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Home My WebLink About; Amato Residence Lot 17 La Costa; Soils Report; 1983-08-03- - . . . SAN MARCOS ENGINEERING Civil Engineers 380 Mulberry Dr. Suite B SAN MARCOS. CALIFORNIA 92069 (619)744-0111 August 3, 1983 - - ,- - - - - -- Mr. Steve Lane P.O. Box 2283 Vista, Ca. 92083 SUBJECT: Preliminary Soils Report and Investigation Proposed Residence-Amato, Lot 17, La Costa Dear MT:. Dane, Enclosed is our report of the preliminary soils investigation performed on the above subject property as per your request. It was undertaken to provide preliminary information for the proposed foundation system. The generalized soils profile at the site can be described as light brown to tan, dry, compact to very compact, fine Silty Clay with fractured rock in the upper stratum overlying some shale and limestone rock which are rippable upto the depths that we have drilled (6 to 9 feet below ground surface). In our opinion, the existing site soils can safely support the proposed house with soil bearing footings with the reconnnendations indicated in the enclosed report to be followed. It is possible that rock blasting may be necessary to attain the desired finish grade shown in the grading plan. If you have any question, please call. Very truly yours, so D. Neis, P.E. ENGINEERING DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive Carlsbad CA92009-4859 - SA?$ MARCOS ENGINEERING CWlL LltOlN‘III. em” a CO”ltD.TIO?d - PRELIMINARY SOILS INVESTIGATION REPORT FOR PROPOSED RESIDENCE AMA'JX-Lot 17, La Costa Estates, Argonauta Street - Descrintion The site is located in Argonauta Street, La Costa Estates in Carl&ad, California, specifically Lot 17 as shown in the La Costa Estates Map. - - - - The site is on a mildly sloping terrain. Calculated slope is about 14%. Loose fractured rocks are found in the area of the project. Also some miscellaneous fill exist at site. The proposed structure to be constructed is a single family a-story house frame and masonry. Scone of Work Our scope of work consist of the following: a. Preliminary soils investigation to include drilling for soils sample and the procurement of samples. - b. Perform the required tests if necessary. c. Prepare foundation report and recommendations. Subsurface Exploration A continous-flight auger drilling rig mounted on a 2-ton truck was used in the subsurface exploration. Four holes were drilled at the site , the location of the holes are shown in Plate 1 of this report. The depths vary accordingly as to the depth of rock encountered. Findincs Plates 2 to 5, inclusive show the boring logs of the soils encoun- tered at site. Boring B-l indicate light brown to tan, dry, com- pact to very compact Silty Clay, some fractured rocks. The depth of rock encountered which appears to be impenetrable is about 8.5’ below the surface. Borings B-2, B-3 & B-4 appear to show the same - -4 -. - - .- - - - - - - - SAP?,.MARCOS ENGINEERING stratification as boring B-l. The depth of bedrock appears though to be of different depths. Throughout the 4 borings, fractured rocks were encountered. No free water was found in the borings. The existing soils appear to be expansive slightly. Some miscellaneous fill dumping exist at the site. Based on our observations of the subsurface explorations soils and the soils in the area, it is our opinion that the existing soils can safely support the proposed structure with soil bearing footings. The following recommendations need to be observed, however, during the design and construction. 1. The allowable soil bearing pressure of 1500 psf can be used in the determination of the footing widths. It is recommended though that perimeter footings should not be less than 12 inches in width. Isolated footings should have a minimum dimension of 24 inches both ways. The bottom of footings should be at least 24 inches below finish grade. 2. Perimeter wall footings should be continuously reinforced with 2-#4 bars placed 3 inches above bottom of footing and 2-#4 bars placed 2 inches below floor level. Isolated footings should be reinforced with 3-#4 bars placed each way. 3. All concrete slabs should be at least 4 inches thick and reinforced with welded wire mesh. There should be at least 4 inches of sand and vapor barrier below the slab. 4. Prior to pouring of concrete, all subgrade soils should be wetted to at least 1% above the optimum moisture content. 5. The existing soils at site can be used as fill material to build up the pad. The fill should be placed in 6 to 8 inches lifts and compacted to at least 96% relative density. The maximum dry density of the existing soils have been determined to be 120 pcf at 12.5% optimum moisture content. 6. Prior to buildup of fill , the existing ground surface have to be scarified, unsuitable and deleterious materials removed. the existing soils need to be wetted prior to receiving fill. A' 7. The existing miscellaneous fill have to be removed and - -’ ; -. - SA&.MARCOS ENGINEERING CWIC Lr4elNlm”,. 301” a COUC(DIT1OII - carted away from site. 8. It is recommended that the depth of cut should not be more 'than 5 to 6 feet below existing ground surface to avoid the need of rock blasting. This is based on our encountering the bedrock surface as indicated in the boring logs. - If you have any Prepared by: question about this report, please call. - - - -a/ , l/J/.,‘0 2. I - ;A _,I~, - .-I - --~__ ‘Ok? i 5 /c’* -5. ..I ’ i - --- i . _ ------- --- I :/’ -- -~ - ii i i i , . i - - - - - - 4 ‘1 r.~: -,. \ -;\ + 2: ;;: -L ,J- -: I _- - -I ~_ - ~/ ,.’ .-‘-~ _,~ -- - ii=- .’ I-_ c % / I ‘. .;. .’ 5.. ? i. 0 (~ . \ ? \; y ‘\ ‘;: -- I I; p T_ 8 ?’ 1’ , ,, . f. ,’ 1. _ .‘ \ . --. 7 ., I ** , ; ‘. ,. -- .<..> <'MISC. 'FILL THIS ARBA \ l-11 .-=-. - __._ ~--_---_--~~___~___---._--_.- - _.__.- __--.-~_-_- ..--- __--- - -- -. r.. +.kL SL, / I PLATE 1. LOCATION OF BORINGS - . '? dLi (Grading Plan Supplied i- Tx'i L- 7- - - - - - - - - ,-~ - - - - - - - - : SAN MARCOS ENGINEERING PLATE 2 ClWL ENOINELRS. SOIL* (L l=OUNo*TION se0 M”LmElnv DRIVE. SYIII . Boring N0.d.L SAN HARCOS. CA 910ss ,610, 744.0111 Sheet No./ofI CONTRACT NO. Amdt Peadcece - BORINGS FOR ~ Grk PURPOSE Material & Remarks -- I I I I I i - SAN MARCOS ENGINEERING PLATE 3 ClYlL LNOIHLI”.. emu L COUI(D*TIO” se0 MUL.L”I* DIN=. Wrm . SAN MAIcOa. GA **a.. tete, ,4..0111 i - Material d Remarks -L - -- - SAN MARCOS ENGINEERING PLATE 4 ClWL &+a,*c*m8. em” L Fe”?4DI7Ie* 3eo ~~UL~IRV 0~~. sms s aAr4 YAm.zO.. CA .ZQ.. <e,e, 7.&O,,, Boring No.& Sheet No./Of/ - - - - - - - - - - - -. CcNTF!ACT NQ. ~ PuRPaaE Blow3 Blow8 On EIW. & CaZng %f%ZiE B Y&A-- ING FOR - -... --- Material a Remsrkr I I I I I I I I I I I I I I I I - - - - - .~ - - - - - - - - - - - - : SAN MARCOS ENGINEERING PLATE 5 CNlL ICNOINIL”.. *em” l ~*“r4~~Io~ 3eo MUL.I”III DIIIY‘. sum=. B~lng No.&% UII “IIICO.. CA .a-. <e,e, ,44.0111 Sheet No.- of- , .-.. r -” .-ycA*ce - clc L&Q. CONTRACT No. PyRFasE Blwe Blows On Elev. 0 ca$ng %%?I: No-1 Sample Depth LO9 Material 6 Remarka I ! c r’ - t .