Loading...
672, Construct a new garage in fron, Studies & ReportsT.I.N. ENGINEERING COMPANY Geotechnical • Structural • Environmental 17834 Bailey Drive • Torrance, CA 90504 Tel: (310) 371-7045 Fax: (310) 371-5856 Ms. Paige Ledeman #1 Pinto Road Rolling Hills, California 90274 File No.: 030847 June 11, 2003 SUBJECT: Limited Soil and Geologic Engineering Investigation and Report for Proposed One -Story Garage to Replace Existing Enclosure at #1 Pinto Road, Rolling Hills, California Dear Ms. Ledeman: In accordance with your authorization, we have completed the subject investigation for the proposed one-story garage to replace an existing enclosure at the subject site. The work was performed within the terms of your authorization using the degree of care and skill ordinarily exercised under similar circumstances by geotechnical and geologic engineers practicing in this locality, and in accordance with generally accepted foundation engineering procedures. The investigation included review of available soil and geologic files and reports, excavation of two test trenches, specific field soil and bedrock logging and sampling, laboratory soil sample tests, and engineering analyses summarized herein. In the opinion of the undersigned, the accompanying report has been substantiated by the available field and laboratory data, and presents the design information you requested. Introduction This investigation was made for the purpose of obtaining information on the subsurface soil condition in the area of the proposed garage on which to base conclusions and recommendations for suitable foundation designs for the proposed garage at the subject property. It is our understanding that the proposed garage is to consist of one-story, light wood frame, residential building construction. The area of the proposed garage is currently occupied by an existing concrete slab with a shed structure over. This shed structure is to be converted to a new one-story garage. The vicinity map of the subject site is shown on Plate 1. The on -site site plan was reproduced from the regional geologic map and is enlarged to 1" = 20' by us as shown on Plate 2.1. The regional topographic map is shown on Plate 2.2. It shows that the subject site is located within the boundaries of the Flying Triangle landslide. This report is not intended as a bidding document, and any contractor reviewing this report should draw their own conclusions regarding required construction quantities and procedures. Ms. Paige Ledeman -2- June 11,2003 Field and Laboratory Investiaation On May 22, 2003, two exploratory hand -dug test trenches were excavated at the locations shown on the attached Plate 2.1. Cross section A -A', drawn through the area of the proposed garage, is shown on Plate 3. The earth materials encountered were logged by us as shown in the Trench Logs presented on Plates 4.1 and 4.2. Representative samples of the earth materials encountered were obtained as appropriate. Intact samples were obtained by carefully driving a hand sampler loaded with thin walled tubes by hand into the trench walls and bottom. Bulk samples were obtained from the trench castings. Samples were returned to our laboratory for determination of their in -situ moisture content and density, classification, direct shear, and other appropriate testing. The results of the in -situ moisture and density tests are summarized in the attached Plate 5. Plots of direct shear test data are presented in the attached Plate 6.1. Plots of stress -strain relationship for the direct shear tests are shown on Plate 6.2. See the attached Appendix A for specific information on testing methods. Location and Site Conditions The subject site is located on the southerly side of Pinto Road, approximately 4,000 feet southeasterly from the intersection of Portuguese Bend and Crest Roads within the City of Rolling Hills of the Los Angeles County. The subject site is located within the boundaries of the Flying Triangle landslide. The subject site consists of a level building pad for the existing house, an approximately 2:1 bedrock cut ascending slope to the north, and an approximately 3:1 natural descending slope to the south. The level building pad is presently occupied by a one-story residential building. An existing pool is located on the north side of the house. The 2:1 bedrock cut slope, approximately 26 feet high, ascends from the north side of the pool to Pinto Road. The 3:1 natural slope, approximately 45 feet high, descends from the south side , of the house to Klondike Canyon The subject site is accessed by a private driveway off the street. Drainage is chiefly by sheet flow to the southern descending slope area. Flvina Triangle Landslide The subject site is located within the boundaries of the Flying Triangle landslide. The Flying Triangle landslide occupies an area of approximately 70 acres on the south side of the crest of Palos Verdes Hills overlooking Portuguese Bend. It was observedto be moving since March 1980, but may have initiated movement as early as 1974. The current landsliding represents reactivation of a relatively large complex compound ancient landslide of probable Pleistocene age unrelated to the infamous Portuguese Bend landslide, Cause of movement is directly related toa period of unusual heavy precipitation during the last decade, ending in March T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledeman - 3 - June 11, 2003 1983, in common with activation of many other ancient landslide along the coastline of Los Angeles County. Most of the homes in the Flying Triangle landslide which experienced severe damage were damaged during the early stages of landslide movement. It is understood that the present rate of movement is lower than in the later 1970's or 1980's. Recent efforts to remove water from the area of the landslide have apparently been successful in slowing the rate of movement. Some portions of the landslide appear to have stopped moving entirely. Public and private roads are continually being damaged and repaired within the active landslide and many utility lines have been placed above the ground with flex joints to allow for the continual landslide movement. The Flying Triangle landslide is an ancient landslide that is likely several tens of thousand of years old that has recently become reactivated. Earth Materials The site earth materials encountered in the exploratory trenches were assumed to be representative of those throughout the area of proposed development. Variations in depth, thickness of strata, and the type of earth materials expected may occur. The design and construction procedures should take this into account. Modification of plans may be required during project construction. Fill and Disturbed Bedrock Fill, approximately up to 6 inches deep, was encountered in all the exploratory trenches. The encountered fill consisted of potting soil, sloughing soil, and leaves. Below the fill, disturbed bedrock was encountered. The encountered disturbed bedrock consisted of light brown, orange brown, and gray, moist, firm, bedded, siliceous shale. The observed bedding planes of the encountered bedrock were dipping approximately from 10 to 22 degrees to the south. It appears that the observed bedding planes were to be daylighted. Groundwater No groundwater was encountered, nor were any springs or seeps observed during the course of this investigation. However, it should be noted that fluctuations in the level of the ground water may occur due to variations in rainfall, temperature, and other factors not evident at the time of our study. Corrosion Potential Chemical laboratory tests were conducted on the existing soil materials obtained from the exploratory trenches during the field investigation for evaluation of a potential of soil corrosion and the attach on concrete by sulfate soils. The testing results are presented below: T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledeman 4 June 11, 2003 SAMPLE LOCATION T-1 @ 2.0', Bedrock MIN. CHLORIDE SULFATE RESISTIVITY PH (PPM) (PPM) (OHM -CM) 7.86 270 360 ppm 1,510 Engineering Analysis Evaluation of Deep -Seated Slope Stability Due to the subject site located within the boundaries of the Flying Triangle landslide, the deep-seated slope stability at the subject site is considered grossly unstable. Evaluation of Local Slope Stability of Northern Ascending Slope The bedding planes of the bedrock encountered in the exploratory trenches indicated that the dip angles of bedding are to be daylighted. Therefore, the northern ascending slope was evaluated for a potential wedge failure along the daylighted component of bedding. The evaluation of the potential for failure along the daylighted component of bedding is shown in attached Plate 7. The computations indicate a minimum factor of safety against a wedge type failure for the northern ascending slope which is greater than 1.5 for static and is greater than 1.1 for seismic, the Building Code minimum. It is our opinion that the northern ascending slope, between Pinto Road and the subject site, can be considered as locally stable. Conclusions and Recommendations General Based upon our evaluation of the site and soil conditions, the foregoing data and information, the following conclusions and recommendations are made. Construction of the proposed one- story garage to replace an existing enclosure is feasible from the standpoint of geotechnical engineering and geologic practice at the subject site, provided all recommendations and conditions made herein, are incorporated into all design. The thickness of earth materials and the depths to foundation stratum indicated in this report are based on the data obtained from the locations of the exploratory trenches. The actual thickness of earth materials and depths to foundation stratum between the exploratory trenches may vary from that indicated herein. The design and construction procedures should take this into account. 1. The proposed one-story garage to replace an existing enclosure may be founded on spread footings penetrating into the underlying firm disturbed bedrock as specified below. The depth to the firm disturbed bedrock is estimated to be approximately 6 inches below the T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledeman - 5 - June 11, 2003 existing grade, although it may be deeper. All proposed continuous footings and isolated pad footings should be laterally tied with grade beams. Alternatively, mat foundations may be utilized. 2. It should be noted that the subject site is located within the boundaries of the Flying Triangle landslide. The slide mass above the slide plane has a potential for future slide movement. Structural distresses resulting from the slide movement may occur in the areas of the existing house and the proposed garage in the future. Structural distresses may result in cracks, separations, tilting up on walls,, ceilings and/or floors of the garage. Current and future owners should be aware of that possibility and be responsible, accordingly. 3. The on -site disturbed bedrock was tested for sulfate content. Sulfate content over 150 ppm was detected. Therefore, It is recommend that the type II cement be utilized for this project. Spread Footing Foundations Spread footings founded into disturbed bedrock may be used to support the proposed garage. The following design criteria for new foundation are considered appropriate. Allowable Bearing Capacity 2,000 psf Minimum Embedment Below Lowest Adjacent Grade and into Firm Disturbed Bedrock One -Story 12 inches Minimum Width of Spread Foundation: One -Story 15 inches All continuous footings should be reinforced with a minimum of four #4 steel bars, two placed near the top, and two placed near the bottom of the footings. Lateral Design Resistance to lateral loading may be provided by friction acting at the base of foundations and by passive earth pressure within firm disturbed bedrock. An allowable coefficient of friction of 0.40 may be used with the dead load forces. For spread footings in firm disturbed bedrock the allowable passive earth pressure may be computed as an equivalent fluid having a density of 500 pounds per square foot per foot with a maximum earth pressure of 5,000 pounds per square foot. T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledernan - 6 - June 11, 2003 When combining the passive and friction values for calculating the lateral resistance, the passive component shall be reduced by one third. The vertical and lateral bearing values indicated above are for the total of dead and all frequently applied live loads and may be increased by one-third for short duration loading which includes the effects of wind or seismic forces. Seismic Coefficients The subject site is located approximately 7 kilometers southerly of the Palos Verdes fault. Therefore, the following seismic coefficients should be utilized for designs of the proposed structures at the subject site: • Soil Profile Type: SB • Near Source Factor, Na = 1.0 • Near Source Factor, N„= 1.13 • Seismic Zone Factor, Z = 0.40 • Seismic Coefficient: C, = 0.40 Nv • Seismic Source Type: B Temporary Construction Excavations Excavations will be required for the proposed construction. The excavation is expected to expose on -site soils which are not suitable for vertical excavations over five feet. Portions of excavations over five feet should be trimmed to a 1:1 slope gradient. All excavations, should be stabilized within 30 days of initial excavation. Water should not be allowed to pond on top of the excavation nor to flow toward it. No vehicular surcharge should be allowed within five feet of the top of cut. All safety provisions of Cal OSHA and other related statutory agencies should be adhered to, especially as related to support of adjacent structures. Temporary shoring should be designed for an active equivalent fluid pressure of 30 pounds per cubic foot. Slabs On -Grade The on -site soils should be considered as expansive soils. Slabs should be cast over a minimum of two inches of vibrated sand placed on firm, compacted subgrade soil. The subgrade soil should be proof -rolled to remove any soft spots prior to covering of sand bedding. The subgrade soil should be re -moistened at least 5% above the optimum moisture content prior to covering of concrete slab. Slabs should be reinforced with a minimum of #4 T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledeman - 7 - June 11, 2003 rebars at 18 inches on center each way. All rebars in slab should be doweled into the stem wall of footings or into foundations. Slabs should be protected by a polyethylene plastic vapor barrier. The barrier should be covered with a minimum two-inch layer of clean sand to prevent punctures and aid in the concrete cure. A minimum 4 inch concrete slab should be designed for interior and exterior concrete slabs and flatwork over expansive soils. As is typical in reinforced concrete construction, cracking of concrete can occur and is a common process. Reinforcement and crack control joints are intended to minimize this risk. In addition, irregularities of new slabs are common. A completed slab is generally not perfectly level and not free of some type of cracking. Gradinci The General Earthwork Specifications, Appendix B, should be used in preparation of the grading plans and job specifications where engineered fills are used and constitute our definition of an engineered fill. We should review all documents prior to submittal for statutory permits or contracting in order to ascertain that the intents of our recommendations are conveyed. Drainaae Control Control of soil moisture is essential for the long term performance of improvements, particularly those located on or near expansive soils. All roof and surface drainage should be conducted away from the development in engineered non -erosive devices to a safe point of discharge. No site nmoff drainage should be allowed to cross over the tops of slopes except in engineered non -erosive devices. Slabs and planted areas immediately adjacent to the dwelling or appurtenant structures should slope away from said structures to mitigate pooling of water. All slabs and planted areas should be sloped to drain to a safe point of collection. Slabs should have a minimum slope of one percent and planted areas a minimum of three percent. All roof drainage should be collected in eave gutters that discharge directly into engineered non -erosive drainage devices. All joints in slab and swales should be maintained sealed with an appropriate joint compound. Drainage devices shall be provided as specified by the Building Code and Grading Ordinances. Declaration for Compliance with Buildinci Code Section 111 It is the opinion of the undersigned, based upon data obtained as outlined in this geotechnical engineering report that if constructed in accordance with our recommendations, and properly T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL. ENVIRONMENTAL Ms. Paige Ledeman - 8 - June 11, 2003 maintained, the proposed garage construction would not adversely impact the stability of the underlying landslide complex, and that the proposed garage would have no adverse effect on the geotechnical stability of property outside the building site. Plan Reviews Final development plans should be reviewed by this office to ascertain that the general intents of the recommendations of this report have been incorporated into the plans. Additional structures not analyzed during this investigation should be reviewed by a representative of this office. On -Site Construction Reviews On -site construction reviews of all grading, drainage, and foundation work should be performed by a field representative of this office to ascertain compliance with the recommendations of this report. Final grading and/or construction should be observed and a written observation form or report issued by this office stating that the work meets the recommendations of this report. The stages at which our on -site construction reviews are to be performed should include, but are not necessarily limited to, the following stages of work: 1. Observation of footing excavations prior to placement of form boards or reinforcing steel. 2. As called for in Appendix B for on -site construction reviews and testing of all grading work. 3. During proof rolling of subgrade soil and pre -moistened subgrade soil to at least 5% above the optimum moisture content before placement of base material or reinforcing steel, and again following the placement of base material prior to placing reinforcing. 4. Observation of installation of drainage structures and completion of all work. All work and materials should comply with the latest applicable specifications of the City of • Rolling Hills. Permits Design and construction should be carried out under applicable conditions and permits of the City of Rolling Hills Building Code and other concerned statutory authorities. T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledeman 9 June 11, 2003 Remark The conclusions and recommendations submitted in this report are based in part upon the data obtained from two trenches and site observations during the exploration operations. The nature and extent of variations between the trenches may not become evident until construction. If variations then appear evident, it will be necessary to reevaluate the recommendations of this report. No warranty is made nor should any be construed that deep- seated soil or geological weaknesses may notexist below the depths explored. This office shall be notified if any unusual conditions differing from that disclosed by this report are encountered during construction. In the event of any change in the assumed nature, or design of the proposed project as planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed by this office and the conclusions of this report modified or verified in writing. This report is issued with the understanding that it is the responsibility of the owner, or of their representative to insure that the information and recommendations contained herein are called to the attention of the architect and engineers for the project and incorporated into the plan, and that the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. This report has been prepared for the exclusive use of the client and authorized agents, and in accordance with generally accepted soil and foundation engineering practices. No other warranties either expressed or implied are made as to the professional advice provided under the terms of this agreement and included in the report. It is recommended that this office 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 specifications. As a condition for use of this report the above described "Plan Reviews" and "On -Site Construction Reviews" are to be performed. (If this office is not accorded the privilege of making the recommended reviews, we can assume no responsibility for misinterpretation of their recommendations). The statement contained in this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they be due to natural processes or to the works of man, on this or adjacent properties. In addition, changes in applicable or appropriate standards occur, whether they result from legislation or the broadening of knowledge. Accordingly the conclusions of this report may be invalidated, wholly or partially, by changes outside of our control. T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledeman - 10 - June 11, 2003 Thank you for this opportunity to be of service. If you have any questions regarding this report, please contact the undersigned at the letterhead location. Very truly yours, T.I.N. ENGINEERING COMPANY Tony S. C. Le M.S., P.E. Project Engineer TSCL:ir v¢G. k�°c No. 16 FZ CERTIFIED ENGINEERING GEOLOGIST Exp.(--?3 C. E. G. #16 Enclosures: Vicinity Map Plate 1 Site Plan Plate 2.1 Regional Topographic Map Plate 2.2 Cross Section A -A' Plate 3 Test Trench Logs , Plates 4.1 - 4.2 Moisture Density Test Results . Plate 5 Direct Shear Test Results Plate 6.1 Plots of Stress -Strain Relationship Plate 6.2 Local Wedge Slope Stability Analysis Plate 7 Exploration and Laboratory Testing Appendix A General Grading .Appendix B Distribution: Client (5) T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL ``:?o S2 i `i BOWIO s p� ' • \y> �y"` . $i it 1\'4'' .i ^ ib �♦ ``obi ( 5.:>' . iy . OE,DR;,FF - -_ r `'m Y. \ ,�`';•' ` op 1.. Rol _ e. `'- % a \ y= g ?.., • O,p ` 4 F `(1,P `f CP 2£ o .oJR y I 'rN� B�Np R1N� RD ,nr L': '" \�`.,RD s-' -- / IT, ar' R SIEITR)WXR.t -,. iim II qpy ♦N�, '' 1 Y-! '� ▪ ,�.� / y J ..-Po e' "ti y\c -- • DAUNT N•R LA RAY < P44,, �45e or 4300 LFSS ��� r •LINOA �O TR ,.: ry�0 PARK `� TR 9 !r '` 5 d'snlSlATE $ 3.tHfG` O,P `PI oq DR /SR7 yr.Df 4P1411, , .c. WtEI� PgIO 4,l yENOEs PALOS �.p�RSE Dq S • DR 900 OR S u SEE'7 JG 1 HYANNIS IN 2 CAPE TER 1 FREEPORT TER ' 4 PORTSMOHTN LH R YA SITE) VICINITY MAP 4F4 G DELUNA" ▪ 1IOO '+� NNRYNOUNT PALOS VERDES COLLEGE D04) . soma, �� , HILL 4ey pRUNN I' - .. -•wNG P", -ix."� of .! p\,ERI '`,, L,y ,SODD RDP- FR ,, ti ,,...'.::•,:: �N S r I M ' (LO � F//�p��51/EEiGR S ''NA_,. .SLGHrOR 4y i �9eerRD `�^..e., ,I r ,\,e+'CAE CpApYiON f/.DE,E• [LE DI .Il. .° i� S0 hr N D-i "`,1 R.D .. s! : QPE S'ACE 1 p m, ' AO ,\ SPpp�EBACK,+ ,• � 3 ��,.� r ` R V V , PP '• 4 ''y ^, N �I r GNP4P Sri SO a ati$,` • �' Ji - '''\ 1 rN�/iN ., :: BR� O.p4P GATE .., vpp i' d—Rr: ��r,' sj3 PO4?:-ills_ GG ~e �p0� 1, F ``y;. za BEND` ���� � aof6 Nasr ��ti5 3 sr� v � IFRr e r gi r < ,`^ ;'�•, WAq�p� \ \y � RD'%rpP6� y� VEL EL 7 1 ➢ "'^ F;='7.'J•i �r�47'' "�"' �(""' , ` �+`E 1 SANTA 0.ENA DR' g O ` Y",y�7• RD \ � dnc �T,'�l SPOR .� p� o o TOS ANINI�" =' 180D 8 6Py RFATA ' ;yam ,/-,.,..: " v`S . ROCRIxW�DyE A r• R :' m GOLDEN SPU R . DR I\ pHES7 RFIELD \ COAy RG G. ?. (' `I Y.,- . LN 1 I y N,�R� VAN DNRAJAN „.'� 00 CP OTILDA• Lry, f�$ . qA> .':Pf2oD oM c. .SpPRTAZ'\D. ' pDT1TH GFk, u i c INT WADE w Nw wFiA, SOURCE: The Thomas Guide, 1996 Sheet No. 823, Los Angeles County JOB NO.: 030847 DATE: June 11, 2003 SITEMs. Paige Ledeman #1 Pinto Road, Rolling Hills, California fRIFNOSMIP PARK„ (, 0000NNUY/0Y vAu %11D ' I COMBREDRg '.;r1 S\+' .IHIAWYTE SVVAC m Vq N,IQ pN reOO �L n 0014ENOR IDTH IHISTLEN000 PARK PLAZA ALP i ^I'S-C'LOH,y a'141(, `,Nr i r•e;Azyf ROBEgl�♦♦ q qf.- APE,. 4 NAVAc °! `',`$`\II. AV RESERVgTIQ'LJ. �, ES$.OR_] OH Py ESTMONT 1000 STONEW000__ CT 1HER-RN- 2a PECKr, ieE4u0_ yySUMMERLAND Q OFARRELL SST AV g 1400x Z' SEPULVEDA 3 ST SANTA CRR i ST 4 = 1ST ST N 8 2N0 ST J•Z - C,a 70.0 a "' ST ��55 SAN PEORO PENINSULA A. HOSPITAL, W 6TH ST w ST c, IN 7TH IS11111. 0 W -' 8TH 5 12ST 9T`H I1300 ST Ia NL TN ST N7'0/ n rn J\ ' W8I12TH 00.kro ST AJf.4t(ill�p ' 1WTN 75r'I ST ..,o 1300 11111 1GTH ' _':af fq ST ;I , I-T 1 1 41 ST MHITi1 1< .AGE 4.g4 1ST SCALE 1" = 2,400' PLATE 1 T.I.N. ENGINEERING COMPANY 17834 BAILEY DRIVE •TORRANCE • CALIFORNIA (310) 371-7045 der MS. PAIGE LEDEMAN #1 PINTO ROAD ROLLING HILLS, CALIFORNIA DATE: JUNE 11, 2003 JOB NO.: 030847 SCALE 1" = 20' LEGEND. t EXPLORATORY TRENCH T- 1 SITE PLAN SCALE: 1"=20' \PLATE 2.1 T.I.N. ENGINEERING COMPA .li <; ._l I` 6, r -ti NCDin POI SOURCE: SLOSSON & ASSOCIATES, GEOLOGIC MAP OF THE FLYING TRIANGLE LANDSLIDE, 1" = 200', DATED FEBRUARY 6, 1987. MS. PAIGE LEDEMAN #1 PINTO ROAD ROLLING HILLS, CALIFORNIA DATE: JUNE 11, 2003 JOB NO.: 030847 SCALE 1" = 200' ''yolr. ot- 4.4 REGIONAL GEOLOGIC MAP SCALE: 1" = 200' ti `-9:09 90 eao deo 09v 900 ,irk y 9i U ti `'\ j"-----.....::,-; ...., PLATE 2.2 T.I.N. ENGINEERING COMPANY g6v— f2Koro5ap iC" iAcrt EIrT Ti\ I a 84-D T____--�_ ,.-- o f Tel: 17II °° ''ifi-r.ry CI'os s SAC' r9,NN 4 -A MS. PAIGE LEDEMAN #1 PINTO ROAD ROLLING HILLS, CALIFORNIA DATE: JUNE 11, 2003 JOB NO.: 030847 CROSS SECTION A -A' SCALE: 1"=20' (PLATE 3 T.I.N. ENGINEERING COMPANY F $ 2© r° EXCAVATED TEST TRENCH T-1 LOG 0.0' - 0.5' Fill - potting soil 0.5' - 2.0' Disturbed Bedrock - light brown and orange brown, moist, firm, bedded, moderately fractured, siliceous shale. N85W/32SW (No caving encountered. No groundwater encountered.) 0.0 0.0 .mow I I I I , 1.0 --r- - - -- 0r 1 S" 0 R13 2 - - - 1 - ; —1.0 2.0 — 2.0 3.0 r - - - - - -+ - — 3.0 I I I I I I I I I I I I I I I I I I 4.0 —.... - ; - —4.0 I I I I I I I I 5.0 6.0 - -- 6.0 7.0 — .._... r ---7.0 8.0 I 8.0 Trench No. T - 1 , Length 3.0' , Width 3.0' , Depth 2.0' THE LOG OF SUBSURFACE CONDITIONS DATE: June 11, 2003 HEREON APPLIES ONLY AT THE SPECIFIC LOCATION AND THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF JOB NO.: 030847 SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. DATE EXCAVATED: 05/22/2003 PLATE 4.1 T.I.N. ENGINEERING COMPANY EXCAVATED TEST TRENCH T-2 LOG 0.0' - 0.5' Fill - sloughing soil and leaves 0.5' - 2.0' Disturbed Bedrock - light brown, gray, and orange brown, moist, firm, bedded, moderately fractured, siliceous shale. N65E/10SE (No caving encountered. No groundwater encountered.) 0.0 1.0PISIU — I 2.0 I , I I I 3.0 - -" 4.0 -- 5.0 6.0 I I I I I I I I I I I I I I I I I i I - I , I I I 7.0- t I i I 8.0 r J L L -r Trench No. T - 2 , Length 3.0' THE LOG OF SUBSURFACE CONDITIONS HEREON APPLIES ONLY AT THE SPECIFIC LOCATION AND THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. , Width 3.0' , Depth 2.0' DATE: June 11, 2003 JOB NO.: 030847 DATE EXCAVATED: 05/22/2003 PLATE 4.2 T.I.N. ENGINEERING COMPANY 0.0 — 1.0 2.0 - 4.0 5.0 — 6.0 — 7.0 8.0 T.I.N. ENGINEERING COMPANY Geotechnical • Structural • Environmental Project : Ms. Paige Ledeman Date: June 11, 2003 MOISTURE -DENSITY RESULTS OF LABORATORY TEST, Trench Depth Moisture Content Dry Density Comment No. (ft) (% dry wt.) (pcf) T-1 2.0 22.0 95.1 Disturbed Bedrock T-2 2.0 24.1 93.2 Disturbed Bedrock PLATE 5 SYMBOL SOIL SAMPLE LOCATION DEPTH (ft) 0 C (psf) ® Bedrock - Shale, 1 Bedding, T-1 2.0 34° 790 Residual, Saturated • Bedrock - Shale, II Bedding, T-2 2.0 20° 270 Repeatedly Re -Sheared Residual, Saturated 3.0 g 0.0 0.0 1.0 2.0 NORMAL PRESSURE, KSF PLOT OF DIRECT SHEAR TEST DATA JOB NO:.030847 SITE Ms, Paige Ledeman !I l Pinto Road, Rolling Hills, California T.I.N. ENGINEERING COMPANY DATE: June 11, 2003 PLATE 6.1 3:0 17834 BAILEY DRIVE •TORRANCE • CALIFORNIA (3l0) 371-7045 i Bedrock - Shale, I Bedding, T-1 @ 2.0', Residual, Saturated Bedrock - Shale, II Bedding, T-2 @ 2.0', Repeatedly Re - Sheared, Residual, Saturated JOB No. : 030847 Soot — ,,.,,'• u_ 1�t ;n i — t �.., -- DATE: June 11, 2003 SITEMs. Paige Ledeman #1 Pinto Road, Rolling Hills, California .150 SHEAR DEFLECTION IN INCHES SHEAR DEFLECTION IN INCHES PLATE 6.2 T.I.N. ENGINEERING COMPANY 17834 BAILEY DRIVE •TORRANCE • CALIFORNIA (310) 371-7045 .200 o 0 = Internal Angle of Soil Friction C = Cohesion of Soil = Unit Weight of soil 0 = Potential Failure Angle A = Area of Potential Failure Wedge W = Weight of Potential Failure Wedge L = Length of Potential Slip Plane K e seism cc co-pmci ev( C�) S 1st4�C ��5 s = psf = 120 pcf 10 O = 4) ft2 = °. kips = fir; ft 0./5- a55L)1,1 I-OCM.L j r��s Zvi YEN ptoro Sim gErtAcEMENT i T i SH517 . -ntuE-or32.° AFpr p'r s1a° kph, y i p ids' / Cross SECTT (2 Ai • A -A .scALa / a = ZO w (AP- - )169 1-ct- _ 4ffie f� - 5-sh /0 %fir 2 f 7)6,5`V WCS,: a _!tI (S,4iv'-1-11,/,;tor,/ a 7 2,- z A I. elk TEMI 4, 6) ritrf ck% j 860 — 630 MS. PAIGE LEDEMAN #1 PINTO ROAD ROLLING HILLS, CALIFORNIA DATE: JUNE 11, 2003 JOB NO.: 030847 SCALE: 1" = 20' CROSS SECTION A -A' (PLATE 7 T.I.N. ENGINEERING COMPANY �'J�41 -Ict/�� izof-C,z9)c 4,1r"7 APPENDIX A EXPLORATION AND LABORATORY TESTING Exploration Field exploration was performed using a truck mounted drill rig, backhoe, or hand -diggers as noted in the report. Undisturbed samples of representative soils were obtained at frequent intervals in the boring or trench excavations. In drilling boring, the samples were obtained by driving a thin walled steel sampler with successive drops of the drilling Kelly Bar. The driving energy required for one foot of penetration is shown on the boring summary . sheets. Soil samples were retained in 2 '/2 inch diameter and 1 inch in height brass, rings. In backhoe or hand -dug trenches, undisturbed samples were obtained with thin walled tubes carefully driven by hand into the trench walls and by carving chunk samples directly from the trench walls. Classification of Soils All soils were visually classified in accordance with the Unified Soil Classification System per ASTM D 2487. Moisture and Density The moisture density information can provide a gross indication of soil consistency and delineate local variations. The information can also be used to correlate soils found on this site with soils on other sites in the general area. The dry unit weight and field moisture content were determined for selected undisturbed samples. Moisture and density were done using the ASTM D 2216 method. Direct Shear Test Shear tests were made with a direct shear machine of the strain control type. The shear tests samples are saturated to simulate expected extreme moisture conditions. Unless indicated otherwise, tests were performed at a constant rate of shear displacement of approximately 0.002 inches per minute, under vary loads and under conditions of saturation. Samples at the indicated moisture conditions, were tested at three or more normal loads in order to determine the Coulomb shear strength parameters. ASTM D 3080 method was followed to perform all shear tests. Consolidation Test. Soil settlement predictions under load are made on the basis of consolidation tests. The consolidation apparatus is designed to receive one -inch high rings. Loads are applied in several increments, in a geometric progression, and the resulting deformations are recorded at selected time intervals. Porous stones are placed in contact with the top and bottom of each specimen to permit addition and release of pore liquid. Samples are generally tested at increased content by adding water to determine the effect of water contacting the bearing soil. The normal load at which water is added is noted on the plate. Results are plotted on the "Load -Consolidation Curve." ASTM D 2435 method is followed during a consolidation test. A-1 T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL d d d N o O v O � Z v 101 C a h L' CV V o. u d c 0 E 00 ▪ ' UNIFIED SOIL CLASSIFICATION SYSTEM Major Divisions Silts 'and Clays Silts and Clays 0 50% or more o, on 0 c O a 0 2 v C ,J coarse fraction E CT J coarse fraction VI h v L 0 0 0 vt 0 z c 0 m C W No. 4 sieve on IA to CL C N 0 .0 d C to v" r 4) c C in Highly Organic Soils Group Symbols GW CP GM CC SW SP SM SC ML CL OL MH CH OH PT A-2 Typical Names Well -graded gravels and gravel -sand mixtures, little or no fines Poorly graded gravels and gravel -sand mixtures, little or no fines Silty gravels, gravel -sand - silt mixtures Clayey gravels,, gravel -sand - clay mixtures Well -graded sands and. gravelly sands, little or no fines Poorly graded sands and gravelly sands, little or no fines Silty sands, sand -silt mixtures Clayey sands, sand -silt mixtures inorganic silts, very fine sands, rock flour, silty or clayey fine sands Inorganic clays or low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays Organic silts and organic silty clays of low plasticity Inorganic silts, micaceous or diatomaceous fine sands or silts, elastic silts Inorganic clays of high plasticity,fat clays Organic clays of medium to high plasticity Peat, muck and other highly organic soils APPENDIX B GENERAL GRADING The following guidelines should be used in preparation of any grading plans and job specifications where engineered fills are used and retaining walls backfilled. We should review all documents prior to submittal for statutory permits or contracting in order to ascertain that the intent of our recommendations is conveyed. 1. The area to receive compacted fill shall be stripped of all vegetation, debris, existing fill, and soft or disturbed soils, The excavated areas shall be reviewed by the geotechnical engineer in the field prior to placing controlled, compacted fill. 2. The exposed grade shall then be benched, appropriately graded, scarified to a depth of six, inches, moistened to optimum moisture and recompacted to 90 percent of the maximum density. 3. The excavated on -site materials are considered satisfactory for reuse in the engineered fill. Remove any organic trash or deleterious materials. Remove boulders larger than 6 inches. 4. Soil shall be spread evenly in layers not to exceed 4 inches while loose for compaction by wackers. Add water as required. Only approved compaction equipment shall be used. 5. The fill shall be compacted to at least 90 percent of the maximum laboratory density for the material used. The maximum density shall be determined by ASTM D 1557- 00. 6. Periodic on -site construction reviews and field tests shall be performed by the geotechnical engineer during grading to assist the contractor in obtaining the required degree of compaction and the proper moisture content. Where compaction is less than required, additional compactive effort should be made with adjustment of the moisture content, or the layer stripped out and replaced in thinner layer, as necessary, until a minimum of 90 percent relative compaction is obtained. The contractor shall call the soil engineer to test every two feet of vertical lift. 7. No fill soils shall be placed during unfavorable weather conditions. When work is interrupted by rains, fill operation shall not be resumed until the field tests by the soils engineer indicate that the moisture content and density of the fill are as previously specified. T.1.N. ENGINEERING COMPANY GEOTECIINICAL • STRUCTURAL • ENVIRONMENTAL Tel: (310) 371-7045 Fax: (310) 371-5856 I� T.I.N. ENGINEERING COMPAIN Geotechnical •Structural • Environmental 17834 Bailey Drive • Torrance, CA 90504 Tel: (310) 371-7045 Fax: (310) 371-5856 Ms. Paige Ledeman #1 Pinto Road Rolling Hills, California 90274 File No.: 030847 January 28, 2003 SUBJECT: Limited Soil Engineering Investigation and Report for Proposed One -Story Garage Replacement at #1 Pinto Road, Rolling Hills, California Dear Ms. Ledeman: In accordance with your authorization, we have completed the subject investigation for the proposed one-story garage replacement at the subject site. The work was performed within the terms of your authorization using the degree of care and skill ordinarily exercised under similar circumstances by geotechnical engineers practicing in this locality, and in accordance with generally accepted foundation engineering procedures. The investigation included review of available soil and geologic files and reports, excavation of two test trenches, specific field soil and bedrock logging and sampling, laboratory soil sample tests, and engineering analyses summarized herein. In the opinion of the undersigned, the accompanying report has been substantiated by the available field and laboratory data, and presents the design information you requested. Introduction This investigation was made for the purpose of obtaining information on the subsurface soil condition in the area of the proposed garage replacement on which to base conclusions and recommendations for suitable foundation designs for the proposed garage replacement at the subject property. It is our understanding that the proposed garage replacement is to consist of one-story, light wood frame, residential building construction. The area of the proposed garage is currently occupied by anexisting concrete slab with a shed structure over. This shed structure is to be converted to a new one-story garage. The vicinity map of the subject site is shown on Plate 1. The on -site site plan was reproduced from the regional geologic map and is enlarged to 1" = 20' by us as shown on Plate 2.1. The regional topographic map is shown on Plate 2.2. It shows that the subject site is located within the boundaries of the Flying Triangle landslide. This report is not intended as a bidding document, and ' any contractor reviewing this report should draw their own conclusions regarding required construction quantities and procedures. Ms. Paige Ledeman - 2'- January 28, 2003 Field and Laboratory Investigation On January 14, 2003, two exploratory hand -dug test trenches were excavated at the locations shown on the attached Plate 2.1. Cross section A -A', drawn through the area of the proposed garage replacement, is shown on Plate 3. The earth materials encountered were logged by us as shown in the Trench Logs presented on Plates 4.1 and 4.2. Representative samples of the earth materials encountered were obtained as appropriate. Intact samples were obtained by carefully driving a hand sampler loaded with thin walled tubes by hand into the trench walls and bottom. Bulk samples were obtained from the trench castings. Samples were returned to our laboratory for determination of their in -situ moisture content and density, classification, direct shear, and other appropriate testing. The results of the in -situ moisture and density tests are summarized in the attached Plate 5. Plots of direct shear test data are presented in the attached Plate 6.1. Plots of stress -strain relationship for the direct shear tests are shown on Plate 6.2. See the attached Appendix A for specific information on testing methods. Location and Site Conditions The subject site is located on the southerly side of Pinto Road, approximately 4,000 feet southeasterly from the intersection of Portuguese Bend and Crest Roads within the City of Rolling Hills of the Los Angeles County. The subject site is located within the boundaries of the Flying Triangle landslide. The subject site consists of a level building pad for the existing house, an approximately 2:1 bedrock cut ascending slope to the north, and an approximately 3:1 natural descending slope to the south. The level building pad is presently occupied by a one-story residential building. An existing pool is located on the north side of the house. The 2:1 bedrock cut slope, approximately 26 feet high, ascends from the north side of the pool to Pinto Road. The 3:1 natural slope, approximately 45 feet high, descends from the south side of the house to Klondike Canyon The subject site is accessed by a private driveway off the street. Drainage is chiefly by sheet flow to the southern descending slope area. Flying Triangle Landslide The subject site is located within the boundaries of the Flying Triangle landslide. The Flying Triangle landslide occupies an area of approximately 70 acres on the south side of the crest of Palos Verdes Hills overlooking Portuguese Bend. It was observed to be moving since march 1980, but may have initiated movement as early as 1974. The current landsliding represents reactivation of a relatively large complex compound ancient landslide of probable Pleistocene age unrelated to the infamous Portuguese Bend Landslide, Cause of movement is directly related to a period of unusual heavy precipitation during the last decade, ending in March T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL . ENVIRONMENTAL Ms. Paige Ledeman - 3 - January 28, 2003 1983, in common with activation of many other ancient landslide along the coastline of Los Angeles County. Most of the homes in the Flying Triangle landslide which experienced severe damage were damaged during the early stages of landslide movement. It is understood that the present rate of movement is lower than in the later 1970's or 1980's. Recent efforts to remove water from the area of the landslide have apparently been successful in slowing the rate of movement. Some portions of the landslide appear to have stopped moving entirely. Public and private roads are continually being damaged and repaired within the active landslide and many utility lines have been placed above the ground with flex joints to allow for the continual landslide movement. The Flying Triangle landslide is an ancient landslide that is likely several tens of thousand of years old that has recently become reactivated. Earth Materials The site earth materials encountered in the exploratory trenches were assumed to be representative of those throughout the area of proposed development. Variations in depth, thickness of strata, and the type of earth materials expected may occur. The design and construction procedures should take this into account. Modification of plans may be required during project construction. Fill and Disturbed Bedrock Fill, approximately up to 6 inches deep, was encountered in all the exploratory trenches. The encountered fill consisted of potting soil, sloughing soil, and leaves. Below the fill, disturbed bedrock was encountered. The encountered disturbed bedrock consisted of light brown, orange brown, and gray, moist, firm, bedded, siliceous shale. The observed bedding planes of the encountered bedrock were dipping approximately from 10 to 24 degrees to the south. It appears that the observed bedding planes were to be daylighted. Groundwater No groundwater was encountered, nor were any springs or seeps observed during the course of this investigation. However, it should be noted that fluctuations in the level of the ground water may occur due to variations in rainfall, temperature, and other factors not evident at the time of our study. Corrosion Potential Chemical laboratory tests were conducted on the existing soil materials obtained from the exploratory trenches during the field investigation for evaluation of a potential of soil corrosion and the attach on concrete by sulfate soils. The testing results are presented below: T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledeman 4 January 28, 2003 SAMPLE LOCATION T-1 @ 2.0', Bedrock MIN. CHLORIDE SULFATE RESISTIVITY PH (PPM) (PPM) (OHM -CM) 7.86 270 360 ppm 1,510 Enaineerina Analysis Evaluation of Deep -Seated Slone Stability Due to the subject site is located within the boundaries of the Flying Triangle landslide, the deep-seated slope stability at the subject site is considered grossly unstable. Evaluation of Local Slope Stability of Northern Ascendina Slope The bedding planes of the bedrock encountered in the exploratory trenches indicated that the dip angles of bedding are to be daylighted. Therefore, the northern ascending slope was evaluated for a potential wedge failure along the daylighted component of bedding. The evaluation of the potential for failure along the daylighted component of bedding is shown in attached Plate 7. The computations indicate a minimum factor of safety against a wedge type failure for the northern ascending slope which is greater than 1.5 for static and is greater than 1.1 for seismic, the Building Code minimum. It is our opinion that the northern ascending slope, between Pinto Road and the subject site, can be considered as locally stable. Conclusions and Recommendations General Based upon our evaluation of the site and soil conditions, the foregoing data and information, the following conclusions and recommendations are made. Construction of the proposed one- story garage replacement is feasible from the standpoint of geotechnical engineering practice at the subject site, provided all recommendations and conditions made herein, are incorporated into all design. The thickness of earth materials and the depths to foundation stratum indicated in this report are based on the data obtained from the locations of the exploratory trenches. The actual thickness of earth materials and depths to foundation stratum between the exploratory trenches may vary from that indicated herein. The design and construction procedures should take this into account. 1. The proposed one-story garage replacement may be founded on spread footings penetrating into the underlying firm disturbed bedrock as specified below. The depth to the firm disturbed bedrock is estimated to be approximately 6 inches below the existing T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Ms. Paige Ledeman - 5 - January 28, 2003 grade, although it may be deeper. All proposed continuous footings and isolated pad footings should be laterally tied with grade beams. Alternatively, mat foundations may be utilized. 2. It should be noted that the subject site is located within the boundaries of the Flying Triangle landslide. The slide mass above the slide plane has a potential for future slide movement. Structural distresses resulting from the slide movement may occur in the areas of the existing house and the proposed garage replacement in the future. Structural distresses may result in cracks, separations, tilting up on walls, ceilings and/or floors of the garage replacement. Current and future owners should be aware of that possibility and be responsible, accordingly. 3. The on -site disturbed bedrock was tested for sulfate content. Sulfate content over 150 ppm was detected. Therefore, It is recommend that the type II cement be utilized for this project. Spread Footing Foundations Spread footings founded into disturbed bedrock may be used to support the proposed garage replacement. The following design criteria for new foundation are considered appropriate. Allowable Bearing Capacity 2,000 psf Minimum Embedment Below Lowest Adjacent Grade and into Firm Disturbed Bedrock One -Story 12 inches Minimum Width of Spread Foundation: One -Story 15 inches All continuous footings should be reinforced with a minimum of four #4 steel bars, two placed near the top, and two placed near the bottom of the footings. Lateral Desian Resistance to lateral loading may be provided by friction acting at the base of foundations and by passive earth pressure within firm disturbed bedrock. An allowable coefficient of friction of 0.40 may be used with the dead load forces. For spread footings in firm disturbed bedrock the allowable passive earth pressure may be computed as an equivalent fluid having a density of 500 pounds per square foot per foot with a maximum earth pressure of 5,000 pounds per square foot. T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL. ENVIRONMENTAL Ms. Paige Ledeman - 6 - January 28, 2003 When combining the passive and friction values for calculating the lateral resistance, the passive component shall be reduced by one third. The vertical and lateral bearing values indicated above are for the total of dead and all frequently applied live loads and may be increased by one-third for short duration loading which includes the effects of wind or seismic forces. Seismic Coefficients The subject site is located approximately 7 kilometers southerly of the Palos Verdes fault. Therefore, the following seismic coefficients should be utilized for designs of the proposed structures at the subject site: • Soil Profile Type: SB • Near Source Factor, Na= 1.0 • Near Source Factor, Nv= 1.13 • Seismic Zone Factor, Z = 0.40 • Seismic Coefficient: C,, = 0.40 N,, • Seismic Source Type: B Temporary Construction Excavations Excavations will be required for the proposed construction. The excavation is expected to expose on -site soils which are not suitable for vertical excavations over five feet. Portions of excavations over five feet should be trimmed to a 1:1 slope gradient. All excavations should be stabilized within 30 days of initial excavation. Water should not be allowed to pond on top of the excavation nor to flow toward it. No vehicular surcharge should be allowed within five feet of the top of cut. All safety provisions of Cal OSHA and other related statutory agencies should be adhered to, especially as related to support of adjacent structures. Temporary shoring should be designed for an active equivalent fluid pressure of 30 pounds per cubic foot. Slabs On -Grade The on -site soils should be considered as expansive soils. Slabs should be cast over a minimum of two inches of vibrated sand placed on firm, compacted subgrade soil. The subgrade soil should be proof -rolled to remove any soft spots prior to covering of sand bedding. The subgrade soil should be re -moistened at least 5% above the optimum moisture content prior to covering of concrete slab. Slabs should be reinforced with a minimum of #4 T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL. ENVIRONMENTAL Ms. Paige Ledeman - 7 - January 28, 2003 rebars at 18 inches on center each way. All rebars in slab should be doweled into the stem wall of footings or into foundations. Slabs should be protected by a polyethylene plastic vapor barrier. The barrier should be covered with a minimum two-inch layer of clean sand to prevent punctures and aid in the concrete cure. A minimum 4 inch concrete slab should be designed for interior and exterior concrete slabs and flatwork over expansive soils. As is typical in reinforced concrete construction, cracking of concrete can occur and is a common process. Reinforcement and crack control joints are intended to minimize this risk. In addition, irregularities of new slabs are common. A completed slab is generally not perfectly level and not free of some type of cracking. Grading The General Earthwork Specifications, Appendix B, should be used in preparation of the grading plans and job specifications where engineered fills are used and constitute our definition of an engineered fill. We should review all documents prior to submittal for statutory permits or contracting in order to ascertain that the intents of our recommendations are conveyed. Drainaae Control Control of soil moisture is essential for the long term performance of improvements, particularly those located on or near expansive soils. All roof and surface drainage should be conducted away from the development in engineered non -erosive devices to a safe point of discharge. No site runoff drainage should be allowed to cross over the tops of slopes except in engineered non -erosive devices. Slabs and planted areas immediately adjacent to the dwelling or appurtenant structures should slope away from said structures to mitigate pooling of water. All slabs and planted areas should be sloped to drain to a safe point of collection. Slabs should have a minimum slope of one percent and planted areas a minimum of three percent. All roof drainage should be collected in eave gutters that discharge directly into engineered non -erosive drainage devices. All joints in slab and swales should be maintained sealed with an appropriate joint compound. Drainage devices shall be provided as specified by the Building Code and Grading Ordinances. Declaration for Compliance with Buildina Code Section 111 It is the opinion of the undersigned, based upon data obtained as outlined in this geotechnical engineering report that if constructed in accordance with our recommendations, and properly T.I.N. ENGINEERING COMPANY GEOTECHNICAL. STRUCTURAL. ENVIRONMENTAL Ms. Paige Ledeman - 8 - January 28, 2003 maintained, the proposed garage replacement construction would not adversely impact the stability of the underlying landslide complex, and that the proposed garage replacement would have no adverse effect on the geotechnical stability of property outside the building site. Plan Reviews Final development plans should be reviewed by this office to ascertain that the general intents of the recommendations of this report have been incorporated into the plans. Additional structures not analyzed during this investigation should be reviewed by a representative of this office. On -Site Construction Reviews On -site construction reviews of all grading, drainage, and foundation work should be performed by a field representative of this office to ascertain compliance with the recommendations of this report. Final grading and/or construction should be observed and a written observation form or report issued by this office stating that the work meets the recommendations of this report. The stages at which our on -site construction reviews are to be performed should include, but are not necessarily limited to, the following stages of work: 1. Observation of footing excavations prior to placement of form boards or reinforcing steel. 2. As called for in Appendix B for on -site construction reviews and testing of all grading work. 3. During proof rolling of subgrade soil and pre -moistened subgrade soil to at least 5% above the optimum moisture content before placement of base material or reinforcing steel, and again following the placement of base material prior to placing reinforcing. 4. Observation of installation of drainage structures and completion of all work. All work and materials should comply with the latest applicable specifications of the City of Rolling Hills. Permits Design and construction should be carried out under applicable conditions and permits of the City of Rolling Hills Building Code and other concerned statutory authorities. T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL. ENVIRONMENTAL Ms. Paige Ledeman 9 January 28, 2003 Remark The conclusions and recommendations submitted in this report are based in part upon the data obtained from two trenches and site observations during the exploration operations. The nature and extent of variations between the trenches may not become evident until construction. If variations then appear evident, it will be necessary to reevaluate the recommendations of this report. No warranty is made nor should any be construed that deep- seated soil or geological weaknesses may not exist below the depths explored. This office shall be notified if any unusual conditions differing from that disclosed by this report are encountered during construction. In the event of any change in the assumed nature, or design of the proposed project as planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed by this office and the conclusions of this report modified or verified in writing. This report is issued with the understanding that it is the responsibility of the owner, or of their representative to insure that the information and recommendations contained herein are called to the attention of the architect and engineers for the project and incorporated into the plan, and that the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. This report has been prepared for the exclusive use of the client and authorized agents, and in accordance with generally accepted soil and foundation engineering practices. No other warranties either expressed or implied are made as to the professional advice provided under the terms of this agreement and included in the report. It is recommended that this office 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 specifications. As a condition for use of this report the above described "Plan Reviews" and "On -Site Construction Reviews" are to be performed. (If this office is not accorded the privilege of making the recommended reviews, we can assume no responsibility for misinterpretation of their recommendations). The statement contained in this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they be due to natural processes or to the works of man, on this or adjacent properties. In addition, changes in applicable or appropriate standards occur, whether they result from legislation or the broadening of knowledge. Accordingly the conclusions of this report may be invalidated, wholly or partially, by changes outside of our control. T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL . ENVIRONMENTAL Ms. Paige Ledeman - 10 - January 28, 2003 Thank you for this opportunity to be of service. If you have any questions regarding this report, please contact the undersigned at the letterhead location. Verytruly yours, T.I.N. ENGINEERING COMPANY TSCL:ir Enclosures: Distribution: ny S. C. Lee, M.S., P.E. roject Engineer Vicinity Map Plate. 1 Site Plan Plate 2.1 Regional Topographic Map Plate 2.2 Cross Section A -A' . Plate 3 Test Trench Logs Plates 4.1 - 4.2 Moisture Density Test Results Plate 5 Direct Shear Test Results Plate 6.1 Plots of Stress -Strain Relationship Plate 6.2 Local Wedge Slope Stability Analysis Plate 7 Exploration and Laboratory Testing Appendix A General Grading Appendix B Client (5) T.I.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL uV l • i 4, P4A� .. ,Huts.,,--',..' �N��' p0. 1.ERIOT',P` wria CRPI-pFUNNE L. ;�T� I pw"': c, O W ` Lp `00LEBAC ROP. R E.�`.1:. ;i..;.•r'a''_ RD �� i.. "`OK ,1 ./Q�=,a!:' BC YNE1/ .,EERhIL �� •� Q9 y ND .: 0-_,,.' OPE S'ACE� / 1'' .,?1, �,� , RD SPODIEDgCk: ,r'yi 3 LI" ri i i '-3 \.N r ( P i + jI �4, i ran , C EPONc� Q, -- R Q;' 9;3 J e0peV. T $', .d,. 28 BEND LL .i\ t �C a.,i yfi 1, I 8..�. L 1\. GFIEST _RP1E(0 `,, =0 _..,' .1 yp. ' RF.ATA ".n�G• RO is."`. Po'z,e4 n R. .6 ``s, o , eQS x % S of \ `Op40 /- OAOryT ' R•• PA91y 9300 LESS 40ES, •, �WY • Cs0 PALOS ND `-T - DDLE.'-W'sr' • • elal :ElNOA P,O GONM � EYO l" t"' ° ',PARK'.TR ' SEE3@ 1 HYANNIS WI 2 CAPE TER • 3 FREEPORT TER "`�, 4 PORTSMOUTH WI PA(0 IsKq VICINITY MAP 3/5G C,ANA00 30t 00 "�5 INN1,-'�.. {;.I:VENfO,G t"FSLIC '' IAGE lC1AN0 WREEb CPR'�R„ , QEOONDE IINN - OR Gr' VF( EZ SANTA SYuny _ TOSCA2ONOINI ROLKINTNIE F� �IW GOLOELNSPU vAH rARA1An OR 0etcwT^ na At G°N CL0T1L,04 LN 5yt�' o �f i_ ' G2�° 1`01;1, SOPRT2 10 a �p021HG�Q� "- 58 <'.Cp � vJ' lS. CUnnO1, .. Jp.Nf,�.' r Da#'• ANT; v` �' ,. O O TauDt a' ^jb, �.'' NACARIIiva •'• ST:1 a�..'.N Y1 LIO ?'UPIAIr • SU81¢A PRAMANTE PT 5T• 2ELUNA G 3500 0, 0RE... A ° o O4.1 R Ok"V2-mooQg�,,P�O n, S�'F(''7.4 MF •`'VF, OR � • ` 0o eAPF4104 P Oi $t3 `f10O 'rm�� ''Y OR AZORESA O, N 0 9 .. ,c� 1rs PACOLLEGGGE SOURCE: The Thomas Guide, 1996 Sheet No. 823, Los Angeles County JOB NO.: 030847 DATE: January 28, 2003 SITEMs. Paige Ledeman #1 Pinto Road, Rolling Hills, California 2 1800' IRSCOSTA CHANOELEUR 'km,1700 UR TERRACE AT. SCRIMP ter p0. RO- <__P0__. 1. l r L CPp P 12p0 ,coo L PAj PLAZA SUMME Q OFARRELL 1400.,, SEPULVEDA € ST _ q GNTA EAu2 i Si 34 AST = ST = 2ND 6 ' ST a Sao ` 9 sr = 1. W ATH ET'" < SAN PE0R0 PENINSULA HOSPITAL W 6TH ST 'H W 7TH ST •E'r `. At. PARK :REC. LAND O ST AV s ri $ W' 8TH 1 GT 9TH� 1300 ST 00 WW T Ior.. LAT= 4,, 9 a ;IN\ W A 12TH g yy THSTE'.1ity,�'< 139r'I PARK' �Y� sr 14TH'\ Cpa 1300 a 1 •ISTN �`• �Y4`o ST 116TH TS, Ylu W S TvcKO�w"Irt`��1300a ST i-IYELxE 4 41RTHd ST ST SCALE 1" = 2,400' PLATE T.I.N. ENGINEERING COMPANY 17834 BAILEY DRIVE •TORRANCE • CALIFORNIA (310) 371-7045 1 OP awe SCALE 1" = 20' LEGEND EXPLORATORY TRENCH T- 1 T - 1 MS. PAIGE LEDEMAN SITE PLAN #1 PINTO ROAD ROLLING HILLS, CALIFORNIA SCALE: 1" = 20' 'PLATE 2.1 T.I.N. ENGINEERING COMPANY DATE: JANUARY 28, 2003 JOB NO.: 030847 I 40 \R • • = z • gy• p.. .9 : •- 01 (DO I►01 o' •G r SOO SOURCE: SLOSSON & ASSOCIATES, GEOLOGIC MAP OF THE FLYING TRIANGLE LANDSLIDE, 1" = Jo 200', DATED FEBRUARY 6, 1987. • 00,,, / MS. PAIGE LEDEMAN #1 PINTO ROAD ROLLING HILLS, CALIFORNIA DATE: JANUARY 28, 2003 JOB NO.: 030847 9 \ \ A 95, 9iC �\ 910 �yt0� lyr REGIONAL GEOLOGIC MAP SCALE: 1" = 200' PLATE 2.2 T.I.N. ENGINEERING COMPANY 86a-- £350 - $40-- 830 -- 920 - - PKoros K IACRA rr P 7tu6Ir240 Afpk n1r 24 C/ O S S SEC i O A/ 4 --A 5c,4c.l v s 20 / yl T-2 TMoIrID MS. PAIGE LEDEMAN #1 PINTO ROAD ROLLING HILLS, CALIFORNIA DATE: JANUARY 28, 2003 JOB NO.: 030847 CROSS SECTION. A -A' SCALE: 1"=20' I P L A T E 3 T.I.N. ENGINEERING COMPANY KID —g¢0 — 30 82o EXCAVATED TEST TRENCH T-1 LOG 0.0' - 0.5' Fill - potting soil 0.5' - 2.0' Disturbed Bedrock - light brown and orange brown, moist, firm, bedded, moderately fractured, siliceous shale. N58E/24SE (No caving encountered. No groundwater encountered.) 0.0 0.0 pt ( 1 1.0 -^ - - 1;q$-rGl R vI2 rev;‹ I 2.0 6.0 7.0 8.0 L r Trench No. T - 1 , Length 3.0' THE LOG OF SUBSURFACE CONDITIONS HEREON APPLIES ONLY AT THE SPECIFIC LOCATION AND THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. DATE EXCAVATED: 01/14/2003 L I- , Width 3.0' , Depth 2.0' DALE: January 28, 2003 JOB NO. : 030847 PLATE 4.1 T.I.N. ENGINEERING COMPANY — 4.0,, 5.0 —6.0 7.0 8.0 0.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 EXCAVATED TEST TRENCH T-2 LOG 0.0' 0.5' Fill - sloughing soil and leaves 0.5' - 2.0' Disturbed Bedrock - light brown, gray, and orange brown, moist, firm, bedded, moderately fractured, siliceous shale. N82W/10SW (No caving encountered. No groundwater encountered.) 4 L I J r 0.0 — 1.0 2.0 4 — 3.0 L — 4.0 — 5.0 -- - ---------6.0 r i - '- 7.0 8.0 Trench No. T - 2 , Length 3.0' THE LOG OF SUBSURFACE CONDITIONS HEREON APPLIES ONLY AT THE SPECIFIC LOCATION AND THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. DATE EXCAVATED: 01/14/2003 Width 3.0' , Depth 2.0' DATE: January 28, 2003 JOB NO.: 030847 PLATE 4.2 T.I.N. ENGINEERING COMPANY T.I.N. ENGINEERING COMPANY Geotechnical • Structural • Environmental Project : Ms. Paige Ledeman Date: January 28, 2003 MOISTURE -DENSITY RESULTS OF LABORATORY TEST, Trench Depth Moisture Content Dry Density Comment No. (ft) (% dry wt.) (pcf) T-1 2.0 22.0 95.1 Disturbed Bedrock T-2 2.0 24.1 93.2 Disturbed Bedrock PLATE 5 SYMBOL SOIL SAMPT F LOCATION DEPTH (ft) 0 C (psf) z ® Bedrock - Shale,l Bedding, T-1 2.0 34° 790 Residual, Saturated T-2 2.0 20° 270 3.0 2.0 1.0 0.0 0.0 Bedrock - Shale, II Bedding, Repeatedly Re -Sheared Residual, Saturated 1.0 2.0 NORMAL PRESSURE, KSF PLOT OF DIRECT SHEAR TEST DATA JOB NO: 030847 SITE Ms. Paige Ledeman #1 Pinto Road, Rolling Hills, California T.I.N. ENGINEERING COMPANY DATE: January 28, 2003 PLATE 6.1 U 3.0 17834 BAILEY DRIVE •TORRANCE • CALIFORNIA (310) 371-7045 Bedrock. - Shale, L Bedding, T-1 @ 2.0', Residual, Saturated Bedrock - Shale, // Bedding, T-2 @ 2.0', Repeatedly Re - Sheared, Residual, Saturated JOB No. : 030847 SITE mot l I DATE: January 28, 2003 Ms. Paige Ledeinan #1 Pinto Road, Rolling Hills, California .050 .100 .150 SHEAR DEFLECTION IN INCHES SHEAR DEFLECTION IN INCHES PLATE 6.2 T.I.N. ENGINEERING COMPANY 17834 BAILEY DRIVE •TORRANCE • CALIFORNIA (310) 371-7045 0 .200 86o — 840 - $30--- 920 0 = Internal Angle of Soil Friction C = Cohesion of Soil y = Unit Weight of soil 0 = Potential Failure Angle 20 0 = 2,70 psf = 120 pcf = A = Area of Potential Failure Wedge = L ' ft2 W = Weight of Potential Failure Wedge = 40 kips L = Length of Potential Slip Plane = 5? ft K; S615r1(c 1cI ' 0,1 'KO'o5P REIVCPMEtir 'f T1 T-2 1ZA51afJ Y - ��i( f14'. � k�= ° c 'i (454D = L.1'2 so/ 41 Lo -' —860 1 N510Ki - 85D — 830 IMLi4 820 WSine ce0 S° - z7)(55.. C/o S s- .S�"Ec T /A --A f-j u 5,���e . fl-lam'2I,5,o,k c.z) SP5111C �St(0320- 5119) _ _.40(0,1-t.155>Z3} 20�L�2 )C `) W � S til 6 ifro "1 ° MS. PAIGE LEDEMAN #1 PINTO ROAD ROLLING HILLS, CALIFORNIA DATE: JANUARY 28, 2003 JOB NO.: 030847 T a' r I D ° LOCAL WEDGE SLOPE STABILITY SCALE: 1" = 20' IP LATE 7 T.I.N. ENGINEERING COMPANY 7x1 -7I,1 p� APPENDIX A EXPLORATION AND LABORATORY TESTING Exploration Field exploration was performed using a truck mounted drill rig, backhoe, or hand -diggers as noted in the report. Undisturbed samples of representative soils were obtained at frequent intervals in the boring or trench excavations. In drilling boring, the samples were obtained by driving a thin walled steel sampler with successive drops of the drilling Kelly Bar. The driving energy required for one foot of penetration is shown on the boring. summary sheets. Soil samples were retained in 2 '/2 inch diameter and 1 inch in height brass rings. In backhoe or hand -dug trenches, undisturbed samples were obtained with thin walled tubes carefully driven by hand into the trench walls and by carving chunk samples directly from the trench walls. Classification of Soils All soils were visually classified in accordance with the Unified Soil Classification System per ASTM D 2487. Moisture and Density The moisture density information can provide a gross indication of soil consistency and delineate local variations. The information can also be used to correlate soils found on this site with soils on other sites in the general area. The dry unit weight and field moisture content were determined for selected undisturbed samples. Moisture and density were done using the ASTM D 2216 method. Direct Shear Test Shear tests were made with a direct shear machine of the strain control type. The shear tests samples are saturated to simulate expected extreme moisture conditions. Unless indicated otherwise, tests were performed at a constant rate of shear displacement of approximately 0.002 inches per minute, under vary loads and under conditions of saturation. Samples at the indicated moisture conditions, were tested at three or more normal loads in order to determine the Coulomb shear strength parameters. ASTM D 3080 method was followed to perform all shear tests. Consolidation Test Soil settlement predictions under load are made on the basis of consolidation tests. The consolidation apparatus is designed to receive one -inch high rings. Loads are applied in several increments, in a geometric progression, and the resulting deformations are recorded at selected time intervals. Porous stones are placed in contact with the top and bottom of each specimen to permit addition and release of pore liquid. Samples are generally tested at increased content by adding water to determine the effect of water contacting the bearing soil. The normal load at which water is added is noted on the plate. Results are plotted on the "Load -Consolidation Curve." ASTM D 2435 method is followed during a consolidation test. A-1 T.I.N. ENGINEERING. COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Fine -Grained Soils d an h N 0 Z h v m CL v L. 40. Ln L 0 UNIFIED SOIL CLASSIFICATION SYSTEM Major Divisions N C Silts 'and Clays Silts and Clays More than E 0- J Liquid Limit coarse fraction 50% or less 0 N Greater than retained on No. t sieve c 0 U d 4v L u d • .0 03 • I u in L c C 1O 3 ii. Highly Organic Soils Group Symbols A-2 GW GP GM CC SW SP SM SC ML CL OL MH CH OH PT Typical Names Well -graded gravels and gravel -sand mixtures, little or no fines Poorly graded gravels and gravel -sand mixtures, little or no fines Silty gravels, gravel -sand - silt mixtures Clayey gravels, • gravel -sand - clay mixtures Well -graded sands and gravelly sands, little or no fines Poorly graded sands and gravelly sands, little or no fines Silty sands, sand -silt mixtures Clayey sands, sand -silt mixtures Inorganic silts, very fine sands, rock flour, silty or clayey fine sands Inorganic clays or low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays Organic silts and organic silty clays of low plasticity Inorganic silts, micaceous or diatomaceous fine sands or silts, elastic silts Inorganic clays of high plasticity, fat clays Organic clays of medium to high plasticity Peat, muck and other highly organic soils APPENDIX B GENERAL GRADING The following guidelines should be used in preparation of any grading plans and job specifications where engineered fills are used and retaining walls backfilled. We should review all documents prior to submittal for statutory permits or contracting in order to ascertain that the intent of our recommendations is conveyed. 1. The area to receive compacted fill shall be stripped of all vegetation, debris, existing fill, and soft or disturbed soils, The excavated areas shall be reviewed by the geotechnical engineer in the field prior to placing controlled, compacted fill. 2. The exposed grade shall then be benched, appropriately graded, scarified to a depth of six inches, moistened to optimum moisture and recompacted to 90 percent of the maximum density. 3. The excavated on -site materials are considered satisfactory for reuse in the engineered fill. Remove any organic trash or deleterious materials. Remove boulders larger than • 6 inches. 4. Soil shall be spread evenly in layers not to exceed 4 inches while loose for compaction by wackers. Add water as required. Only approved compaction equipment shall be used. 5. The fill shall be compacted to at least 90 percent of the maximum laboratory density for the material used. The maximum density shall be determined by ASTM D 1557- 00. 6. Periodic on -site construction reviews and field tests shall be performed by the geotechnical engineer during grading to assist the contractor in obtaining the required degree of compaction and the proper moisture content. Where compaction is less than required, additional compactive effort should be made with adjustment of the moisture content, or the layer stripped out and replaced in thinner layer, as necessary, until a minimum of 90 percent relative compaction is obtained. The contractor shall call the soil engineer to test every two feet of vertical lift. 7. No fill soils shall be placed during unfavorable weather conditions. When work is interrupted by rains, fill operation shall not be resumed until the field tests by the soils engineer indicate that the moisture content and density of the fill are as previously specified. T.1.N. ENGINEERING COMPANY GEOTECHNICAL • STRUCTURAL • ENVIRONMENTAL Tel: (310) 371-7045 Fax: (310) 371-5856