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895, Demo existling SFR and Constru, Studies & ReportsHAMILTON & Associates 1641 Border Avenue • Torrance, CA 90501 T 310.618.2190 888.618.2190 Concord 5959 Development & Construction Smithway Street City of Commerce, CA 90040 Attention: Jack Ng Subject: Geotechnical Engineering and Engineering Geology Investigation Proposed Residential Additions 10 Bowie Road Rolling Hills, California Gentlemen: By 771, JAN 272016 City of Rolling Hills F 310.618.2191 W hamiltonassoclates.net May 11,2015 Project No. 15-1942 Submitted herewith is the Hamilton & Associates, Inc. (H&A) report of a geotechnical engineering and engineering geology investigation for the subject project. This investigation was made for the purpose of obtaining information on the subsurface soils on which to base recommendations for a suitable foundation design for the proposed single family residence. Location of the site, relative to general topography, streets and landmarks, is shown on the attached Site Location Map, Figure 1. As outlined in our Proposal of December 15, 2014, our work consisted of geotechnical and geological observations, subsurface exploration and sampling, field and laboratory testing, engineering calculations and analyses, and preparation of this report. PROPOSED DEVELOPMENT It is understood that the proposed development will consist of the construction of a one story single family residence, garage, and retaining walls. Anticipated site grading could consist of compaction of fill placed for the purpose of structural support and/or drainage improvements, and for slab -on -grade support, as well as retaining wall backfill. Hamilton & Associates, Inc. Geotechnical Engineering Construction Testing & Inspection Materials Laboratory TN �/MN V13° TOP01 map printed on 03/31/15 from "Callfomla.tpo' and "Untltled.tpg" 118.35000° W 118.33333° W APPROXIMATE SITE LOCATION 1,18.35600° W i118r* 3333° W Q�000 FEET O _ _ 500 1000 METERS Map created with TOPOIOD 02003 National Geographic (www.nationalgeographic.comkopo) Concord Development- 10 Bowie Road, Rolling Hills, CA P.N. 15-1942 WGS84 118.31667° W WGS84 118.31667° W SITE LOCATION MAP FIGURE 1 DESCRIPTION OF SITE The subject site is an irregularly shaped parcel, situated on the south side of and fronting Bowie Road, west of Chuckwagon Road, in the City of Rolling Hills. From Bowie Road, the lot ascends at a gradient of 1:1 (horizontal to vertical) from the property boundary up to a level pad. From this pad the lot ascends at a gradient of 2:1 (horizontal to vertical) to a level building pad. The property is occupied by a single family residence and a detached garage reportedly constructed in 1959. The property is bound on the north, south and east by Bowie Road, because it is within a "hairpin" curve along the road. Single family residences bound the site on the west and southwest. Maximum topographic relief over the property is approximately 60 feet. DOCUMENT REVIEW A number of nearby geotechnical reports were found within this firm's and County of Los Angeles files. The REFERENCES section of this report lists these documents. None of the project encountered abnormal geotechnical problems which prevented the planned construction. Of most importance are site -specific studies of the site perimeter slopes by Gregory W. Axten (1983) and a Pacific Soils, Engineering, Inc. (1971) report about the existing rear yard retaining wall. Additionally, stereo -paired aerial photographs archived at this office and at the County were assessed. FIELD INVESTIGATION On March 24, 2015, six test pits were excavated by means of hand equipment to depths ranging from 2 to 10.5 feet at the locations shown on Plate A-1. The approximate locations of the test pits were determined by tape measurement from existing structures and property boundaries, as shown on a Grading Plan, prepared by Outland & Associates, dated 1983. A continuous record of the soils and bedrock encountered during test pit excavations was made by our field engineer and a Certified Engineering Geologist associated with this firm, and is presented on Plates B-1 through B-6, Summary of Test Pits. The lines designating the interface between materials on the Summary of Test Pits, and on geotechnical section, Plate A-2, represent approximate boundaries. The actual Concord Residential Development 15-1942 May 11,2015 Page 2 HAMILTON & Associates transition between materials was gradual. Undisturbed and bulk samples were obtained at selected intervals from the test pits for laboratory testing. SITE -SPECIFIC GEOLOGIC/SUBSURFACE CONDITIONS Stratiaraphv Onsite earth materials underlying the proposed construction area are artificial fill and in - place colluvium mantling bedrock of the Altamira Shale Member of the Monterey Formation that is, in turn, in angular unconformity with basement rock of the Catalina Schist (Plates A-1 through A-3). Middle Miocene -aged basalt flows and dikes have been mapped at or near the site (for example, SWN SOIL TECH CONSULTANTS, 2004; Dibblee,1999; Cleveland, 1976 (Figure 2, following pages; but, site -specific explorations by Pacific Soils Engineering, Inc. (1971), Axten (1983), and the current investigation did not expose basalt to the depths explored. Surficial Deposits Fill: Test Pits No. 3 through 6 encountered an abundant surface mantle of fill that varied up to ten feet deep. The fill is typically locally -derived mottled gray brown silty clay with scattered angular Altamira bedrock chips composed of very hard siliceous shale or siltstone. This unit varies from dry to moist with depth and is generally firm to stiff; and contains roots. Soil/Colluvium: Test Pits No. 1 through 3 encountered a ubiquitous surface mantle of colluvium up to six feet deep. The colluvium is typically locally -derived gravelly dark brown silty clay. The gravel fraction consists mainly of abundant angular Altamira bedrock chips composed of very hard siliceous shale or siltstone. This unit varies from dry to moist with depth and is generally firm to very stiff; and contains roots. Bedrock Monterey Formation (Altamira Shale): Shale/siltstone bedrock assigned to the Monterey Formation was encountered beneath the fill and colluvium in the test pits by this firm (this study) and by Pacific Soils Engineering (1971). The bedrock generally consists of relatively fresh tan brown gray orange to locally iron -oxide stained thin - bedded, diatomaceous to siliceous shale and siltstone. The rock is usually distinctly bedded and generally has moderately to well -developed bedding plane partings. The rock became very firm to hard below approximately one foot of weathered shale. Concord Residential Development 15-1942 im May 11,2015 Page 3 HAMILTON & Associates REGIONAL GEOLOGY MAP Key Geological Units Qaf — Modern Artificial Fill Qsw — Pleistocene -Holocene Slope Wash Qls — Landslide Deposit Qter — Pleistocene Terrace Deposits Tma — Miocene Altamira Shale Member of the Monterey Formation Tb — Miocene Basalt pkc — Pre -Miocene Catalina Schist Approx Scale 1 "=2000' From: Geology of the northeast part of the Palos Verdes Hills, Los Angeles County, California, G.Cleveland (1976) Hamilton & Associates, Inc. Concord Development-10 Bowie Road -Rolling Hills, CA PROJECT NO: 14-1942 DATE: April2015 FIGURE 2 Catalina Schist: Based on subsurface exploration by Gregory W. Axten, Geotechnical Consultant (1983) and observations of surficial exposures by this firm, pre -Cretaceous metamorphic rock of the Catalina Schist supports most of the northerly -facing cut slope between the area to be improved and subjacent Bowie Road. As noted by Axten (1983) the local schist is principally quartzite schist with some sericite and glaucophane resultant from chemical weathering of the rock and by perhaps contact metamorphism during injection of middle Miocene basalt (Axten,1983; Cleveland, 1976). The blue -gray to dark gray (when relatively fresh) schist varies from fresh to extremely weathered. Occasional quartzose sills/veins parallel to foliation are rare but present. Foliation is moderately to well -developed, but is wavy and discontinuous. Axten (1983) encountered such folded and wavy schist in his Test Pits. That investigator also noted that the schist can be hard where fresh. Structural Geology and Geomorphology The site lies on the upper northeastern flank of the Palos Verdes Hills, a structural high formed by transpressional deformation along the regional Palos Verdes fault. Most investigators (Woodring and others, 1946; Cleveland, 1976; Dibblee, 1999) portray the hills as an anticlinorium composed of many smaller folds generally trending northwest, with local variations, near the site. (See Regional Geologic Map, Figure 2, following page). Regional The characteristic topographic form on the northeastern slope of the Palos Verdes Hills is a flight of 13 wave -cut marine terraces that formed during varying stands of sea level through the last millions of years or so (for example, Dibblee, 1999; Cleveland, 1976; Woodring, and others, 1946). The youngest being the current shoreline: A combination of uplift of the Palos Verdes Hills along the yet active Palos Verdes fault (about 1.75 miles to the northeast; (Figure 3, herein) and episodic sea level decline has elevated the terraces, giving the local slopes their classic "stair -step" profile. During ongoing uplift the terraces have been and are being incised by large canyons, leaving intervening ridges capped by gentle terrace topography. The study site lies on the flat of one such elevated terraced ridge that is but typical of series of locally northeast -trending ridges separated by steep, V-shaped canyons that drain to the northeast and ultimately south into the Pacific Ocean (Figures 1 and 2). Concord Residential Development 15-1942 May 11,2015 Page 4 HAMILTON & Associates LEGEND: Approx Scale 1"=12 Miles REGIONAL FAULT MAP Geologic Time Scale i a at 6 61 Years Before Fault Present Symbol (Approx.) 200 11,100 — 700,000 1,1300,000' 4.5 billion des Recency Of Movement i ON LAND DESCRIPTION OFFSHORE Dleplecement doling hielore erne (e.g. San Andreas fatal 1900), Iodides wears of known fault creep Displacement during Holocene lime. Nitrite Meeting evidence of displacement during late Quaternary erne. Undivided Quaternary faults. most faults In lhie category Mow wldance of displacement during the last 1.000,000 years; possible exceptions ars faults which displace mcae of undifferentiated PilaPieekcene sae. Faults without recognized Quaternary diepleceinem or showing cold00ce of no displacement during Ouatemery erne. Not maenad/ inactive. Fault offsets eeancar sedlmente or musts of Holocene age. Fault cuts seek of Late Phlaloosne lags. Fault cuts strata of Quaternary age. Fauh cuts seek of Pliocene or older age, From.' "Fault Activity Map of California," compiled by Charles W. Jennings and William A. Bryant, California Geological Survey, Map No. 6, California Geologic Data Map Series, 2010 PROJECT: Concord Development- 10 Bowie Road- Rolling Hills, CA PROJECT NO: 15-1942 DATE: April 2015 Hamilton & Associates, Inc. FIGURE 3 Local The local structural geologic setting at and near the site is varied owing to the presence of three distinct geologic terranes: Schist basement rock, middle Miocene basalt that has intruded and deformed the schist; and the overlying Altamira Shale that is an angular unconformity with the underlying schist and basalt. Based on the work of Axten (1983 and this firm's observations), the foliation within the schist is quite contorted and folded as would be expected of metamorphosed rock intruded by basalt. Typically, the contacts between the basalt and the schist and Altamira Shale are not planar and are irregular. Likewise, the basalt generally lacks persistent planes of weakness amenable to slope failure. None of the on -site explorations (Pacific Soils Engineering, 1971; Axten, 1983, and this study) exposed the Catalina Schist/Altamira Shale contact. Based upon the outcrop patterns mapped by Dibblee (1999) and Cleveland (1976), the contact is about flat or dips very gently to the north; however some irregularity is probable owing to the erosional nature of the angular unconformity. The cross -sections contained herein (Plates A-2 and A-3) model an irregular about -horizontal contact. Bedding within the Altamira Shale varies across the site. Near the southeast corner of the site the formation is folded and displaced by a small northeast -trending fault. Elsewhere, the bedding seemingly dips northeast, but some irregularities in orientation occur. Such structure is common to rocks within the Palos Verdes anticlinorium. No faults were encountered during the recent investigation. Pacific Soils Engineering mapped one small northeast -trending fault in the Altamira Shale that trends away from the area to be improved. Further, the local outcrop patterns mapped by Cleveland (1976) and Dibblee (1999) indicate continuity and absence of displacements by faulting at the site. Elements of the Cabrillo fault have been mapped within about 300 feet of the study site (see Figure 2, for example). As noted above, continuity of local geologic contacts (see Figure 2) indicate that elements of the fault, including those mapped (Cleveland, 1976), do not intersect the site. Woodring and others (1946) initially identified the fault and characterized it as a northwest -trending, northeast -dipping, normal fault. The State of California, based on a 1998 study (Treiman and Lundberg, 1998b), did not place the fault in an Alquist-Priolo Earthquake Fault Zone that mandates special geological investigations. The preponderance of interested parties have found the fault not to be active from the viewpoint of potential ground rupture, thus, special investigations have not been triggered. The California Geological Survey (Cao and others, 2003) does not Concord Residential Development 15-1942 May 11,2015 Page 5 HAMILTON & Associates list the fault as seismogenic. On the other hand, the USGS suggests that the fault has the potential to produce an Mw 6.0-6.8 earthquake. SEISMICITY The site, as is the case with most of the tectonically-active Southern California area, will be periodically subject to moderate to intense earthquake -induced ground shaking from earthquakes along nearby or regional faults. Significant damage can occur to the site and structural improvements during a strong seismic event. Neither the location nor magnitude of earthquakes can accurately be predicted at this time. Following is a brief summary of the tectonic setting followed by various estimates for ground motions that might occur during regional earthquakes. Setting As can be seen by inspection of Figure 3, herein, the site is within a tectonic setting characterized by many faults considered seismically active. Local examples include the Palos Verdes fault about 1.75 miles to the northeast of the site. That fault is surmised as being capable of generating an Mw7.1 earthquake (Cao and others, 2003). .According to the "Fault Activity Map of California and Adjacent Areas" (Jennings, 2010), Cao and others (2003) and Blake (2004) the subject site lies approximately 5 miles south of the Compton blind thrust fault (surmised Mw6.8), and approximately 9 mi southwest of the Newport -Inglewood fault, thought capable of producing an M6.9 earthquake (see Figure 2). According to geologic mapping (Cleveland, 1976; Dibblee, 1999), surface traces of the Cabrillo fault lies approximately 300 feet north of the subject site. Information regarding the enigmatic Cabrillo fault, obtained from the Southern California Earthquake Center (SCEC), US Geological Survey (1998), and Jennings (2010) indicates that the onshore portion of this fault is late Quaternary in age, has a right -normal sense of motion and may be capable of producing an earthquake of probable magnitude Mw 6.0-6.8. Representative among the local historical earthquakes are: The Mw5.9 Whittier Narrows earthquake occurred October 1, 1987 approximately 25 miles northeast of the subject site on a previously -unknown, north -dipping blind thrust fault in the eastern Los Angeles region, with no recorded surface rupture (Woods and Seiple, 1995). The Mw6.7 Northridge earthquake occurred January 17, 1994 approximately 31 miles northwest of the subject site, at a focal depth of 19 km (12 miles), on a south -dipping blind thrust fault with no direct surface rupture. The historic Long Beach M6.3 earthquake of March 10, 1933 occurred approximately 26 miles southeast of the subject site (Ziony, 1985). All of Concord Residential Development 15-1942 May 11,2015 Page 6 HAMILTON & Associates these , earthquakes caused considerable damage near . their epicenters and id surrounding cities. The subject site also lies approximately 50 to 60 miles southwest of the San Andreas Fault zone, which was the source of the 1857 Fort Tejon MI7.9 earthquake. Surface Rupture Potential There are no mapped active or potentially active faults with surface expression that trend through the subject property, per the references cited herein and this investigation. The site is not within a designated Alquist-Priolo Earthquake Fault Zone (Hart and Bryant, Rev.2OO7) or the City of Rolling Hills fault zone study area. Similarly, the site is not within a State imposed Seismic Hazards Zone per Figure 4. Estimated Ground Motion The Department of Conservation (1998) estimated probabilistic peak ground acceleration for soft rock conditions at the site to be about O.457g with a 10% probability of being exceeded in 50 years. And the estimated peak ground acceleration in alluvium is reported to be about O.6g with the same recurrence interval. A probabilistic seismic hazard analysis incorporates seismic and geologic information for a regional area to consider the probability of ground motion from damaging earthquakes. The analysis, usually used for seismic -resistant design, calculates the potential range of ground motions for each potential earthquake and arrives at level of ground shaking that has a given probability within a given time span. It is not necessarily representative of a specific future earthquake. The Predominant Earthquake affecting the site vicinity is indicated to be an Mw7.1 event at a distance of about 1.75 miles (the Palos Verdes fault) according to the Seismic Hazard Zone Report for the Torrance 7.5-Minute Quadrangle (Department of Conservation, 1998. MASS WASTING Axten (1983) mapped two landslides (slumps) onsite; one along Bowie Road and one along the canyon wall in the southwest corner of the site. These are interpreted to be relatively surficial failures within localized areas of unfavorably oriented foliation or weathering in the Catalina Schist. That 1983 Axten report spells out recommendations for engineered repair of the slumps. This firm did not see evidence that the repairs were carried out. Concord Residential Development 15-1942 May 11,2015 Page 7 HAMILTON & Associates SEISMIC HAZARD ZONES MAP STATE OF CALIFORNIA SEISMIC HAZARD ZONES Delineated In Compilana with Chapter 7.0, Dhdslon 2 of the California Public Resources Code (Seismic Hazards Mapping Act) TORRANCE QUADRANGLE OFFICIAL MAP Released: March 25,1999 (z) PROJECT: Concord Development-10 Bowie Road -Rolling Hills, CA Approx Scale 1"=2000' MAP EXPLANATION Zones of Required Investigation: Liquefaction Areas where historic occurrence of liquefaction, or local geological, geotechnical and groundwater conditions Indicates potential for permanent ground displacements such that mitigation as defined in Public Resources Code Section 2693(c) would be required Earthquake -Induced Landslides Areas where previous occurrence of landslide movement, or focal topographic, geoiogka4 geotechnicaI and subsurface water conditions indicate a potential for permanent ground displacements such that mitigation as defined In Public Resources Code Section 2693(c) would be required. PROJECT NO: 15-1942 DATE: April 2015 Hamilton & Associates, Inc. FIGURE 4 Neither the literature, nor online, historical aerial photographs, nor local published and proprietary geologic maps (see REFERENCES, herein) indicate the presence of landslides other than the aforementioned onsite. Most importantly, local mapping (see Plates A-2 and A-3 indicate that the onsite geologic structure is not conducive to large- scale landsliding. Additionally, the enclosed stability analysis indicates a sufficient factor of safety against large-scale instability onsite. Creep, which is a nearly imperceptible movement of surficial soils downslope caused by the forces of gravity, was observed on the property. It is believed this movement extends to a depth of 4 feet below the surface. In sum, no signs of deep-seated instability were evidenced on the site, or upon immediately adjacent properties. The area to be improved is not in a State of California Seismic Hazards Zone that requires assessment of the potential for slope instability during regional earthquakes as shown on Figure 4 (Department of Conservation, 1999). GROUND WATER AND DRAINAGE Groundwater was not encountered and none is anticipated within depths pertinent to the proposed construction. Fluctuations in the level of groundwater may occur due to variations in rainfall, temperature and other factors not evident at the time of the measurements reported herein. Fluctuations may also occur across the site. Surface drainage is comprised of sheet flow run-off of incidental rainfall derived primarily within the parcel boundaries. No signs of significant adverse erosion were observed during the course of this investigation. LABORATORY TESTS Laboratory testing was programmed following a review of the field investigation and after considering the probable foundation designs to be evaluated. Laboratory testing included the determination of density, moisture content and shearing resistance of the materials, as well as consolidation and compaction characteristics. Details of the sampling and test procedures are given in the Appendix. Concord Residential Development 15-1942 May 11,2015 Page 8 HAMILTON & Associates SLOPE STABILITY Slope stability analyses were performed on the subject site and on the overall slope of which the subject site is a part. The following represents the criteria used for calculating the theoretical failure surface determined as having the lowest factor of safety for the given material, and/or slope: Material Saturated Unit Cohesion Friction Angle Weight (pcf) (psf) (degrees) Fill/Colluvium 110 350 23 Bedrock - Shale 110 200 30 Bedrock — Schist* 125 465 23 *From Axten (1983) Circular Stability Analysis Gross stability analyses were performed by the "Stabl" slope stability computer program written by Ronald A. Siegel of Purdue University. "Stabl" calculates the factors of safety against instability of a slope by a method of slices, employing an adaptation of the Modified Bishop Method. For each theoretical failure surface presented in the report, "Stabl" has generated 100 analyses of which the surface shown provides the lowest factor of safety for the slope, and/or material in question. The detailed printout for the cross sections explored herein is provided the Appendix. Based upon the analysis of Sections A -A' and B-B', the circular plane which resulted in the lowest factor of safety is plotted on Plates E-1 and E-2. Surficial Slope Stability Surficial stability analysis was performed on the steepest fill slope on the property. The result of the analysis, as shown on Plate E-3, indicates the factor of safety is in excess of the normally accepted minimum for stable slopes. The schist slopes have been found to be surficially unstable in the road cut and side canyon by Axten. Concord Residential Development 15-1942 May 11,2015 Page 9 HAMILTON & Associates DISCUSSIONS AND GENERAL COMMENTS Hillside developments are subject to some inherent risks that can never be completely eliminated. This report presents an assessment of the risks involved in the development and recommendations to minimize these risks. Based on the findings summarized in this report, and provided the recommendations of this report are followed, and the designs, grading and construction are property and adequately executed, it is our finding that the proposed building and anticipated site grading would not adversely affect the stability of the site from slippage or settlement, nor adjacent properties, with the same provisos listed above, within the standard limits of the geotechnical practice. All new foundations shall penetrate the soil/colluvium and be embedded into the firm shale/siltstone a minimum 12 inches, generally found at about 3 to 10 feet below grade. Any structures shall be supported entirely by like material. CONCLUSIONS AND RECOMMENDATIONS Setbacks The foundation slope setback, required by the City of Rolling Hills, is for the placement of buildings and structures on, or adjacent to, slopes steeper than 3:1 (horizontal to vertical) to provide protection from water, mudflow, loose slope debris and shallow slope failures. This setback, shown on Figure 5 is the horizontal clearance from the face of the foundations to the slope face. Seismicity The below site -specific seismic design parameters were determined as a part of this study in accordance with the 2013 California Building Code, which is based on the 2012 International Building Code (IBC). Additionally, seismic design parameters were determined using the USGS Seismic Hazard Curves and Uniform Hazard Response Spectra v.3.1.0, dated July 11, 2013. The 2013 CBC seismic design parameters that apply to the site are as follows: Concord Residential Development 15-1942 May 11,2015 Page 10 HAMILTON & Associates 1808.7 Foundation on or adjacent to slopes. The placement of building and structures on or adjacent to slope steeper than one unit vertical in three units horizontal (33.3-percent slope) shall comply with Section 1808.7.1 through 1808.7.5 1808.7.1 Building clearance from ascending slopes. In general, building below slopes shall be set a sufficient distance from the slope to provide protection from slope drainage, erosion and shallow failures. Except as provided in Section 1808.7.5 and Figure 1808.7.1, the following criteria will be assumed to provide this protection. Where the existing slope is steeper than one unit vertical in one unit horizontal (100-percent slope), the toe of the slope shall be assumed to be at the intersection of a horizontal plane drawn from the top of the foundation and a plane drawn tangent to the slope at an angle of 45 degree (0.79 rad) to the horizontal. Where a retaining wall is constructed at the toe of the slope, the height of the slope shall be measured from the top of the wall to the top of the slope. 1808.7.2 Foundation setback from descending slope surface. Foundations on or adjacent to slope surfaces shall be founded in firm material with an embedment and set back from the slope surface sufficient to provide vertical and lateral support for the foundation without detrimental settlement. Except as provided for in Section 1808.7.5 and Figure 1808.7.1, the following setback is deemed adequate to meet the criteria. Face of Structure ti For SI: 1 foot = 304.8 mm. [WI Hamilton & Associates, Inc. Toe of Slope Where the slope is steeper than 1 unit vertical in 1 unit horizontal (100-percent slope), the required setback shall be measured from an imaginary plane 45 degree (0.79 rad) to the horizontal, projected upward from the toe of the slope. Where the slope is steeper than 1 unit vertical in 1 unit horizontal (100-percent slope), the required setback shall be measured from an imaginary plane 45 degree (0.79 rad) to the horizontal, projected upward from the toe of the slope. 1808.7.3 Pools. The setback between pools regulated by this code and slope shall be equal to one-half the building footing setback distance required by this section. That portion of the pool wall within a horizontal distance of 7 feet (2134 mm) from the top of the slope shall be capable of supporting the water in the pool without soil support. 1808.7.4 Foundation elevation. On graded sited, the top of any exterior foundation shall extent above the elevation of the street gutter at point of discharge or the inlet of an approved drainage device a minimum of 12 inches (305 mm) plus 2 percent. Alternate elevations are permitted subjected to the approval of the building official, provided it can be demonstrated that required drainage to the point of discharge and away from the structure is provided at all location on the site. 1808.7.5 Alternate setback and clearance. Alternate setback and clearances are permitted, subject to the approval of the building official. The building official shall be permitted to require a geotechnical investigation as set forth in Section 1803.5.10. Top of Slope J At least the smaller of H/2 and 15 feet Figure 1808.7.1 Foundation Clearance From Slopes At least the smaller of H/3 and 40 feet SLOPE SETBACK — Sec. 1808.7 Concord Development- 10 Bowie Road Rolling Hills, CA Face of Footing Project No.: 15-1942 FIGURE 5 CBC Seismic Parameter Site Classification (per ASCE/SEI 7-10 Table 20.3-1) Mapped Spectral Response at 0.2 Sec Acceleration, SS Mapped Spectral Response at 1.0 Sec Acceleration, Si Maximum Considered Earthquake Spectral Acceleration, SMs Maximum Considered Earthquake Spectral Acceleration, SM1 5-Percent Damped Design Spectral Acceleration, SDS 5-Percent Damped Design Spectral Acceleration, SD1 Site Seismic Design Category (per 1613.3.5) Value or, Classification C 1.541 0.589 1.541 0.766 1.027 0.510 D The structural consultant should review the above parameters and the 2013 CBC to evaluate the seismic design. Final selection of design coefficients should be made by the structural consultant based on the local laws and ordinances, expected building response, and the desired level of conservatism. Foundations on Bedrock An allowable bearing value of 2500 pounds per square foot, for square or continuous footings, is recommended for foundations placed at a depth of at least 12 inches below the lowest adjacent final grade (top of slab -on -grade for interior footings) and bearing 12 inches into the terrace siltstone. This value may be increased by 500 pounds per square foot, for each additional foot in depth over 2 feet, and 225 pounds per square foot for each additional foot in width over 1 foot, to a maximum of 5000 pounds per square foot. For detailed calculations of these recommended bearing values, see Figure 6. Due to the expansive characteristics of the foundation soils, it is recommended that all footings be continuous and reinforced with a minimum of 4 No. 4 bars (2 top and 2 bottom). The structural engineer's reinforcing requirements should be followed if more stringent. Settlement of footings up to 2 feet wide continuous and 5 feet square is not expected to exceed 1/2 inch under the recommended fully applied bearing pressure. Differential settlement between footings is expected to be on the order of inch. The bearing capacities given are net allowable bearing values and the weight of the concrete foundations can be ignored. The bearing value is for dead plus live load, and may be increased by one-third for momentary wind or seismic loads. Concord Residential Development 15-1942 May 11,2015 Page 11 HAMILTON & Associates ALLOWABLE BEARING VALUE (For Shale/Siltstone) Reference: Terzaghi and Peck, Soil Mechanics in Engineering Practice , 1967, Pp. 222 and 223. Properties: Wet Density (y) = 110 pcf Cohesion (C) = 300 psf Angle of Friction (0 = 28 degrees Footing Depth (D) = 1.0 feet Footing Width (B) = 1.o feet Factor of Safety = 3.0 Calculations - Ultimate Bearing Capacity From Figure 33.4 on P. 222 Nc = 25.80 Nq = 14.72 Ny = 16.72 QU = 1.2 C N, + y D Nq + 0.4 y B Ny (Square Footing) = 1.2* 300 * 25.80+ 110 * 1.0 * 14.72+ 0.4* 110 * 1.0 * 16.72 = 9288 + 1619 + 736 = 11643 psf Allowable Bearing Capacity for Square Footing, Qaii = Qu/ F.S. = 3881 psf Use 2500 psf Q„ = 1.0 C Nc + y D Nq + 0.5 y B Ny (Continuous Footing) = 1.0* 300 * 25.80+ 110 * 1.0 * 14.72+ 0.5* 110 * 1.0 * 16.72 = 7740 + 1619 + 920 = 10279 psf Allowable Bearing Capacity for Continuous Footing, Qau = Qu/ F.S. = 3426 psf Use 2500 psf Increases: 500 psf / ft in depth over 1.0 feet 225 psf / ft in width over 1.0 feet Geotechnical Engineering and Engineering Geology Investigation 10 Bowie Road Rolling Hills, California Project No. 15-1942 Figure 6 HAMILTON & ASSOCIATES, INC. The maximum edge pressure of any eccentrically loaded footing should not exceed the values recommended for either permanent or momentary loads. . Lateral Loads — Spread Footings An allowable lateral bearing value against the sides of footings of 300 pounds per square foot, per foot of depth, to a maximum of 3500 pounds per square foot may be used, provided there is positive contact between the vertical bearing surface and the undisturbed terrace deposits/siltstone. Friction between the base of the footings, and/or floor slabs, and the underlying material may be assumed as 0.30 times the dead load. Friction and lateral pressure may be combined, provided either value is limited to two-thirds of the allowable. Creep Isolated footings placed on a slope steeper than 5:1 (horizontal to vertical), in contact with soil/colluvium, shall be designed for creep loads. For design purposes, the lateral creep pressures may be assumed as one keep per foot of depth, to a depth of 4 feet, for footings in contact with the creeping soils. Retaining Walls Walls retaining drained earth may be designed for the following: Surface Slope of Retained Material Horizontal to Vertical Level 5 to 1 4 to 1 3 to 1 2 to 1 Static Equivalent Fluid Pressure Pounds per Cubic Foot Clay Granular 60 30 64 32 70 35 76 38 86 43 Seismic Loading Pounds per Foot of Wall Width* Clay 16H2 17H2 19H2 21H2 23H2 Granular 10H2 11 H2 12H2 13H2 14H2 *(H = Wall Height) Per the Southern California Structural Engineer's Association, an inverted triangle loading is recommended, with the point of load application at 2/3 H above the base of the wall. Concord Residential Development 15-1942 May 11,2015 Page 12 HAMILTON & Associates Backfill should consist of clean sand and gravel. While all backfill should be compacted to the required degree, extra care shall be taken working close to walls to prevent excessive pressure. A proper drainage system should be utilized to prevent hydrostatic pressure behind the retaining wall. It is therefore recommended that either weep holes or a drainage pipe be installed. A four inch perforated pipe (holes down) surrounded by at least 12 inches of 3/ inch gravel enveloped in a drainage fabric, such as Mirafi 140N or equivalent, should be placed at the base of the footing at the wall. If weep holes are chosen, these openings should be four feet on center, and also situated at the base of the wall with a gravel and drainage fabric backdrain. Basement Walls The basement walls will be retrained from deflection by the structural frame. Therefore, the walls should be designed for "at -rest" active earth pressure. For the level backfill conditions, an equivalent fluid pressure of 60 pounds per cubic foot may be used for design, assuming the backfill is free draining. Temporary Excavation Slopes Temporary excavation slopes in the existing surface soil may be made vertical for cuts of less than five feet. For deeper cuts, temporary excavation slopes shall be made no steeper than 1:1 (horizontal to vertical). In areas where soils with little or no binder are encountered, shoring or flatter excavation slopes shall be made. Your attention is directed to the fact that while caving was not encountered in the test excavations, it is possible that a trench or excavation could react in an altogether different manner. All excavations shall be made in accordance with the regulations of the State of California, Division of Industrial Safety. These recommended temporary excavation slopes do not preclude local raveling and sloughing. Concord Residential Development 15-1942 May 11,2015 Page 13 HAMILTON S Associates Site Drainage In accordance with the 2013 CBC (unless the exception applies), the ground immediately adjacent to the foundation should be sloped away from the building at a slope of 5% for the first 10 feet. If physical obstructions or lot lines prohibit 10 feet of horizontal distance, the 5% slope should be provided to an alternate method of diverting water from the foundation system, such as swales (sloped at 2%). Impervious surfaces within 10 feet of the building foundation shall be sloped a minimum of 2% away from the building. Site drainage should be dispersed by non -erosive devices in accordance with the grading regulations of controlling agencies to preclude concentrated run-off and erosion over the site. In no case shall water be allowed to pond or drain down the slope in a concentrated and uncontrolled manner. Water shall be conducted to Bowie Road. SOIL CORROSIVITY Chemical test analyses were performed on a select sample of site soils by Cal Land Engineering, Inc. These chemical tests were selected to give a general idea as to the corrosive nature of on -site soils to proposed concrete foundations, rebar, and any underground metal conduit. The Project Structural Engineer should employ the below described corrosion results for minimum structural design and concrete requirements. A corrosion engineer/specialist should be consulted for any advanced analysis or recommendations relating to corrosion at the subject site. The chemical test results are presented on Figure 7. Results are summarized below. Concrete Corrosion: Disintegration of concrete may be attributed to the chemical reaction of soil sulfates and hydrated lime and calcium aluminate within the cement. The severity of the reaction resulting in expansion and disruption of the cement is primarily a function of the soluble sulfates and the water -cement ratio of the concrete. Laboratory testing indicates a sulfate concentration of 0.0045 percent by weight of dry soils in the tested soil sample. Soils with sulfate concentrations less than 0.10 percent are generally reported to have a negligible corrosive effect on concrete. Metal Corrosion: In the evaluation of soil corrosivity to metal, the hydrogen ion concentrate (pH) and the electrical resistivity of the site and backfill soils are the principal variables in determining the service life of ferrous metal conduit. The pH of soil and water is a measure of acidity or alkalinity, while the resistivity is a measure of the soil's resistance to the flow of electrical current. Currently available design charts indicate that corrosion rates Concord Residential Development 15-1942 May 11,2015 Page 14 HAMILTON & Associates SOIL CORROSIVITY RESULTS Cal Land Engineering, Inc. Quartech Consultants, Inc. Geotechnical, Environmental, and Civil Engineering Client: Hamilton and Associates QC! Project No.: 15-154-003b Project Name: Concord Dev Date: April 2, 2015 Project No.: 15-1942 Summarized by: KA Corrosivity Test Results SampleSample pH Chloride Sulfate Depth CT 532 CT-422 CT-417 CT-532 Resistivity ID (ft) (643) (npm) (% By Weight) (ohm -cm) TP-3 2-5' 7.76 80 0.0045 1100 678 East Lambert Road, Brea, California 92821; 714.671.1050; Fax: 714.671-1090 PROJECT: Concord Development-10 Bowie Road -Rolling Hills, CA PROJECT NO: 15-1942 DATE: April 2015 Hamilton & Associates, Inc. FIGURE 7 • ..decrease with increasing resistivity and increasing alkalinity. It can also be noted that for alkaline soils, the corrosion rate is more influenced by resistivity than by pH. The resistivity value of 1,100 ohm -cm, as well as a pH -value of 7.76 classifies the on - site soils tested to be "Moderately" corrosive to buried ferrous metals. Based on California Test 643, the year to perforation for 18-gauge steel in contact with soils of similar resistivity and pH -value is approximately 35 years. In lieu of additional testing, alternative piping materials, i.e. coatings, plastic piping, may be used instead of metal if longer service life is desired or required. Where more detailed corrosion evaluation is required we recommend that a qualified corrosion consultant be engaged to provide further evaluation and recommendations. A soluble chloride content of 80 ppm recorded in our limited laboratory tests are considered moderate to the threshold values of 100 ppm per Federal Highway Administration Standards (FHWA), 2002. Slabs -on -Grade The surface soils found on -site are primarily silty clay. Based on expansion tests, these soils are considered highly expansive. In order to mitigate the potential effects of expansion, it is recommended that slabs -on -grade should be a minimum of five inches thick and reinforced with No.4 bars, 12 inches on -center each way. It is further recommended that the subgrade soils be moistened to a depth of 18 inches prior to placing of the membrane and pouring of floor slabs. The moisture content should be at least three percent greater than the optimum moisture content. A moisture barrier beneath the slabs -on -grade, preferably consisting of at least four inches of sand, with a waterproof vapor barrier, such as a plastic membrane of at least ten mils in thickness, covered with two inches of clean sand, is recommended in areas where soil moisture would be detrimental. Grading The following general specifications are recommended: 1. Areas to be graded or paved shall be grubbed and stripped of all vegetation, debris and other deleterious material. All loose soil disturbed by the removal -of trees, structures and existing fill shall be removed. Concord Residential Development 15-1942 May 11,2015 Page 15 HAMILTON & Associates 2. In all cases where the ground slope is steeper. than 5 (horizontal) to 1 (vertical), the existing ground shall be benched, as the fill thereon is brought up in layers. That existing ground which slopes flatter than 5 to 1 may also require benching, if the geotechnical engineer considers such to be necessary. 3. Where compacted soil is to provide support for structural loads, all of the existing fill and loose natural soil, to a depth of 5 feet below shall be excavated. The area of removal shall extend at least three feet below all footings, and five feet beyond the edge of footings, or equal to the depth of removal, whichever is greater. The exposed surface shall be compacted to at least 90 percent. All new fill shall be brought to near optimum moisture content, placed in layers not exceeding six inches thick and compacted to at least 90 percent. 4. The existing subgrade soils within the building and paved areas shall be compacted prior to construction of floor slabs and paving to secure uniform support and to minimize differential settlement. It is recommended the degree of compaction within the upper 12 inches be at least 90 percent. 5. All other fills and backfills shall be compacted to at least 90 percent. 6. The compaction characteristics of all fill soils shall be determined by ASTM D- 1557-12. The field density and degree of compaction shall be determined by ASTM D- 1556, or by other acceptable ASTM standard methods which are acceptable to the governing public agency. 7. Imported fill shall consist of clean, granular, non -expansive soil, free of vegetation and other debris, and shall be placed in layers not exceeding six inches near optimum moisture content. No rocks over three inches in dimension shall be used. No soil shall be imported to the site without prior approval by the geotechnical engineer. The surface soils found on the project would be suitable for use in compacted fills, provided any deleterious and oversized material are removed. 8. No jetting or water tamping of fill soils shall be permitted. 9. Care shall be exercised during rough grading so areas involved will drain properly. Water shall be prevented from running over slopes by temporary berms. 10. At all times, the contractor shall have a responsible field superintendent on the project, in full charge of the work, with authority to make decisions. He shall cooperate fully with the geotechnical engineer in carrying out the work. Concord Residential Development 15-1942 May 11,2015 Page 16 HAMILTON & Associates 11. No fill shall be placed, spread or rolled during unfavorable weather. When the • work is interrupted by rain, operations shall not be resumed until field tests by the geotechnical engineer indicate that conditions will permit satisfactory results. Plan Review. Observations and Testing All excavations should be observed by a representative of this office to verify minimum embedment depths, competency of bearing soils and that the excavations are free of loose and disturbed materials. Such observations should be made prior to placement of any fill, reinforcing steel or concrete. All grading and fill compaction should be performed under the observation of and testing by a Geotechnical Consultant or his representative. As foundation and grading plans are completed, they should be forwarded to the Geotechnical Consultant for review for conformance with the intent of these recommendations. As a necessary requisite to the use of this report, the following shall be observed by the geotechnical engineer: 1. Observation of all grading observations. 2. Observation of all surface and subsurface drainage systems. 3. Observation of all backfill wedges, drainage blankets and weep holes for retaining walls. 4. Observation of premoistening of subgrade soils and placement of sand cushion and vapor barrier beneath the slab. 5. Observation of all foundation excavations for the proposed construction. 6. As foundation and grading plans are completed, they should be forwarded to the Geotechnical Consultant for review for conformance with the intent of these recommendations. The consultant should be notified at least two days in advance of the start of construction. A joint meeting between the contractor and geotechnical consultant is recommended prior to the start of construction to discuss specific procedures and scheduling. Concord Residential Development 15-1942 DJ May 11,2015 Page 17 HAMILTON & Associates • REMARKS The conclusions and recommendations contained herein are based upon findings and observations made at the 6 test pit locations. While no great variations in soil conditions are anticipated, if conditions are encountered during construction which appear to differ from those disclosed by the test excavations, this office should be notified, so as to consider the need for modifications. No responsibility for construction compliance with the design concepts, specifications or recommendations is assumed unless on -site construction review is performed during the course of construction which pertains to the specific recommendations contained herein. Footings should be located below a line measured at a 45 degree angle from the bottom of any utility trench, unless reviewed and approved by the geotechnical engineer. This report is subject to review by controlling public agencies having jurisdiction. This report has been compiled for the exclusive use of Concord Development and Construction, they're authorized representatives. It shall not be transferred to, or used by a third party, to another project, or applied to any other project on this site, other than as described herein, without consent and/or review by this facility. Should the project be delayed beyond the period of one year after the date of this report, the site and report shall be reviewed to consider possible changed conditions. Samples obtained in this investigation will deteriorate with time and will be unsuitable for further laboratory testing within three months from the date of this report. Unless otherwise advised, the samples will be discarded at that time. This investigation was made in accordance with generally accepted engineering procedures and included such field and laboratory tests considered necessary in the circumstances. In the opinion of the undersigned, the accompanying report has been substantiated by mathematical data in conformity with generally accepted engineering principles and presents fairly the information requested. In the opinion of the undersigned, the accompanying report has been substantiated by mathematical data in conformity with generally accepted engineering principles and presents fairly the information requested. Concord Residential Development 15-1942 May 11,2015 Page 18 HAMILTON & Associates No other warranty expressed or implied, is made as to the professional advice included in this report. Respectfully submitted, HAMILTON & ASSOCIATES, INC. Aaron Martinez Project Manager/Field Te Richard A. Martin, MS., P Geotechnical Engineer RAM/MFM/AM:car (5) Addressee Concord Residential Development 15-1942 Michael F. Mills, C Engineering Geologist May 11,2015 Page 19 HAMILTON Associates REFERENCES The following reports were reviewed while preparing the geotechnical report for 10 Bowie Road, Rolling Hills, California: Bishop, K., and Ehlert, K. 2001, Engineering Geology of the Palos Verdes Hills: A memorial to Perry Ehlig, in Dunne, G. and Cooper, J., compilers, Geologic excursions in southwestern California: Fieldtrip Guidebook and Volume, Cordilleran Section, U.S. Geol. Soc. and Pacific Section Amer. Assoc. Pet. Geol., April 11, 2001, pp. 1-20. California Geological Survey, 2002/2011, Interactive probabilistic seismic hazards map: http://conservation.ca.gov/cgs/rregional/pshamap//html. Cao, T., Bryant, W.A., Rashandel, B., Branum, D., and Wills, C. J., 2003, The revised 2002 California probability seismic maps: Calif. Geol. Surv. Online Rpt. Cleveland, G.B., 1976, Geology of the northeast part of the Palos Verdes Hills, Los Angeles County, California: Calif. Div. Mines and Geol. Map Sheet 2. County of Los Angeles, 2013, Department of Regional Planning, GIS Section, Topographic Map of * Golden Spur area: Local Map Taken From County Website. Department of Conservation, Division of Mines and Geology, 1999, Seismic Hazard Zones Special Map, Torrance 7.5—Minute Quadrangle. Dibblee, T.W., Jr., 1999, Geologic map of the Palos Verdes Peninsula and vicinity: Dibblee Foundation Map DF-70. Gregory W. Axten, 1983, Preliminary geotechnical investigation, proposed retaining walls (2), 10 Bowie Road, Rolling Hills, California: Consultant's Technical Report, dated October 15, 1983, File No. 1053.01. Hart, E.W. and Bryant, W.A., Revised 2007, Fault -rupture hazard zones in California, Alquist-Priolo earthquakes fault zoning act with index to earthquake fault zones map; California Division of Mines and Geology Special Publication 42. Haydon, W.D., 2007, Landslide Inventory Map of the Palos Verdes Peninsula, Los Angeles County, California: Calif. Geol. Surv. Concord Residential Development 15-1942 May 11,2015 Page 20 HAMILTON & Associates International Conference of Building Officials, 1998, Maps ,of known active faults near - Source Zones in California and adjacent portions of Nevada. Jennings, Charles, 2010, "Fault activity map of California": Online. Pacific Soils Engineering, Inc., 1971, Wall design criteria, proposed retaining wall, #10 Bowie Road, Rolling Hills, California: Consultant's Report, dated September 24, 1971, W.O. 8917-A. SWN Soil Tech Consultants, 2004, Update report, proposed residential development, 12 Bowie Road, Rolling Hills, California: Consultant's Technical Report, dated March 18, 2004, Project Ref. 4548-04. Treiman, J.J., and Lundberg, M.M., 1998, Fault number 129a, Cabrillo fault, onshore section, in Quaternary fault and fold database of the United States: U.S. Geol. Surv. Website, http//earthquakes.usgs.gov/regional/faults. United States Geological Survey, Java ground motion parameter calculator website: Version 5.1.0. , Work Order 02-3401. Woodring, W.P., Bramlette, M.N., and Kew, W.S.W., 1946, Geology and paleontology of the Palos Verdes Hills, California: U.S. Geol. Survey, Prof. Paper 207. Woods, M. C., and Seiple, W. R., ed., 1995, "The Northridge, California Earthquake of January 17, 1994", California Division of Mines and Geology, Special Publication 116. Ziony, J. I. ed., 1985, Evaluating earthquake hazards in the Los Angeles region — an earth science perspective: U.S. Geol. Surv. Professional Paper 13 Concord Residential Development 15-1942 May 11,2015 Page 21 HAMILTON & Associates . APPENDIX A The following Appendix contains the substantiating data and laboratory test results to complement the engineering evaluations and recommendations contained in this report. Plate A-1 Plate A-2 Plate A-3 & A-4 Plates B-1 through B-6 Plate C-1 and C-2 Plates D-1 through D-4 Test Pit Location Plan/Geologic Map City Topographic Map Geologic Cross Sections A -A' & B-B' Logs of Test Pits Consolidation Test Results Shear Test Results SITE EXPLORATION On March 24, 2015, a field exploration was performed by excavating six (6) test pits at the approximate locations indicated on the attached Test Pit Location Plan, Plate A-1. The exploratory test pits were excavated utilizing hand digging equipment. The test pits extended to a maximum depth of 10.5 feet from existing grade. The soils were classified in the field by visual and textural examination and these classifications were supplemented by obtaining bulk soil samples for future examination in the laboratory. Relatively undisturbed samples of soils were extracted in a barrel sampler lined with 2.416-inch I.D. by one -inch high rings. All samples were secured in moisture -resistant bags as soon as taken to reduce the loss of field moisture while being transported to the laboratory and awaiting testing. Upon completion of explorations, the test pits were backfilled with excavated materials and compacted by tamping. Description of the soils encountered in the exploratory test pits are provided on Plates B-1 through B-6. Information regarding the depth of samples, field density and field moisture contents and other geotechnical laboratory tests are provided in the following sections. Concord Residential Development 15-1942 May 11,2015 Page 22 HAMILTON & Associates LABORATORY TESTS • After samples were visually classified in the laboratory, a testing program that would provide data for our evaluation was established. The results are presented in the following sections. • MOISTURE CONTENT AND DENSITY TESTS The undisturbed soil retained within the sampler rings was tested in the laboratory to determine in -place dry density and moisture content. The results are presented below: Test Pit Depth No. Feet bgs TP-1 6.0 TP-2 2.5 TP-2 6.0 TP-3 2.0 TP-4 6.0 TP-5 2.0 TP-6 10.0 Dry Density, pcf 92.2 87.0 92.0 76.4 77.5 67.0 78.0 CONSOLIDATION AND DIRECT SHEAR TESTS Moisture Content, % 16.5 24.2 16.5 37.7 14.4 32.4 35.1 Consolidation and Direct Shear tests were performed on selected relatively undisturbed samples to estimate the settlement characteristics and shear strength parameters of various soil samples, respectively. The results of these tests are shown graphically on the appended "D" Plates. MAXIMUM DENSITY TEST The following maximum density test was conducted in accordance with ASTM D1557- 00, Method C, using 5 equal layers, 56 blows each layer, 10-pound hammer, 18 inch drop in a 1/13.3 cubic foot mold. The results are as follows: Maximum Dry Test Pit No. Depth, Feet Density, pcf TP-3 0-5" Concord Residential Development 15-1942 95.2 Optimum Moisture Content, 16.0 Material Classification Silty Clay May 11,2015 Page 23 HAMILTON & Associates EXPANSION TEST An expansion test was performed on a soil sample to determine the swell characteristics. The expansion test was conducted in accordance with ASTM D4829, Expansion Index Test. The expansion sample was remolded to approximately 90 percent relative compaction at near optimum moisture content, subjected to 144 pounds per square foot surcharge load and saturated. Molded Dry Molded Moist. % Expansion Expansion Location Density, pcf Content, % Saturation Index Classification TP-3 82.9 18.5 50.0 91 High Concord Residential Development 15-1942 May 11,2015 Page 24 HAMILTON & Associates IMO MN INN 11111 111111 NMI MI NEI MIN 11111 nil MI SIN - — 11111 EXPLORATORY TEST PIT LOCATION PLAN AND GEOLOGIC MAP • ncpttfal Locatipn osed Constfiction " Building Pa LEGEND —A— TEST PIT LOCATION ORIENTATION OF CLOT ZONE r FOLIATION ANGLE. PLUNGING ANTICLINE. - SYNCLINE SLOPE FAILURE OMIALIOPLOST. RECOSIMENDEITORAINMSE INTENCESTMAS: EQL:C*1QMAR. !'s• ESTIMATED LOCATION . Gr9tIgrY,W:AXterr: - - uses OFREDOMMENDED FILL COY VS.'ISsi'TZ1711.40,Te ZUZI1,-4.TDOST. PROJECT: Concord Development — ' • Hamilton & Associates, Inc. faFt.),TepI17.11, :.;=-ror-ouvr.or1 : . March 2015 Concord Development Proposed Residential Development 10 Bowie Road Rolling Hills, California 90274 LEGEND Exploratory Test Pits by Hamilton & Associates, Inc. 2015 Boring by Pacific Soils 22* 5 13 TP-1 0 B-1 GEOLOGIC LEGEND — Geologic Contact; Queried where Inferred AF- Fill Qcol- Colluvium Tma-Altamira Shale Pkc— Catalina Schist Strike and Dip of Bedding Minor Fault Geologic Cross Sections by Hamilton & Associates, Inc. 2015 CI OEJ REFERENCE: Grading Plan, prepared by Outland & Associates, Licensed surveyors; dated 1983 APPROX SCALE: 1" = 40! PROJECT NO: 15-1942 PLATE A-1 MO UN M MO SIMI MINI Mil MI MINI MI OM NMI W IIIIII INN MI CROSS SECTION A -A' A A' 100- 80- — / 60- 40— Edsnsg Residence and Antiapated Conceptual Location of Now Construction TP-3-H8A 9edseck - Typical Footings into�Tma Bedrock PROJECT: Concord Residential Development Tma TP6-H8A Fa Bedro k pkc Hamilton & Associates, Inc. — 100 — 80 — 60 Her-e Trai Landside per Aden (1983 pkc AN., Concord Development Residential Development 10 Bowie Road Rolling Hills, CA LEGEND. Projected Location of Test Pits by Hamilton & Associates, Inc., 2015 0 TP-1-H&A APPROX SCALE: 1" = 20' April 2015 PROJECT NO: 15-1942 PLATE A-2 all 11111 0 CROSS SECTION B-B' BR B' 100— Qcol 80- 60- 40— Eaise g Garage a. Residence Meager.Co. dctiocap non of New New Ce�strun TP-3-H&A r o-HBA c—Js Typical Footings into Tma ✓ -1,.� Bedrock • PROJECT: Concord Residential Development pkc TP-5-H&A Bedrock = — Hamilton & Associates, Inc. Concord Development Residential Development 10 Bowie Road Rolling Hills, CA LEGEND Projected Location of Test Pits by Hamilton & Associates, Inc., 2015 TP-1-H&A Bowie Road — •APPROX SCALE: 1" = 20' April 2015 ' PROJECT NO: 15-1942 PLATE A-3 Date: 3/24/05 a) C in.a V) LL' N n ..0 0 0 U B 92.2 16.5 III 5 10 'SUMMARY OF TEST PIT NO. 1 . Description NATURAL SOIL/COLLUVIUM: Clay, silty, scattered shale/siltstone bedrock fragments, roots, - animal burrows in the upper foot, slightly moist (CL) End of Test Pit at 6 Feet No Caving - No Water Logged by AM/MM Preliminary Geotechnical Engineering and Engineering Geology Investigation 10 Bowie Road Rolling Hills, California Hamilton & Associates, Inc. O • U Dark Brown Project No. Plate U Very Stiff 15-1942 B-1 Date: 3/24/05 a) E u) • U B 0. a) 0 SUMMARY OF TEST PIT NO. 2 Description NATURAL SOIL/COLLUVIUM: Clay, silty, scattered shale/siltstone bedrock fragments, roots, - moist (CL) 87 24.2 ® - 5 BEDROCK (Altamira Shale) : Shale/Siltstone, diatomaceous, moist. N20E, 23NW -- bdg 92 16.5 III End of Test Pit at 6 Feet No Caving - No Water Logged by AM/MM 10 Preliminary Geotechnical Engineering and Engineering Geology Investigation 10 Bowie Road Rolling Hills, California Dark Brown Very Stiff Tan/Brown/ Hard Orange/Gray Project No. 15-1942 Plate B-2 Hamilton & Associates, Inc. Date: 3/24/05 I.. 76.4 37.7 SUMMARY OF TEST PIT NO. 3 Description. FILL: Clay, silty, planter soil, roots, moist (CL) BEDROCK (Altamira Shale): Shale/Siltstone, - diatomaceous, moist N3OW, 10 NE -bedding End of Test Pit at 2 Feet No Caving - No Water Logged by AM/MM 5- 10— Preliminary Geotechn cal Engineering and Engineering Geology Investigation 10 Bowie Road Rolling Hills, California Hamilton & Associates, Inc. w O• O Dark Brown Tan/Brown/ Orange/Gray C.)) C a) U) N C O 0 Stiff Hard Project No. 15-1942 Plate B-3 Date: 3/24/05 : ' ▪ 0 -- ▪ 2' a) C � O o_ 5 a E o 2� O U B 77.5 14.4 5 10 SUMMARY OF TEST PIT NO. 44 Description FILL: Clay, silty, scattered shale/siltstone bedrock fragments, roots, uniform, dry to slightly moist (CL) End of Test Pit at 7 Feet No Caving - No Water Logged by AM/MM Preliminary Geotechnical Engineering and Engineering Geology Investigation 10 Bowie Road Rolling Hills, California C U Mottled Brown Gray Firm to Stiff Project No. 15-1942 Plate B-4 Hamilton & Associates, Inc. Date: 3/24/05 U B 67 32.7 5 10 SUMMARY OF TEST PIT NO. 5 0 C Description a 0 U FILL: Clay, silty, scattered bedrock fragments, Dark Brown Firm moist (CL) BEDROCK (Altamira Shale): Shale/Siltstone,diatomaceous, moist N8OW, 25NE -- bdg N2OW, 25NE -- bdg End of Test Pit at 3 Feet No Caving - No Water Logged by AM/MM Preliminary Geotechnical Engineering and Engineering Geology Investigation 10 Bowie Road Rolling Hills, California Hamilton & Associates, Inc. Tan/Brown/ Hard Orange/Gray Project No. 15-1942 Plate B-5 Date: 3/24/05 a) fl. E ca cn U B 78 35.1 SUMMARY OF TEST PIT NO. 6 Description FILL: Clay, silty, scattered shale/siltstone bedrock Mottled Brown Firm to fragments, roots„ dry to slightly moist Gray Stiff (CL) 5 10 BEDROCK: Siltstone/Shale, diatomaceous, moist Tan/Orange/Gray Hard _ End of Test Pit at 10.5 Feet No Caving No Water Pit Hand Augered 3 to 10.5 Feet Logged by AM/MM Preliminary Geotechnical Engineering and Engineering Geology Investigation 10 Bowie Road Rolling Hills, California Hamilton & Associates, Inc. Project No. 15-1942 Plate B-6 Consolidation (Percent) 0.1 0.00 II 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 CONSOLIDATION TEST RESULTS Test Pit No. 2 @ 6 Feet 1 Pressure (Kips Per Square Foot) 1 10 •-r N HII tH I±I 0 Test Specimen at In -Situ Moisture 0 Test Specimen Submerged Preliminary Geotechnical Engineering and Engineering Geology Investigation 10 Bowie Road Rollina Hills. California Project No. 15-1942 Plate C-1 LW] Hamilton & Associates, Inc. Consolidation (Percent) 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 15.00 0.1 CONSOLIDATION TEST RESULTS Test Pit No.4 @ 6 Feet Pressure (Kips Per Square Foot) Ij b 1 e 10 H 0 Test Specimen at In -Situ Moisture 0 Test Specimen Submerged Preliminary Geotechnical Engineering and Engineering Geology Investigation 10 Bowie Road Rollina Hills. California Project No. 15-1942 Plate C-2 111 Hamilton & Associates, Inc. Stress (kips/sq. ft) 5 4 3 2 1 0 SHEAR TEST RESULTS Test Pit No..2 at 6 Feet N 1 2 3 Confining Pressure (kips/sq. ft.) Stress - Displacement Diagram ♦♦♦♦♦♦♦♦ ♦♦, is • la.. 4 ♦ 1 • ■ ■ 0 1 2 3 Horizontal Displacement (X 1/10 inch) 4 4 Shale/Siltstone samples were submerged for at least 24 hours. The samples had a density of 90 lbs./cu.ft. and a moisture content of 31.1 % Cohesion = 200 psf Friction Angle = 30 degrees Based on Ultimate Strength ♦ 1 Kip •2 Kips ♦ 3 Kips Preliminary Geotechnical Engineering and Engineering Geology Investigation Project No. 15-1942 10 Bowie Road Rolling Hills, California Plate D-1 LW Hamilton & Associates, Inc. Stress (kips/sq. ft) 5 4 3 SHEAR TEST RESULTS Test Pit No. 3 at 2 Feet I 1 2 3 Confining Pressure (kips/sq. ft.) Stress - Displacement Diagram 4 • 1 Kip ■2 Kips ■ ■ ■ ♦ 3 Kips 3 4 Horizontal Displacement (X 1/10 inch) Shale/Siltstone samples were submerged for at least 24 hours. The samples had a density of 74 lbs./cu.ft. and a moisture content of 46 % Cohesion = 400 psf Friction Angle = 32 degrees Based on Ultimate Strength Preliminary Geotechnical Engineering and Engineering Geology Investigation Project No. 15-1942 10 Bowie Road Rolling Hills, California Plate D-2 In Hamilton & Associates, Inc. Stress (kips/sq. ft.) 3 Stress (kips/sq. ft) 5 4 3 2 1 0 0 SHEAR TEST RESULTS Test Pit No. 4 at 6 Feet I 1 2 3 Confining Pressure (kips/sq. ft.) Stress - Displacement Diagram ♦!♦♦♦ ♦ ♦♦ .k ■-■-•-• i ■ • ■ I ♦♦♦N♦♦♦♦♦♦♦♦t ♦ ♦ ♦ r 1 2 3 Horizontal Displacement (X 1/10 inch) 4 4 Silty Clay samples were submerged for at least 24 hours. The samples had a density of 77 lbs./cu.ft. and a moisture content of 43 % Cohesion = 350 psf Friction Angle = 25 degrees Based on Ultimate Strength ♦ 1 Kip ■ 2 Kips ♦ 3 Kips Preliminary Geotechnical Engineering and Engineering Gelogy Investigation Project No. 15-1942 10 Bowie Road Rolling Hills, California Plate D-3 Hamilton & Associates, Inc. 0 Stress (kips/sq. ft) SHEAR TEST RESULTS Test Pit No. 5 at.2 Feet (Normal Shear) I 1 2 3 Confining Pressure (kips/sq. ft.) Stress - Displacement Diagram 5 4 3 2 A A A, ,1 _ 1—A—, L • 1 I -III ■■■•■ ■■ I ♦ ♦♦NN�♦♦ ♦ ♦ ♦ t ♦ ♦ ♦ 7 0' 0 1 2 3 Horizontal Displacement (X 1/10 inch) 4 4 Shale/Silstone samples were submerged for at least 24 hours. The samples had a density of 66 lbs./cu.ft. and a moisture content of 56.1 % Cohesion = 220 psf Friction Angle = 29 degrees Based on Ultimate Strength ♦ 1 Kip ■2 Kips ♦ 3 Kips Preliminary Geotechincal Engineering and Engineering Geology Investigation Project No. 15-1942 10 Bowie Road Rolling Hills, California Plate D-4 Hamilton & Associates, Inc. SHEAR TEST RESULTS Test Pit No. 5 at 2 Feet (Repeated Reshear) M 1 2 3 Confining Pressure (kips/sq. ft.) Stress - Displacement Diagram A ,1 A A A ,1 1 ��-II AA 0 �� ♦ ♦ ♦ 0 1 2 3 4 Horizontal Displacement (X 1/10 inch) 4 Shale/Silstone samples were submerged for at least 24 hours. The samples had a density of 66 lbs./cu.ft. and a moisture content of 56.1 % Cohesion = 100 psf Friction Angle = 27 degrees Based on Ultimate Strength • 1 Kip ■ 2 Kips • 3 Kips Preliminary Geotechincal Engineering and Engineering Geology Investigation Project No. 15-1942 10 Bowie Road Rolling Hills, California Plate D-5 Hamilton & Associates, Inc. APPENDIX B SLOPE STABILITY ANALYSIS NAME: Concord Development ADDRESS: 10 Bowie Road ROLLING HILLS, CALIFORNIA PROJECT NO. 14-1942 Concord Residential Development 15-1942 al May 11,2015 Page 25 HAMILTON & Associates NM UN— NM i 1 N MN In l S— MO NE EN N CROSS SECTION A -A' SLOPE STABILITY ANALYSIS A A' 100— 80 — 60- 40— Emtng Residence end MBoyrafed Cen.96,4 Location of NexConstruction TP3-H&A Typical Footings into Bedrock ? Bedrock Tma Tma ? --. - ? �- PROJECT: Concord Residential Development TPBNSA Fit Bedrock pkc F.S. min = 1.63 (Static) F.S. min = 1.20 (Pseudpstatic) Hamilton & Associates, Inc. pkc Horse Trail PL Landslide per Porten (1983) — 100 — 80 — 60 40 April 2015 Concord Development Residential Development 10 Bowie Road Rolling Hills, CA LEGEND. Projected Location of Test Pits by Hamilton & Associates, Inc., 2015 0 . TP-1-H&A APPROX SCALE: 1" = 20' PROJECT NO: 15-1942 PLATE E-1 OM EN NM NE INN 11111 Mil M CROSS SECTION B-B' SLOPE STABILITY ANALYSIS 3 R B' F "stag Garage a. aesitlence MEcialetl CanrapUd LomEon of Near Gnseru.on 100— Qcol TP-3-H&A so — Typical Footings into Bedrock ? 60- 40— PROJECT: Concord Residential Development / Fll TP-6-H&A Tma 7 • pkc TP-5-H&A F.S. min = 1.25 (Pseudpstatic) Hamilton & Associates, Inc. F.S. min = 1.60 (Static) Bowie Road — April 2015 Concord Development Residential Development 10 Bowie Road Rolling Hills, CA LEGEND Projected Location of Test • Pits by Hamilton & Associates, Inc., 2015 TP-1-H&A APPROX SCALE: 1" = 20' PROJECT NO: 15-1942 PLATE E-2 SURFICIAL SLOPE STABILITY ANALYSIS. ( for Fill Slope ) Reference: "Soils Slips, Debris Flows, and Rainstorms in the Santa Monica Mountains and Vicinity, Southern California", . U.S. Geological Survey Professional Paper No. 851, 1975. Calculations: where, F.S. = C+(y-7w)*Z*(cos3)2*tan4) 7*Z*(sing)*(cos(3) F.S. is the Factor of Safety C (Cohesion) = 350 psf y (Saturated Soil Density) = 110 pcf y, (Density of Water) = 62.4 pcf Z (Depth of Slide) = 4 feet 13 (Slope Angle) = 33 degrees (I) (Friction Angle) = 23 degrees F.S. = 350+(47.6)*(4)*(0.839)2*(0.424) (110)*(4)*(0.545)*(0.839) 350 + 56.83 201.19 406.83 201.19 2.022 This factor of safety is in excess of the normally accepted minimum for stable slopes. Geotechnical Engineering and Engineering Geology Investigation Project No. 15-1942 10 Bowie Road Rolling Hills,California Plate E-3 Hamilton & Associates, Inc. 11111 i UN V I in NM 1 N-- r r N N-- NI 106.25 85.00- 63.75- 42.50- 21.25- 00 21:25 42.50 63.75 85.00 106.25 127.50 148.75 170.00 Section B-B', Pseudostatic Safety Factors 1.25 1.27 1.27 1.28 1.28 1.28 1.29 1.29 1.30 1.30 Profile.out ** PCSTABL6 ** by, Purdue university modified by Peter 3. Bosscher University of Wisconsin -Madison --Slope stability Analysis -- simplified 3anbu, simplified Bishop or Spencer's Method of slices PROBLEM DESCRIPTION: Section B-B', Pseudostatic 10 Bowie Rd., Rolling Hills F. S. min = 1.25 BOUNDARY COORDINATES 8 Top Boundaries 12 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type No. (ft) (ft) (ft) (ft) Below Bnd 1 0.00 20.00 10.00 20.00 3 2 10.00 20.00 38.00 48.00 3 3 38.00 48.00 54.00 49.00 3 4 54.00 49.00 67.00 54.00 2 5 67.00 54.00 78.00 54.00 2 6 78.00 54.00 88.00 62.00 1 7 88.00 62.00 109.00 70.00 1 8 109.00 70.00 170.00 70.00 1 9 78.00 54.00 130.00 65.00 2 10 130.00 65.00 162.00 67.00 2 11 162.00 67.00 170.00 68.00 2 12 54.00 49.00 170.00 50.00 3 ISOTROPIC SOIL PARAMETERS 3 Type(s) of soil Soil Total saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No. 1 110.0 110.0 175.0 23.0 0.00 0.0 1 2 110.0 110.0 200.0 30.0 0.00 0.0 1 3 125.0 125.0 465.0 23.0 0.00 0.0 1 A Horizontal Earthquake Loading coefficient Page 1 Profile.out of.0.160 Has Been Assigned A vertical EarthquakeLoading coefficient Of 0.000 Has Been Assigned Cavitation Pressure = 0.0 psf BOUNDARY LOAD(S) 1 Load(s) specified Load X-Left X-Right Intensity Deflection No. (ft) (ft) (lb/sgft) (deg) 1 134.00 160.00 200.0 0.0 NOTE - IntensityIs specified As A Uniformly Distributed Force Acting On A Horizontally Projected Surface. A Critical Failure surface searching Method, using A Random Technique For Generating Circular Surfaces, Has Been Specified. 100 Trial Surfaces Have Been Generated. 10 surfaces Initiate From Each of 10 Points Equally spaced Along The Ground Surface Between X = 10.00 ft. and X = 10.00 ft. Each surface Terminates Between X = 30.00 ft. and X = 170.00 ft. Unless Further Limitations Were Imposed, The Minimum Elevation At Which A surface Extends Is Y = 0.00 ft. , 10.00 ft. Line segments Define Each Trial Failure surface. The Following Displays The Most critical of The Trial Failure Surfaces Examined. Page 2 Profile.out. * * safety Factors Are Calculated By The Modified Bishop Method * * Failure surface specified By 14 coordinate Points Point x-surf Y-surf No. (ft) (ft) 1 10.00 20.00 2 19.91 21.32 3 29.74 23.17 4 39.45 25.56 5 49.01 28.49 6 58.40 31.93 7 67.59 35.88 8 76.54 40.33 9 85.24 45.26 10 93.66 50.66 11 101.76 56.52 12 109.54 62.81 13 116.95 69.52 14 117.43 70.00 circle Center At X = -9.0 ; Y = 201.3 and Radius, 182.3 1.255 *** Page 3 INN W N ■■O - I I I NM M- NM r r OM I I NM' OM Section B-B', Static 106.2E 85.00-, 63.751 42.50- 21.2E 00 21:25 42.50 63:75 85:00 106.25 127.50 148.75 17C.00 Safety Factors 1.60 1.63 1.63 1.64 1.67 1.68 1.69 1.70 1.72 1.75 Profile.out ** PCSTABL6 ** b Purdue University modified by Peter J. Bosscher University of Wisconsin -Madison --Slope Stability Analysis -- Simplified Janbu, Simplified Bishop or Spencer's Method of Slices PROBLEM DESCRIPTION: Section B-B', Static 10 Bowie Rd., Rolling Hills F. S. min = 1.60 BOUNDARY COORDINATES 8 Top Boundaries 12 Total Boundaries Boundary x-Left Y-Left X-Right Y-Right soil Type No. (ft) (ft) (ft) (ft) Below Bnd 1 0.00 20.00 10.00 20.00 3 2 10.00 20.00 38.00 48.00 3 3 38.00 48.00 54.00 49.00 3 4 54.00 49.00 67.00 54.00 2 5 67.00 54.00 78.00 54.00 2 6 78.00 54.00 88.00 62.00 1 7 88.00 62.00 109.00 70.00 1 8 109.00 70.00 170.00 70.00 1 9 78.00 54.00 130.00 65.00 2 10 130.00 65.00 162.00 67.00 2 11 162.00 67.00 170.00 68.00 2 12 54.00 49.00 170.00 50.00 3 ISOTROPIC SOIL PARAMETERS 3 Type(s) of Soil Soil Total saturated cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No. 1 110.0 110.0 175.0 23.0 0.00 0.0 1 2 110.0 110.0 200.0 30.0 0.00 0.0 1 3 125.0 125.0 465.0 23.0 0.00 0.0 1 BOUNDARY LOAD(S) 1 Load(s) Specified Load X-Left X-Right Intensity Deflection No. (ft) (ft) (lb/sgft) (deg) 1 134.00 160.00 200.0 0.0 Page 1 Profile.out • NOTE - Intensity Is specified As A uniformly Distributed Force Acting On A Horizontally Projected Surface. A Critical Failure Surface searching Method, Using A Random Technique For Generating Circular Surfaces, Has Been Specified. 100 Trial Surfaces Have Been Generated. 10 Surfaces Initiate From Each of 10 Points Equally Spaced Along The Ground Surface Between X = 10.00 ft. and X = 10.00 ft. Each Surface Terminates Between X = 30.00 ft. and X = 170.00 ft. Unless Further Limitations Were Imposed, The Minimum Elevation At Which A Surface Extends Is Y = 0.00 ft. 10.00 ft. Line segments Define Each Trial Failure Surface. The Following Displays The Most Critical of The Trial Failure surfaces Examined. * * safety Factors Are Calculated By The Modified Bishop Method * * Failure Surface specified By 7 Coordinate Points Point x-surf Y-Surf No. (ft) (ft) 1 10.00 20.00 2 19.89 21.47 3 29.22 25.09 4 37.51 30.67 5 44.37 37.94 6 49.46 46.55 7 50.18 48.76 Circle Center At X = 8.4 ; Y = 65.0 and Radius, 45.1 * * * 1.602 * * * Page 2 111111 IMO N= MI M MS i I I 1 M= OM S N M I. Section A -A', Static 143.75 115.00- 86.25- 57.50- 28.75 0 28:75 57.50 86.25 115.00 143.75 172.50 201.25 230.00 Safety Factors 1.63 1.64 1.65 1.65 1.66 1.66 1.67 1.67 1.67 1.68 Profile.out ** PCSTABL6 **: by Purdue University modified by Peter J. Bosscher university of Wisconsin -Madison --Slope Stability Analysis -- Simplified Janbu, simplified Bishop or Spencer's Method of slices PROBLEM DESCRIPTION: Section A -A', Static 10 Bowie Rd., Rolling Hills F. S. min = 1.63 BOUNDARY COORDINATES 11 Top Boundaries 13 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type No. (ft) (ft) (ft) (ft) Below Bnd 1 0.00 25.00 7.00 18.00 3 2 7.00 18.00 18.00 28.00 3 3 18.00 28.00 49.00 28.00 3 4 49.00 28.00 63.00 41.00 3 5 63.00 41.00 75.00 41.00 3 6 75.00 41.00 93.00 53.00 3 7 93.00 53.00 104.00 56.00 3 8 104.00 56.00 110.00 62.00 2 9 110.00 62.00 128.00 78.00 1 10 128.00 78.00 182.00 78.00 1 11 182.00 78.00 230.00 78.00 2 12 110.00 62.00 182.00 78.00 2 13 104.00 56.00 230.00 55.00 3 ISOTROPIC SOIL PARAMETERS 3 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No. 1 110.0 110.0 175.0 23.0 0.00 0.0 1 2 110.0 110.0 200.0 30.0 0.00 0.0 1 3 125.0 125.0 465.0 23.0 0.00 0.0 1 BOUNDARY LOAD(S) 1 Load(s) specified Load x-Left X-Right Intensity Deflection No. (ft) (ft) (lb/sqft) (deg) 1 175.00 225.00 Page 1 200.0 0.0 Profil.e.out .. NOTE - IntensityIs Specified As A uniformly Distributed Force Acting On A Horizontally Projected surface.. A Critical Failure Surface Searching Method, Using A Random Technique For Generating Circular surfaces, Has Been Specified. 100 Trial Surfaces Have Been Generated. 10 Surfaces Initiate From Each of 10 Points Equally Spaced Along The Ground surface Between X = 49.00 ft. and X = 49.00 ft. Each surface Terminates Between x = 130.00 ft. and X = 170.00 ft. Unless Further Limitations Were Imposed, The Minimum Elevation At which A Surface Extends Is Y = 0.00 ft. 10.00 ft. Line Segments Define Each Trial Failure surface. The Following Displays The Most Critical of The Trial Failure Surfaces Examined. * * safety Factors Are Calculated By The Modified Bishop Method * * Failure surface specified By 13 coordinate Points Point X-surf Y-Surf No. (ft) (ft) 1 49.00 28.00 2 58.98 27.32 3 68.97 27.61 4 78.89 28.86 5 88.65 31.08 6 98.14 34.22 7 107.28 38.28 8 115.99 43.20 9 124.17 48.94 10 131.77 55.44 11 138.69 62.66 12 144.89 70.51 13 149.70 78.00 Circle center At X = 61.0 ; Y = 130.3 and Radius, 103.0 * * * 1.630 *** Page 2 IN — i i• N NB -- ---— r MN MB r M— Section A -A', Pseudostatic 143.75 115.00- 86.25- 57.50- 28.75- 0 28.75 57.50 86:25 115.00 143.75 172.50 201.25 230.00 Safety Factors 1.20 1.20 1.20 1.21 1.21 1.21 1.21 1.22 1.22 1.22 Profile.out **• PCSTABL6 *'* Purdue University modified by Peter J. Bosscher University of Wisconsin -Madison --slope Stability Analysis -- simplified Janbu, Simplified Bishop or Spencer's Method of slices PROBLEM DESCRIPTION: Section A -A', Pseudostatic 10 Bowie Rd., Rolling Hills F. S. min = 1.20 BOUNDARY COORDINATES 11 Top Boundaries 13 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right soil Type No. (ft) (ft) (ft) (ft) Below Bnd 1 0.00 25.00 7.00 18.00 3 2 7.00 18.00 18.00 28.00 3 3 18.00 28.00 49.00 28.00 3 4 49.00 28.00 63.00 41.00 3 5 63.00 41.00 75.00 41.00 3 6 75.00 41.00 93.00 53.00 3 7 93.00 53.00 104.00 56.00 3 8 104.00 56.00 110.00 62.00 2 9 110.00 62.00 128.00 78.00 1 10 128.00 78.00 182.00 78.00 1 11 182.00 78.00 230.00 78.00 2 12 110.00 62.00 182.00 78.00 2 13 104.00 56.00 230.00 55.00 3- ISOTROPIC SOIL PARAMETERS 3 Type(s) of Soil Soil Total saturated cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit wt. Intercept Angle Pressure constant surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No. 1 110.0 110.0 175.0 23.0 0.00 0.0 1 2 110.0 110.0 200.0 30.0 0.00 0.0 1 3 125.0 125.0 465.0 23.0 0.00 0.0 1 Page 1 Profi l e.out A Horizontal Earthquake Loading Coefficient of 0.160 Has Been Assigned A vertical Earthquake Loading coefficient of 0.000 Has Been Assigned Cavitation Pressure = 0.0 psf BOUNDARY LOADS) 1 Load(s) specified Load X-Left X-Right Intensity Deflection No. (ft) (ft) (lb/sqft) (deg) 1 175.00 225.00 200.0 0.0 NOTE - Intensity Is specified As A uniformly Distributed Force Acting On A Horizontally Projected surface. A Critical Failure surface searching Method, using A Random Technique For Generating circular Surfaces, Has Been specified. 100 Trial Surfaces Have Been Generated. 10 Surfaces Initiate From Each Of 10 Points Equally spaced Along The Ground Surface Between X = 49.00 ft. and X = 49.00 ft. Each Surface Terminates Between X = 130.00 ft. and X = 170.00 ft. Unless Further Limitations Were Imposed, The Minimum Elevation At Which A surface Extends Is Y = 0.00 ft. 10.00 ft. Line segments Define Each Trial Failure surface. The Following Displays The Most critical of The Trial Failure surfaces Examined. Page 2 Profile.out * * safety Factors Are Calculated By The Modified Bishop Method * * Failure surface Specified By 13 coordinate Points Point X-Surf Y-Surf No. (ft) (ft) 1 49.00 28.00 2 58.98 27.32 3 68.97 27.61 4 78.89 28.86 5 88.65 31.08 6 98.14 34.22 7 107.28 38.28 8 115.99 43.20 9 124.17 48.94 10 131.77 55.44 11 138.69 62.66 12 144.89 70.51 13 149.70 78.00 circle Center At X = 61.0 ; Y = 130.3 and Radius, 103.0 * * * 1.196 *** Page 3