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0002-078 (SFD) Geotechnical Engineering Report0coujWY- ZQZOVmCO W ~QZ30-W 0 0ccGEOTECHNICAL ENGINEERING w UJ THE ORCHARD - � z o' TRACTS 26524 & 2652 wz w 0 j r LA QUINTA, CALIFORNI12 arc 0 Nzu. O UOW �y'SZ� H 2JQu`W Www -J� Uf..� CL WCCp � Q OO�ZOw "Zcc8oU. ca =QZWN PREPARED FOR STROTHER CONSTRUCTION B7 -2823-P1 DECEMBER 18, 1990 BUENA ENGINEERS, INC. 0 0 G aBuena Engineers, Inc. + AN EARTH SYSTEMS, INC. COMPANY 79-811 B COUNTRY CLUB DRIVE • BERMUDA DUNES, CALIFORNIA 92201 • PHONE (619) 345-1588 • FAX (619) 345-7315 December 18, 1990 Strother Construction B7 -2823-P 1 90-12-786 41-555 Cook Street o Palm Desert, California 92260 N 0(nUjW>- M Attention: Chuck Strother z z 0 (D m N a0P►-� Project: The Orchard - Tracts 26524 & 26525 � o Q z w La Quinta, California � z a o W 00—J5cc m Subject: Geotechnical Engineering Report W UJ U Q i a ca °C .- Z Presented herewith is our Geotechnical Engineering Report :) r&Oor t proposed residential development to be located in the C t\F" J W(W auint California. W O :) — (nXWV3 _ ul'R002N c This report incorporates the tentative information supplied to oto&t d in accordance with the request, recommendations for4c9-e@tt&osite development and foundation design are provided. LU LU X U. W This report was prepared to stand as a whole n � 2 -' a U. uW. p p p , and no p �lt2laedqDort should be excerpted or used to exclusion of any other part. cr < w cc a O0 Z LU This report completes our scope of services in accord(M2(gaw.our agreement. Other services which may be required, such as pkdlq�. Eg\6 nd grading observation are additional services and will be billeigr& to the Fee Schedule in effect at the time services are provided. Please contact the undersigned if there are any question,- concerning this report or the recommendations included herein. Respectfully submitted, BUENA ENGINEERS, INC. Hogan R. Wright Staff Engineer R. Layne Richins Staff Geologist PC HD/SER Copies: 6 - Strother Construction 1 - P. S. File Reviewed and Approved, 01411e Brett L. Anderson, 1 - VTA File Cl) W r N U) M r cr W BERMUDA DUNES BEAUMONT BAKERSFIELD LANCASTER VENTURA (619)345-1588 (714)845-9883 (8051327-5150 (8051a4A-7518 (80S)R42-A727 TABLE OF CONTENTS INTRODUCTION...........................................................................................................1 PURPOSE AND SCOPE OF WORK........................................................................1 SITEDESCRIPTION.....................................................................................................2 FIELDEXPLORATION................................................................................._...............2 LABORATORYTESTING.............................................................................................3 SOILCONDITIONS....................................................................................-aw.ui.Lwa GROUNDWATER....................................................... z z M c� REGIONALGEOLOGY ............................................................................. LOCALGEOLOGY f=•Q•Z. .............................................................:.......................�.®.�.o. GEOLOGIC HAZARDS Z CL ................................. Primary.................................................................................................ca.e t�• Secondary........................................................................................:L ►U z 0 �•- Non-Seismic ....................................................................................... �6 CONCLUSIONS AND RECOMMENDATIONS .. ................................... QV-wwUz 'w• SITE DEVELOPMENT AND GRADING .................................................... `u' z Site Development - Grading ..................................................... .W.W.0.-- Site Development - General ..................................................... Excavations........................................................................................0�,a.Q.u, TrafficAreas...................................................................................... �.�.�.�9Z o UtilityTrenches...................................................................................Z ..�.v o•jE — cn STRUCTURES...............................................................................................�..a.0 w.0.W uW. o Foundations z- .....Z,LU•z cc Slabs on Grade .................. a ¢ Irk a a Settlement Considerations ........................................................... Jae .�.o w Frictional and Lateral Coefficients.................................................z 0 RetainingWalls................................................................................W J SlopeStability.................................................................................. X Z 2: o Expansion.........................................................................................................15 AdditionalServices........................................................................................15 LIMITATIONS AND UNIFORMITY OF CONDITIONS...........................................15 REFERENCES.............................................................................................................17 APPENDIX A Site and Vicinity Map Logs of Borings APPENDIX B Summary of Test Results Table 2 APPENDIX C Standard Grading Specifications BUENA ENGINEERS. INC. co 0 N Cn N Q V 5 December 18, 1990 -1- B7 -2823-P1 90-12-786 This Geotechnical Engineering Report has been prepared for the two (2) proposed residential tracts to be located in the City of La Quinta, California. A It is assumed that the structures will be of lightweight one or two story construction. It is assumed that the buildings will be sL-pported by o normal continuous or pad footings. N B. act) I w >- Structural considerations for building column loads of u04c9- s CO N and a maximum wall loading of 2.0 kips per linear foot w Lwaas Q a basis for recommendations related to the construe fz-We -z::residential - buildings. Z) z CL o tU -0Qocc C. These are estimated values since foundation plan3„ix��r9ot o available at the time of production of this report. If desigi �e �� is to exceed these assumed values, it will be necessary to bei Waite the given recommendations.'l' z uJ ►_- i D. cn'LwOU� All loading is assumed to be dead plus reasonable live .c� o Cn�U-opa UO Z PURPOSE AND SCOPE OF WORK Zt v o � U N CC LL. ZCn �QOLL, LL The purpose of our services was to evaluate the site soil congt1p2sh-4 to provide conclusions and recommendations relative to iMac the proposed development. The scope of work includes theft:WO A A general reconnaissance of the site. cn } o w O Q B. Shallow subsurface exploration by drilling. ~ Q ~ C. Laboratory testing of selected soil samples obtained from the exploratory borings drilled for this project. D. Review of selected technical literature pertaining to the site. E. Evaluation of field and laboratory data relative to soil ccnditions. F. Engineering analysis of the data obtained from the exploration and testing programs. G. A summary of our findings and recommendations in written report. Contained In This Report Are: A Discussions on regional and local geologic and soil conditions. B. Graphic and/or tabulated results of laboratory tests and field studies. BUENA ENGINEERS, INC. E- N W i f- N CO 2 w } W Cr Q LU December 18, 1990 IM 67-2823-P1 90-12-786 C. Discussions and recommendations relative to allowable foundation bearing capacity, recommendations for foundation design, estimated total and differential settlements, lateral earth pressures, site grading criteria, geologic and seismic hazards. Not Contained In This Report: A Our scope of services did not include any en,iironmental o assessment or investigation to determine the presence ofd hazardous or toxic materials in the soil, surface water, cQ5gyn,49ter or air, on, below or around this site. z z m m a0� SITE DESCRIPTION i �' a z _ �c o - DZC The proposed project is located on the south side of Avenu�9 of g Jefferson Street in the City of La Quinta, California. vro— Wa o cn 1.- A The majority of the site is in an existing citrus grove. a cn U z O B. C. D. E. There are residential tracts presently under south and west edges of the site. cc construction 191arty O CC 0 O_ N>-pWwQ Exploratory borings were drilled for observing the soil profile and obtaining samples for further analysis. A Six (6) borings were drilled for soil profiling and sampling to a maximum depth of thirty-six (36) feet below the existing ground surface. The borings were drilled on November 20 and November 21, 1990, using an eight (8) inch diameter hollow -stem auger powered by a CME 45-B drilling rig. The approximate boring locations as indicated on the attached plan in Appendix A, were determined by pacing and sighting from existing streets and topographic features. The boring locations should be considered accurate only to the degree implied by the method used. B. Samples were secured within the borings with a two and one-half (2.5) inch inside diameter ring sampler (ASTM D 3550, shoe similar to ASTM D 1586). The samples were obtained by driving the sampler with a one hundred forty (140) pound hammer, dropp ng thirty (30) inches. The number of blows required to drive the samoler one foot BUENA ENGINEERS, INC. WZH2H The site is fairly level throughout with the exception of �la;'asynd dune in the southeast corner of the site. N a o z � Avenue 50 forms the northern edge of the site. MLL0OQ 0 0 N Z There are underground and overhead utilities along Av4�r underground irrigation lines traversing the site. UJ LL z-401.1 �. w O There are residential tracts presently under south and west edges of the site. cc construction 191arty O CC 0 O_ N>-pWwQ Exploratory borings were drilled for observing the soil profile and obtaining samples for further analysis. A Six (6) borings were drilled for soil profiling and sampling to a maximum depth of thirty-six (36) feet below the existing ground surface. The borings were drilled on November 20 and November 21, 1990, using an eight (8) inch diameter hollow -stem auger powered by a CME 45-B drilling rig. The approximate boring locations as indicated on the attached plan in Appendix A, were determined by pacing and sighting from existing streets and topographic features. The boring locations should be considered accurate only to the degree implied by the method used. B. Samples were secured within the borings with a two and one-half (2.5) inch inside diameter ring sampler (ASTM D 3550, shoe similar to ASTM D 1586). The samples were obtained by driving the sampler with a one hundred forty (140) pound hammer, dropp ng thirty (30) inches. The number of blows required to drive the samoler one foot BUENA ENGINEERS, INC. December 18, 1990 -3- B7-2823-P1 90-12-786 was recorded. Recovered soil samples were sealed in containers and returned to the laboratory for further classification and testing. C. Bulk disturbed samples of the soils were obtained from cuttings developed during excavation of the test borings. The bulk samples were secured for classification purposes and represent a mixture ofo soils within the noted depths. v 0(n D. The final logs represent our interpretation of the conten% logs, and the results of the laboratory observations and2 field samples. The final logs are included in the apper I6 report. The stratification lines represent the approximate LU >- M f� f PeId,-,j jqf3the �f�his= es between soil types although the transitions may be gra&ol j o a WwU= LABORATORY TESTING °' b z o wZ�M� After a visual and tactile classification in the field, samples wprii &8I;oed to the laboratory, classifications were checked, and a test9341 lam' was established. W o o o Q ¢UOwa.O A Samples were reviewed along with field logs to dete� ! vV8* would be further analyzed. Those chosen were coits 6(Lo gs representative of soil which would be exposed anc#cr22n grading and those deemed within building influence. o cc < w ac 2L 0ZQo B. In-situ moisture content and unit dry weights for the Mr99 9s were developed in accordance with ASTM D 2937.0 } o w w Q =Qz=cnJ C. Settlement and hydroconsolidation potential was evaTuM6 Pro9n the results of consolidation tests performed in accordance with ASTM 2435. D. The relative strength characteristics of the subsurface soils were determined from the results of direct shear tests. Specimens were placed in contact with water at least twenty-four (24) hours before testing, and were then sheared under normal loads ranging from 0.5 to 2.0 kips per square foot in general accordance with ASTM D 3080. E. Classification tests consisted of: Expansion Index (UBC 'Standard No. 29-2), Maximum Density -Optimum Moisture (ASTM D 1557) and Hydrometer Analysis (California Test Method 203). F. Refer to Appendix B for tabular and graphic representation of the test results. SOIL CONDITIONS As determined by the borings, site soils were found to consist primarily of fine windblown sands with interbedded clay layers. The boring logs in Appendix A contain a more detailed description of the soils encountered. BUENA ENGINEERS, INC. f - U) w H D U) U) Z w a W December 18, 1990 -4- B7-2823-P 1 90-12-786 A The soils were found to be fairly loose throughout with blow counts indicating relative compaction as low as seventy one (71) percent of maximum density. B. The soils were found to be moist throughout with the majority of the deeper clay layers being saturated. C. Clay and silt contents of the soils exhibit low plasticity. Expansion tests o indicate the surface soils in the "very low" expansion X in accordance with Table 2 in Appendix B of this report. ThiQyt-rs #eR were found to be In the medium expansion catego;� oto N section B of the structures section for specific expla i'Q' z&d requirements dealing with expansive soil. n z a o LU 00 J � CC m D. Soils should be readily cut by normal grading equipment UJ9 r a o acF-Z aF.UZO GROUNDWATER o ►- w w z LU Z f— 2 �— F - Free groundwater was not encountered in any of the borings nlie) to groundwater in the area is generally in excess of forty„ (�1Q)�f - _ Fluctuations in groundwater levels may occur due to variatiom'W (n D temperature and other factors. r U) 0 a LU CC LL LU QW ZJOu REGIONAL GEOLOGY w w o J O - 2 gwZF-wC �¢QZ¢a H The project site is located in the southern Coachella Vall We w � base of the Santa Rosa Mountains. The Coachella Valley is @rt: tectonically active Salton Basin. This basin is a closed, intern fi fZRt- _ that has been filled with a complex series of continCh Qtrough materials during Pleistocene and Holocene time (Van de Carp,'1973) w The San Andreas rift zone dominates the geology of the Coachella Valley. The Banning and Mission Creek faults, which are parts of the San Andreas system are responsible for earthquakes recently felt in the Coachella Valley. Other regional faults that have produced events felt in the Coachella Valley are the San Jacinto, Imperial and Elsinore faults (see figures 1 & 2). Based upon the historical and prehistorical record, the Coachella Valley segment of the San Andreas fault. system is likely to generate a magnitude seven (7.0) or greater earthquake within the next fifty (50) years. The potential for a magnitude seven (7.0) earthquake within the next fifty (50) years is estimated by Seih (1985) as 'High' (50%-90%). The project is in an area that has once been covered by Ancient Lake Coahuila. Lithologic units observed consist chiefly of Quaternary lake deposits. The boring logs in Appendix B contain specific descriptions of the soils encountered on site. BUENA ENGINEERS, INC. * n _ Oy 0 N :s rt� 3 rx o U) d-M 0 b 4 N tA 0 gir rt O o 3 n a '~. c:rt m _ O• �. v d o r c��CD r OANYO N 3JV Y /i 3 ~' a + a o 1 N rbd3� o dpa�, a h ao� o T'vorn3 f It- 03 o a C u d �dy+ i Thi '�1MeN ,� WA ISSUED° EVIOU�LY AND rn -" H +` 3 M 4• RfFL �. �RRENT SI CONDITIONS o z o ►++ ^�� a NDARbS O GE CAL PRACTICE. �►'Tof l cjrdT T OF TI ICD CU ENT 31 IOULD NOT DC rn r �i �d'� l S D� R L D UPON I HOUT A REVIEW BY m rn _—� + i; O S. N H d • �' ` Init Date MAY 2 2000 4 - .-• ,� v z o N E. RTH SYSTEMS SOUTHWEST r• m 1927 (6) \ U: 1 \`\ CO CD QO _1-;h-3.. v/ \` • Z Z a O �yw��.. 1 O CC ,Lone Pine \\ > U Q O Q \�-� wWU= ° ru/ore% CJ U Z O \\ z' —2F— cnCr 03- 1946 (6.3) \ O J °Chino Lok -� OOZ �� 0 a Bokers/ie/d° / 3-.F- U) = D 1952(7.7,6.4,6.1,6.1) Z �w /dojove 1947(62) u) U. O -� °Sonfo Marion= W Z Z W Cr -(19!6 (6) \ °Borslow-� ¢ F-- LU Ir a —��Sonfo -o-76-0-'a—\- \�. Polmdo/e \� \ �� O O O LL 1941 (6.0) \•Z O U -- 1925 (63) \� 1971 (6.4) _• °Son Bernardino F- Q F- 0 a o --1 Los Ange/e 1948:6.5) AT 1923 W/4) \s�� — — �n +:.. �. I ,SITE 1918 (6.81 Ino'.° 1933 (6.3) �o 1937(6.0) 1�. CC- C-_ n. Cw n� m c F— W W W F— W } 2 F— cr Q W \ 1954(6.2) • QS 1968 (6.4) B ° orregoj� .6row/ey \t\\ 1942(6.5) �\ ° V 1940(6.7) 19 15 (61/4 04 A Son Dego erica/i sumo 1934+6.5) 1934(7.1) 1915(7.1) f f1-935(6.0)[-* \ 0 /00 Mi/es EnsenoCo 195 6(68,6.1,6.3,6.4) O /00Z-00 Kms. 1954(6.3 6.0) 1966(6.3•',' Earth Quakes of magnitude 5.9 and greater in the Southern California Region, 1912 — 1972 (including the North Palm Springs Earthquake). From I(ileman et al (1973) I December 18, 1990 -5- B7-2823-P1 90-12-786 The project site is approximately six and eight tenths (6.8) miles southwest of the San Andreas fault system. Figure 3 shows the project site in relation to the local geology. 0(n,jw>. ZZUMco GEOLOGIC HAZARDS a o ►_'_ � ~Q0 ZW A Primary Seismic Hazards: C/) Z a o w 00 5. CL Primary seismic geologic hazards that may affect any50ri in the seismically active Southern California area include: a. `- _ _ =) 1. Fault Rupture: W I.- o wa:Lu � a. The project site is not located in any Alquist-Motd) I study zones. Nor are any faults mapped�twr�W �r adjacent to the project area. At the time c��dll�5)o surface expression of faulting was observed. r w u. o W Z_j<0�=W W U- O J b. Fault rupture would most likely occur along w�j y established traces. However, fault rupture rra¢ o t other locations not previously mapped. p o QZCCo o W 2. Ground Shaking: N >QW w Q ><ZXU)Z a. Strong ground motion is the seismic hazard mostliteiylo affect the site during the life of the intended structures. Using methods developed by Seed and Idriss (1982) and modified by Krinitzsky (1988) the following table was compiled for anticipated accelerations which may be experienced during an earthquake at the project site. Maximum Design` Acceleration LQU11 Earthquake in Rock TABLE 1 Estimated Maximum Repeatable Approximate Acceleration Ground" Distance to in Soil Accelerations Project Site San Andreas 7.5 .48g .37g. .24g 6.8 mi. San Jacinto 6.5 .18g .15g 10g 18.5 mi. ` Richter Magnitude, Maximum Probable " Ploessel & Slosson 1974 b. Because of the alluvial sedimentary nature of the soils on site, ground shaking characteristics are expected to include low frequency vibration with relatively high amplitudes. Duration of shaking could be from fifteen (15) to thirty-six (36) seconds. The project area is mapped in Ground Shaking Zone III C as designated by the County of Riverside, California. Ground Shaking Zones are based on distance from causative faults and soil types. BUENA ENGINEERS, INC. r 01 - CV m �� I_ ...='CULCS:S•: ,!'r`1l� , .rci y , Fal s s�Z.��\,/ / ..� vlrl�. 54:. n, s `'-/•\- . _ Cct-Cs R �T�,f ,Tl ��'\ !\,. � j:i:S.. �' �.. � Cs'•' Cs vt, �:� Fri- �, •r� I.. ` yr�,�tl'9 + - 9r ,�D c"✓ . IA cc 7 I .�.' yrs \ -.J N. \ ''`y-\• _\' �/.J,`1 //�)� t/ -�' -,'�-OCc': •a%/csi_ �\ I. ��. ��c t•'tt .f �'.._. 9r r Rotir'ies 'er.zs::' �- �� s �_�r,_ os� cct� _ _.' _1�D O`er <SY 1. cs-'f'?IGI- I -'. 9�9 ccl � r,/• -i-•tet. r _.- ! ._ , Oct '_''ala Gesea � ` ` 1 i 1 4 ,a • ' 0-•,t Ts �.� 9r.`` G. -^/ ,k.'�' _ �. ::I- .41 ` Cs i Cct �',t' v` )i J• Ni,c JJLu11J�� Go:-L's1T j G:C L.!::2 �. s' •.� __ �;� = •�-� . 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','.>Ti(7i�''.i• _ =s- -` �'• =lam ,'.-_.,�.. C '�� .��.~\s. t,•�,-� Cc \,: r .ff�.� - c V _ `� "i'/U — il• ' ' :C•��j.i' r.:fil.'4r'� \Crr __ :V'y r'''✓�-.__. _ _�- -"-_.'-•-*j••-G- .. _ � _ I �,� _ ��' _: �"+•n __. .' _ ':::: = - ``"-`' - x317 •PfL_C /1 .� ^t- `�=.•y\+l'}T��-m_ ;-r`s' o• •"'�_.�;�� ...,__ _•._-_T ��c`�i�.� ;�:�EY-r - � _-- _yrs 'yf" �'��.��-- _y�'. • _; 1 •,_.� -j- - _-� _. .'_' cl - } '-'� �,- l r �'\l • ' rbc " _ ^`,..��. •7• - _ '., MAP OF PFOJECT SITES `;ortlh- ---= _b• RELATION TC LOCAL GEOLOGY SANTA ANP HAP SHEET Scale 1. 250000 �• FF�_ ? �' "GN,-4'Ap.ult�s "' �' ``� BUENA ENGINEERS, INC - r ,v 1, 91 j • 4_ `=° -�' 7'. _'_ -- . �• DATE: /z — /8 — 90 FILE H0. ZY7-aBL3—ol December 18, 1990 M B7 -2823-P1 90-12-786 C. The project is mapped near the Riverside County Liquefaction Study Zone, however, no groundwater was observed in our borings. B. Secondary Seismic Hazards: 0cnww>- Secondary seismic geologic hazards that may affect the @r�ijec c � �, site area include settlement, liquefaction and ground lurchi O w '' QZ_ , � cnod: > Pei - 1. Settlement, whether seismically related or not, is c-DnVo�if' ._ potential hazard in this area. Historic records repo.-tn1episodes m of settlement in the Coachella Valley area Liue=to seismic forces and/or heavy rain fall and flooding. Cr'_ _ �UZ0 2. Liquefaction is the loss of soil strength as a result of an ing �--_dsw �_ pore water pressure due to cyclic seismic loading. ai n-� w for liquefaction include relatively high water table twifbim cif W 3: surface), low relative densities of the saturated tc z Z of the soil to liquefy based on grain sze� Nlq„tee o D groundwater was encountered in our exploratory burin o �- o � o ZJQ0w� 3. Ground lurching is generally associated with fault ruritEg=d o !� w liquefaction. Because of the sites distance from am/ak�Sm— a- ."active" ll active"faults, the possibility of ground lurching affectit te ne o is considered low. o Z M o° L O Up - _ 4. Other secondary seismic geologic hazards that may r�s�tgr'gm o w earthquake include tsunamis (tidal waves) 64 sae*Fens LU (waves oscillating in an enclosed area, i.e., storage tanks, lakes). Based on the project sites geologic Iccation and topography, it is our opinion that the probability cf the above hazards affecting the property are negligible.' C. Non -Seismic Hazards: Other geologic hazards that could affect the project site include landslides, flooding and erosion. 1. No evidence of past landsliding was observed at the site nor are any known landslides mapped in or around the project site. The subject property is not at the immediate base :)f any steep hills and is located on relatively flat ground. 2. Flooding and erosion are always a consideration in arid regions. The properties flat topography suggests this is an area of deposition. No gullies or areas of active Erosion were observed on site. Increased erosion, either fluvial or aeolian, may occur as a result of construction activity. CONCLUSIONS AND RECOMMENDATIONS Based on a review of selected technical literature cnd the site investigation, it is our opinion that the site is suitable for the intended development provided it is designed around the noted geologic BUENA ENGINEERS, INC. December 18, 1990 IVA B7 -2823-P1 90-12-786 hazards. The following is a summary of our conclusions and professional opinions based on the data obtained. Recompaction of soil is recommended to limit settlement and improve bearing capacity. U A The primary geologic hazard relative to site developmi? re m ground shaking from earthquakes originating on nearby4o s,- the N site is located in Southern California which is an active seJsFm rea. In our opinion, a major seismic event originating on the 56I Mas fault zone would be the most likely cause of significant I qLU m activity at the site within the estimated design life of they (ir8d o development. w W - M a-Fn_�-D B. Settlement due to seismic factors or flooding is a potential �h r@ in the Coachella Valley area. � w o 2 L LU C. Areas of alluvial soils may be susceptible to erosion. P e CC U # E measures to minimize seasonal flooding and erosionQ hc& incorporated into site grading plans. 3: U) z I - D. Fluvial erosion may affect the site during construction. z � Q 0 - U- WU-0 -Jo E. Other hazards including liquefaction, lurching, landslides, and seiches are considered negligible. o �- co Z ct o 0ZCC0�U- F. It is our opinion that the upper native soil will not provide �,unff' riypw adequate support for the proposed structures wi�M — Wig recommended sitework. To decrease the potent`ic :?65? consolidation and to provide a more uniform and firm bearing support for the proposed structures, we recommend constructing recompacted soil mats beneath all foundations and slabs -on - grade. G. The project site is in seismic Zone 4 as" defined in Section 2312 (d) 2. of the Uniform Building Code. Itis recommended that any permanent structure be designed according to the current additions of the Uniform Building Code and Standards. H. It is further recommended that any permanent structure constructed on the site be designed to accommodate expected repeatable ground accelerations resulting from the predicted maximum probable earthquake as stated in Table 1 on page 5 of this report. I. Adherence to the following grading recommendations should limit potential settlement problems due to seismic forces, heavy rainfall, flooding and the weight of the intended structure. J. It is recommended that Buena Engineers, Inc. be retained to provide Geotechnical Engineering services during site development; excavation, grading, and foundation construction phases of the work. This is to observe compliance with the design concepts, specifications. and recommendations, and to allow design changes in the event that subsurface conditions differ from those anticipated prior to the start of construction. BUENA ENGINEERS, INC. w i 0 w W r Q LU December 18, 1990 M B7 -2823-P1 90-12-786 K. Plans and specifications should be provided to Buena Engineers, Inc. prior to grading. Plans should include the grading plans, foundation plans, and foundation details. Preferably, s#ru,cctuppa-loads should be shown on the foundation plans. z Z U CO m N QO�Z �- 3: SITE DEVELOPMENT AND GRADING _ o < Z d J W Prior to any construction operations, areas to be graded shbL%d bero cleaned of vegetation and other deleterious materials.>�lix CP "Standard Grading Specifications" contains specific suwg` (B s for removal and disposal of deleterious substances and, as `�R&4zms part of these Site Development and Grading Recommenda#i. T_ Z A. Site Development - Grading Cn s � ui .. —M 0Z -J c DU -00< Site grading and the bottom of all excavations shoulcVktmCbbs:e ed by a representative of Buena Engineers, Inc. prior to bra of fill. Local variations in soil conditions may warrant idhe depth of recompaction and/or overexcavation. w U_ o° � 0 gwZZwcr 1. Because the majority of the site is in an existin-cc�tt $2��e, proper clearing is very important. Prior to siteluts, ny existing structures, stumps, roots, foundations, & leachfields, uncompacted fill, trash piles, and anClSed underground utilities should be removed from 6r3posed building and paving areas. The top surface should be stripped of all organic growth and non -complying fill which, along with other debris, should be removed from the site. 2. Depressions resulting from these removals should have debris and loose soil removed and be filled with suitable fill soils compacted as recommended herein. No compacted fill should be placed unless the underlying soil, has been observed by Buena Engineers, Inc. 3. In order to help minimize potential settlement problems associated with structures supported on a non-uniform thickness of compacted fill, Buena Engineers, Inc. should be consulted for site grading recommendations relative to backfilling large and/or deep depressions resulting from removal under item one above. In general, all proposed construction should be supported by a uniform thickness of compacted soil. 4. Testing showed the surface soils are loose and susceptible to settlements due to the introduction of water and the additional loading of structures. In addition the inevitable presence of roots may dictate the actual depth of overexcavation deemed necessary. To control differential settlement and to produce a more uniform bearing condition we recommend that the structure be supported by a recompacted soil mat. Compaction is to be verified by testing. 5. Building areas should be overexcavated to a depth of two (2) feet below original grade or the bottom of footings whichever BUENA ENGINEERS, INC. UJ 0 UJ a W December 18, 1990 -9- B7 -2823-P1 90-12-786 is greater. The exposed surface should be scarified, moisture conditioned and compacted so that a minimum of ninety (90) percent of maximum density is obtained to a dept -i of one (1) �. foot. The previously removed soil and any fill materdalns�aZu[d c, then be placed in eight (8) inch layers in a loose cont§r) & 1b N near optimum moisture and compacted to a mi9JrnLtVi6 c ! ninety (90) percent of maximum density. The intent is to qV gt ' least three (3) feet of soil compacted to a minimum=o rM percent of maximum density compose the buil iWpad 2 Ca beneath the footings. Compaction is to be verified b Wte. r�< � a. - T 6. Due to the granular nature of the site soils in the argil I large r sand dune, it may be possible to obtain comfiog a depth of three (3) or four (4) feet by watai trid . U) w compacting from the surface. Regardless of the methodNa in the area, the recommended depth of compaq3i�R — indicated in item five should be attained. � �- cn M o U4 7. These grading recommendations apply to building grecs ca ' 11 W at least five (5) feet beyond building limits. Z. w z �-- w ° w U.11 a: 8. Auxiliary structures including freestanding or retainingt W �- have the existing soils beneath the structure process &8p e� = items five (5) and six (6), above. The grading r�rmt apply to three (3) feet beyond the face of the walIs. f - I� � w auxiliary structures and walls are provided for our review, i ese recommendations may be revised. 9. It is anticipated that during grading a loss of approximately one tenth (.1) of a foot due to stripping, and a shrinkcge factor of about fiffeen (15) to twenty (20) percent for the upper three (3) feet of soil, may be used for quantity calculations. This is based on compactive effort needed to produce an average degree of compaction of approximately ninety= hree (93) to ninety-four (94) percent and may vary depending on contractor methods. Subsidence is estimated between one - tenths (.1) to three -tenths (.3) of a foot. 1. The following general recommendations listed in this section are in addition to those listed in the 'Grading' section A above. 2. All rocks larger than eight (8) inches in greatest dim ension should be removed from fill or backfill material. 3. Import soil used to raise site grades should be equal to or better than on-site soil in strength, expansion, and compressibility characteristics. Import soil will not be prequalified by Buena Engineers, Inc. Comments on the cha-acteristics of import will be given after the material is on the project, either in- place or in stockpiles of adequate quantity to complete the project. BUENA ENGINEERS, INC. December 18, 1990 C0 -10- B7-2823-P1 90-12-786 4. Areas around the structures should be graded so that drainage is positive and away from the structures. Gutters and down, spouts should be considered as a way to convey wa#ffLout of., the foundation area. Water should not be allowecltg p&d onj or near pavement sections. —I -Z � O w J—<Z ,rn LO 5. Added moisture within previously compacted fill co resQ14n a number of reactions at the surface dependin (819he amount of moisture increase, the in-place density 49 AV s k in- � situ moisture content and soil type. Although the§cdl t_ddFd in reality be expanding, collapsing, moving laterallyndxe 1d the phenomenon "creep", the result is usually moven VtW will most likely manifest itself visually in structural slat &_ eet areas as cracks, (horizontal, lateral or vertical displ&�&Aamp.J n0U_00Q - UJ z b. The apparent cure to the problem is to not introg�M ��ss moisture into fill material once in place. To help) �'inj e increased moisture into the fill material, site dr�lAc!�tdd landscape is critical. Site drainage should be in thE�f�rgFet@f gutter, concrete brow ditcher, ribbon gutters and �z stem drain and other drainage devices. Landscapir 14�18 L§e such that water is not allowed to pond. Additcoaq,A cme should be taken -so as not to over water landscape, Q H- ".E . 7. The Recommended Grading Specifications ncluded In Appendix C are general guidelines only and should not be included directly into project specifications without first incorporating the site specific recommendations contained in the Site Development - Grading section of this report. Chapter 70 of the Uniform Building Code contains specific considerations for. grading and is considered a part of the genercr guidelines. 8. It is recommended that Buena Engineers, Inc., be retained to provide soil engineering services during construction of the grading, excavation, and foundation phases of the work. This is to observe compliance with the design concepts, specifications or recommendations and to glow design changes in the event that subsurface condition3 differ from those anticipated prior to start of construction. Excavations All excavations should be made in accordance with applicable regulations. From our site exploration and knowledge of the general area, we feel there is a potential for construction problems involving caving of relatively deep site excavations (i.e. utilities, etc.). Where such siluations are encountered, lateral bracing or appropriate cut s opes should be provided. BUENA ENGINEERS. INC. LU i O UJ } cr Q W December 18, 1990 -11- 137-2823-P1 90-12-786 2. No surcharge loads should be allowed within a horizontal distance measured from the top of the excavation slope, equal to the depth of the excavation. D. Traffic Areas ocnwW>- 1. Curbs and streets should be provided with one 4 bMW of subgrade compacted to ninety (90) percent o&Wm density. n� o ¢ > �Za. W 2. On-site parking should be provided with one10 tQof subgrade compacted to ninety (90) percent oQ O m density. a - v z o o�ww= 3. Final preparation of subgrade will depend on pay 8Eg-.!+on designs. N ¢ W 0 ?-� vi Dcc(90ZJ :)uLDOQ 4. Sidewalks should be provided with one (1) foot OT M5Qr § compacted to ninety (90) percent of maximum derfs:lt�.o � � - O N E. Utili Trenches Z_j a o W U_ W lL 0 J Q MWZ__J0 W¢ 1. Backfill of utilities within road right-of-way should �I a - strict conformance with the requirements of then agency (Water District, Road Department, etc.). 0 0 0 Q OwWQ 2. Utility trench backfill within private property should be <PI��u' l strict conformance with the provisions of this report relating to minimum compaction standards. In general, service lines extending inside of property may be backfilled with native soils compacted to a minimum of ninety (90) percent of maximum density. 3. Backfill operations should be observed and tested by Buena Engineers, Inc., to monitor compliance with these recommendations. Based upon the results of this evaluation, it is our opinion that the structure foundation can be supported by compacted soils placed as recommended above. The recommendations that follow are based on "very low" expansion category soils. It is anticipated that foundations will be placed on firm compacted soils as recommended elsewhere in this report. The recommendations that follow are,,based on "very low" expansion category soils. 1. Table 2 gives specific recommendations for width, depth and reinforcing. Other structural considerations may be more BUENA ENGINEERS, INC. r � J �V co N m 0 c W W F- r W a W December 18, 1990 -12- B7-2823-P1 90-12-786 stringent and would govern in any case. A minimum footing depth of twelve (12) inches below lowest adjace-)t grade for one (1) story structures and eighteen (18) inches for two (2) story structures should be maintained. ' 2. Conventional Foundations: W ocn,j;� ZZUmm Estimated bearing values are given below for foun"id pn recompacted soils, assuming import fill (if required) tell to or better than site soils: 00M> o �za-Jw 00-J :3¢ a. Continuous foundations of one (1) foot wide cswib' lve (12) inches below grade: a Z u) a --=E-00 2: i. 1300 psf for dead plus reasonable live a.. ii. 1700 psf for wind and seismic considercMdng) S 3 N¢(DU b. Isolated pad foundations 2' x 2' and bottomec &ialE2 inches below grade: a v O W a 3: U) �p i. 1500 psf for dead plus reasonable live U- w ii. 2000 psf for wind and seismic considerc03p 0 -J 0 �Qz�a� 3. Allowable increases of 200 psf per one (1) foot Cf (-OrJ bt�rc�a� footing width and 300 psf for each additional six (62i ¢des footing depth may be used. The maximum allowal &M will be 2000 psf. The allowable bearing values indi----�B LUU been determined based upon anticipated maxrPrunQltrct-IP indicated in the "Introduction" section of this report. If the indicated loading is exceeded then the allowable bearing values and the grading requirements must be reevaluated by the soil engineer. 4. Although footing reinforcement may not be required per Table 2; nominal reinforcement should be considered to reduce the potential for cracking due to temperature and shrinkage stresses and in order to span surface imperfections. Other requirements that are more stringent due to structural loads will govern. 5. Soils beneath footings and slabs should be premoistened prior to placing concrete. 6. Lateral loads may be resisted by soil friction on floor slabs and foundations and by passive resistance of the soils acting on foundation stem walls. Lateral capacity is based partially on the assumption that any required backfill adjacent to foundations and grade beams is properly compacted. 7. Foundation excavations should be visually observed by the soil engineer during excavation and prior to placement of reinforcing steel or concrete. Local variations in corditions may warrant deepening of footings. BUENA ENGINEERS, INC. 0 C=) N 1 m 76 0 U) W 2 D 0 w } cc Q w December 18, 1990 -13- 137-2823-P1 90-12-786 8. Allowable bearing values are net (weight of foot ng and soil surcharge may be neglected) and are applicab e for dead plus reasonable live loads. B. Slabs -on -Grade €�' 1. Concrete slabs -on -grade should be support Mt'4q `� compacted structural fill placed in accordant m `Y' applicable sections of this report. o _JZ w 2. In areas of moisture sensitive floor coverings, an appr.� EO LU w vapor barrier should be installed in order to minFniz� ar¢ m transmission from the subgrade soil to the slab. Mt&n HiQ that the o suggest floor slabs be underlain by a four (4) it &--t5C� layer of gravel or by an impermeable memrrarjgz�i capillary break. A suggested gradation for the gravp�l r? would be as follows: w O � — SQ a: Sieve Size Percent Passing , 0 o o Q vw LLQ _ < 0 LLJ Z ►- 3/4" 90- 100 � b d ~- 0 o No.4 0-10 z�QpwUW_ co No. 100 0-3 ww_J O �wZF-wCl: ��UJ w� If a membrane is used, a low -slump concrete should cu d o help minimize shrinkage. The membrane shy e Ly U?to U) covered with two (2) inches of sand to help protecMit,. fi � M construction. The sand should be lightly moistened j '*E6�'� � Q placing the concrete. Q o w C. 3. Reinforcement of slab -on -grade is contingent upon the structural engineers recommendations and the expansion index of the supporting soil. Since the mixing of fill soil with native soil could change the expansion index, additional -ests should be conducted during rough grading to determine the expansion index of the subgrade soil. Additional reinforcement due to the expansion index of the site soil should be provided as recommended in section G below. Additional reinforcement may also be required by the structural engineer. 4. It is recommended that the proposed perimeter slabs (sidewalks, patios, etc.) be designed relatively independent of foundation stems (free-floating) to help mitigate crocking due to foundation settlement and/or expansion. ttlement Consideration Estimated settlement, based on footings founded on firm soils as recommended, should be less than one (1) inch. Differential settlement between exterior and interior bearing members should be less than one-half (1/2) inch. 2. The majority of settlement should occur during construction. BUENA ENGINEERS, INC. December 18, 1990 -14- D. Frictional and Lateral Coefficients E. B7 -2823-P1 90-12-786 1. Resistance to lateral loading may be provided b1 f&ict�� ; acting on the base of foundations, a coefficient of fricZa 0054b may be used for dead load forces. a 0 ►_ �_ 'j cZ W 2. Passive resistance acting on the sides of foundaterx kff equal to 300 pcf of equivalent fluid weight, may be in& klifor �m resistance to lateral loading. W W o Q o ¢�_2cn►- 3. Passive resistance of soils against grade beams °'cm6�� frictional resistance between the floor slabs and tl•-e 20 Ing soils may be combined in determining the �ot 1 resistance, however the friction factor should be redue3i w of dead load forces. U_ oQ <0Ouj ►_— O 4. A one-third (1/3) increase in the quoted passive value�d4ga o used for wind or seismic loads. z J Q o w LU W W p J Retaining Walls 0 Cr Q z a cc �w U�� 1. For cantilever retaining walls backfilled with compact d= raj soils, it is recommended that an equivalent fluid c� e96 -411 p of = thirty-five (35) pcf be used for well drained 1� � x conditions. ~ ¢ ►- o w 2. The lateral earth pressure to be resisted by the retcdning walls or similar structures should be increased to allow for surcharge loads. The surcharge considered should include the loads from any structures or temporary loads that would influence the wall design. 3. A backdrain or an equivalent system of backfill dra nage should be incorporated into the retaining wall design. Backfill immediately behind the retaining structure should be a fee - draining granular material. Alternately, the back of the wall could be lined with a geodrain system. 4. Compaction on the retained side of. the wall within a horizontal distance equal to one (1) wall height should be performed by .hand -operated or other light weight compaction equipment. This is intended to reduce potential "locked -in' lateral pressures caused by compaction with heavy grading equipment. 5. Water should not be allowed to pond near the top of the wall. To accomplish this the final backfill site grade shculd be such that all water is diverted away from the retaining wa I. BUENA ENGINEERS, INC. December 18, 1990 -15- B7-2823-P1 90-12-786 Slope stability calculations were not performed due to the anticipated minimal slope height (less that 5'). If slopes exceed five (5) feet, engineering calculations should be performed to substantiate the stability of slopes steeper than 2 to 1. should be overfilled and trimmed back to competent matefid.p �EiQZUJ - G. Expansion U) o cr > �Za0w The design of foundations should be based on the°r expansion index (UBC Standard No. 29-2) of the soil. As sta cdbii e soil properties section, the expansion index of the surf oceasbillsf ie the very low (0-20) classification. During site preparation, ifCJl%w9 � thoroughly mixed and additional fill is added, the expansN� may change. Therefore, the expansion index should be eNt after the site preparation has been completed, and I Of. foundation design adjusted accordingly. a v U- wn o Z H. Additional Services 3 v o 0 0 zJQp�'W This report is based on the assumption that an adequate�prc --'0 cc of client consultation, construction monitoring and test ia-v01IMAea- performed during the final design and construction phases ��`h qo compliance with these recommendations. Maintaining Buffo o u Engineers, Inc., as the soil engineering firm from begin ning4o,-Q afl the project will help assure continuity of services. Co0P4Yna monitoring and testing would be additional services provided by our firm. The costs of these services are not included in our present fee arrangements. The recommended tests and observations include, but are not necessarily limited to the following: 1. Consultation during the final design stages of the project. 2. Review of the building plans to observe that recommendations of our report have been properly implemented inti the design. 3. Observation and testing during site preparation, grading and placement of engineered fill. 4. Consultation as required during construction. LIMITATIONS AND UNIFORMITY OF CONDITIONS The analysis and recommendations submitted in this report are based in part upon the data obtained from the six (6) borings perfcrmed on the site. The nature and extent of variations between the borings may not become evident until construction. If variations then appear evident, it will be necessary to reevaluate the recommendations of this; report. Findings of this report are valid as of this date. However. changes in conditions of a property can occur with passage of time whether they be due to natural processes or works of man on this or adjacent properties. In addition, changes in applicable or appropricte standards occur whether they result from legislation or broadening of knowledge. BUENA ENGINEERS, INC. r - i m co 0 U) w 0 U) UJ U) M Ir Q w December 18, 1990 -16- B7 -2823-P1 90-12-786 Accordingly, findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of eighteen (18) months. 0cnww>- In the event that any changes in the nature, design or locatio6 6fgffe00 building are planned, the conclusions and recommer�i¢t'�qo contained in this report shall not be considered valid unless the gt)a LU are reviewed and conclusions of this report modified or verified inptirbaLu -UJa: This report is issued with the understanding that it is the responsibil "I owner, or of his representative, to insure that the informatJB4 J%6dS recommendations contained herein are called to the attentiqp''owt:i1? architect and engineers for the project and are incorporated�M-ete- plans and specifications for the project. It is also the owners respd ' 'i or his representative, to insure that the necessary steps are -ak& that the general contractor and all subcontractors carry � �&I? z recommendations in the field. It is further understood that the. ow�gr grJhA o representative is responsible for submittal of this report to the appfd@iatg governing agencies. Z J Q o w w UJ LL 0 J �WZf"WCr Buena Engineers, Inc., has prepared this report for the exc usi LJi & Cr the client and authorized agents. This report has been prepb4& o accordance with generally accepted soil and foundation en2i�eve i r L- practices. No other warranties, either expressed or implied, aread�,atQ the professional advice provided under the terms of this agteOrff,� and included in the report. - ` � r � " It is recommended that Buena Engineers, Inc., be provided the opportunity for a general review of final design and specifications in order that earthwork and foundation recommendations may be properly interpreted and implemented in the design and specifications. If Buena Engineers, Inc., is not accorded the privilege of making this recommended review, we. can assume no responsibility for misinterpretation of our recommendations. Our scope of services did not include any environmental assessment or investigation to determine the presence of hazardous or toxic materials in the soil, surface water, groundwater or air, on, below or around this site. Prior to purchase or development of this site, we suggest that an environmental assessment be conducted which addresses environmental concerns. END OF TEXT Appendices BUENA ENGINEERS, INC. ,, cL m CU 0 I UJ c = 0 W } Cr Q LU December 18, 1990 -17- 67-2823-P1 90-12-786 1. 2. 3. 4. 5. 6. REFERENCES ocnww} ZZUmm � Envicom, Riverside County, 1976, Seismic Safety Elemeni. >- o N J _ Q Z w Greensfelder, Roger W., 1974, Maximum Credibtop ip Accelerations from Earthquakes in California, CDMG Mai S ro W UJ 0. Krinitzsky, E.L., Chang, F.K., Magnitude -Related EarthquakE G@ n8 i Motions, Bulletin of the Association of Engineering Geologistsolnw r? No. 4, 1988, Pgs. 399-423. z �_ �- cwIC) w Ploessel, M. R. and Slosson, J. E., Repeatable High`0&r LTn:d -j Accelerations from Earthquakes", 1974 California Geology . Q No. 9, Pgs. 195-199. 3: U o o 0 Seed, H. B. and Idriss, ~ w w 1982, Ground Motio-)s z �c l Liquefaction During Earthquakes. 2 w I. M. Z w° w :)a:< CC Seih, Kerry, 1985, "Earthquake Potentials Along The Sang �r WO Fault", Minutes of The National Earthquake Predictior EQYL�a n�- _ Council, March 29-30, 1985, USGS Open File Report 85-507. Ln r o w o Q Cr =QZ=WZ) Q ►- 2 < :) 0 w BUENA ENGINEERS, INC. co c m z D m z G) z m m z n U) r (D 0c) D Q p m h< Z 02 X THIS DOC::3k NT�NAS ISSUED PREVIOUSLY AND MAY NOT(REKLECT CURRENT SITE CONDITIONS AND/OR STAOARDS OF GEOTECHNICAL PRACTICE. THE CONTENT OF THE DOCUMENT SHOULD NOT BE USED OR RELIED UPON WITHOUT A REVIEW BY QUALIFIED PROFESSIONALS Init Date EARTH SYSTEMS SOUTHWEST AVF-NLJF- E50 THE ORCHARD LA QUINTA, CALIFORNIA BUENA ENGINEERS, INC. DACE 12/19/90 JOB 67-2823—P1 CLI)a � PROJECT LXAT70V -7� cn w >- Z Z CRC0 LA Ql"Tc) CL, ui V < N.Ta. LOCATIO��,V Cc w C) z 0 0 ui ui 2: ui z �- 2 � ui U) cr ui0 C) (n LD m 0 0 Z -j ..E U) Z) u- 0 0 < 0 0 Z < Lu CL �.— cl) 1: :D U) 0 C) 0 �— uj a: u 0- U) cl) W z —i < 0 — uLU- APPROXIMATE BORING LOICAT�N!jj ►— U-jj 0 co 2 w cr < Z Cc cc c uj - U) )Z�— cr0 0 oLu cr0 0 Z c/)>- 0 Uj LU < < cr < D o w THE ORCHARD LA QUINTA, CALIFORNIA BUENA ENGINEERS, INC. DACE 12/19/90 JOB 67-2823—P1 The Orchard Date: 11/20/90 Location: Per Plan BORING NO. 1 =ile No. 67-2823-P1 n. E 0 .. 3 DESCRIPTION a o m :3m o c .0 m a REMARKS a� c O >. U)cn U o o -- -- 2 E c a o o U il 0 c - 12 A 1 :Grey brown slightly SM 96.8 2.1 90 ocnwW� ZZU�Dr� - silty very fine to fine Q O - c\j - 5 sand O W >. - 8 84.1 8.8 79 0 7o¢o> -' 0za.JW _ 00-:¢ m A2: Brown clayey silty SM W W U = Q O N _ very fine to fine sand ¢ 1- Z a_ = F- 10 15 91.9 25.8Clay laye®wt = v WZUJIF-tel- � ¢�U�cn Interbedded%lays)6r012 E265 15 A 1: Grey brown slightly SM U) U O Z 23 silty very fine to fine 96.5 7.0 90 < _ O sand U o ~0� _ Z.JQQWLL WLLa J0 - - gwz�w¢ u 20 17 97.8 6.8 91 CC U¢~H¢a OZOW crC) U D�Q 2QZ2o7D 25 QDO u 12 97.2 4.6 91 30 21 A2: Brown clayey silty SM - - very fine to fine sand 35 32 Al 116.0 5.3 100+Some coarse sand ® Relatively undisturbed Total Depth = 36' - ring sample No Free Water 40 ® No recovery No Bedrock 45 - Note: The stratification - lines represent the - approx mate boundaries - between the soil types; the 50 transitions may be gradual. The Orchard Date: 11/20/90 Location: Per Plan BORING NO. 2 File No. 137-2823-P1 ° 0 E o w o DESCRIPTION (D CL � 4)o > o > ._ `° " REMARKS o .`_. cn U n o ,. a CL Cr E U) E o o 0 0 _ A2: Brown clayey silty SM ocnLLjw>- r� very fine to fine sand Z Z U M co N 7 90.7 21.1 79 <0►7- Cl: CL —QZ_ � _ 5 cn ¢ > A1: SM 95.4 5.9 89 00�� m _ 13 5UQOQ cv C1 : Brown very fine to CL Q 1- Z U) _ fine sandy very silty n- U.Z O 10 1 3 cla w w= �J 86 UJ ZOO— }- (nww�� W A 1 :Grey brown slightly SM Interbedac�Clp laffsJ c silty very fine to fine throughd�tU p O Z 15 17 sand 97.7 7.9 91 Q = O D �u N o�OCu~.Ou) LU LU - wtLaoJ� 2 C 2WZZWCr - FWUj CL 20 - 8 C1: Brown very fine to CL 83.3 37.7 71 O O - O W N O Z _ fine sandy very silty O U O j r/1}OWtu� _ clay Q :r rACC Al : Grey brown slightly SM 99.0 1 7.5 92 Interbedded C1 layers Y 25 30 _ silty very fine to fine throughout - sand 30 28 Relatively undisturbed Total Depth = 31' - - ring sample No Free Water 35 No Becrock 40 45 - Note: The stratification - lines rearesent the approximate boundaries - between the soil types; the 50 transiticns may be gradual. �. The Orchard Date: 11/21/90 Location: Per Plan BORING NO. 4 File No. 67-2823-P1 CL E o w o DESCRIPTION a o m o m a > m a REMARKS O to o «. '� CC E Z) o o U 0 _ A 1 :Grey brown slightly SM 7 silty very fine to fine 89.3 0.7 83 _ sand 5 4 849 3 0 79 Clay laver 6" thick - Scatter3d roots throughout 1 0 A 2. Brown clayey silt Y Y Y SM O CI) J W mm Z Z - 14 very fine to fine sand Q 0 0 w _ O Q Z — jZaow 00 C 15 13 90.5 3.8 79 v >VU0Q O . Relatively undisturbed FO Total D�t' v 'O - - ring sample No Free P O W = ° 20 ® No recovery No BedraZf, O S ~ W 3:Ln CC (D C :3u_OOQ Q UOWaZ 25 25 C/) U1 a: LL LLj 2JQOwtwi - WurO -jO _ 2 W Z Z WCC �a:< CC CL F- Cr 00ZOW Q 30 OZOUOJ - oWwQ =aZ=cn0 35 40 45 - Note: The stratification - lines represent the - approximate boundaries - between the soil types; the 50 transitions may be gradual. The Orchard Date: 11/21/90 Location: Per Plan BORING NO. 3 File No. 67-2823-P1 =. .W 3: > N c > .2 E a o DESCRIPTION o^ co a REMARKS C c 0 _. cn o .- U E j a o o U il0 - 7 Al :Grey brown slightly SM 92.5 3.2 86 0 co ul W } - silty very fine to fine zQ Z U a7 m 2 5sand _ 15 82.1 1 9.6 77 ~ p C1 layer. t Q z w _ U) > Interbedd� s m 76 - Q O 10 10 89.3 4.7 83 Waw ZOO n.— _ o U z 0 A2: Brown clayey siltyS(N fine LU z '-) H Scatter -ad)' Vj g5s W - - very to fine sand Cn 15 1 0 84.2 24.2 74 t� O z Q S_ - - Relatively undisturbed Total aof# w A'� o p - ring sample No Fr t@ LL, Cn (n to NoBedr&eoo�W 20 gwzzWCr H _ � �< �a ` _ C� UOOzp Cr W OzoLL = 25 ��'ooC) CC - < SCJ W 30 35 40 45 - Note: The stratification - lines represent the - approximate boundaries - between the soil types; the 50 transitions may be gradual. The Orchard Date: 11/21/90 Location: Per Plan BORING NO. 5 File No. 137-2823-131 0 — 0 _0 E ID "0 (n DESCRIPTION CL0 a) (n —m 0 (D >. co REMARKS CL 0 Z 'E0 2 CL Cc E U) 5 -.0 C- 0 0 U) I LU >- W CY) z z M co 23 A 1 Grey brown slightly silty very fine to fine sm C\j t 00 < Z W— % % sand Q> 0 5 % 0z CL LU - — -j -- : % ; % 8 90.1 19.8 79 5 U < 0 % < Scatter--(t( ArfL % throughom % U)d—C) z 0 LLJ Lij -T 10 10 A2: Brown clayey silty SM 85.2 13.6 74 W Z Z) 0 W D very fine to fine sand (n U.J > W cc U U)vi cc 0 0 z D00< S U) LL. % < 0 LLJ a-z 15C/) 0 94.4 10.9 82 C)0 — 0 C/) U) Relatively undisturbed . -- t 1 Total Djtj� DZ l_6'-J 0 ring sample z LU Cr W No Free--Mt Ct Q- 20 F��j No recovery No Becr C/) ft in Cc C) >- 0 (r, z r-t LU C/) V-j — 0 Z 0 LL 0 LU < < UJ Cr Z U) D < < LU 25 30 35 40 45 - Note: The stratification - lines represent the - approximate boundaries - between the soil types; the 50 transiticns may be gradual. �• The Orchard Date: 11/21/90 Location: Per Plan BORING NO. 6 F le No. B7 -2823-P1 a) c 0 E o DESCRIPTION o m o > ._ `� c REMARKS o c. U) o •E oC E o cn ui >- c ; U) a o o U z Z M co n 0%JQQZLU - Al : Grey brown slightly. SM u)¢ > _ 8 silty very fine to fine 91.3 3.7 85 O O a --1 J m sand �UQOQ o LU w U = 5 4 Cc i-- zcn� A2: Brown clayey silty SM w= Scatteredi 1 a Fs - - very fine to fine sand vii w Ow � w - 10 Cl: CL _ _ tz O z —� c 05. QUOwaO - 17 %A 1 : Grey brown slightly SM = _ silt%y very fine to fine `U U sand Z JQOw� Lu 0 2 1523 U. —10 2WZZwcr H M Relatively undisturbed 9 w N Total C - �fj p - - ring sample No Free te'U LL _ 20 ® No recovery p Q No owwCr ZH ? Q W 25 30 35 40 45 - Note: Fhe stratification - lines represent the - approximate boundaries - betweer• the soil types; the 50 1 1 1 transitions may be gradual. a) c m z D m z G) z m m M z n. c 3 3 Q D q0 Z m --4 v_ Nc X THIS DOCUMENT VOIS SUT SITE ED PREVIOUSLY AND NDITIONS MAY NOT REFLEC-16CURREN F G OTECHN CALOPRACTIICE. AND/OR STANDARDO CONTENT OF TI`S- E DOCUMENT SHOULD NOT BE Y I•�E . tSED OR RELIED UOPOAS 'WITHOUT A REVIEW B +ALIFIED PROFESS Init Date c�IITHWEST December 18, 1990 B-1 137-2823-P1 90-12-786 BORING/DEPTH 1 @ 0-5' 1 @ 7-10' USCS SM SM SOIL DESIGNATION Al A2 MAXIMUM 107.2 114.5 DENSITY (pcf) J U) rs 48.8 OPTIMUM MOISTURE (%) 13.9 14.0 ANGLE OF INT. FRIC. 320 310 COHESION (psf) 130 200 EXPANSION INDEX 0 0 GRAIN SIZE DISTRIBUTION (%) GRAVEL 0.0 SAND 89.4 SILT 8.0 CLAY 2.6 0.0 a U) uj >- 0.0 62.5 Z Z U m m 11.6 21.0 S(�rClay' 39.6 1 @ 30 J U) rs 48.8 S Z CL p0 - a: a) >UQOQ @ CL z4nf- C1per- O i ujZ~�~�►- uj D �; Cn 117.8 U) 3 0T w CC 0.0 �pw00Q _ _ Q 0 O Wcl- Z 13.0 27° �- w CE: w 0 cn w i o J 0 va 2wz�wCr �; 330 U�Z�a 0 v' 00 Z 0 q: 0 0 W cr, 8 2 cnZ�t'C) }OWwQ — �.. 0.0 0.0 0.0 62.5 31.3 11.6 21.0 32.0 39.6 16.5 36.7 48.8 SOIL DESCRIPTIONS: Al: Grey brown slightly silty very fine to fine sand (SM) A2 Brown clayey silty very fine to fine sand (SM) C1: Brown very fine to fine sandy very'silty clay (CL) C2: Brown slightly sandy very silty clay (CL) BUENA ENGINEERS. INC. December 18, 1990 B-2 B7 -2823-P1 90-12-786 BORING & DEPTH 1 @a 2.0 5.0 10.0 15.0 20.0 25.0 35.0 2 @a 2.0 5.0 10.0 15.0 20.0 25.0 30.0 3 t7a 2.0 5 Qa 5.0 10.0 15.0 4 t7a 2.0 5.0 15.0 5 @a 5.0 10.0 15.0 6 @a 2.0 10.0 IN-PLACE DENSITIES DRY DENSITY 96.8 84.1 91.9 96.5 97.8 97.2 116.0 90.7 95.4 92.7 97.7 83.3 99.0 103.9 92.5 82.1 89.3 84.2 89.3 84.6 90.5 90.1 85.2 94.4 91.3 105.6 % MOISTURE 2.1 8.8 25.8 7.0 6.8 4.6 5.3 21.1 5.9 6.2 7.9 37.7 17.5 7.4 3.2 19.6 4.7 24.2 0.7 3.0 3.8 19.8 13.6 10.9 3.7 11.4 BUENA ENGINEERS, INC. .RELATIVE COMPACTION 90% 5111 o U792%. C-0 :z��ME 50 uJ O w (k N W Z r- W t c to � ac 0A 3 Q C = tOn W Ute. Q" " 0 awZ~w� w a¢<-k%a r•- 0w LL 0 - 2 f�QawW-CC Q O W 79% 79% 79% 74% 82% 85% 99% B7 -2823-P1 MOISTURE CONTENT IN PERCENT OF DRY WEIGHT r 2 to �. 8 w -� .}.J~UZ U 107= �ZaQ m U OV�� ccw a CLz 0 D 106 a Z N .. cn O�ww� -31 Q c S z O � N o WO5 Q V O W Cc a W cc t� Wti p0 _ 12 14 16 H� cPJa W ��FQ.. W METHOD OF- COMPACTION U �[ ASTM D-1557-78, METHOD A or C $OIL TYPE MAXIMUM DENSITY OPTIMUM MOISTURE Al 107.2 pcf 13.9 % Boring 1 @ 0 - 5' MAXIMUM DENSITY - OPTIMUM MOISTURE CURVES ZZUm .}.J~UZ �ZaQ OV�� O�ww� Z �¢WQ Q V O W Wti p0 ��FQ.. W U �[ O O Z .� �ZOU�� B7 -2823-P1 MOISTURE CONTENT IN PERCENT OF DRY WEIGHT 0 0 N QO_�1--3. c� N 8 Q �Oa�. U m 115 U m Er � p Lu a U= OWC FW- Z N 0 z 114 a W �WO�, w z ,. Q c = U) ZO z o (n O LLJ CC LL 3 O z�¢C m Q._ w Q w } cn LL �- mQ O Z 12 14 16 =Qz=u)� ►-2<-UO w METHOD OF COMPACTION ASTM D-1557-78, METHOD A or C SOIL TYPE MAXIMUM DENSITY OPTIMUM MOISTURE A2 114.5 pcf 14.0 % Boring 1 @ 7 - 10' MAXIMUM DENSITY - OPTIMUM MOISTURE CURVES ZZVm� QO_�1--3. yF.UOW �Oa�. �UQO U= OWC FW- Z N aN�z W �WO�, ��Cw7Q ��a QU�w z�¢C wLL.o �wzZ O Z o��G B7 -2823-P 1 MOISTURE CONTENT IN PERCENT OF DRY WEIGHT C7 C i r, Q O f:. 1- CV >- 1- U O Lu �i f— N 8 V m 1.18- U m �N2� w CL U 0 z O D a 117 F - z w c w O QUOw u� O cr O t17 6 u- U) O 2 w CL f— � � Q Z w w 0) 11 13 15 2QZ=U)J Q f--�QF—p0 W METHOD OF COMPACTION ASTM D-1557-78, METHOD A or C SOIL TYPE MAXIMUM DENSITY OPTIMUM MOISTURE Cl 117.8 pcf 13.0 % Boring 2 @ 7 - 10' MAXIMUM DENSITY - OPTIMUM MOISTURE CURVES Z Z W � Q O f:. 1- >- 1- U O �ZaO ODUO �N2� U O ❑wQ QUOw ZJQW � W LL. ❑ � � Q Z w 67-2823-P1 4.0 3.5 c� C-) N ' C1-- 3.0 S ZZUmao cn 2.5 — a �~UZ W a zz Y Opa�aWc CD W 2.0 _Uri 0CL z 1.5 �nUZp LU W it W ~ m Q � � U 'S W 1 .0 O c = m�u�mp aUOwa f- 0.5 N Z�Qu'L W 0.5 1.0 1.5 2.0 2.5 C1 3. 0(0) �-�? m o 0 w O ►- >- a UO a Q cn NORMAL LOAD (KIPS / FOOT2) a: ►=-�< Da w DIRECT SHEAR DATA Soil type: Al Boring and depth: 1 (a) 0 - 5' Angle of internal friction: 32° Cohesion: 13 0 ® Samples remolded to 90 % of maximum density ❑ Samples relatively undisturbed WLL.�� W F-' B7-2823-P1 4.0 3.5 J cl�- 3.0IU S ZZUm© a0►=''3 IQ _ C/) 2.5 a J~QZLJ O = Y pOa�� CD 2.0 —UQO 0CC WW-t=1- a�vZ� z 1.5 � ►- N Q Q W U � w 1.0 � O c = �OliO� QUOwa 1— �UQhO 0.5 v0) ZJ¢lLW WILO�J 4-1 W 0.5 W 1.0 1.5 2.0 2.5 3.�0� ®W w OZOOOL NORMAL LOAD (KIPS / FOOT2) Q Z Uf < F- = = f--�Q►-�O Q w DIRECT SHEAR DATA Soil type: A2 Boring and depth: 1 (a) 7 - 10' Angle of internal friction: 312 Cohesion: 200 ® Samples remolded to 90 % of maximum density ❑ Samples relatively undisturbed f"'w t � . B7 -2823-P1 4.0 3.5 V � 3.0 O O za°C.ow}+ U- _ cn 2.5 a Y CC U2 O U) 2.0 a�►-z a�UZ4 cc H kw z 1.5 wZ��._ cn�Ov� Lu cf. w U) 1.0 H ¢UOwa O � U � � r 0.5LL C w z�QOu� U) 0.5 0OP zow 1.0 1.5 2.0 2.5 3.0oZOZ)G >- U) J � °� w ac. QpwwQ oc NORMAL LOAD (KIPS / FOOT2) ZQ 0 w 2 DIRECT SHEAR DATA Soil type: -- C1 Boring and depth: 2 Cad 7 - 10' •l Angle of internal friction: 27° Cohesion: 330 ® Samples remolded to 90 % of maximum density ❑ Samples relatively undisturbed oU3,�w>- O Lll -�~ ¢ z . �0 za°C.ow}+ �UQO� U2 a�►-z a�UZ4 O wZ��._ cn�Ov� ¢UOwa � U � � r C z�QOu� wwo gwzZua � °� w ac. TABLE NO. 2 MINIMUM FOUNDATION REQUIREMENTS* (1) (10) Footings for slab & Raised Floor Systems (2) (5) (10) Concrete Slabs 3 1/2" Minimum Thickness Weighted En All Perimeter Interior footings Premoistening control N U) -aFootings Z6 a)Expansion Y (6) for slab and raised floors (6) for soils under footings, Piers under Index C L Reinforcement Reinforcement Total piers and slabs raised floors 65 s for (4) thickness (5) (6) _� c continuous of sand o Z E m u2. o Depth below natural footings Inches &5 LL surface of ground (3) (8) and finish grade INCHES 0-20 1 6 12 6 12 12 None None Moistening of ground prior to Piers allowed Verylow 2 8 15 7 18 18 Required Required 2 placing concrete for single g (Non- 3 10 18 8 24 24 recommended floor loads only expansive) 21-50 1 6 12 6 15 12 144 top 6X6- 120% of optimum moisture Piers allowed Low 2 8 15 7 18 18 and bottom content to a depth of 21" for single 3 10 18 8 �24 24 WWF �� 4 below lowest adjacent rade. 1 9 floor loads only Y Testing Required 6X6- 1 6 12 6 21 12 144 top 6/6 WWF 130% of optimum moisture Piersnot 51-90 2 8 12 8 21 18 and bottom or #3 bars 4 content to a depth of 27" Medium 3 10 15 8 24 24 @ 24" e.w. below lowest adjacent grade. #3 bars @24" in exterior footing Testing Required and ben ' I i u slab, 9 PREVIOUSLY AN 91-130 1 2 6 8 12 12 6 8 27 12 _ M FL i -#Stop AN /O DARDS and botto CT CURR OF GE 4DOC N T -E ai� T ��V&f'l d Piers not 27 18 rTH C V TO THE Ad allowed High 3 10 15 8 27 24 4" I estW%gTa #3 bars @ t f D UPON W ITHOI�estiAg V�qJ&P JE� and hnQVAAtfiFaB ROF SSIONALS. Above 130SPECIAL DESIGN BY LICENSED ENGINEER/ARCHITEC 1"�'; '' � 01/09/90/SS 'Refer to next page for footnotes. (1) through (10) EARTH SYSTEMS SOUTHWEST 1. Premoistening is required where specified in Table 2 in order to achieve maximum and uniform expansion of soils prior to construction and thus limit structural distress caused by uneven expansion and shrinkage. Other systems which do not include premoistening may be approved by the Building Official when such alternatives are shown to provide equivalent safegucq a%wst adverse effects of expansive soils. o O o `m" C 2. Underfloor access crawl holes shall be provided �7 Po ` 'bs extending not less than six. (6) inches above adjaced E to prevent surface water from entering the foundation arecao 0 a o Q 0 3. Reinforcement for continuous foundations shall be placeLU ` Ue ass than three (3) inches above the bottom of the footings ar�d5(51�Qess than three (3) inches below the top of the stem.w 6- W w = LU 4. Reinforcement shall be placed at mid -depth of slab. T C (D o Z -- �LLC�ZQ _ 5. After premoistening, the specified moisture content of 0sill o maintained until concrete is placed. Required moistli�s Eb�nt,§(U) shall be verified by an approved testing laboratory no S cn twenty-four (24) hours prior to placement of concrete. ul w z w ° w 6. Crawl spaces under raised floors need not be pr � ~ w ¢I } except under interior footings. Interior footings whicQ Q enclosed by a continuous perimeter foundation usys w LU); CnCr equivalent concrete or masonry moisture barrier cornuIRI, Z)� Q UBC Section 2907 (b) shall be designed and con0r c dad's w specified for perimeter footings in Table 2. 7. A grade beam not less than twelve (12) inches by twelve (12) inches in cross section, reinforced as specified for continuous foundations in Table 2 shall be provided at garage door openings. 8. Foundation stem walls which exceed a height of three -;3) times the stem thickness above lowest adjacent grade shall be reinforced in accordance with Sections 2418 and 2614 in the UBC or as required by engineering design, whichever is more restrictive. 9. Bent reinforcing bars between exterior footing and s ab shall be omitted when floor is designed as an independent, "floating" slab. 10. Fireplace footings shall be reinforced with a horizontal grid located three (3) inches above the bottom of the footing and consisting of not less than number four (#4) bars at twelve (12) inches on center each way. Vertical chimney reinforcing bars shall be hooked under the grid. BUENA ENGINEERS, INC. c m z D m z Q z m m z n Q Q. Q Q_ G% Q Q_ m cQ v � nX THIS DOCUMENT VW%S ISSUED PREVIOUSLY AND MAY NOT REFLECTEF,URRENT SITE CONDITIONS AND/OR STANDARDSQOF GEOTECHNICAL PRACTICE. THE CONTENT OF TF#f DOCUMENT SHOULD NOT BE USED OR RELIED &ON WITHOUT A REVIEW BY QUALIFIED PROFESSIONALS. a _ Init Date EARTH 4YSTFMS SQVTHWEST 1 6 December 18, 1990 C-1 STANDARD GRADING SPECIFICATIONS PROJECT: THE ORCHARD - TRACTS 26524 & 26525 E 7-2823-P 1 90-12-786 CLIENT: STROTHER CONSTRUCTION ZZww>- 1. These Standard Grading Specifications have been preibar fpo the exclusive use of our client for specific application to r & — — project in - accordance with generally accepted vs®i� rid foundation engineering practices. No other warranty, E.xgr& Lbr implied, is made. 5; C)Q O m 0 WwU2Q 2. These specifications shall be integrated with the Engineer n:6 § N Qrt of which they are a Should conflicting part. statemen;sWt��}iWd between these standard specifications and theme iad �- recommendations contained in the main body of the epggriig,; w report, the latter shall govern. — � O z J W D U- 0 O Q QUOwaZ 2 f- 3. Buena Engineers, Inc., referred to as the soil engineer '3th aaldf b ° J retained to provide continuous soil engineering serv�ie-� ,' U construction of the grading, excavation and foundatior.6ph es V ,o the work. This is to observe compliance with the desigrrcVirlisz u specifications or recommendations and to allow design, ahaA�� v the event that subsurface conditions differ from that anticRW' c W U,, to start of construction. z o a J o =Q �wwQ 4. The presence of our field representative will be for ther'Pw< pi(ice oc providing observation and field testing. Our work does not include supervision or direction of the actual work of the contractor, his employees or agents. The contractor for this project should be so advised. The contractor should also be informed that neither the presence of our field representative nor the observation and testing by our firm shall excuse him in any way from defects discovered in his work. It is understood that our firm will not be responsible for job or site safety on this project. Job and site safety will be the sole responsibility of the contractor. 5. If the contractor encounters subsurface conditions at the site that (a) are materially different from those indicated in the contract plans or in specifications, or (b) could not have been reasonably anticipated as inherent in the work of the character provided in the contract, the contractor shall immediately notify the owner verbally and in writing within 24 hours. This notification shall be a condition precedent before any negotiations for "changed or differing site conditions" can proceed. If the owner determines that conditions do materially so differ and cause an increase or decrease in the contractor's cost of, or the time required for, performance of any part of the work under this contract, then negotiations shall BUENA ENGINEERS, INC. December 18, 1990 C-2 137-2823-P1 90-12-786 commence between owner and contractor to provide equitable adjustment to owner or contractor resulting therefrom. 6. Whenever the words "supervision", "inspection", or "control" appear they shall mean periodic observation of the work and the taking of soil tests as deemed necessary by the soil engineer for substantiafRI compliance with plans, specifications and design concE%V.ui m m CO 7. These specifications shall consist of clearing and*& preparation of land to be filled, filling of the land,d compaction and control of the fill, and subsidiarywork complete the grading of the filled areas to conform wgrO grades and slopes as shown on the accepted plans. r w aN 8. The standard test used to define minimum densities of work shall be the ASTM Test Procedure D 1557. Densis expressed as a relative compaction in terms of thq density obtained in the laboratory by the foregoin� procedure. 9. Field density tests will be performed by the soil engiA grading operations. At least one (1) test shall be made fgr, hundred (500) cubic yards or fraction thereof plaam minimum of two (2) tests per layer in isolated aregc sheepsfoot rollers are used, the soil may be disturbed tj several inches. Density tests shall be taken in compacfZ49 below the disturbed surface. When these tests indicMQ density of any layer of fill or portion thereof is below $Z density, the particular layer or portion shall be reworked required density has been obtained. ~ g c to m Iges, a on iZlltbe 04�1§66' 3 LL0 C 1= - CO Ic�° o CC! W 1".5 (0 f _f � t 601 M cc�4� Q until the w 10. Earth -moving and working operations shall be controlled to prevent water from running into excavated areas. Excess wafer shall be promptly removed and the site kept dry. Fill material shall not be placed, spread or rolled during unfavorable weather conditions. When the work is interrupted by heavy rain, fill operations. shall not be resumed until field tests by the soil engineer indicate that the moisture content and density of the fill are as previously specified. 11. Compaction shall be by sheepsfoot rollers, vibrating sheepsfoot rollers, multiple -wheel pneumatic -tired" rollers or other types of acceptable compacting rollers. Rollers shall be of such design that they will be able to compact the fill to the specified density. Rolling shall be accomplished while the fill material is within the specified moisture content range. Rolling of each layer shall be continuous over its entire area and the roller shall make sufficient trips to insure that the required density has been obtained. BUENA ENGINEERS, INC. M December 18, 1990 C-3 B 7-2823-P 1 90-12-786 12. Existing structures, foundations, trash, debris, loose fill, trees (not included in landscaping), roots, tree remains and other rubbish shall be removed, piled or burned or otherwise disposed of so as to leave the areas that have been disturbed with a neat cnd finished appearance free from debris. No burning shall be permitted in the area to be filled. 13. When fill material includes rock, large rocks will not be allowed to nest and voids must be carefully filled with small stones o4Xmq iva_d properly compacted. Rock larger than eight (8) inches 4 99"r will not be. permitted in the compacted fill without rEyi�(Mlo location by the soil engineer.Z max y DZa.ow 14. Organic matter shall be removed from the surface u o e g p ' fill, foundations or pavement sections are to be placed. ei � e shall then be plowed or scarified to a depth of at lead H X68) inches and until the surface is free from ruts, hummoc& zcff@er uneven features which would tend to prevent uniform c!rrmmiibn by the equipment to be used. Specific recomnapt pertaining to stripping and minimum depth of recorr.3c9fl o native soils are presented in the main body of the soil rep o w a �f—cn=DO 15. Native soil free from organic material and other cleleteric�8ig4�cr may be used as compacted fill; however, during operations the soil engineer will re-examine the nati�,s® organic content. Q < Uj Ix a I.-� �o 16. Imported material should be tested and reviewed &8�Fa Engineers, Inc., before being brought to the site. The and i(&„y &bQ1 shall be free from organic matter and other deleterious nT§"( D o 17. Where fills are made on hillsides or exposed slope areas, greater than ten (10) percent, horizontal benches shall be cit into firm undisturbed natural ground to provide a horizontal base so that each layer is placed and compacted on a horizontal Diane. The initial bench at the toe of the fill shall be at least ten (10) fleet in width on firm, undisturbed natural ground at the elevation of tl-e toe stake placed at the natural angle of repose or design slope. The width and frequency of succeeding benches will vary w th the soil conditions and the steepness of slope. 18. The selected fill material shall be placed in layers w-)ich, when compacted, shall not exceed six (6) inches in thickness. Layers shall be spread evenly and shall be thoroughly blade -mixed during spreading. After each layer has been placed, mixed and spread evenly, it shall be thoroughly compacted to a relative compaction of not less than ninety (90) percent. The fill operation shall be continued in six (6) inch compacted layers, as specifiedabove, until the fill has been brought to the finished slopes and graded as shown on the accepted plans. BUENA ENGINEERS, INC. December 18, 1990 s 19. 21 FM ME B7 -2823-P1 90-12-786 When the moisture content of the fill material is not sufficient to achieve required compaction, water shall be added until the soils attain a moisture content so that thorough bonding is achieved during the compacting process. When the moisture content of the fill material is excessive, the fill material shall be aerated by blading or other satisfactory methods until the moisture content is reduced to an acceptable content to achieve proper compaction. z z uj m m Q0 -I, - Existing septic tanks and other underground storage tae removed from the site prior to commencement of buildir2 g 11 or fill operations. Underground tanks, including connecting, _qra)ln fields and other lines, must be totally removed and tl�ec$ depressions properly reconstructed and filled. DepressiojY00 gemtag tree removal shall also be properly filled and compacteb.v, 2:►- � 0UZO The methods for removal of subsurface irrigation and ut*g 6gs~wil( depend on the depth and location of the line. One of tt ' (1l methods may be used: 1) Remove the pipe and compy5t tI in the trench according to the applicable portions of thas9 gaa recommendations, 2) The pipe shall be crushed in the 4r8rt-ti. :11� trench shall then be filled and compacted accord applicable portions of these grading specifications, )uCd :fl' p ends of the line with concrete to mitigate entrance ogecNP `ut length of the cap shall not be less than five (5) feet. To c mix shall have a minimum shrinkage. o o o w Abandoned water wells on the site shall be ca Z o # o J the requirements of the appropriate regulatory ge T0e g ry � '� strength of the cap shall be at least equal to the adjacent soils. The final elevation of the top of the well casing must be a minimum of thirty-six (36) inches below adjacent grade prior to grading or fill operations. Structure foundations should not be placed over the capped well... BUENA ENGINEERS, INC. N m 0 J. P. W. CONSTRUCTION, LLC 78-365 HIGHWAY 111, SUITE 309 LA QUINTA, CALIFORNIA 92253 0 0 0 N C/1 u j W c')ZZUmm N QO�OLu � �- ch cc �za�Lu >0<O� W W U M SOIL ENGINEERING REPORT Oca , LAS ESTANCIAS (PARCEL Me2E4x LA QUINTA, CALIFORI�IW CC cc 0 U AVO©© A0oh° W Wti O 7t�a5¢ OpyZp 42 a ac t»>.a— w File No. SS -6883-P1 98-07-770 V IV Earth Systems Consultants Southern California 79-8118 Country Club Drive Ber-nuda Dunes, CA 92201 (760)345-1588 (800)924-7015 FAX (760) 345-7315 July 16, 1998 J. P. W. Construction, LLC 78-365 Highway 111, Suite 309 La Quinta, California 92253 Attention: Mr. Blake Haddock File No. SS -6883-P1 98-07-770 Project: Las Estancias (Parcel Map 26525) La Quinta, California o 0 w W >- ZZU0300 Subject: Soil Engineering Report Update ¢ 0 P t- � tiQO ZW Presented herewith is our soil engineering report update that has been prep Estancias residential development in La Quinta, California. This development isHe�lar on Parcel 26525, which was previously rough graded as part of the OrchLRP NQI(q Homes were never constructed, however several walls were constructed subseiloL-t ip This report is based on a review of the reports referenced herein and a recent recouNslsaacR site. Our understanding of the currently proposed residential development is•,dps(� �r� information from you. tu Z �-- N ►_. 0rrUWv� In general, our review indicates that the recommendations contained in the refer s %&Dtee engineering report (Buena, 1990) were implemented during grading of the frac im ?CM our opinion that the property is geotechnically suitable for its intended residentiilise,.t additional verification and site preparation, as recommended herein. U p ►- G 7~rW9CU-W o 0 0 N co N Las ng. This report was prepared to stand as a whole, and no part of the report should be aFe teda5sed to exclusion of any other part. This report completes our scope of services in acic,42 tRour agreement dated June 22, 1998, and authorized on July 6, 1998. Other servraa �w�M &lay be required, such as plan review and grading observation are additional services ;S(OW1 filled according to the Fee Schedule in effect at the time services are provided. ZOO c W >-aw W Please contact the undersigned if there are any questions concerning th. the recommendations included herein. Respectfully submitted, EARTH SYSTEMS CONSULTANTS Southern California eE CE David Goodrich, CEG Craig S. Hilt, CE SER/pc Copies: 65. P. W. Construction, LLC 1/VTA Office 1/BD File July 27, 1.998 -1- File No. SS -6883-P1 98-07-770 INTRODUCTION This soil engineering report update has been prepared for the Las Estancias resi&ntial development in La Quinta, California. This development is to be constructed on Parcel 26525, which was previously rough graded as part of the Orchards development. A. It is our understanding that the proposed development will consist of a residential tract with utilities and landscaping. B . Structural loading information is not available at this time, however, for planning purposes, building column loads of up to 20 kips and a maximum wall loading of 1.5 kips per linear foot were used as a basis for recommendations related to the construction of the proposed buildings. All loading is assumed to be dead plus actual live loads. C. The loads indicated above are preliminary estimated values. If design loading is to exceed; these estimated values, it may be necessary to reevaluate the recommendations provided iR this report. m ocnww>- PURPOSE AND SCOPE OF WORK z z U m °° C\1 y.F-UC) Q The purpose of our services was to evaluate the site soil conditions, and to prsions and recommendations relative to the site and the proposed development. ThQ 8486P 868 work includes the following: 9V Q O= °C A W W U= a O A. Reconnaissance of the site to evaluate current site conditions. ac F_ z a-2: o 8N B. Review of the reports referenced herein. w Z W W 2 1- DW0:5 V� C. Presentation of our findings and recommendations in this report. (n CC W Ov 3 co 0 Not Contained In This Report: Q U p LU a z — DN A. Although available through ESCSC, our current scope of services did not =pc gee ft or LU any environmental assessment or investigation to deternline the presenc+girCimJor toxic materials in the soil, surface water, groundwater or air, on, below or ts vF¢.~WW¢a SITE DESCRIPTION 0c) Z w U. The Las Estancias project site consists of Parcel No. 26525, which surrounds tt *)%1lRRs81t the �c south end of Orchard Lane in La Quinta, California. This property currentlgmzsW cof ee smaller parcels. Rough grading was performed in April, May and June o-_�"'1§95 t)0NZevo Engineers as a part of the Orchards residential development. The project site area was identified in the geotechnical engineering report (Bue:ia 1990) as being underlain by a large sand dune. The report of compaction testing during grading (Buena 1991) indicates that building areas were prepared by overexcavation to a depth of at =east 3 feet below existing grade. An additional 12 inches of compaction was achieved by scarifying and recompacting the excavation bottom. However, the compaction report indicates :hat no compaction tests were performed on Parcel 2, perhaps because this parcel was constructed entirely in cut. It is therefore assumed the building area of Parcel 2 was not overexcavated and recompacted. In addition, none of the compaction tests taken on Parcel 3 were within approximately 5 feet of existing grade. This suggests that additional fill was placed subsequent to the teEting performed by Buena Engineers, Inc. EARTH SYSTEMS CONSULTANTS SOUTHERN CALIFORNIA July 27, 1998 -2- File No. SS -6883 -PI 98-07-770 Based on our site reconnaissance, it appears that the current site conditions are essentially the same as existed at the completion of grading with the exception of the construction of Several block walls and retaining walls. One retaining wall, along the boundary of Parcels 2 ar.d 3 has not been backfilled. In addition, soils have been removed from the southeast corner of Parcel 1, resulting in an approximately 3 foot deep depression. PROPOSED DEVELOPMENT We understand that the proposed development will consist of a tract of one and two story single family homes. It is assumed that the structures will be wood framed and wiE be supported on continuous footings with slabs -on -grade. We also.understand that the existing three parcels will be further divided into five smaller lots and that approximately 15,000 cubic yardls of additional fill materials will be imported onto the site. o N GROUNDWATER o cn ui w >- co ZZUm[a N ¢O—f.- The depth to groundwater in the area is generally in excess of 50 feet. Fluctuation�.iVcaC vater- levels may occur due to variations in rainfall, temperature and other factors. p ¢ Z CONCLUSIONS AND RECOMMENDATIONS 2 Z a cc w >UQO< U= 0 Based on our review of the referenced reports and a reconnaissance of the site, at � ;ehfP Sinion that, in general, the site is geotechnically suitable for the proposed residential tra&. &(Srl ou review of the compaction report (Buena 1991) suggests that the compaction teat Wt arceJ was performed to document the compaction of the deeper fill soils, and was $i►j ed to document final building area preparation, as recommended in the geotechnical e m ort«, (Buena 1990). As a result, verification of adequate compaction to the depths reC(@dzithe geotechnical engineering report will be required in the proposed building areas. Q U O w n0. z 3�cn=DO A. Site Development - Grading ca wccu-ww z-jQO—w Site grading and the bottom of excavations should be observed by a represelRo€ 62SC prior to placement of fill. Local variations in soil conditions may varMIg L:5ii7itwnal recommendations. UO i,- v) z Q w OZX00if 1. The building areas and any areas to receive fill, should be cleared of vQggtiQ�ris, and other deleterious materials. Any depressions resulting from these -2c i uld have debris and loose soil removed and be filled with suitable fill sMsk"pae�a as recommended below. No compacted fill should be placed unless the underlying soil has been observed by ESCSC. 2. Prior to construction or placement of additional fill, adequate moisture content and compaction should be verified in building and pavement areas using test holes. As recommended in the geotechnical engineering report, soils should be compacted to a minimum of 90% relative compaction to a depth of at least 2 feet below the bottom of proposed footings. If these requirements are not met, additional moisture conditioning and/or compactive effort will be required. 3. Fill soils should be placed in thin lifts, not exceeding 8 inches in loose thickness, moisture conditioned, and wheel rolled to achieve a minimum of 90% relative compaction. EARTH SYSTEMS CONSULTANTS SOUTHERN CALIFORNIA w N D N co W caN 10 - cc W July 27, 1998 B . Site Development - General -3- File No. SS -6883-P1 98-07-770 The following general recommendations listed in this section are in addition to those listed in the "Grading" section A above. 2. Rocks larger than 3 inches in greatest dimension should be removed from fill or backfill material. 3. Import soil used to raise site grades should be equal to or better Clan on-site soil in strength, expansion, and compressibility characteristics. Import soil will not be prequalified by ESCSC. Comments on the characteristics of import will be given after the material is on the project, either in-place or in stockpiles of acequate quantity to, complete the project. g N 4. Areas around the structures should be graded so that drainage is p@i��i gl awap from the structures. Gutters and down spouts should be considered as*LYoto onve§" water out of the foundation area. Water should not be allowed to *tea nea% pavement sections.p < > :3Z0- LU C. Excavations O O V cc Q 0 1. Excavations should be made in accordance with applicable regulatioW _f r site exploration and knowledge of the general area, we feel there is a poten�i�f�r�n ng o relatively deep site excavations (i.e. utilities, etc.). Where snc@ ►-sofa fls encountered, lateral bracing or appropriate cut slopes should be provicMd O UccUJ UU N 2. No surcharge loads should be allowed within a horizontal distance n eaSZcethey top of the excavation slope, equal to the depth of the excavation. Q v O W a Z �VOiDO N D. Utility TrenchesW W 0 U) Z-J¢OWuw. 1. Backfill of utilities within road right-of-way should be placed in con WQ the requirements of the governing agency (Water District, Road DepartrnaA, . °C a UH -00 oCo 2. Utility trench backfill within private property should be placed in conf Pt# the provisions of this report relating to minimum compaction standards. J pre"�_ ha,� ice lines extending inside of property may be backfilled with native scilR e5to a minimum of 90% of maximum dry density. ' 1-- Z)O Backfill operations should be observed and tested by ESCSC, to monitor compliance with these recommendations. STRUCTURES Based upon the results of this evaluation, it is our opinion that the structure foundations can be supported by firm and dense soils as recommended above. The foundation recommendations contained in the geotechnical investigation report (Buena Engineers, 1990) remain applicable for single story structures, or two story structures with one supported floor. All footing excavations should be observed by a representative of ESCSC pr --or to placement of form boards and reinforcing steel. Compaction testing should be performed to verify that the footings and slabs will be supported on firm and dense soils. Where these tests indicate less than 90% relative compaction, additional moisture conditioning and compaction effort may be required. EARTH SYSTEMS CONSULTANTS SOUTHERN CALIFORNIA F- N W f - D W N W F- W July 27, 1998 -4- File No. SS -6883-P1 L 98-07-770 ADDITIONAL SERVICES This report is based on the assumption that an adequate program of client consultation, construction monitoring and testing will be performed during the final design and construction phases to check compliance with these recommendations. Maintaining Earth Systems Consultants, as the soil engineering firm from beginning to end of the project will help assure continuity of services. Construction monitoring and testing would be additional services provided by our firm. The costs of these services are not included in our present fee arrangements. The recommended tests and observations include, but are not necessarily limited to the following: Consultation during the final design stages of the project. 2. Review of the building plans to observe that recommendations of our report have been properly implemented into the design. oU)UJ ZZUmm cY) 3. Observation and testing during site preparation, fine grading and placement of &Firseod fill' —J��QZW � 4. Consultation as required during construction. o p0a�X m LIMITATIONS AND UNIFORMITY OF CONDITION V a O Q o IW92:�-- The analysis and recommendations submitted in this report are based on as ~ m1wf the referenced reports and our reconnaissance of the site. The nature and extent of rii�q�rJs n soi conditions at the site may not become evident until construction. If variations the t& tzident it will be necessary to reevaluate the recommendations of this report. N W C t2 a: 0zQ c Findings of this report are valid as of this date. However, changes in conditions acan— occur with passage of time whether they be due to natural processes or works or adjacent properties. In addition, changes in applicable or appropriate standards o o 1.- l r jey result from legislation or broadening of knowledge. Accordingly, findings of tt_Ws�t4t mmLq be invalidated wholly or partially by changes outside our control. Therefore, this r (WQ 0su eat to review and should not be relied upon after a period of one year. ¢ Z z a a f.. w In the event that any changes in the nature, design or location of the buildingWS �,trm� the conclusions and recommendations contained in this report shall not be considerePAlj4 unjs4 the changes are reviewed and conclusions of this report modified or verified in writin' >- ow w This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to insure that the information and recommendations contained herein are called to the attention of the architect and engineers for the project and are incorporated into the plans and specifications for the project. It is also the owners responsibility, or his representative, to insure that the necessary steps are taken to see that the general contractor and all subcontractors carry out such recommendations in the field. It is further understood that the owner or his representative is responsible for submittal of this report to the appropriate governing agencies. ESCSC, has prepared this report for the exclusive use of the client and authorized agents. This report has been prepared in accordance with generally accepted soil and foundation engineering practices. No other warranties, either expressed or implied, are made as the professional advice provided under the terms of this agreement, and included in the report. It is recommended that ESCSC, be provided the opportunity for a general review of final design and specifications in order that earthwork and foundation recommendations may be properly interpreted and implemented in the design and specifications. If ESCSC, is not accorded the privilege of making this recommended review, we can assume no responsibility for misinterpretation of our recommendations. EARTH SYSTEMS CONSULTANTS SOUTHERN CALIFORNIA o E` 9 . � \'O § D ƒ27 -h � 00 9�D CD K A /• ) § § » q � CD go� 77`z� 0 \ $ k n �7%% kRi �0 k CD s. 8- ta.§ P, co CD 7CD \ 2 C § § o_ § El / § k k. . n§§� o e n ® THIS DOCUMENT WAS ISSUED PREVIOUS/ D MAY NOT REFLECT CURRENT SITE CON E AND/On STANDARDS OF GEOTECHN|CALPR Z ® THE CONTENT OF THE DOCUMENT SHOULD N�A �§' 7 USED OR RELIED UPON WITHOUT A REVIA BB$ cn QUALIFIED PROFESSIONALS. 7 0 & AA' m m � 20"7' � hi 00 Date w EARTH SYSTEMS SOUTHWEST . 3 q E o �July 27, 1998 -6- Fi-e No. SS -6883-P1 98-07-770 References Buena Engineers, Inc., 1990, Geotechnical Engineering Report, The Orchard, Tracts 26524 and 26525, La Quinta, California, File No. B7 -2823-P1, Document No. 90-12-786, dated December 18, 1990. o Un w >- Buena Engineers, Inc., 1991, Report of Testing and Observations During Grad� ,`' uprchar Tracts 26524 and 26525, La Quinta, California, File No. B7-2823-P3,}`DY�cc n No. _11 09-764, dated September 24, 1991. J — Q Z w Wo¢o> oZa Buena Engineers, Inc., 1992a, Report of Field Densities, Blockwall Backfill aid Dryv§l�"Backf' , The Orchards Residential Tract 26524 and Tract' 26525, La Quinta CaliW MilzleiNo. ] - 2823-P3, Document No. 92-01-719, dated January 15, 1992. Cr Z 1 Buena Engineers, Inc., 1992b, Report of Field Densities, Retaining Wall Ba fil 1POrc , Parcel l - PM 26525, La Quinta California, File No. B7 -2823-P3, D�r_No. 92-0 - 752, dated June 26, 1992. cr �w v w _ tL0�Q ¢UOwaZ ►- �Up►=-OO w¢U-o(n U)wU- wILoOJ Z. :DCr: Fa- W ¢a F- v►—tnf"¢o 00¢ZCw cn } cn OZLL OO�- -�F- -J pwwQ Q Cr Q ►'�QO w EARTH SYSTEMS CONSULTANTS SOUTHERN CALIFORNIA