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2002-7425 CN/G CHRISTIAN WHEELER- ENGINEERING January 10,2002 Soil Testers CWE 202.050.1 Post Office Box 1195 Lakeside,CA 92040 SUBJECT: SEISMIC DESIGN CRITERIA,PROPOSED RESIDENTIAL BUILDING SITE, 195 LAMESAAVENUE,ENCINITAS,CALIFORNIA REFERENCES: 1) Site Inspection,Proposed Residential Building Site, 195 La Mesa Avenue,City of Encinitas,California by Soil Testers,File No. 10299,dated January 7,2002. 2) Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada by California Division of Mines and Geology,dated February 1998. 3) Geologic Maps of the Northwestern Part of San Diego County,California; • California Division of Mines and Geology Open-File Report 96-02 by Siang S.Tan and Michael P.Kennedy Dear Ladies and Gentlemen: In accordance with your request,we have prepared this letter to present pertinent seismic/geotechnical information regarding the project site. The scope of our limited study consisted of a review of the referenced soils report,a review of other pertinent literature,and the preparation of this letter that includes our findings. GENERAL GEOLOGIC SETTING:The project site is located in the Coastal Plains Physiographic Province of San Diego County and is underlain by Teniaryage and Qujatemary--age sediments, associated surficial soils,and artificial fill. The materials at the site are described in the referenced report by Soil Testers. SEISMIC DESIGN PARAMETERS:Based on a maximum magnitude(Mmax)earthquake of 6.9 along the nearest portion of the Rose Canyon Fault Zone,the Maximum Bedrock Acceleration at the site would be approximately 0.49 g. For structural design purposes,a damping ratio not greater than 5 percent of critical dampening,and Soil Profile Type SD are recommended(L)BC Table 16-J). Based upon the location of the site at approximately four kilometers from the Rose Canyon Fault Zone(Type B Fault),Near Source Factors N, equal to 1.10 and N,equal to 1.33 are also applicable. These values,along with other seismically related design 4925 Mercury Street + San Diego, CA 92111 f 858-496-9760 ♦ FAX 858-496-9758 1 ' CWE 202.050 January 10,2002 2 r parameters from the Uniform Building Code(LIBC) 1997 edition,Volume H,Chapter 16,utilizing a Seismic Zone 4 are presented in tabular form below. UBC— CHAPTER 16 SEISMIC RECOMMENDED TABLE No. PARAMETER VALUE 16-I Seismic Zone Factor Z 0.40 16-J Soil Profile Type SD 16-Q Seismic Coefficient Q 0.44 N. 16-R Seismic Coefficient C, 0.64 N, 16-S Near Source Factor N, 1.10 16-T Near Source Factor N, 1.33 16-U Seismic Source Type B LIQUEFACTION:Liquefaction is the phenomenon that may result in large total and/or differential ground surface settlement and possible lateral ground spreading during an earthquake. Liquefaction occurs when loose,saturated,generally fine sands and silts are subject to strong ground shaking. The soil loses all shear strength and becomes a viscous liquid for a short period of time,and their usually solidifies. Settlement of the ground surface and failure of foundations caused by liquefaction is usually only affected i by the soils that liquefy within the upper 30 feet;the effect of liquefaction of soils below this depth is not usually manifested at the ground surface. Four conditions usually must be present before liquefaction can occur. 1) The soil is below the groundwater table,i.e.,saturated; 2) The soil is composed predominantly of fine sand and silt; 3) The soil is in a loose to medium denfie state; 4) The soil is subject to a sufficient magnitude and duration of strong ground shaking. Based on the available information,it appears that the ground water table is relatively deep and that the native materials at the site below the foundation elevation are generally medium dense to dense and are not subject to liquefaction. If you have any questions after reviewing this letter,please do not hesitate to contact this office. Respectfully submitted, CHRISTIAN WHEELER ENGINEERING RED GAG Ft.BURO�C�\ No 1 a90 R E.G.# 1090 Burdett,C CERTIFIED ° ENGINEERING ° CRB:crb GEOLOGIST cc: (4)Submitted p'1002 OF C� SOIL TENTER& P.O. Box 1195 Lakeside,California January 7,2002 92040 (619)443-0060 Traci Tolman D 4413 Seashore Drive DEC_Newport Beach, California 92663 SUBJECT: File No. 10299 ENGIN RI N C�R A� SITE INSPECTION Proposed Residential Building Site 195 La Mesa Avenue City of Encinitas Dear Ms. Tolman: SCOPE In accordance with your request, a Site Inspection has been performed at the subject site. The purpose of this investigation was to examine existing site conditions and provide engineering recommendations for the proposed residential structure. -It is our understanding that the project will consist of a two-story, single family residential structure. FIELD INSPECTION In order to accomplish this purpose, a representative of this firm visited the site, reviewed the topography and site conditions and visually and textually classified the surface and near surface soils. Representative samples of the on-site soils were obtained from a test exploration approximately 3 feet in depth and tested for density, shear strength and expansive characteristics. An in-place field density test was taken in the bottom of the test exploration in accordance with A.S.T.M. D1556-82. The test results indicate relative compaction of the native soils at approximately 3 feet in depth is 84.3percent SITE CONDITIONS The subject site is a small residential property located on the east side of La Mesa Drive in an older established neighborhood. The parcel sits approximately 18 inches above the sidewalk retained by a small wall. The site is relatively level with irregular surfaces and a gentle slope east to the rear of the property. The site is presently occupied by an old boarded-up single-family residence and various types of fences on the side and rear property lines. It is our understanding 1 Traci Tolman File No. 10299 January 7, 2002 that these structures will be removed to make way for the proposed new development. Adjacent properties are also occupied by single family residences. Vegetation consists of sparse grasses and 8 small trees. Man made fill soils were not encountered in the test explorations; however, native soils were loose and compressible to approximately 3 feet in depth. SOIL CONDITIONS The soils encountered on site were red brown, silty fine to medium sands. The surface soils were loose and compressible to approximately 1 to 3 feet in depth where they became dense. Tree roots were observed throughout the test exploration as well as in the bottom. The sandy soils encountered in the test exploration were not considered to be detrimentally expansive with respect to change in volume with change in moisture content(Expansion Index(11) and will not require special foundation design to resist expansive soils. CONCLUSIONS AND RECOMMENDATIONS 1. In order to provide uniform support for the proposed structure, the loose and compressible soils in proposed building areas should be excavated to firm natural ground (approximately 3 feet in depth), replaced and recompacted to 90 percent compaction in accordance with the following Grading Specifications. The recompaction should extend at least 5 feet outside the proposed building footprint. Any organics such as tree roots or other deleterious material that may be encountered should be removed prior to recompaction. 2. Conventional spread footings founded a minimum of 12 inches below lowest adjacent grade and having a width determined by the allowable soil bearing value as detailed above are recommended for foundation support. Footing widths should be at least 12 inches for continuous footings and 24 inches for square footings due to practical considerations as well as Building Code requirements. This footing design is a minimum based upon the foundation soil type and does not take into consideration structural requirements. 3. Reinforcing in footings should consist of at least one #4 steel bar placed continuously in the top and bottom of continuous footings regardless of structural requirements. Reinforcing for isolated footings are dictated by the structural requirements. These recommendations are based upon on the soil type encountered and do not take into consideration the proposed bearing load. 4. Concrete slabs-on-grade should be constructed to have a nominal thickness of 4" and underlain with a sand blanket of 3 inches in thickness. Provide minimum temperature reinforcement consisting of 6X6-10/10 welded wire mesh. The sand subbase (sand blanket) should have a sand equivalent exceeding 30 per ASTM D2419. All slabs 2 Traci Tolman File No. 10299 January 7,2002 should either have a conventional thickened edge or be poured monolithically with continuous footings at the slabs perimeter. Conventional thickened edges should be 8" thick at slab edge, uniformly tapering to 4" thick at 2' from slab edge. The thickened edges or monolithic footings should extend completely around the slab's perimeter. Construction and expansion joints should be considered slab edges. Maximum spacing of expansion joints is 50'for interior slabs and 30'for exterior slabs. 5. A representative sample of the foundation soil was remolded to 90% of maximum dry density (131.7). Based on the following test results, a safe allowable bearing value of at least 2500 pounds per square foot may be used in designing the foundations and slab for the proposed structure. This value may be increased by one third for wind and/or seismic loading. Angle of internal friction 380 Cohesion 140 psf Unit weight 119.1 pcf RECOMMENDED GRADING SPECIFICATIONS Proposed Residential Building Site 195 La Mesa Avenue City of Encinitas GENERAL: Soil Testers and 'Soil Engineer' are synonymous hereinafter and shall be employed to inspect and test earthwork in accordance with these specifications, the accepted plans, and the requirements of any jurisdictive governmental agencies. They are to be allowed adequate access so that the inspections and tests may be performed. The Soil Engineer shall be appraised of schedules and any unforeseen soil conditions. Substandard conditions or workmanship, inadequate compaction, adverse weather, or deviation from the lines and grades shown on the plans, etc., shall be cause for the soil engineer to either stop construction until the conditions are corrected or recommend rejection of the work. Refusal to comply with these specifications or the recommendations and/or interpretations of the soil engineer will be cause for the soil engineer and/or his representative to immediately terminate his services. Deviations from the recommendations of the Soil Report, from the plans, or from these Specifications must be approved in writing by the owner and the contractor and endorsed by the soil engineer. SOIL TEST METHODS: Maximum Density& Opt Moisture --ASTM D1557-70 Density of Soil In-Place --ASTM D1556,D2922 and D3017 3 Traci Tolman File No. 10299 January 7,2002 Soil Expansion --UBC STANDARD 29-2 Shear Strength --ASTM D3080-72 Gradation& Grain Size --ASTM D1140-71 Capillary Moisture Tension --ASTM D2325-68 Organic Content --%Weight loss after heating for 24 hours at 300°F and after deducting soil moisture. LEMUTING SOII,CONDITIONS: Minimum Compaction 90% for'disturbed'soils. (Existing fill, newly placed fill,plowed ground, etc.) 84% for natural,undisturbed soils. 95% for pavement subgrade within 2' of finish grade and pavement base course. Expansive Soils Expansion index exceeding 20 Insufficient fines Less than 40%passing the#4 sieve. Oversized Particles Rocks over 10"in diameter. PREPARATION OF AREAS TO RECEIVE FILL: Brush, trash, debris and detrimental soils shall be cleared from the areas to receive fill. Detrimental soils shall be removed to firm competent soil. Slopes exceeding 20% should be stepped uphill with benches 10' or greater in width. Scarify area to receive fill to 6" depth and compact. FILL MATERIAL shall not contain insufficient fines, oversized particles, or excessive organics. On-site disposition of oversized rock or expansive soils is to be at the written direction of the Soil Engineer. Select fill shall be as specified by the soil engineer. All .fills shall be compacted and tested. SUBDRAINS shall be installed if required by and as directed by and detailed by the soil engineer and shall be left operable and unobstructed. They shall consist of 3" plastic perforated pipe set in a minimum cover of 4" of filter rock in a'vee'ditch to intercept and drain free ground from the mass fills. Perforated pipe shall be schedule 40, Poly-Vinyl-Chloride or Acrylonitrile Butadienne Styrene plastic. Rock filter material shall conform to the following gradation: Sieve size: 3/4" #4 #30 #200 %Passing: 90-100 25-50 5-20 0-7 Subdrains shall be set at a minimum gradient of 0.2% to drain by gravity and shall be tested by dye flushing before acceptance. Drains found inoperable shall be excavated and replaced. CAPPING EXPANSIVE SOILS: If capping expansive soils with non-expansive soil to mitigate the expansive potential is used, the cap should be compacted, non-expansive, select soil 4 Traci Tolman File No. 10299 January 7,2002 placed for a minimum thickness 3' over the expansive soil and for a minimum distance of 8' beyond the exterior perimeter of the structure. Special precautions should be taken to ensure that the non-expansive soil remains uncontaminated and the minimum thickness and dimensions around the structure are maintained. The expansive soils underlying the cap of non-expansive cap should be pre-saturated to a depth of 3'to obtain a degree saturation exceeding 90%before any construction supported by the compacted cap. The non-expansive soil comprising the cap should conform to the following: Minimum Compaction 90% Maximum Expansion Index 30 Minimum Angle of Internal Friction 33 Deg Cohesion Intercept 100 psf UNFORESEEN CONDITIONS: Soil Testers assume no responsibility for conditions which differ from those described in the applicable current reports and documents for this property. Upon termination of the soil engineer's services for any reason, his fees up to the time of termination become due and payable. If it is necessary for the soil engineer to issue an unfavorable report concerning the work that he has been hired to test and inspect, the soil engineer shall not be held liable for any damages that might result from his'unfavorable report'. If we can be of any further assistance, please do not hesitate to contact our office. This opportunity to be of service is sincerely appreciated. Respectfully submitted, QPOFESSION QUO �Q f1 C. Jos h CFSm �RC��l s No.2y,sso rn EXP.grawm JCS/ss s, civn. cc: (3) submitted �rF OF CAIA 5 SIIII. T1;1TFKN P.O. Box 1195 Lakeside,California March 14, 2003 92040 (619)4434)060 Declan Caulfield 1730 S. El Camino Real H2O3 Encinitas, California 92024 Subject: File No. 10299 Report of Compacted Filled Ground Proposed Residential Building Site 195 La Mesa Avenue City of Encinitas Dear Ms. Caulfield: In accordance with your request, our firm has inspected the grading operation and tested the fill soils that were placed and compacted during the preparation of the subject side. This is to report the results of our soil tests. The work was performed during the period between January 6, 2003 and February 28, 2003. The site is located at 195 La Mesa Avenue, City of Encinitas. To briefly summarize the work, we found the compaction of the fill soils to conform to the recommended and approved grading specifications and current standard practices. SECTION No. 1. SCOPE Our function consisted of providing the engineering services involved with determining the degree of compaction of fill placed on the site in accordance with the recommendations set forth in our Site Inspection dated January 7, 2002. The results of the field density tests are presented on Page T-1 under "Table of Test Results". The laboratory determinations of the maximum dry densities and optimum moisture contents of the fill soils are set forth on Page L-1 under "Laboratory Test Results". The approximate locations of the filled ground and the field density tests are presented on Plate No. 1 entitled "Location of Field Density Tests". The grading was performed for the purpose of recompacting loose native soils and providing a level building pad for the construction of the proposed residential building site. 1 Declan Caulfield File No. 10299 March 14, 2003 SECTION No. 2. SOIL CONDITIONS Soils used in the fill were those generated from the on-site excavation. EARTHWORK Preparation: Prior to placement of fill, the areas to receive fill were scarified, watered and compacted to 90 percent. Natural ground to receive fill was tested to determine its relative compaction. Native soils having a relative compaction of less than 85 percent were removed, replaced and compacted to 90 percent. Placing and compacting fill: Fill soil was placed, watered and mechanically densified in the areas indicated on attached Plate No. 1. During grading, any fill found to have a relative compaction of less than 90 percent was reworked until the proper density of 90 percent had been achieved. Field density test results: To verify compaction, field density tests were performed in accordance with applicable American Society of Testing and Materials(ASTM)test methods. Test method ASTM D1556-82 was used at the indicated locations. SECTION No. 3. SUMMARY AND RECOMMENDATIONS Based on the work and tests described hereinbefore and work description set forth in Section 1, 'Scope', we conclude: 1. The filled ground has been compacted to 90%. 2. The placement of fill has been accomplished in accordance with the grading specifications and with current standard practices. 3. Two areas of uncompacted fill where seepage pits had been located were encountered during grading. The uncompacted fill soils were removed and replaced in the area on the north side of the property. In the area on the south side of the property, the fill soils were removed and backfilled with slurry to five feet from finish grade. The final five feet was recompacted with on-site soils. 4. Spread footings will have a minimum allowable bearing value of at least 2500 pounds per square foot. The allowable bearing value will be considerably more for footings larger than 12 inches wide and/or 12 inches deep. If loads heavier than 2500 pounds per square foot for continuous footings are anticipated, we 2 Declan Caulfield File No. 10299 March 14, 2003 should be contacted for an increased bearing value. 5. The soils encountered during grading were the same as those in the previously referenced report. Therefore,the design values and foundation design presented therein are still applicable and should be used for this project. SECTION No. 4. LIMITATIONS UNIFORMITY OF SOIL CONDITIONS: The values presented in this report are based on our evaluation of the observed, exposed soil conditions. We have assumed that the soil conditions in the remaining portions of the site can be interpolated without significant deviation in physical properties. We have made a conscientious effort to select representative test locations and to provide enough tests for a statistically adequate population in excess of current standard practices. However, parameter values may be substantially different in other areas due to unforeseeable variations in the soils. Also, the parameters are affected in time by the moisture-expansion(volume)-pressure changes that seriously affect the tested values. ENGINEERING INTERPRETATION: We are available for consultation and should be made aware of any pertinent condition or problem. Our conclusions will be re-evaluated and any problem or potential problem solved with a minimum effort and cost before it gets out-of-hand. TIME LIMITS: This report presents conclusions and findings that are valid as of this date. Changes on this site and adjacent property including grading, improvements, drainage, erosion, etc. may directly affect the findings, conclusions and recommendations presented herein. Subsequent alterations or conditions may invalidate these recommendations and values. The values in this report will probably remain applicable for one year provided the site conditions remain unaltered. After this period, we should be contacted to inspect the site and review this report so that we may verify its validity. WARRANTY: Certain risks are involved with geotechnical and soil engineering work, which should be recognized by those involved. We have performed our services in accordance with current standard practices and procedures. These practices and procedures are those presently utilized by members of our profession in this region. We do not express or imply a warranty or guarantee regarding these services. OUTSIDE RESPONSIBILITY: It is the responsibility of the client (firm or person to whom this report is submitted)to insure 3 Declan Caulfield File No. 10299 March 14, 2003 that the information presented herein is made available to the concerned parties. In addition it is the client's responsibility to make certain that any construction reflects any applicable requirements and conforms with the current codes of jurisdictive governmental agencies. PROJECT CONCEPT: We should be notified of any changes in the proposed structures, construction, or site grading, or project concept so that any addendum or modifications to this report may be provided as necessary. Summary of the GRADING SPECIFICATIONS USED for Proposed Residential Building Site 195 La Mesa Avenue City of Encinitas SOIL.TEST METHODS: Maximum Density& Opt Moisture -- ASTM D1557-78 Density of Soil In-Place -- ASTM D1556-82 Soil Expansion -- UBC STANDARD 29-2 Shear Strength -- ASTM D3080-72 Gradation& Grain Size -- ASTM D1140-71 Capillary Moisture Tension -- ASTM D2325-68 LIMITING SOIL CONDITIONS: Minimum Compaction -- 90%for "disturbed" soils. (Existing fill, newly placed fill, plowed ground, etc.) -- 84%for natural, undisturbed soils. -- 95%for pavement subgrade within 2' of finish grade and pavement base course. Expansive Soils -- Expansion index exceeding 20 Insufficient Fines -- Less than 401/o passing the#4 sieve. Oversized Particles -- Rocks over 10" in diameter. PREPARATION FOR FILL: Brush, trash, debris and detrimental soils were cleared from the area to receive fill. Detrimental soil was removed to competent soil. Slopes exceeding 20%were stepped with benches 10' or greater in width. The area to be filled was scarified to a 6" depth and compacted. 4 Declan Caulfield File No. 10299 March 14, 2003 FILL MATERIAL: Contained sufficient fines and did not contain oversized particles or excessive organics. Special attention was given to the disposition of any oversized rock, organic soils and expansive soils. Please read this report carefully. If you have any questions, please contact our office. This opportunity to be of service is sincerely appreciated. Page L-1, Page T-I and Plate No. 1 are parts of this report. Respectfully submitted, O QPOFESS/OA Q �qN C.'s, �c W s NO.21AM m �Jo ph . Smyth, RCE 550 * 0� * JCS/m1j9OF1FO�'`'`P cc: (3) submitted 5 Declan Caulfield File No. 10299 March 14, 2003 Page L-1 LABORATORY TEST RESULTS The maximum dry densities and optimum moisture contents of the fill materials as determined by the A.S.T.M., D1557-78, Method A, which uses 25 blows of 10 pound rammer falling from a height of 18 inches on each of 5 layers in a 4 inch diameter 1/30 cubic foot compaction cylinder, are presented as follows: Maximum Optimum Expansion Dry Density Moisture Soil Type Index lb/cu ft Content dry wt 1 Red brown, silty, fine to medium sand 11 131.7 8.4 Dedlan Caulfield File No. 10299 March 14, 2003 Page T-1 TABLE OF TEST RESULTS A.S.T.M., D1556-82 DEPTH MAXIMUM OF FILL FIELD DRY DRY TEST SOIL AT TEST MOISTURE DENSITY DENSITY PERCENT NO. TYPE IN FEET % P.C.F. P.C.F. COMPACTION 1 1 +2 11.1 119.9 131.7 91.0 2 1 +2 10.7 121.0 131.7 91.8 3 1 +4 8.1 124.3 131.7 94.4 4 1 +2 8.9 126.2 131.7 95.8 5 1 +4 9.2 121.8 131.7 92.5 6 1 +6 8.7 120.8 131.7 91.7 7 1 f g• 9.0 122.9 131.7 93.3 f.g. =finish grade •A .5 3 y` 1414 I4EX -naA nl srQgET 1 2 H 14#CA THAA/ OrRCE-7- Si Dr WAc.K LA ME3A 0 COMPACTEI) tjtt. • RELO Mvisry TEST 10"TION p �oBNo. �+NO /oz 99 F11 L 9 D EMS S 1 r r !Es TS BY AVX7 DATE 11421 Woodside Ave., Suite C PIA TE Santee, California 92071 (619)562-0500 "'q [S94111, TESTERS .,;e,,o P.O. Box 1195 Lakeside,California January 7, 2002 92040 (619)443-0 al - L Traci Tolman 4413 Seashore Drive Newport Beach, California 92663 SUBJECT: File No. 10299 SITE INSPECTION Proposed Residential Building Site 195 La Mesa Avenue City of Encinitas Dear Ms. Tolman: SCOPE In accordance with your request, a Site Inspection has been performed at the subject site. The purpose of this investigation was to examine existing site conditions and provide engineering recommendations for the proposed residential structure. -It is our understanding that the project will consist of a two-story, single family residential structure. FIELD INSPECTION In order to accomplish this purpose, a representative of this firm visited the site, reviewed the topography and site conditions and visually and textually classified the surface and near surface soils. Representative samples of the on-site soils were obtained from a test exploration approximately 3 feet in depth and tested for density, shear strength and expansive characteristics. An in-place field density test was taken in the bottom of the test exploration in accordance with A.S.T.M. D1556-82. The test results indicate relative compaction of the native soils at approximately 3 feet in depth is 84.3 percent STTE CONDITIONS The subject site is a small residential property located on the east side of La Mesa Drive in an older established neighborhood. The parcel sits approximately 18 inches above the sidewalk retained by a small wall. The site is relatively level with irregular surfaces and a gentle slope east to the rear of the property. The site is presently occupied by an old boarded-up single-family residence and various types of fences on the side and rear property lines. It is our understanding 1 Traci Tolman File No. 10299 January 7, 2002 that these structures will be removed to make way for the proposed new development. Adjacent properties are also occupied by single family residences. Vegetation consists of sparse grasses and 8 small trees. Man made fill soils were not encountered in the test explorations; however, native soils were loose and compressible to approximately 3 feet in depth. SOIL CONDITIONS The soils encountered on site were red brown, silty fine to medium sands. The surface soils were loose and compressible to approximately 1 to 3 feet in depth where they became dense. Tree roots were observed throughout the test exploration as well as in the bottom. The sandy soils encountered in the test exploration were not considered to be detrimentally expansive with respect to change in volume with change in moisture content(Expansion Index(11) and will not require special foundation design to resist expansive soils. CONCLUSIONS AND RECOM MNDATIONS 1. In order to provide uniform support for the proposed structure, the loose and compressible soils in proposed building areas should be excavated to firm natural ground (approximately 3 feet in depth), replaced and recompacted to 90 percent compaction in accordance with the following Grading Specifications. The recompaction should extend at least 5 feet outside the proposed building footprint. Any organics such as tree roots or other deleterious material that may be encountered should be removed prior to recompaction. 2. Conventional spread footings founded a minimum of 12 inches below lowest adjacent grade and having a width determined by the allowable soil bearing value as detailed above are recommended for foundation support. Footing widths should be at least 12 inches for continuous footings and 24 inches for square footings due to practical considerations as well as Building Code requirements. This footing design is a minimum based upon the foundation soil type and does not take into consideration structural requirements_ 3. Reinforcing in footings should consist of at least one#4 steel bar placed continuously in the top and bottom of continuous footings regardless of structural requirements. Reinforcing for isolated footings are dictated by the structural requirements. These recommendations are based upon on the soil type encountered and do not take into consideration the proposed bearing load. 4. Concrete slabs-on-grade should be constructed to have a nominal thickness of 4" and underlain with a sand blanket of 3 inches in thickness. Provide minimum temperature reinforcement consisting of 6X6-10/10 welded wire mesh. The sand subbase (sand blanket) should have a sand equivalent exceeding 30 per ASTM D2419. All slabs 2 Traci Tolman File No. 10299 January 7,2002 should either have a conventional thickened edge or be poured monolithically with continuous footings at the slabs perimeter. Conventional thickened edges should be 8" thick at slab edge, uniformly tapering to 4" thick at 2' from slab edge. The thickened edges or monolithic footings should extend completely around the slab's perimeter. Construction and expansion joints should be considered slab edges. Maximum spacing of expansion joints is 50'for interior slabs and 30'for exterior slabs. 5. A representative sample of the foundation soil was remolded to 90% of maximum dry density (131.7). Based on the following test results, a safe allowable bearing value of at least 2500 pounds per square foot may be used in designing the foundations and slab for the proposed structure. This value may be increased by one third for wind and/or seismic loading. Angle of internal friction 380 Cohesion 140 psf Unit weight 119.1 pcf RECOMMENDED GRADING SPECIFICATIONS Proposed Residential Building Site 195 La Mesa Avenue City of Encinitas GENERAL: Soil Testers and 'Soil Engineer' are synonymous hereinafter and shall be employed to inspect and test earthwork in accordance with these specifications, the accepted plans, and the requirements of any jurisdictive governmental agencies. They are to be allowed adequate access so that the inspections and tests may be performed. The Soil Engineer shall be appraised of schedules and any unforeseen soil conditions. Substandard conditions or workmanship, inadequate compaction, adverse weather, or deviation from the lines and grades shown on the plans, etc., shall be cause for the soil engineer to either stop construction until the conditions are corrected or recommend rejection of the work. Refusal to comply with these specifications or the recommendations and/or interpretations of the soil engineer will be cause for the soil engineer and/or his representative to immediately terminate his services. Deviations from the recommendations of the Soil Report, from the plans, or from these Specifications must be approved in writing by the owner and the contractor and endorsed by the soil engineer. SOIL TEST METHODS: Maximum Density& Opt Moisture --ASTM D1557-70 Density of Soil In-Place --ASTMD1556,D2922 and D3017 3 Traci Tolman File No. 10299 January 7,2002 Soil Expansion --UBC STANDARD 29-2 Shear Strength --ASTM D3080-72 Gradation&Grain Size --ASTM D 1140-71 Capillary Moisture Tension --ASTM D2325-68 Organic Content --%Weight loss after heating for 24 hours at 300°F and after deducting soil moisture. LEVIITING SOIL CONDITIONS: Minimum Compaction 90%for'disturbed'soils. (Existing fill, newly placed fill,plowed ground, etc.) 84%for natural,undisturbed soils. 95%for pavement subgrade within 2' of finish grade and pavement base course. Expansive Soils Expansion index exceeding 20 Insufficient fines Less than 40%passing the#4 sieve. Oversized Particles Rocks over 10"in diameter. PREPARATION OF AREAS TO RECEIVE FILL: Brush, trash, debris and detrimental soils shall be cleared from the areas to receive fill. Detrimental soils shall be removed to firm competent soil. Slopes exceeding 20% should be stepped uphill with benches 10' or greater in width. Scarify area to receive fill to 6" depth and compact. FILL MATERIAL shall not contain insufficient fines, oversized particles, or excessive organics. On-site disposition of oversized rock or expansive soils is to be at the written direction of the Soil Engineer. Select fill shall be as specified by the soil engineer. All fills shall be compacted and tested. SUBDRAINS shall be installed if required by and as directed by and detailed by the soil engineer and shall be left operable and unobstructed. They shall consist of 3" plastic perforated pipe set in a minimum cover of 4" of filter rock in a 'vee'ditch to intercept and drain free ground from the mass fills. Perforated pipe shall be schedule 40, Poly-Vinyl-Chloride or Acrylonitrile Butadienne Styrene plastic. Rock filter material shall conform to the following gradation: Sieve size: 3/4" #4 930 #200 %Passing: 90-100 25-50 5-20 0-7 Subdrains shall be set at a minimum gradient of 0.2% to drain by gravity and shall be tested by dye flushing before acceptance. Drains found inoperable shall be excavated and replaced. CAPPING EXPANSIVE SOILS: If capping expansive soils with non-expansive soil to mitigate the expansive potential is used, the cap should be compacted, non-expansive, select soil 4 Traci Tolman File No. 10299 January 7,2002 placed for a minimum thickness 3' over the expansive soil and for a minimum distance of 8' beyond the exterior perimeter of the structure. Special precautions should be taken to ensure that the non-expansive soil remains uncontaminated and the minimum thickness and dimensions around the structure are maintained. The expansive soils underlying the cap of non-expansive cap should be pre-saturated to a depth of 3'to obtain a degree saturation exceeding 90%before any construction supported by the compacted cap. The non-expansive soil comprising the cap should conform to the following: Minimum Compaction 90% Maximum Expansion Index 30 Minimum Angle of Internal Friction 33 Dea Cohesion Intercept 100 psf UNFORESEEN CONDITIONS: Soil Testers assume no responsibility for conditions which differ from those described in the applicable current reports and documents for this property. Upon termination of the soil engineer's services for any reason, his fees up to the time of termination become due and payable. If it is necessary for the soil engineer to issue an unfavorable report concerning the work that he has been hired to test and inspect, the soil engineer shall not be held liable for any damages that might result from his 'unfavorable report'. If we can be of any further assistance, please do not hesitate to contact our office. This opportunity to be of service is sincerely appreciated. Respectfully submitted, QPpFESSN, �Q�o5�e�c.sy��Fyc+ �hRCE S h C. Smyt 2165 Q NO'21. 0 E►.WWW * JCS/ss sr elm cc: (3) submitted qTe op cA��F°� 5 A • tic r �aq - 3 &d t F � � 1 a6 r'!