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Home My WebLink AboutCDP 01-41; Garfield Street Homes; Preliminary Soils Investigation; 2001-07-17PREUMINARY SOILS INVESTIGATION Uloolsey Soil Classification Garfield St. (A.P.N. 204-240-19) Joh§ 015-855 July 17, 2001 GEORGE SOILS TESTING 3208 CAROLYN CIRCLE, OCEANSIDE, CALIFORNIA 92054 J SOILS TESTING 3208 Carolyn Circle • Oceanside • Califomia 92054 (760) 435-9534 Job#01S-855 July 16, 2001 Richard and Richard Construction Attn: Mr. Richard Woolsey 4751 Oceanside Bl., Oceanside, Ca. 92054 Dear Mr. Woolsey: In accordance with your authorization, on 7/5/01 an agent of our firm performed a limited soils investigation of the subject property. We are pleased to submit herewith the report of that mvestigation. This report presents our findings Srom the investigation and our conclusions and recommendations, based upon those findings. Location: Vacant lot on East side of Garfield St. two lots North of Juniper Ave. in Carlsbad, Ca. 92008 (A.P.N. 204-240-19) Investigation: The investigation was conducted to classify soils at the base of the proposed foundations. Bulk samples were removed fi'om the site and analyzed for Grain Size Distribution and Expansion Index. Conclusions and Recommendations: Soils of Type SC were found at foundation level by sieve analysis with a safe bearing capacity of 1500 PSF per UBC Table 18A and an Expansion Index of 21.9 (Low Potential Expansion). Our foundation and slab recommendations for the proposed construction are contained herein. It is our opinion the site is suitable for the proposed construction. Geotechnical Engineering Due to the high density of formational sandstone on site and the relatively deep groundwater in tiie area, it is our opinion this site has a very low potential for seismically induced soil liquefaction. Witii regards to tiie near-source factor in Seismic Zone 4, tiie Rose Canyon fault, approximately 7 kilometers Soutiiwest of tiie site, appears to present tiie greatest seisniic risk to tiie subject site. The following table contains site specific seismic desiga criteria for tiie calculation of seismic base shear. The design criteria was obtained fi-om die Uniform Building Code (1997 edition). A coefficient of fiiction of 4.0 times the dead load may be used between the bearing soils and concrete foundations, walls, or floor slabs. Parameter Value Reference Seismic Zone Factor. Z 0 40 Table 16-1 SoUProglgTypg SQ Table 16-J Seismic Coefficient Ca 0.40Na Table 16-0 Seismic Coefficient. Cv 0.56Nv Table 16-R Near-Source Factor. Na TO Table 16-S Near-Source Factor. Nv 1J2 Table 16-T Seigmic Spurce Typg B Table 16-U This report is for the samples tested only and tiiere are no guarantees eitiier stated or implied relative to the stability ofthe site. Should you have any questions regarding tiiis matter please feel fi-ee to contact our office. Sincerely, George i^^Kropotofl^ RCE233 Project Engineer GK:kw End. cc: (1) Client; (1) FUe, (5) James Chinn, Architect P.S. Site conditions may vary with time, hence this report is valid for one year only. Geotechnical Engineering FOUNDATION AND SLAB RECOMMENDATIONS FOR EXPANSIVE SOILS 1 Story Footings 2 Story Footings 3-t- Story Footings Garage Door Grade Beam Occupied Area Floor Slabs Unoccupied Area Floor Slabs Pre-soaking of Sub-Slab Soils Expansion Index - 21-50 - Low Expansion All footings 12 inches deep. 12" wide minimum. Width per bearing capacity calcuktions. Footings continuous. 1 no. 5 bar top and bottom All footings 18" deep. 15" wide mioimum. Width por bearing capacity cakulations. Footings continuous, 1 no. 5 bar top and bottom. All footings 24" deep. 18" wide minimum. Width per bearing capacity calcuktbns. Footings continuous. 1 no. 5 bar top and bottooL 12 inches deep. 1 no. 5 bar top and bottont 4 inches thick. 6x6-6/6 wire mesh at nud-height. 2 mches gravel or sand base. 6 mil. visqueen moisture barrier phis 1 inch sand 4 inches thick. 6x6-6/6 wire mesh or quarter slabs. Isolate fi-om stem wall footings. 2 inches rock, gravel or sand base. No moisture barrier required. Soak to 12 inches depth to 4% above optimum moisture content. NOTES: 1) AH depths are relative to slab subgrade. 2) All footings shouM be continuous. Slab subgrade Depth of exterior ftg I—III—I Depth of exterior ftg m *o m M Concrete slab with Welded wire fabric Sand layer Visqueen Gravel or sand base if required MIllllllllllHlilllilllllliHHflHiiliHIllllHM Depth of presoaked soil Depth of interior ftg Footing and stem wall reinforcing per structural design r Floor diaphragm Joists Clearance Depth of presoaked soil Depth of interior ftg Footing and stem wall reinforcing per structural design /M_TERNATIVE Foundation embedment and slab on grade SOILS TESTING 3208 Carolyn Circle - Oceanside, Ca. 92054 - (760) 435-9534 Job No.(i?ls-855 Date ^/(Cg/oT O I LJ- m o tn 1 IS Q LU CD , . ir ZJ OL ^1 o DC Z o § O O TEST PIT No. T.P.-1 DESCRIPTION SC 21.S Slightly Damp, Med. Beige, Slightly Silty Rne to Med. Sand with Organics (Topsoil) 10- Slightly Damp. Pale Reddish Med. Brown, Fine to Med. Sand -End of Excavation-No Changes GROUND ELEVATION: Exist. Grade METHOD OF EXCAVATION: Hond-Excovated UJ Q O § O to Qu X UJ a 2 Q- ZD Zl Q_ =3 CD O O « UJ LU O Q Q- >- a: zz. o i o o TEST PIT No. T.P.-2 DESCRIPTION SC Slightly Damp, Med, Beige, Slightly Silty Rne to Med. Sand with Organics (Topsoil) 5- O L 10 Slightly Damp, Pale Reddish Med. Brown, Fine to Med, Sand -End of Excovatlon-No Changes DATE OBSERVED: 7/5/01 LOGGED BY: KBW LOCATION: (A P N 204-940 10^ TEST PIT LOG SOILS TESTING 3208 Carolyn Circle - Oceanside, Ca. 92054 - (760) 435 9534 SOILS TESTING 3208 Carolyn Circle - Oceanside, Ca. 92054 - (760) 435 9534 Job No.OIS-855 SOILS TESTING 3208 Carolyn Circle - Oceanside, Ca. 92054 - (760) 435 9534 Date 7/15/01 8 5 to z < to UJ Is. cn ^ S- l/l ^5- tn a ro- CM CM 8 8 S HI y' t / J / o 8 o O oo o o to o in ZS0ILS12 o PERCENT PASSING o o CM i z O S in % o z o CD 0 0:1 GRAIN SIZE DISTRIBUTION SOILS TESTING 3208 Carolyn Circle - Oceanside. Co. 92054 - (760) 435-9534 SOILS TESTING 3208 Carolyn Circle - Oceanside. Co. 92054 - (760) 435-9534 Job No.t?|S-855 SOILS TESTING 3208 Carolyn Circle - Oceanside. Co. 92054 - (760) 435-9534 Date ^llipl<>l jn "5 CO M / PLOT PLAN SOILS TESTING 3208 Carolyn Circle - Oceanside. Ca. 92054 - (760) 435-9534 Job No.oi5-QS5 Date l^lllojol J ABOUT YOUR ^ GEOTECHNICAL ENGINEERING REPORT More construction problems are caused by site subsur- face conditions than any other factor As troublesome as subsurface problems can be. their frequency and e.xtent have been lessened considerably in recent years, due in large measure to programs and publications of ASFE/ The Association of Engineering Firms Practicing in the Geosciences. The following suggestions and observations are offered to help you reduce the geotechnical-related delays, cost-overruns and other costly headaches that can occur during a construction proiect. A GEOTECHNICAL ENGINEERING REPORT IS BASED ON A UNIQUE SET OF PR0IECT-5PECIFIC FACTORS A geotechnical engineering report is based on a subsur- face exploration plan designed to incorporate a unique set of proiect-specific factors. These typically include-, the general nature of the structure involved, its size and configuration: the location of the structure on the site and its orientation-, physical concomitants such as access roads, parking lots, and underground utilities, and the level of additionai risk which the client assumed by virtue of limitations imposed upon the exploratory program. To help avoid costly problems, consult rhe geotechnical engineer to determine how any factors which change subsequent to the date of the report mav affect its recommendations. Unless your consulting geotechnical engineer mdicates otherwise, your geotechnical euginecrifig report sluniUi mn be used: . When the nature of the proposed structure is changed, for example, if an office building will be erected instead of a parking garage, or if o refriger- ated warehouse will be built instead of an unre- frigerated one: • when the size or configuration of the prcposed structure is altered: • when the location or orientation of the proposed structure is modified: • when there is a change of ownership, or • for application to an adjacent site. Ceofecfinical engmeers cannot accept responsibilitu lor problems which mau deve'lov if they are mt consulted alter factors consid- ered in their report's development have changed. MOST GEOTECHNICAL "FINDINGS" ARE PROFESSIONAL ESTIMATES Site exploration identifies actual subsurface conditions only at those points where samples are taken when they are taken Data derived through sampling and sub- sequent laboratory testing are extrapolated by geo- technical engineers who then render an opinion about overall subsurface conditions, their likely reaction to • proposed construction activity and appropriate founda- tion design. Even under optimal circumstances actual conditions may differ from those inferred to exist, because no geotechnical engineer, no matter how qualified, and no subsurface exploration program, no matter how comprehensive, can reveal what is hidden by earth, rock and time. The actual interface between mate- rials may be far more gradual or abrupt than a report indicates. Actual conditions in areas not sampled may differ from predictions. Nothing can be done to prevent the unanticipated, but steps can be taken to help minimize their impact. For this reason, most experienced owners retain their geotechnical coiisultfltils through the construction stage, to iden- tify variances, conduct additional tests which may be needed, and to recommend solutions to problems encountered on site. SUBSURFACE CONDITIONS CAN CHANGE Subsurface conditions may be modified by constantly- changing natural forces. Because a geotechnical engi- neering report is based on conditions which existed at the time of subsurface exploration, construction decisions should not be based on a geotechmcal engineering report whose adequacu mau have been afjected bu time. Speak with the geo- technical consultant to learn if additional tests are advisable before construction starts. Construction operations at or adiacent to the site and natural events such as floods, earthquakes or ground- water lluctuations may also affect subsurface conditions and. thus, the continuing adequacy of a geotechnical report. The geotechnical engineer should be kept apprised of any such events, and should be consulted to determine if additional tests are necessary GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND PERSONS Geotechnical engineers reports are prepared to meet the specific needs of specific individuals. A report pre- pared for a consulting dvil engineer may not be ade- quate for a construction contractor or even some other consulting civil engineer Unless indicated otherwise, this report was prepared expressly for the client involved and expressly for purposes indicated by the client. Use by anv other persons for any purpose, or by the dient for a different purpose, may result in problenis. No indi- vidual other than the client should apply tfiis report for its intended purpose without f\rst conjernng with the geotechnical engineer No person should applu this report for any purpose other than that originally contemplated without first conferring with the geotechmcal engineer A GEOTECHNICAL 0IGINEERING REPORT IS SUBIECT TO MISINTERPRETATION Costly problems can occur when other design profes- sional? develop their plnns based on misintcrpr'^tnrions of .T geotechnical engineering report Tb help nvnid Mipr:e problems, the geotechnical er-igineer itmiild b" retained to work with other appropriate d^nipn prole-, "ionnis to e.xpiain relevant geotechnical fiiKlinrr •HKI IO rpvi^w the ndequacv of their plans and sperilifniirMi'-; relative to geotechnical issues BORING LOGS SHOULD NOT BE SEPARATED FROM THE ENGINEERING REPORT Hnal boring logs are developed by geotechnical engi- neers based upon their interpretation of field loen lassembled by site personnel) and laboratorv evaluation of field samples. Only final boring lops customarily are induded in geotechnical engineering reports Tfif.<:r logs 'hould not under any circumstances be redrawn fpr inclusion in 'irchitectural or other design drawings, becnus" rlralt^rs rnay commit errors or omissions in the transfer process .•Mtfiough photographic reproduction eliminates this problem, it does nothing to minimize the possibility of contractors misinterpreting the logs during bid prepara- fion When this occurs, delays, disputes and unantici- pated costs are the all-too-frequent result To minimize the likelihood of boring log misiriterprrt.-i- tion. give contractors ready access to the complete gcrlahntcal enaineering report prepared or authorized for their use Those who do not provide such access may proceed un- der the tyu^en impression that simply disdaiming re- sponsibil^ifor the accuracy of subsurface information al-A/ays insulates them from attendant liability Providing the best available information to contractors helps pre- vent costly construction problems and the adversarial attitudes which aggravate them to disproportionate scale READ RESPONSIBILITY CLAUSES CLOSELY B^caur;e RTitechnicnl engineering is based extensively on judgment and f-)piriion. it is Iar less exact than other design disciplines. This situation has resulted in wholly unwarranted daims being lodged against geotechnical consultants lb help prevent this problem, geotechnical engineers have developed model clauses for use in writ- ten transmittals. These are nol exculpatory clauses ' designed to foist geotechnical engineers' liabilities onto someone else Rather they are definitive dauses which identify where geotechnical engineers responsibilities begin and end. Their use helps all parties involved rec- ognize their individual responsibilities and take appro- priate action Some of these definitive dauses are likely to appear in your geotechnical engineering report, and you are encouraged lo read them dosely Your geo- technical engineer will be pleased to give full and frank answers to your questions OTHER STEPS YOU CAN TAKE TO REDUCE RISK Your consulting geotechnical engineer will be pleased to discuss otfier techniques whicfi cnn be employed to mit- igate risk. In addition. ASFE has developed a variety of materials which may be beneficial. Contact ASFE for a complimentary copy of its publications directory rtiHr.lini hu mE ASSOCIATION OF EMGIHEERING FIRMS PRACnCING IN THE GEOSCIENCES 8811 Col°9yille Road/Suit'-' •.K)^ '^,ilv-r Spiiiip,. Mntyland .VVin/l WW -A--27•^^l