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HomeMy WebLinkAboutCe-6866; Single Family Site Adjacent to 3446 Madison Street; Site Adjacent to 3446 Madison Street; 2003-03-26NORTH COUNTY COMPACTION ENGINEERING, INC. PRELIMINARY SOILS INVESTIGATION FOR PROPOSED SINGLE FAMILY DWELLING AND DETACHED GARAGE ADJACENT TO 3446 MADISON STREET CARLSBAD, CALIFORNIA (CARLSBAD NO. AV 03-01) PREPARED FOR MONICA MffiRS C/O HIRAM ANDRADE 1818 EL DORADO TERRACE ESCONDIDO,CA 92025 MARCH 26, 2003 PROJECT NO. CE-6866 NORTH COUNTY COMPACTION ENGINEERING, INC.March 26,2003 Project No. CE-6866 Monica Miers c/o Hiram Andrade 1818 El Dorado Terrace Escondido,CA 92025 SUBJECT: Preliminary Soils Investigation Proposed Single Family Dwelling and Detached Garage Adjacent to 3446 Madison Street Carlsbad, California (Carlsbad No. AV 03-01) Dear Ms. Miers: In response to your request, we have performed a Preliminary Soils Investigation for the subject project. The purpose of our investigation was to evaluate the suitability of the site for the proposed development and make recommendations with regard to site grading and foundation design. Briefly, our investigation revealed favorable soil conditions and in our opinion, the site is suitable for the proposed development, provided recommendations set forth in the attached report are adhered to. If you have any questions, please do not hesitate to contact us. This opportunity to be of service is sincerely appreciated. Respectfully submitted, North County COMPACTION ENGINEERING, INC. Ronald K. Adams Dale R. Regll President Registered' Geotechnical Engineer 000713 RKA:paj cc: (4) submitted P.O.BOX3O2OO2 * ESCONPIPO, CA 92O3O * (76O)48>O-1116 FAX (760)741-656£> MORTH COUNTY COMPACTION ENGINEERING, INC. TABLE OF CONTENTS 1.) Purpose and Scope 2.) Location and Description of Site 3.) Field Investigation 4.) Soil Conditions 5.) Laboratory Soil Testing 6.) Recommendations and Conclusions A.) Grading B.) Foundations C.) Slopes (IfRequired) D.) Retaining Walls (IfRequired) E.) Estimated Paving Sections F.) Seismic Design Considerations G.) Review of Grading Plan Page 1 1 1 2 2 2 3 4 5 5 5 6 6 7.) Uncertainty and Limitations APPENDIX Appendix A: Exploration Legend & Unified Soil Classification Chart Plate No. One Plate No. Two & Three Plate No. Four Test Pit Location Plan Exploration Logs Tabulation of Test Results Appendix B: Recommended Grading Specifications MORTH COUNTY COMPACTION ENGINEERING, INC. Project No. CE-6866 Page 1 1. PURPOSE AND SCOPE The purpose of the investigation was to determine if the site is suitable for the proposed single family dwelling and detached garage. The scope of the investigation was to: A. Determine the physical properties and engineering characteristics of the surface and subsurface soils. B. Provide design information with regard to grading, site preparation, and foundation design of the proposed structure(s). 2. LOCATION AND DESCRIPTION OF SITE The site is located adjacent to 3446 Madison Street in the City of Carlsbad, California. The 25 foot X 140 foot rectangular shaped lot is bordered by single family dwellings to the north and south, an alley to the east and Madison Street to the west.. Site topography consists of a predominantly flat lot pitched downhill to the west. The site is presently occupied with a metal storage container and is utilized as a side yard for the adjacent property. Vegetation consists of recently mowed native grasses and small trees. 3. FIELD INVESTIGATION The field investigation was performed on March 17, 2003 and included an inspection of the site and the excavation of two exploratory trenches, with a backhoe to depths of 8 feet. Location of test pits are shown on the attached Plate No. One, entitled "Test Pit Location Plan". As excavation proceeded, representative bulk samples were collected. In place natural densities and moisture contents were determined at different depths in the excavations and are included on Plate No.'s Two and Three. Subsequent to obtaining soil samples, our exploratory excavations were backfilled. NORTH COUNTY COMPACTION ENGINEERING, INC. Project No. CE-6866 Page 2 4. SOIL CONDITIONS Loose surficial soils (silty-sands) consisting of plowed ground were found to be 2 feet and 3 feet in depth in Test Pit No.'s One and Two, respectively. Underlying native soils to depths explored were medium dense to dense silty-sandstones of the Coastal Terrace Formation. On-site soils were found to have an expansion index of less than 5 and are classified as being "very low" in expansion potential. Groundwater was not encountered at the time of our investigation, nor did caving of exploratory trenches occur. In addition, due to the dense nature of the underlying sandstone formation at the site, it is our opinion, soil liquefaction is unlikely to occur in the event grading is performed in accordance with the recommendations set forth in this report. 5. LABORATORY SOIL TESTING All laboratory test were performed on typical soils in accordance with accepted test methods of the American Society for Testing and Materials (ASTM). Tests conducted include: A). Optimum Moisture & Maximum Density (ASTM D-1557) B). Direct Shear (Remold) (ASTM D-3080) C). Sieve Analysis (ASTM D-421) D). Field Density & Moisture (ASTM D-1556) E). Expansion Potential (FHA Standard) Test results are tabulated on the attached Plate No.'s Two through Four entitled "Exploration Log" and "Tabulation of Test Results". 6. RECOMMENDATIONS AND CONCLUSIONS General It is our understanding, the proposed dwelling and detached garage will consist of wood frame construction utilizing slab on grade foundations. NORTH COUNTY COMPACTION ENGINEERING, INC. Project No. CE-6866 Page3 In our opinion, the site is suitable for the proposed single family dwelling and detached garage. Recommendations presented in this report should be incorporated into the planning, design and construction phases of the subject project. Grading at the site will be performed to remove and recompact loose compressible top soils and to create level building areas to accommodate the dwelling and detached garage. Due to the narrow width of the lot, the limits of grading will be carried under and a minimum of 3 feet horizontally beyond the proposed structure(s). Therefore, to provide an adequate soil bearing envelope and to protect the foundation(s) from the narrow side yard surface drainage, we recommend alf'^Wflpteit^^ adjacent grade. 6 A. Grading All grading should be performed in accordance with the City of Carlsbad Grading Ordinance and the Recommendations/Specifications presented in this report. Subsequent to site demolition, loose surficial soils (plowed ground), as indicated on the attached Plate No's Two and Three, should be undercut or removed to firm native ground and recompacted in accordance with the attached Appendix 'B' entitled "Recommended Grading Specification". Firm native ground may be determined as undisturbed soil having an insitu density of greater than ninety percent (90%) of maximum dry density. We should be contacted to document firm native ground is exposed and properly prepared prior to filling. The removal area should extend under and a minimum of 3 feet beyond the proposed structures and/or surface improvements. All fill soils generated from earthwork construction should be placed in conformance with the attached Appendix 'B' entitled, "Recommended Grading Specifications". If required, imported soils should be non-expansive (less than 2% swell) and granular by nature, having strength parameters equal to or greater than the prevailing on-site soils. We should be contacted to inspect an/or test imported soils prior to hauling then on-site to assure they will be suitable for the proposed construction. Particles of asphalt and concrete debris, having a diameter of greater than 6 inches, will not be suitable fill material and should be separated from fines during grading and hauled off-site. If encountered, leach lines and/or pipes should be removed. Concrete pipes may be crushed in place. Trench lines should be recompacted in accordance with Appendix 'B'. NORTH COUNTY COMPACTION ENGINEERING, INC. Project No. CE-6866 Page 4 It is highly probable the proposed structure will be traversed by a transition from native ground to fill. Therefore, to reduce structural damage occurring from foundations bearing on two different soil types, the following measure should be employed: It is recommended transitional areas be removed to a depth of 1 foot below the bottom of the deepest proposed footing and brought back to grade with properly compacted fill. This will allow the proposed structure to bear entirely on a compacted fill mat, thus reducing the probability of differential settlement. The removal area should extend under and a minimum of 3 feet beyond the proposed structures. 6B. Foundations General On-site soils are comprised of non-expansive soils with above average strength parameters. However, to protect the foundations from the narrow side yard surface drainage, we recommend all footings be deepened a minimum of 24 inches below lowest adjacent grade. This will also provide an adequate soil bearing envelope for the proposed building(s) setbacks of 3 feet from the property line. For One- and Two-Story Construction: All continuous footings having a minimum width of 12 inches and founded a minimum of 24 inches below lowest adjacent grade will have an allowable soil bearing pressure of 2000 pounds per square foot. All continuous footings are to be reinforced with one #4 bar top and bottom. Steel should be positioned 3 inches above bottom of footing and 3 inches below top of footing. Interior slabs should be a minimum of 4 inches thick and reinforced with #3 bars at 18 inch centers both ways at mid-point of slab thickness. Slab underlayment should consist of 4 inches of washed concrete sand with a visqueen moisture barrier installed at mid-point of sand (2 inches sand, visqueen, 2 inches sand). Sand should be tested in accordance with ASTM D-2419 to insure a minimum sand equivalent of 30. Foundation set-backs from top of slopes should be a minimum of 8 feet. If this cannot be achieved, footings near or on adjacent slopes should be founded at a depth such that the horizontal distance from the bottom outside edge of footing to the face of the slope is a minimum of 8 feet. NORTH COUNTY COMPACTION ENGINEERING, INC. Project No. CE-6866 Page5 Prior to pouring of concrete, North County COMPACTION ENGINEERING, INC. should be contacted to inspect foundation recommendations for compliance to those set forth. 6C. Slopes (If Required) Cut and compacted fill slopes constructed to maximum heights of 10 feet with maximum slope ratios of 2:1 (horizontal to vertical units) will be stable with relation to deep seated failure, provided they are properly maintained. During grading, positive drainage away from top of slopes should be provided. Subsequent to completion of grading, slopes should be planted as soon as possible with light groundcover indigenous to the area. 6D. Retaining Walls (If Required) For static conditions, the prevailing soils will have an allowable equivalent passive fluid pressure of 309 psf, increasing 309 psf per foot in depth. Allowable pressures assume walls are backfilled with a non-expansive sand a distance behind the wall equivalent to two-thirds the retained height. Allowable active pressures may be assumed to be equivalent to the pressure of a fluid weighing 44 pcf for unrestrained walls. These values assume a vertical, smooth wall, and a level, drained backfill. Should these conditions not be met, we should be contacted for new values. Allowable active pressures for restrained walls may be assumed to be equivalent to the pressure of a fluid weighing 44 pcf, plus an additional uniform lateral pressure of 8H. H=height of retained soils above top of wall footing in vertical feet. Allowable active pressures for retaining walls with 2:1 inclinations of sloping surcharge may be assumed to be equivalent to a pressure of fluid weighing 63 pcf. The coefficient of friction of concrete to soil may be assumed to be .34 for resistance to horizontal movement. 6E. Estimated Paving Section Structural section for asphaltic paving for the proposed driveways and parking area are based on an estimated R-Value of 45. The following section is provided for bid purposes only. Actual sections should be determined subsequent to completion of grading operations. NORTH COUNTY COMPACTION ENGINEERING, INC. Project No. CE-6866 Page 6 Assumed Traffic Index = 4.5 (Light Vehicular Traffic) 2'/2 inches of asphaltic paving on 4 inches of select base coarse on 6 inches of recompacted native subgrade. All materials and construction for asphaltic paving and base should conform to the Standard Specifications of the State of California Business and Transportation Agency, Department of Transportation, Sections 39 and 26, respectively. Class II base material should have a minimum R-Value of 78 and a sand equivalent of 30. All materials should be compacted to a minimum of ninety-five percent (95%). Rigid Concrete Paving: 4 inches of concrete reinforced with #3 bars on 18 inch centers, both ways, on 12 inches of recompacted native subgrade 95% minimum compaction. NOTE: All concrete should have a minimum compressive strength of 3250 psi. 6F. Seismic Design Considerations (Soil Parameters) A.) Soil Profile = SD (Table 16-J of the 1997 Uniform Building Code) B.) Type 'B' Fault (Rose Canyon) C.) Distance = 7 km (California Department of Conservation, Division of Mines and Geology [maps], in conjunction with Tables 16-S and 16-T of the 1997 Uniform Building Code) 6G. Review of Grading Plan Approved site and grading plans were not available at the time of our investigation. Therefore, upon their completion, we should review them to assure compliance with the recommendations presented in this report. Preliminary Plans used during our investigation were prepared by Hiram S. Andrade Planning & Design Consultant. NORTH COUNTY COMPACTION ENGINEERING, INC. Project No. CE-6866 Page? 7.UNCERTAINTY AND LIMITATIONS Surface and subsurface soils are assumed to be uniform. Therefore, should soils encountered during construction differ from those presented in this report, we should be contacted to provide their engineering properties. It is the responsibility of the owner and contractor to carry out recommendations set forth in this report. During our investigation of the subject site, evidence of faulting was not encountered. Subsequent to review of available geologic literature, we feel any faulting in the vicinity of the site may be classified as inactive. However, it should be noted that San Diego County is located in a high seismic area with regard to earthquake. Earthquake proof projects are economically unfeasible. Therefore, damage as a result of earthquake is probable and we assume no liability. We assume the on-site safety of our personnel only. We cannot assume liability of personnel other than our own. It is the responsibility of the owner and contractor to insure construction operations are conducted in a safe manner and in conformance with regulations governed by CAL-OSHA and/or local agencies. Should you have any questions, please do not hesitate to contact us. This opportunity to be of service is sincerely appreciated. Respectfully submitted, North County COMPACTION ENGINEERING, INC. Ronald K. Adams President Dale R. Regl" Registered Civi Geotechnical Engineer 000713 RKA:paj cc: (4) submitted MORTH COCINTY COMPACTION ENGINEERING, INC. EXPLORATION LEGEND UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION I. COARSE GRAINED: More than half of material is larger than No. 200 sieve size. GRAVELS CLEAN GRAVELS More than half of coarse fraction is larger than No. 4 sieve size, but smaller than 3". GRAVELS WITH FINES (Appreciable amount of fines) SANDS CLEAN SANDS More than half of coarse fraction is smaller than No. 4 sieve size. SANDS WITH FINES (appreciable amount of fines) II. FINE GRAINED: More than half of material is smaller than No. 200 sieve size. SILTS AND CLAYS Liquid Limit less than 50 SILTS AND CLAYS Liquid Limit greater than 50 HIGHLY ORGANIC SOILS GROUP SYMBOL TYPICAL NAMES GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Well graded gravels, gravel-sand mixtures, little or no fines. Poorly graded gravels, gravel sand mixtures, little or no fines. Silty gravels, poorly graded gravel- sand-silt mixtures. Clayey gravels, poorly graded gravel-sand, clay mixtures. Well graded sand, gravely sands, little or no fines. Poorly graded sands, gravely sands, little or no fines. Silty sands, poorly graded sand and silt mixtures. Clayey sands, poorly graded sand and clay mixtures. Inorganic silts and very fine sands, rock flour, sandy silt or clayey- silt-sand mixtures with slight plasticity. Inorganic clays of low to medium plasticity, gravely clays, lean clays. Organic silts and organic silty clays of low plasticity. Inorganic silts, micaceous or diatomaceous find sandy or silty soils, elastic silts. Inorganic clays of high plasticity, fat clays. Organic clays of medium to high plasticity. Peat and other highly organic soils. US - Undisturbed, driven ring sample or tube sample CK - Undisturbed chunk sample BG - Bulk sample V - Water level at time of excavation or as indicated APPENDIX 'A' NORTH COUNTY COMPACTION ENGINEERING, INC. SOIL TESTING & INSPECTION SERVICES TEST PIT LOCATION PLAN PROPOSED SINGLE FAMILY DWELING and DETACHED GARAGE MADISON STREET CARLSBAD, CALIFORNIA TEST PIT :•-" #2 t! 7T0 i- *^ $\m *) '^ /<?' > XP 1 w \ 1- !l^ ^if1 *?' TEST PIT '#1 APPROX. SCALE 1" = 22' 3 MADISON ST. PROJECT NO. CE-6866 PLATE NO. ONE MORTH COUNTY COMPACTION ENGINEERING, INC. EXPLORATION LOG PROJECT NAME: MADISON STREET. CARLSBAD DATE LOGGED: 03/17/03 ELEVATION: EXISTING GRADE TEST PIT NO. ONE Depth (Feet) 1- 9, 3- 4- 5- 6- 7- 8- Sample Type BG CK Dry Density (pcf) 117.4 Moisture Content (%) 5.6 Passing #200 Sieve 28.9 Sample Depth 1' 6' Soil Classi- fication SM SM Description & Remarks Dark Brown Red, Moist, Loose Silty-Sand (Plowed Ground) (Remove and Recompact) Tan Red, Moist, Medium, Dense Silty-Sand (Firm Native) (Coastal Terrace Deposit) (Increase Density with Depth) Bottom of Test Pit PROJECT NO. CE-6866 PLATE NO. TWO NORTH COCIMTY COMPACTION ENGINEERING, INC. EXPLORATION LOG PROJECT NAME: MADISON STREET. CARLSBAD DATE LOGGED: 03/17/03 ELEVATION:EXISTING GRADE TEST PIT NO. TWO Depth (Feet) 1- 2- •j. 4- 5- 6- 7 Sample Type RG Dry Density (pcf) Moisture Content (%) Passing #200 Sieve 71 0 Sample Depth V Soil Classi- fication SM SM Description & Remarks Dark Brown, Moist, Loose Silty-Sand (Plowed Ground) (Remove and Recompact) Tan Red, Humid, Dense Silty-Sand (Firm Native) (Increase Density with Depth) (Becomes Olive-Tan) Bottom of Test Pit PROJECT NO.CE-6866 PLATE NO. THREE NORTH COUNTY COMPACTION ENGINEERING, INC. TABULATION OF TEST RESULTS DENSITY SOIL DESCRIPTION TYPE Dark Brown Red Silty Sand PI @ 1' Tan Red Silty Sand P2 @ 3' MAX. DRY DENSITY (LB. CU. FT) 129.1 129.4 OPT. MOISTURE (% DRY WT) 09.3 10.3 EXPANSION POTENTIAL SAMPLE NO. CONDITION INITIAL MOISTURE (%) AIR DRY MOISTURE (%) FINAL MOISTURE (%) DRY DENSITY (PCF) LOAD (PSF) SWELL (%) EXPANSION INDEX PI (§). 1' Remold 90% 9.4 1.7 12.8 116.7 150 .000 Less than 5 P2 (a), 3' Remold 90% 10.2 2.1 13.6 116.5 150 .000 Less than 5 SAMPLE NO. DIRECT SHEAR PI (a). I' CONDITION Remold 90% ANGLE INTERNAL FRICTION 27 COHESION INTERCEPT (PCF) 300 PROJECT NO. CE-6866 PLATE NO. FOUR NORTH COUNTY COMPACTION ENGINEERING, INC. RECOMMENDED GRADING SPECIFICATIONS (General Provisions) 1. INTENT The intent of these specifications is to provide procedures in accordance with current standard practices regarding clearing, compacting natural ground, preparing areas to receive fill, and placing and compacting of fill soil to the lines , grades, and slopes delineated on the project plans. Recommendations set forth in the attached "Preliminary Soils Investigation" report or special provisions are a part of the "Recommended Grading Specifications" and shall supercede the provisions contained hereinafter in case of conflict. 2. INSPECTION & TESTING A qualified Soils Engineer shall be employed to inspect and test the earthwork in accordance with these specification and the accepted plans. It will be necessary that the Soils Engineer or his representative be allowed to provide adequate inspection so that he may certify that the work was or was not accomplished as specified or indicated. It shall be the responsibility of the contractor to assist the Soils Engineer and to keep him appraised of work schedules, changes, new information and dates, and new unforeseen soils conditions so that he may make these certifications. If substandard conditions (questionable soils, adverse weather, poor moisture control, inadequate compaction, etc.) Are encountered, the Soils Engineer will be empowered to either stop construction until conditions are remedied or recommend rejection of the work. Soil tests used to determine the degree of compaction will be performed in accordance with the following American Society for Testing and Materials (ASTM) test methods: *Maximum Density & Optimum Moisture Content (ASTM D-1557-78) * Density of Soil In-Place (ASTM D-1556 or ASTM D-2922 & 3017) 3. MATERIALS Those soils used as fill will have a minimum of forty percent (40%) passing a #4 sieve. They will be free of vegetable matter or other deleterious substances and contain no rock over 6 inches in size. Should unsuitable material be encountered, the Soils Engineer will be contacted to provide recommendations. APPENDIX 'B' NORTH COUNTY COMPACTION ENGINEERING, INC. 4. PLACING AND SPREADING OF FILL The selected fill material shall be placed in layers which when compacted will not exceed 6 inches in thickness. Each layer shall be spread evenly and shall be thoroughly blade mixed during the spreading to insure uniformity of material in each layer. When moisture content of the fill material is below that recommended by the Soils Engineer, water shall then be added until the moisture content is as specified to assure thorough bonding during the compacting process. When the moisture content of the fill materials is above that recommended by the Soils Engineer, the fill material shall be aerated by blading or other satisfactory methods until the moisture content is as specified. 5. COMPACTION After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted to not less than ninety percent (90%) relative compaction. Compaction shall be by sheepsfoot rollers multiple-wheel pneumatic tired rollers or other types of rollers. Rolling shall be accomplished while the fill material is at the specified moisture content. Rolling each layer shall be continuous over it's entire area and the roller shall make sufficient trips to insure that the desired density has been obtained. The fill operation shall be continued in 6 inch compacted layers, or as specified above, until the fill has been brought to the finished slopes and grades shown on the project plans. 6. WALL BACKFILL Backfill soils should consist of non-expansive sand, Compaction should be achieved with light hand-held pneumatic tampers to avoid over compaction and hence cause structural damage. Wall backfill should be compacted to a minimum of ninety percent (90%) of maximum density. 7. TRENCH BACKFILL All trench backfill located within structural areas should be compacted to a minimum of ninety percent (90%) of maximum density. APPENDIX 'B'