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Home My WebLink About; Hayes Land Lots 53-54 Block A; Soils Report; 1970-12-09INSPECTION * TESTING * RESEARCH . DEVELOPMENT 6280 Riverdale St.* San Diego,California 92120. Phone 283-6134 December 9,197O Mr. Per Stiko. A.I.A. 851 Loring Street San Diego, California 92109 Job NO. 20097 SUBJECT: Addendum to Soils Investigation for Proposed Apartment Site, Lots 53 and 54, Block A, Hayes Land Company Addition, Map No. 2, City of Carlsbad, County of San Diego, State of California. Dear Sir: -' As was decided at our meeting of this date, we recommend that all fill soils existing on the subject lot be recompacted. In addition we recommended that the soils under spread footings be recompacted to a depth of 20 for continuous and 1B for square footings where B is the footing width. The compacted prism of soil sould extend at a 1:l slope from the edge of the footing. If you have ank/<uestions please contact us. We appreciate the opportunity to serve YCXI on this project and hope to serve you again. Respectfully submitted, SOUTHERN CALIFORNIA TESTING LAB.,INC. DN/dh cc: (6) Submitted c. H.wood, - .- .- .- ,~ - .- - - - .- /&c/d g/24/7J .- SOUTHEi2N CrALIFOE1NIA TESTINCI L’ABDF1PITDF)Y INcOFlt=aP.aTEO 8280 RIVEROALE BT. SAN O,E00, CAL,F. 82120 . TELE 283.8134 . P. 0. eox em33 S&N q IE00, CALIF. 82120 73.038 HIGHWAY 111 PALM OESERT, CALIF. 92260 . TELE 346-1078 August 19, 1970 Mr. Per Stiko, A.I.A. 851 Lorinq Street San Diego, California 92109 SCT 20097 SUBJECT: Soils Investigation for Proposed Apartment Site, Lots 53 and 54, Block A, Hayes Land Company Addition, Zip No. 2, City of Carlsbad, San Dieqo County, California. Gentlemen: In accordance with your request we have performed a soils investi- gation of the conditions at the subject site. We are transmitting herewith a report of this investigation. The analysis of our findings is intended to provide the required information to design the grading and foundation plans for the sub- ject project. In general we found the site to be underlain by varying amounts of loose fill and loose native sands and we recommend that conventional spread footings founded on recompacted native and fill soils be utilised for the support of the proposed structure. If you have any questions after reviewing our report, please do not hesitate to contact this office. . This opportunity to be of service is sincerely appreciated. TVL/bi. cc: (4) Submitted (2) SCTL, Escondido Respectfully submitted,.,~.-_ . SOUTHERN CALIFORNIA TESTING LAB., INC. PdJd C./H. Wood, R.C.E. 10778 y:, %?a ; ;, ; ,.,; 3 yy: - -- - - TABLE OF CONTEXTS - PAGE - .- INTRODUCTION SCOPE .- - FINDINGS AND RECOMMENDATIONS SITE AND SOIL CONDITIONS Foundations - - Bearing Capacity Expansive Characteristics Settlement - - SLAB ON GRADE CONSTRUCTION EARTH RETAINING STRUCTURES Allowable Passive Pressure - Active Soil Pressure EARTHWORK - FIELD EXPLORATION - ' LABORATORY TESTS APPENDIX - PLOT PLAN, TRENCH LOGS AND LABORATORY TEST RESULTS. - RECOMMENDED GRADING SPECIFICATIONS. UNIFIED SOIL CLASSIFICATION CHART. - 1 1 2 2 2 2 3 4 4 4 - - - - INSPECTION * TESTING l RESEARCH * DEVELOPMENT - 6280 Riverdale St. l San Diego,California 92120. Phone 283-6134 - - - - - - - - - .- - - - - - .- - REPORT OF SOILS INVESTIGATION PROPOSED APARTMENT BUILDING N.W. C-R OF OCEAN STREET AND GRAND AVENUE CARLSBAD. CALIFORNIA INTRODUCTION This report presents the results of our soils investigation for the proposed apartment site to be located as shown on Plate No. 1. A brief legal description of the site is Lots 53 and 54, Block A, Hayes Land Company Addition, City of Carl&ad, San Diego County, California. It is our understanding that a three story, five-level, wood frame apartment structure is planned for the site. It is further understood that maximum wall loads in the order of 3 kips per lineal foot'and column loads of up to 28 kips are anticipated. SCOPE The scope of our work consisted of: 1) a review of available soils information relative to the site; 2) subsurface explorations to examine and sample the various soil types encountered'and 3) labora- tory testing and engineering analysis to: a. Determine the physical characteristics of the prevailing soils. b. Determine the supporting capacities and settlement charac- teristics of the native soils. - - - - .- - .- .- - - SCT 20097 August 19, 1970 -- Page 2 c. Provide design information regarding site preparation and foundations. d. Determine potential construction difficulties and provide recommendations concerning these difficulties. FINDINGS AND RECOMMENDATIONS 1.10 SITE AhTD SOIL COXDITIONS: The site slopes to the west exhibiting a vertical relief of approxi- mately 30 feet. Two fill benches consisting of loose silty sands were existent along the north property line and an area of loose end-dumped fill was encountered on the east end of the site. Natural ground was found to consist of loose medium to fine sands and silty sands. Groundwater was encountered at a depth of 9 feet in Trench No. 3. - 1.20 FOUNDATIONS - GENER9L - Due to the presence of the loose fill and native soils described above, it is recommended that the soil within a perimeter five-feet-outside - -.___ -.,-ti of the proposed structure be removed and recompacted to a minimum - .- - of 90 percent relative compaction. Since the foundations will pro- bably be stepped down the slope, the necessary depth of recompaction will vary. In general, however, the depth should be a minimum of 2 B (where B = Footing Width) below the base~of the proposed footings. --._l__l ,_., - The existing fill and native soils will be suitable for recompacting pro- . . . . ._ vided that any rubble or deleterious material is removed prior to re- - compacting. - 1.21 BEARING CAPACITY - The allowable bearing pressure for the prevailing soils recompacted to 90 percent is expressed by the following formulas for continuous and - SCT 20097 August 19, 1970 - square footings: ~~..~. ,, - 1 _-_- Continuous Footings q = 0.77 D + 0.43 B Square Footings q = 0.77 D + L ___, .."-. ,-, 0.34 B ' & ‘ 2 (3 j ;,' Page 3 Where q = Allowable soil bearing pressure as limited by shear in kips per square foot for full live and dead loads. - - D = Footing depth below lowest adjacent grade in feet. B = Footing width in feet. The above allowable stresses may be increased l/3 for wind and/or - seismic loading and should be decreased l/4 for dead load only. - It is recommended that conventional spread footings be founded a minimum of 18 inches below adjacent finish grade and have a minimum - width of 12 inches for continuous footings and a minimum width of 24 - inches for square footings. The allowable bearing pressures in kips per square foot for full live and dead loads for minimum size foot- - ings are as follows: - Continuous Footings 1.58 Square Footings 1.83 - The allowable bearing pressures for other size footings may be com- the bearing pressures so com- - , puted from the above formulas. However, puted should be limited to 2.00 ksf. Adjacent footings founded at - different bearing levels should be so located that the slope from bear- .- - ing level to bearing level is flatter than one horizontal to one verti- cal. 1.22 EXE'ANSIVE CHARACTERISTICS _' .+_ .- - The expansive characteristics of the prevailing foundation soils will not require special consideration and/or design so that structural damage' is not likely to occur. - - ,- SCT 20097 August 19, 1970 Page 4 - 1.23 SETTLEMENT CHARACTERISTICS Excessive and/or differential settlement may be considered negli- .- gible provided that the recommendations of this report are followed. - .- 1.30 SLAB ON GRADE CONST2UCTIOX It is recommended that all slab-on-grade construction have a minimum thickness of four inches and be reinforced with 6 x 6 - lO/lO welded - wire mesh. - .- 1.40 BARTH RETAINING STRUCTURES 1.41 ALLOWABLE PASSIVE PRESSURE The allowable passive pressure for the prevailing soil condition may - be assumed to be equivalent to the pressure of a fluid weighing 136 pcf. This passive pressure has been computed using a factor of safety - of three and may be increased l/3 for wind'and/or seismic loading. - The coefficient of friction of concrete to soil may be assumed to be - 0.43 for resistance to horizontal movement. 4 .,_~ ,..- - .- ' 1.42 ACTIVE SOIL PRESSURE Active pressures for the design of cantilevered retaining structures --- that are free to move at the top may be assumed to be equivalent to - the pressure of a fluid weighing 35 pcf. If the retaining structure - is fixed at the top as in the case of basement walls, the active pres- - - .- sure should be increased to 60 pcf per foot of depth,..,.These active A~ pressures are for no surcharge and a level and 'drained backfill condi- tion. If these'conditions are not met, this office should be contacted for the necessary increase in the active pressures. - 1.50 EARTHWORK - Earthwork and grading contemplated for the site preparation should be - SCT 20097 'August 19, 1970 Page 5 - .- - accomplished in accordance with the attached Recommended Grading Specifications. Structural backfill should be compacted to a mini- mum relative compaction of 90 percent of maximum dry density as de- termined ay A.S.T.M. 1557-66T, Method A. FIELD EXPLORATION 2.10 GENERAL Three subsurface explorations were made at the locations indicated on attached Plate No. 1 on August 4. 1970. These explorations consisted ,- of trenches dug by means of a backhoe. The explorations ware conducted under the direct supervision of our engineering geologist. The explorations were carefully logged when made. These logs are pre- sented on the following Plate No. 2 through No. 4, inclusive. The soils are described in accordance with the Unified Soils Classification - System as illustrated on the attached simplified chart. In addition, a verbal textural description, the wet color, the apparent moisture, and the density or consistency are given on the logs. Soil densities for - s granular soils are given as either very loose, loose, medium dense, dense, or very dense. The consistency of silts or clays are given as - either very soft, soft, medium stiff, stiff, very stiff, or hard. Dis- turbed samples of typical and representative soils were obtained and re- turned to the laboratory for testing. LABORATORY TESTS _ . :_ ._ - 3.10 GENERAL .- Laboratory tests were performed in accordance with generally accepted American Society for Testing and Materials ( A.S.T.M.) test methods - or suggested procedures. Representative samples were tested for their - - - - - - - - - - - - - -- SCT 20097 August 19, 1970 Page 6 natural moisture content. The results of these tests are presented on the trench logs. In addition, the gradation, maximum densities, angles of internal friction and cohesion were determined for typical and representative samples. The results of these tests are presented in tabular form on Plate Nos. 5 and 6. - - - - - - - - - - - - - - - - - - - - . APPENDIX _’ .I_ . . - - - .- - - - - - _- - - - - - - - - - - - XEAN ST. WOOD RETAINING WALL G;@T%+5.m ‘:. , - I m TRENCH LOCATIONS ._’ .%_ ._ . SOUTHERN CALIFORNIA TESTING IABORATORY, INC. Proposed Apartment Site 6280 RIVERDALE STREET N.W. Corner of Ocean Street and SAN DIEGO. CALIFORNIA 92120 7142836134 Grand Avenue Carlsbad, California By K.N. DATE a-18-70 PLOT PLAN JOB NO. 20097 Plate No. 1 - .- Trencn No. 1 Description @.&tc,"',fyf, Dry, Very Loose, (Fill) ... . * SW Light Orange-Tan, Humid, Loose, . . . . . '. Medium to Fine SAND & 4 . . . . .'. (Natural Ground) ,.. . . . . *... 4J 8 :: .': :. i! . . . . . & :. '. *. .;. E; q .". : . . . :. . . . 8 . . . . . 2 ,O Y I:. co a a 5 8 ca .>a ._ . SOUTHERN CALIFORNIA TESTING LABORATORY, INC. Proposed Apartment Site 6280 RIVERDALE STREET N.W. Corner of Ocean St. and SAN DIEGO. CALIFORNIA 92120 Grand Avenue 714-283-6134 By TVL DATE 8-18-70 trench log JO8 NO. 20097 Plate No. 2 - Trench No. 2 CL Description 0 . . '... SM Brown Dry, Medium Dense . . . SILTY SAND I- .:I:. . (Fill) . : 2'. I ,.. . . . SW Gray-Brown, Dry, Very Loose, Sand .*. . ..' (Fill) ~ Light Orange - Tan Humid, Loose Medium to Fine Sand E! . : . -s (Natural Ground) ... . . . . . ; 5-f: ,:.;; .,.: ., 2 d- 1 ':; :':.'.: 7-.“. 2 ‘Z. rn i5 2 a 5 k? !a _’ .c* ._ SOUTHERN CALIFORNIA TESTING LABORATORY, INC. Proposed Apartment Site N.W. Corner of Ocean St. and 6280 RIVERDALE STREET SAN DIEGO. CALIFORNIA 92120 Grand Avenue 714.263-6134 Carlsbad, California BY TVL DATE a-18-70 trench log JOB NO. 20097 Plate No. 3 -. - O-S- /- Z- .?- f-' 5- 6- 7 . . ‘. . . . . . . . : . . . . . . . . . . . * ‘. . . . . . . . . : . : . . . * . * . . . . . . . 6. .c 6%: +A” ., 0’ 0:o; 0 . : SW- ;W e r Trench No. 3 E Y M S Light Brown, Dry, Very Loose, SLIGHTLY SILTY MEDIUM SAND (natural ground-beach sands) Orange Brown, Humid, Loose GRAVELLY SAND il.0 i7.4 Legend: 1 = Sample Location M = Natural Moisture Content += Water Table SOUTHERN CALIFORNIA TESTING IABORATORY, INC. Proposed Apartment Site N.W. Corner of Ocean St. and 6260 RIVERDALE STREET SAN DIEGO. CALIFORNIA 92120 714-2636134 Grand Avenue Carlsbas, California . J BY TVL DATE 8-18-70 trench log JOB NO.20097 Plate No. 4 DIRECT SHEAR --EST RESULTS MAXIMUM DFNSITY 8. OPTIMUM MQISTURE CONTENT m--2 DESCRIPTION ._ .I_ ._ SOUTHERN CALIFORNIA TESTING LABORATORY, INC. Proposed Apartment Site N.W. Corner of Ocean Street and 6280 RIVERDALE STREET SAN DIEGO. CALIFORNIA 92120 Grand Avenue 714-263-6134 Carlsbad, CaLifornia BY TVL DATE 8-18-80 sumniiry of test results JOB NO. 20097 Plate No. 5 GRAIN SIZE -\NALY_S IS + ATTEKLURG LIMITS ( U.S. Std Sieves) T 3 @. SAMPLE 3.5-4' Liquid Limit Plastic Limit Plasticity Index CLASSlFlCATlON SP-SM I _’ . ., . . SOUTHERN CALIFORNIA TESTING LABORATORY, INC. Proposed Apartment Site 6280 RIVERDALE STREET N.W. Corner Ocean Street and SAN DIEGO. CALIFORNIA 92120 Grand Avenue 714-283-6134 Carlsbad, California I I BY TVL DATE 8-18-70 * JO8 NO. 20097 I Plate No. 6 - .- - - - - .- - - - - - - - - - - - - - - RECOMMENDED GRADING SPECIFICATIONS GENERAL PROVISIONS GENERAL INTENT: The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled and placing and compacting fill soil to the lines and grades shown on the accepted plans. The recommendations ~contained in the preliminary soils investigation report and/or the attached special provisions, are a part of the recommended grading specifications and shall supercede the pro- visions contained hereinafter, in the case of conflict. INSPECTION AND TESTING: A qualified soil engineer shall be employed to inspect and test the earthwork in accordance with these specifications. It will be necessary that the soil engineer or his representative provide adequate inspection so that he may certify that the work was or was not accomplished as specified. If, in the opinion of the soil engineer, substandard conditions are en- countered, such as questionable soil, poor moisture control, inadequate compaction, adverse weather, etc., he will,be empowered to either stop construction until the conditions are remedied or corrected or recommend rejection of the work. Soil tests used to determine the degree of compaction.wil.1 be performed in accordance with the following American Society for Testing and Materials test methods: Maximum Density and Optimum Moisture Content. A.S.T.M. D 1557-66T Density of Soil In-Place. A.S.T.M. D 1556-64. - - - .- - .- - - - - .,- - - - - - - - _- - RECOMMENDED GRADING SPECIFICATIONS GENERAL PROVISIONS Page (2) PREPARATION OF AREAS TO RECEIVE FILL: All vegetation, brush and debris shall be removed, piled and burned or otherwise disposed of. After clearing, the natural ground shall be scarified to a depth of 6 inches, brought to the proper moisture content, compacted and tested for the minimum density specified in the special provisions or the recommendations contained in the preliminary soils investigation report. When the slope of the natural ground receiving 'fill exceeds 20% (5 Hori- zontal to 1 Vertical), the original ground shall be stepped or benched. Benches shall be cut to a firm consistent soil condition. The lower bench shall be at least 10 feet wide and all other benches at least 6 feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as specified hereinbefore for compacting natural ground. Ground slopes flatter than 20% shall be benched when considered 'necessary by the soil engineer. 'FILL MATERIAL: Materials placed in the fill shall be approved by the soil engineer and shall be free of vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks, expansive and/or detrimental soils are covered in the special provisions: Expansive soils, soils of poor gradation or strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the soil engineer. - - - RECOMMENDED GRADING SPECIFICATIONS GENERAL PROVISIONS Page (3) - PLACING AND COMPACTION OF FILL: Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in compacted thickness. Each - -- - layer shall have a uniform moisture content in the range that will allow the conpactive effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly compacted to the minimum specified density with adequately sized equipment, either - specifically designed for soil compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either the - special provisions or the recommendations contained in the preliminary soils investigation report. - Field density tests to check the degree of compaction of the fill will be taken by the soil engineer or his representative. The location and - frequency of the tests shall be at the soil engineer's discretion. In - general, the density tests will be made at an interval not exceeding 2 feet in vertical rise and/or 500 cubic yards of fill placed. - SEASON LIMITS: - Fill shall not be placed during unfavorable weather conditions. When - work is interrupted by heavy rain, filling operations shall not be resumed until the proper moisture content anddensityjof the fill has been achieved. Damage xesulting from weather shall,be repa.ired before accep- - tance of the work. - UNFORESEEN CONDITIONS: In the event that conditions are encountered during the site preparation and construction that were not encountered during the preliminary soils - RECOMMENDED GRADING SPECIFICATIONS Page (4) - GENERAL PROVISIONS investigation, Southern California Testing Laboratory, Inc. shall be notified immediately. Southern California Testing Laboratory, Inc. assumes no responsibility for conditions encountered which differ horn the conditions encountered and described in the preliminary soils in- vestigation report. - - - -, -’ .I. ._ - - _- - - - - - .- - - - - - - - ~- UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION GROUP SYMBOL TYPICAL NAMFL ~1. COARSE C-RAINED, 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 (Appreciable of fines) SANDS CLEAN SANDS More than half of coarse fraction is smaller than No. 4 Gw GP FINES GM amount GC SW SP sieve size. SANDS WITH FINES SM (Appreciable amount 'of fines) . SC 11.' 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 ML CL OL hm CH OH PT : Well graded gravels, gravel- sand mixtures, little or no fines. Poorly graded gravels, grave 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,gravelly sands, little or no Fines. Poorly graded sands,gravelly 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 flcur, sandy silt or clayey-silt-sand mixtures with slight plast- icity Inorganic clays of lcw to medium plasticity,gravelly clays, sandy clays,silty clays, lean clays. Organic silts and organic silty clays of lcw plasticity Inorganic silts, micaceous or diatonaceous fine 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. \ SOUTHERN CALIFORNIA TESTING LABORATORY