN MAY BE USED AS AN ALTERNATIVE TO GRAVEL OR CLASS 2, INSTALLATION SHOULD BE PERFORMED IN ACCORDANCE WITH MANUFACTURER'S SPECIFICATIONS. n O CD m O m O SIDE HILL STABILITY FILL DETAIL EXISTING GROUND SURFACE. FINISHED SLOPE FACE PROJECT 1 TO 1 LINE FROM TOP OF SLOPE TO OUTSIDE EDGE OF KEY FINISHED CUT PAD F5KC O M P A C TE DSE5S OVERBURDEN OR UNSUITABLE MATERIAL PAD OVEREXCAVATION DEPTH AND DECOMPACTION MAY BE RECOMMENDED BY THE QEOTECHNICAL CONSULTANT BASED ON ACTUAL FIELD CONDITIONS ENCOUNTERED. MIN.KEY DEPTH 13* MIN.LOWEST BENCH(KEY) IOMPETENT BEDROCK OR MATERIAL AS EVALUATED BY THE QEOTECHNICAL CONSULTANT NOTE: Subdrain details and key width recommendations to be provided based on exposed subsurface conditions CANYON SUBDRAIN DETAILS GROUND SURFACE BENCHING REMOVE UNSUITABLE MATERIAL SUBDRAIN TRENCH SEE BELOW SUBDRAIN TRENCH DETAILS FILTER FABRIC ENVELOPE ,(MIRAFI 140N OR APPROVED EQUIVALENT)* 6* MIN. OVERLAP 3/4*-1-1/2* CLEAN GRAVEL (9M.3/ft. MIN.) PERFORATED PIPE 3/4'-1-1/2' CLEAN GRAVEL <9ft.3/ft. MIN.) *IF CALTRANS CLASS 2 PERMEABLE MATERIAL IS USED IN PLACE OF 3/4--1-1/2' GRAVEL. FILTER FABRIC MAY BE DELETED DETAIL OF CANYON SUBDRAIN TERMINAL DESIGN FINISH GRADE SUBDRAIN TRENCH SEE ABOVE I-l 15' MIN.S'MIN.-PERFORATED 6*,0 MIN. PIPE SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size 1" 3/4" 3/8" No. 4 No. 8 No. 30 No. 50 No. 200 % Passing 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 Sand Equivalent>75 Subdrain should be constructed only on competent material as evaluated by the geotechnical consultant. SUBDRAIN INSTALLATION Subdrain pipe should be Installed with perforations down as depicted. At locations recommended by the geotechnical consultant, nonperforated pipe should be Installed. SUBDRAIN TYPE-Subdraln type should be Acrylonltrlle Butadiene Styrene (A.8.S.), Polyvlnyl Chloride (PVC) or approved equivalent. Class 125, SDR 32.5 should be used for maximum fill depths of 35 feet. Class 200,SDR 21 should be used for maximum fill depths of 100 f*et. STABILITY FILL / BUTTRESS DETAIL OUTLET PIPES 4* 0 NONPERFORATED PIPS.100' MAX. O.C. HORIZONTALLY, 30' MAX. O.C. VERTICALLY BACK CUT 1:1 OR FLATTER 1-2% MINZ-I-Z-I-I SEE 3UBORAIN TRENCH DETAIL LOWEST SUBORAIN SHOULD BE SITUATED A3 LOW AS POSSIBLE TO ALLOW SUITABLE OUTLET 10' MIN. EACH SIDEPERFORATED PIPE *i-U' 1 K3«55-»T • «fe:->>-NON-PERFORATED OUTLET PIPE•>z->r->i-2% MIN T-CONNECTION DETAIL KEY DEPTH KEY WIDTH A3 NOTED ON GRADING PLANS 15' MIN. 8* MIN.OVERLAP 3/4'-1-1/2* CLEAN GRAVEL <3ft?/ft. MIN.) NON-PERFORATED PIPEv FILTER FABRIC ENVELOPE (MIRAFI 140N OR APPROVED EQUIVALENT)* SEE T-CONNECTION DETAIL 6* MIN. COVER 4' 0 PERFORATED PIPE 4* MIN. BEDDING SUBDRAIN TRENCH DETAIL *IF CALTRANS CLASS 2 PERMEABLE MATERIAL IS USED IN PLACE OF 3/4'-1-1/2* GRAVEL, FILTER FABRIC MAY BE DELETED SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size 1" 3/4" 3/8" No. 4 No. 8 Ho. 30 No. 50 No. 200 % Passing 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 Sand Equivalent>75 NOTES: For buttress dimension*, see geotechnical report/plans. Actual dimensions of buttress and aubdratn may be changed by the geotechnical consultant based on field conditions. SUBORAIN INSTALLATION-Subdraln pipe should be Installed with perforations down as At locations recommended by the geotechnical consultant, nonperforated pipe should be installed SUBORAIN TYPE-Subdraln type should be Acrylon trlle Butadiene Styrene (A.8.S.), Polyvinyl Chloride (PVC) or approved equivalent. Class 125, 30R 32.5 ahould be used for maximum fill depths of 35 « CUas 200, SDR 21 ahould be used for maximum fill depths of 10O feat. FILL SLOPE KEY AND BENCHING DETAILS PROJECT 1 TO 1 LINE FROM TOE OF SLOPE TO COMPETENT MATERIAL^^ggggzggg=gg^g:^^. ^GROUND SURFACE ^^- REMOVE UNSUITABLE MATERIAL BENCH 2' MIN. KEY DEPTH -15' MIN. LOWEST BENCH (KEY) FILL-OVER-CUT SLOPE EXISTING GROUND SURFACE f U—15' MIN.—H2' ' LOWEST 'MIN. BENCHKEY (KEY)DEPTH CUT SLOPE (TO BE EXCAVATED PRIOR TO FILL PLACEMENT) EXISTING GROUNDSURFACE- REMOVE UNSUITABLE MATERIAL CUT-OVER-FILL SLOPE CUT SLOPE (TO BE EXCAVATED PRIOR TO FILL PLACEMENT) PROJECT 1 TO 1 LJNE FROM TOE OF SLOPE TO COMPETENT MATERIAL REMOVE UNSUITABLE MATERIAL BENCH KEY DEPTH 15' MIN,—HLOWEST IBENCH (KEY) NOTE: Back drain may be recommended by the geotechnical consultant based on actual field conditions encountered. Bench dimension recommendations may also be altered based on field conditions encountered. ROCK DISPOSAL DETAIL PINI4H OAAD6 SLOPE PACE OVERSIZE WINDROW GRANULAR SOIL (3.E.5 30) TO BE DEN3IPIEO IN PLACE 8Y FLOODING DETAIL TYPICAL PROFILE ALONG WINDROW 1) Rock with maximum dimensions greater than 6 inches should not be used within 10 feet vertically Of finish grade (or 2 feet below depth of lowest utility whichever is greater), and 15 feet horizontally of slope faces. 2) Rocks with maximum dimensions greater than 4 feet should not be utilized in fills. 3) Rock placement, flooding of granular soil, and fill placement should be observed by the geotechnical consultant. 4) Maximum size and spacing of windrows should be in accordance with the above details Width of windrow should not exceed 4 feet. Windrows should be staggered vertically (as depicted). 5) Rock should be placed in excavated trenches. Granular soil (S.E. greater than or equal to 30) should be flooded in the windrow to completely fill voids around and beneathrocks. APPENDIX -C- APPENDIX C LABORATORY TESTING PROCEDURES Direct Shear Tests: Direct shear tests are performed on remolded and/or relatively undisturbed samples which are soaked for a minimum of 24 hours prior to testing. After transferring the sample to the shearbox, and reloading, pore pressures are allowed to dissipate for a period of approximately 1 hour prior to application of shearing force. The samples are sheared in a motor-driven, strain controlled, direct- shear testing apparatus. After a travel of approximately 1/4 inch, the motor is stopped and the sample is allowed to "relax" for approximately 15 minutes. Where applicable, the "relaxed" and "peak" shear values are recorded. It is anticipated that, in a majority of samples tested, the 15 minutes relaxing of the sample is sufficient to allow dissipation of pore pressures set up due to application of the shearing force. The relaxed values are therefore judged to be good estimations of effective strength parameters. Expansion Index Tests: The expansion potential of representative samples is evaluated by the Expansion Index Test, U.B.C. Standard No. 29-2. Specimens are molded under a given compactive energy to approximately the optimum moisture content and approximately 50 percent saturation. The prepared 1-inch thick by 4-inch diameter specimens are loaded to an equivalent 144 psf surcharge and are inundated with tap water for 24 hours or until volumetric equilibrium is reached. Classification Tests: Typical materials were subjected to mechanical grain-size analysis by wet sieving from U.S. Standard brass screens (ASTM 0422-65). Hydrometer analyses were performed where appreciable quantities of fines were encountered. The data was evaluated in determining the classification of the materials. The grain-size distribution curves are presented in the test data and the Unified Soil Classification is presented in both the test data and the boring logs. APPENDIX -D- HOMEOWNERS MAINTENANCE GUIDELINES Residential homesrtes require periodic maintenance of irrigation and drainage systems to insure proper performance and overall retention of property value. Often, homeowners are not aware of the importance of these systems and allow them to deteriorate. During the construction phase of development, governing agencies require property developers to utilize specific methods of engineering and construction to protect the public interest. For instance, the developer may be required to grade the property in such a manner that rainwater will be drained away from the building pad, install brow ditches & terrace drains, and to,plant slopes to minimize erosion. However, once the lot is purchased, it becomes the buyer's responsibility to maintain these safety features by observing a prudent program of lot care and maintenance. Failure to make regular inspection and perform necessary maintenance of drainage devices and sloping areas may cause severe financial loss. In addition to his/her own property damage, the property owner may be subject to civil liability for damage occurring to neighboring properties as a result of negligence. The following maintenance guidelines are provided for the protection of the homeowner's investment A. All roof gutter and downspout systems, installed on the residence, should be tightened to a suitable outlet away from the structure. Under no circumstances should water be allowed to pond onsfte, particularly against the perimeter foundation system. 8. Soils grades adjacent to the foundation of the structure should be sloped to direct water away from the foundation'and into a collective drainage system. Soil grades should slope at a minimum of 2% for a horizontal distance of 5 feet away from the structure. C. The irrigation of planter systems located immediately adjacent to the foundation should be strictly controlled to avoid over watering. Saturation of soils in these planters may result in soil settlement/expansion and associated distress. D. Care should be taken to ensure that slopes, terraces, berm, and proper lot drainage are not disturbed. E. In general, roof and yard runoff should be directed to either the street or storm drain by non-erosive devices such as sidewalks, drainage pipes, ground gutters, and driveways. Drainage systems should not be altered without expert consultation. F. All drains should be kept dean and undogged, including gutters and downspout's. Terrace drains or gunite ditches should be kept free of debris to allow proper drainage. During periods of heavy rain, the performance of the drainage systems should be inspected. Problems, such as gullying and ponding, if observed, should be corrected as soon as possible. G. Any leakage from pools, wateriines, etc. or surface runoff bypassing drains should be repaired as soon as possible. H. Animal burrows should be eliminated since they may cause diversion of surface runoff, promote accelerated erosion, and even trigger shallow slope failures. I. Slopes should not be altered without expert consultation. Whenever a homeowner plans a topographic modification of a lot or slope, a qualified geotechnicai consultant should be contacted. J. If unusual cracking, settling, or earth slippage occurs on the property, the owner should consult a qualified geotechnical consultant immediately. K. The most common causes of slope erosion and shallow slope failures are as follows: • Gross neglect of the care and maintenance of onstte slopes and drainage devices • Inadequate and/or improper planting. Barren areas should be replanted as soon as possible. • Excessive or insufficient irrigation or diversion of runoff over the slope. L. Property owners should not let conditions on their property adversely impact their neighbors. Cooperation with neighbors could prevent problems and increase the aesthetic attractiveness of the community.