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Home My WebLink About1.7-5516 PH 223-40000059 01/25/24 23-40000059 01/25/24 23-40000059 01/25/24 VARIES 1040- ------------------------- ------� 1040 >-,__ ____ _ c:,:z EX. 10JO 1030 �PAD \,t.� ✓'j;✓ 1020 f-------+-----+-----+------+------+----f-------+--------,1020 .,, $"" .,... ....-I .it,i>EX..,,,."1:.'PAD 1010 1010 "16' 15•lt EXISTING GROUND l ....-< .... --- ----� ✓ Qi, .....�-'=- 1000 f-------+-----+-----+------+----,f-----"1---+-----+------+---------j 1000ALL LAND CONTAINED 1'11THIN EACH LOT SHALL BE MAINTAINED BY THE HOMEOl'INER EXCEPT FOR DRAINAGE WAYS MAINTAINED BY THE H.O.A . 990 ii I I 2 ' BENCH VARI ES 990 SECTION "A" TYPICAL GRADING AT BOUNDARY �� i F 980 ..,, C c• -k,-- -"'-j----c 0::--+-----+-- ------ju.J�-t------J 980i--�c, ---------,-------.,r :. >-,- V ---t:-<SL•"OPE-SrTBA K ::i1 NO SCALI 970 �SEE NOTE 35 1 >- 1 970i�--, f;,-/.,,--�..!� PA IL__--),1 ... �l..,----_IX.J'AD ___ g--l 2960 1 ---+.d---ltJ--c,'----+-----+---,'---+=--------==-----'<----1-----w",------------1 960 ",r y 2% MIN,-/i'--2% MIN.' I 1VARIES 950 /2:1 MAX.2:1 MAX. \L___ -✓950 940 �-1 L ATCH EXISTING GROUND LEXISTIN; GROUND 940 930 930 SECTION "B"NO SCALI � f-------+-----+-----+------+------+----f-------+--------,920 BLOG. PAD ANISH PAD 21 MIN2:1 MAX. lR/W VARIES 16' TYPE •c• ROLL CURB .A. It SlREET 16, l'l'PE •r::ROil. CURB .1L SECTION "F" NO SCALE wl�, Fls1 I I ItR/W VARIES MATCH EXISTING GROUND \_ 2:1 TO I ----------- DAY UGHTL EX. PAD -- / <: 2.1 TO 2' BENCHEX. PAD .,,, ---� DAYLJGHTSECTION "D"SCALE: 1 ' = 50' LEGEtl> MATERIAL LAY-DO\\lol AND STOCKPILE AREA le EQUIPMENT PARKINGI\HH PROTECTIVE OIL PANS UNDER EQUIPMENT. (SEE DETAIL C le \\M-3) -GRATE INLET (SEE DETAIL D & SE-1O) CONSlRUCT CONCRETE WASHOUT (PER DETAIL E & v.M-8) ------ SITE BOUNDARY - - - - PHASE BOUNDARY - " ___ ,. - ABER ROLLS (SE-5) - --- - -ll--- PROPOSED STORM DRAIN LINE ----------35� ANISHED GROUND CONTOUR ----------354---------- EXISTING GROUND CONTOUR CONSTRUCTION NOTES: 0 MATERIAL LAY-DO\\lol AND STOCKPILE AREA. (WM-1, WM-3) 0 EOOIPMENT PARKING 111TH PROTECTIVE OIL PAINS UNDER EOOIPMENT. (NS-9, NS-1O) 0 INLIT PROTECTION 111TH GRAVEL BAGS. (SEE DETAIL D & SE-1O) 0 STOCKPILE [PLACE ABER ROLLS AT TOE Of SLOPE ALL THE WAY AROUND THE STDCKPILI) (SE v.M-3) 0 CONSlRUCT CONCRETE WASHOUT (PER VIM-8) *NOTE: MOVE STAGING AREA AND GRAVEL ENllRANCE AS NEEDED TO ACCOMODA llE CONSTRUCTION PHASING. ONLY ONE GRAVEL APRON IS REQUIRED AT A TIME DURING CONSTRUCTION. CONllRACTOR SHALL RESTRICT VEHICLE llRAFFIC TO USING DESIGNAllED ENTRANCE WITH GRAVEL APRON. Cl'.) � BLDG. PAO ANISH PAD 2X MIN: 1 MAit "' "' '° "' "'SECTION "C"SCALE: 1• = 50'HOR I ZONTALSCALE : 1• = 20' VERTICAL R(,!' Cl'.)� It S1REET 16' VARIES BLOG. PAD 2' BENCH I �=-.1 ...I �Q �i'f. I i!; is 2' BENCH TYPE "C"I � CURB�I I � ANISH PAD �2 X MIN 2:1 MAX. SECTION "G"NO SCALI '°..,_"' VARIES I 2' BENCH I EX.PAD2' BENCH VARIES 10',,,,------- 1:'.\,· //1'/ L / /[1' TOE-DOWN .,,,,,,,--t:: -.::=J _:/--'-�I------..-';,'-------"--x-I ,,-,_,,/ \. 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(!J ... z() C - ICC... < a: (!J .. :::, 0 a= z a= Ill I .. 23-40000059 01/25/24 UPDATE GEOTECHNICAL REPORT PROPOSED SINGLE•fAMIL Y RESIDENTIAL DEVELOPMENT RIO BRAVO COUNTRY CLUB AREA LOTS 1-22, PHASE 2 -TRACT NO, 5516 LEVANTO STREE T AND VIVALDI DRIVE CITY OF BAKERSFIELD, KERN COUNTY, CALIFORNIA PROJECT No. 3145-CR PREPARED FOR JCA ENTERPRISEIMBK CONSULTING 26040 ACERO, SUITE 110775 MISSION VIEJO, CALIFORNIA 92691 PREPARED BY GEOTEK, INC. I 548 NORTH MAPLE STREET CORONA, CALIFORNIA 92878 GEOTEK jUN E 3, 2022 JCA Enterprise/MBK Consulting Project No. 3145-CR Update Geotechnical Report, Lots 1 -22, Phase 2 -Tract No. 5516 June 3, 2022 City: of Bakersfield, Kern County:,�C~'~li~fo~'~"~'•�-------------------P�a.ge 5 More specific to the property, the site is located in an area geologically mapped to be underlain by engineered fill placed over older alluvium (USGS 1986). The referenced Leighton report indicated that the Kern River Formation (QTKr) underlies the site. 4.2 GENERAL SOIUGEOLOGIC CONDITIONS A brief description of the soils encountered on the site is presented in the following sections. Based on recent test trenches and previous site borings, the site is generally underlain by documented fill and alluvium. 4.2.1 Fill The test trenches encountered fill to depths ranging from about O (Lot 22) to 12 feet below grade in the test trenches. A!:. encountered in the test trenches, the fill consisted of silty sands, clayey sands and silty/clayey sands that possess a high relative density. Based on review of the referenced Leighton report (Leighton, 2007), it appears that the fill possesses a relative compaction of at least 90%. Based on the laboratory test results, the upper fill soils have a "very low" (0-20) to "low" (21-50) expansion potential (ASTM D 4829). Based on the laboratory test results, some of the upper fill soils have a soluble sulfate content of greater than 0.2 percent (ASTM D 4327). This classifies the soils as having a "S2" ("Severe") sulfate exposure. The test results are provided in Appendix B. 4.2.2 Alluvial Deposits Alluvial deposits were encountered at the surface in test trench T-9 an d beneath the existing fill in the remaining cesc trenches and extended to th e maximum depth explored of about 13 feet below grade. The encountered alluvial deposit.s generally consisted of interbedded layers of silty sands and clayey sands (SM and SC soil types based upon the Unified Soil Classification System). The alluvial deposits encountered were found to be dense to very dense. 4.3 SURFAC E AND GROUNDWATER 4.3.1 Surface Water Surface wate r was not observed during the site visit or during drilling. If encountered during earthwork construction, surface water on this site will most likely be the result of precipitation � GEOTEK ,,Q GeoTek, Inc. 1548 North Maple Street, Coron�, California 92B78 G EOT EK (9SI) 710-1160 Office (9SI) 710-1167 Fax www.geotekusacom JCA Enterprises/MBK Consulting 26040 Acern, Suite 1 10775 Missio n Viejo, California 92691 Attention: Subject: Mr. Mohammad Kashani Update Geotechnical Report Proposed Single-Family Residential Development Rio Bravo Country Club Area Lots 1 -22, Phase 2-Tract No. 5516 Levanto Street an d Vivaldi Avenue City of Bakersfield, Kern County, California Dear Mr. Kashani: June 3, 2022 Project No. 3145-CR Geo T ek, Inc. (Geo T ek) is pleased to provide the results of this Update Geotechnical Report for the subject site located in the Ri o Bravo Country Club area of the City of Bakersfield, Kern County, California. This report presents a discussion of GeoTek's evaluation and provides preliminary geotechnical recommendations for site preparation, infrastructure construction and foundation design. Based on the results of this evaluation, development of the property appears feasibl e from a geotechnical viewpoint provided that the recommendations presented in chis report and in future reports are incorporated into design and construction. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS JCA Enterprise/MBK Consulting Project No. 3145-CR Update Geotechnical Report, Lots 1-22. Phase 2 -Tract No. 5516 June 3, 2022 Cit;1: of Bakersfield, Kem County:, C_a-li~fo~'-"~'•�-------------------�Pag� or possibly some minor surface run-off from immediately surrounding properties. Provisions for surface drainage will need to be accounted for by the project civil engineer. 4.3.2 Groundwater Groundwater was not encountered in any of the test trenches at the time of excavation (maximum depth explored of 13 feet. Based on a review of groundwater depths noted on the Stat e Department of Water Resources Water Data Library website, it is estimated a historic high groundwater depth in excess of 50 fee t below existing grade exists at the site. It is possible that seasonal variations (temperature, rainfall,etc.) will cause fluctuations in the groundwater level. Additionally, perched water may be encountered at shallow depths following extensive rain events. If shallow perched water is encountered, it is anticipated that it can be managed with conventional sump pumps or other means. 4.4 SEISMICITY The geologic structure of the entire California area is dominated mainly by northwest-trending faults associate d with the San Andreas system. The site is in a seismically active region. No active or potentially activ e fault is known to exist at this site nor is the site situated within a State of California designated "Alquist-Priolo" Earthquake Faul t Zone. As discussed in the referenced Leighton report (Leighton. 2007), several short discontinuous faults were observed in the northern and southern portions of tile site. These faults generally trend to the north and northwest and are generally consistent with the discontinuous faults observed during Leighton's fault investigacions on the adjacenc Trace 5517 to the south an d which were not deemed t o be active. Only one active fault was observed on Tract 5517, in the southeastern corner of that site and generally trends in a northwest direction. Leighton concluded that this fault terminates approximately 780 feet southeast of the southern limits of Tract 551 6. 4.4.1 Seismic Design Parameters The site is located at approximately 35.4068" Latitude and -1 1 8.8328 ° Longitude. Due to the presence of artificial fill overlying older alluvium and presence of the Kern River Formation bedrock. a Class "C" is deemed appropriat e for this site. Site spectral accelerations (Sa and S1) for 0.2 and 1.0 second periods for a Class "C" sit e were determined from the SEAOC/OSHPD web interface that utilizes the USGS web services and retrieves the seismic design data and presents that information in a report format. These values are presented in the following table: � (iEOTEK JCA Enterprise/MBK Consulting Update Geotechnical Report, Lots 1-22, Phase 2 -Tract No. 5516 City of Bakersfield Kern County California Project No. 3145-CR June 3, 2022 P age ii The oppon:unity to be of service is sincerely appreciated. If you have any ques-cions, please do not hesitate co contact Geo T ek. Respecdully submitted, Geo T ek, Inc. Bruce A. Hick Edward H. LaMont GE 2284, Exp. 12/31 /24 Geotechnical Engineer CEG 1892, Exp. 07/31/24 Principal Geologist Distribution: (I)Addressee via email (one PDF file) G:\ProJem\J/01 r,, 3/50\3/45CR jCAIEnterprise/MBK Consuking Ri<.o Brovu Country Club Luts 1-22 Pfiase 2 -Troct No. 5516 Bokers(,ekf.Ge.itedmirnf Evafl.l()licm\3145CR Update Gaitedmirnl Reprut Rio Brnvo CouJ1!,Y Club.docx GEOTEK JCA Enterprise/MBK Consulting Project No. 3145-CR Update Geotechnical Report, Lots 1-22, Phase 2 -Tract No. 5516 June 3, 2022 Citx of Bakersfield_, Kern Counzy, C~a- li~fo~'�"~'•�-------------------�Page 7 SIT E SEISMIC PARAMETERS Mapped 0. 2 sec Period Spectral Acceleration, s� Mapped 1.0 sec Period Spectral Acceleration, SI Site Coefficient for Site Class "D," Fa Site Coefficient for Site Class "D," Fv Maximum Considered Earthquake Spectral Response Acceleration f or 0.2 Second, SMS Maximum Considered Earthquake Spectral Response Acceleration for 1.0 Second, SMI 5% Damped Design Spectral Response Acceleration Paramecer at 0.2 Second, SDS 5% Damped Design Spectral Response Acceleration Parameter at I second, SDI Seismic Design Category 0.94og 0.333g 1.2 1.5 1.136g 0.5g 0.757g 0.333g 0.488g D Final selection of the appropriate seismic design coefficient.s should be made by the project structural engineer based upon the local practices and ordinances, expected building response and desired level of conservatism. 4.5 LIQUEFACTIO N ANALYSIS Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake.induced ground motion, create excess pore pressures in relatively cohesionless soils. These soils may thereby acquire a high degree of mobility, which can lead to lateral movement, sliding, settlement of loose sediments, sand boils and other damaging deformations. This phenomenon occurs only below the water table, but, after liquefaction has developed, the effects can propagate upward into overlying non-saturated soil as excess pore water dissipates. The project site is located within an area that has not yet been mapped by the St.ate of California for liquefaction potential. The site is not located within a liquefaction hazard area designated by the City of Bakersfield or County of Kern. Based on the depth to groundwater the potential for liquefaction to occur as a result of seismic activity is considered very low. � GEOTEK JCA Enterprise/MBK Consulting Update Geotechnical Report, Lots 1 -22, Phase 2 -Tract No. S516 City of Bakersfield Kern County California Project No. 3145-CR June 3, 2022 age 3 mitigation of differential fill settlement potential and that one lot (Lot 22) was graded as a "cut" lot which will require "capping". The referenced report stated that finish grade laboratory testing for expansion potential and sulfate content on each lot, and overexcavation of cut.fill transitions and mitigation of differential fill conditions were not performed during the rough grading discussed in the report. Leighton indicated that design plans for each individual lot be reviewed and recommendations be provided to mitigate cut-fill and differential fill conditions. 2.3 PROPOSED DEVELOPMENT Based upon discussions, site development is to consist of the conscruction of one- to two-story single-family residential structures on each of the 22 graded building pads. Given the graded nature of the site, additional cuts and fills (not including remedial grading or building pad precise grading) are expected to be minimal. Although structural loading information has not been provided, it is assumed that the proposed residences will consist of wood framed structures supported by conventional shallow foundation and will utilize a slab on-grade ground floor. Maximum column and wall loads of about 50 kips and 2.5 kips per foot are assumed for the residential structures. 3.1 3. FIELD EXPLORATION AND LABORATORY TESTING FIELD EXPLORATION Recently, Geo T ek performed a reconnaissance of the site. In addition, ten ( I 0) test trenches were excavated by GeoTek in order t o review site soils conditions and sample the subsurface soils for laboratory testing. The test trenches were excavated on April 28. 2022 by means of a rubber-tire backhoe. Bulk soil samples were obtained for laboratory testing. The approximate locations of these excavations are shown on Figure 2, Trench Location Map. Gl:OTEK JCA Enterprise/MBK Consulting Project No. 3145-CR Update Geotechnical Report, Lots 1-22, Phase 2 -Tract No. 5516 June 3, 2022 C .h;y : of Bakersfield, Kern County:, C~•�li~fo~'~"~'•�------------------�Pa�ge 8 4.6 OTHER SEISMIC HAZARDS Evidence of ancient landslides or slope instability at this site was not observed during the site reconnaissance o r field exploration. Thus, the potential for landslides is considered negligible for design purposes. 5. CONCLUSIONS AND RECOMMENDATIONS 5.1 GENERAL The anticipated site development appears feasible from a geotechnical viewpoint provided that th e following recommendations, and those provided by this firm at a later date are incorporated into the design and construction phases of development. Site development and grading plans should b e reviewed by GeoTek, Inc. when they become available. The referenced Leighto n (Leighton, 2007) report documented chat th e fill soils placed at chis site were tested by Leighton to confirm that they were properly compacted when placed. Recent subsurface exploration of the site by Geo T ek confirms this assessment. However, Leighton stated in the referenced report that with the exception of Lots 20 and 21 of Phase 2, over excavation (lot capping) of the cut and cut-fill transition pads was not performed during rough grading. Remedial grading will be required to recompact the upper building pad soils on most of the lots and to perform a lot capping on Lot 22. The approximate maximum total and differential fill thickness across each lot was presented in Table I of the referenced Leighton report. Review of this Table indicates that the lots in Phase require mitigation of differential fill settlement potential. After the completion of the recommended remedial grading, it is Geo T ek's recommendation that site structures be supported on post-tensioned (PT) slabs which should be designed in consideration of a maximum differential setdement (combined static plus seismic) of 1.5 inches over a horizontal dist.ance of 30 feet. � GEOTEK JCA Enterprise/MBK Consulting Update Geotechnical Report, Lots 1-22, Pl-iase 2 -Tract No. S516 City of Bakersfield Kem County California 3.2 LABORATORY TESTING Project No. 3145-CR June 3, 2022 Page 4 Laboratory testing was performed by GeoTek on selected soil samples obtained from the test trenches. The purpose of the laboratory testing was co confirm the field classification of che soils encountered and to evaluate the physical properties of the soils for use in engineering design and analysis. A direct shear tes t was conducted on a select soil type remolded to approximately 90 percent of maximum dry density to review the shear strength parameters of the test soils. The optimum moisture content-maximum dry density relationship was established for typical soil types so that the relative compaction of the subsoils could be determined. Expansion index testing was performed on three selected sample to evaluate the expansion potential of the site soils. Chemical testing, comprised of pH, soluble sulfate, chloride and resistivity testing, was conducted on selected samples. The maximum density, expansion index and chemical test dat.a are presented in Appendix B. 4. GEOLOGIC AND SOILS CONDI TIONS 4.1 REGIONAL SETTING The property is situated in the Grea t Valley geomorphic province. The Grea t Valley province is one of the largest geomorphic units in western North America It extends approximately 440 miles from the Sacramento Valley, drained by the Sacramento River, to the San Joaquin Valley, drained by the San Joaquin River, to the southeasterly adjacent the Sierra Nevada province. This province varies in width from about 30 to 80 miles. The Great Valley is a trough in which sediments hav e been deposited since the Jurassic (about 160 millio n years ago). Great oil fields have been found in southernmost San Joaquin Valley and along anticlinal uplifts on its southwestern margin. In the Sacrament o Valley, the Sutte r Buttes, the remnants of an isolated Pliocen e volcano rise above th e valley floor. It is bounded on th e west. northwest and southwest by the Coast Ranges province and on the east, northeast and southeast by the Sierra Nevada province. The San Joaquin Fault borders the northwestern portion of the Great Central Valley province, adjacent to the Coast Ranges province, while th e White Wolf Fault borders the southeastern portion adjacent to the Sierra Nevada province. IGl:OTEK 1.7-5516 PH 2 CITY RECORDS NO: :I: � F-z � � "'-0 -0"'N"' @O> (I) !! V .z>-"' o5 3: 0 ... I !: ...Jw <C ......J u "'<C • DO"'Cl�u -w "',-"-"'"'� ow0 "'DO <C om - � V)z0 ;;;5 w0: N Ill GO -c :c.. N00gJ"'0 Ii � ..J0 •• !:•C I- a:0 D.. wI'a:.. - a en... -c - a:... 0 en w LC)iJj .. :::, 0 a= .,. .,. z a= Ill Ill z .,. z Ill z Ill.,. ii: Ill z ...� 0 ' �� @i 5 i� � m .. � 23-40000059 01/25/24