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Home My WebLink About20170130_Geotechnical Investigation_08-30-2016COfiS/1/tants EGA Consultants, LLC C 0 V E R engineering geotecJmica/ applicaliofls FAX 5 H E E T To: William Simpson & Assoc., Inc., ATTN: Plamen Petrov, PE Fax#: Via Fax: (949) 206-9955 Ph: 949-206-9929 ext. 403 Subject: PROJECT MEMORANDUM -PROPOSED SEA WALL/TEMPORARY SHORING RESIDENTIAL DOCKSIDE LOT: 2772 BAYSHORE DRIVE NEWPORT BEACH, CALIFORNIA Date: November 8, 2016 Pages: l , including this cover sheet. Reference: "Geotechnical Investigation for Proposed Pool House Located at 2772 Bayshore Drive, Newport Beach, California," by EGA Consultants dated August 30, 2016. Project Memo- Please incorporate the following specifications for the new bulkhead tiebacks/temporary shoring assuming a 1.5 Safety of Factor: Unit weight of soil (in situ moisture): Unit weight of soil (saturated): Active pressure (saturated sand): Active pressure (submerged): Passive Pressure: Passive Pressure (submerged): Seismic Lateral Soil Pressure: Cohesion: Angle of Internal Friction: 105 pet 125 pet 40 psf/ft 90 psf/ft (includes 62.4 pet water pressure) 300 psf/ft 200 psf/ft 10 x H2 lb/ft run of wall ( H=retained height of seawall) 240 psf 29.0 degrees All future excavations and compaction backfill shall be inspected and tested by the geotechnical consultant. This memo shall be considered an addendum to our Soils Report dated August 30, 2016. Thank You From the desk of... cc: lan Harrison, AlA David A. Worthington, CEG 2124 EGA CONSULTANTS, LLC 375-C Monte Vista Avenue Costa Mesa, CA 92627 (949) 642-9309 Fax: (949) 642-1290 375-C Mo nte V is ta Ave nu e • Costa M esa, CA 92627 • (949) 642-9 3 09 • FAX (9 49) 64 2 -1290 PA2017-019 J ~I .... ... :., ..... ~ < .. ';> in T.O. WALL ELEV•+12.68' NAV088=+ 12.86'MLLW PASSIVE PRESSURE WATER SIDEmO.OO' M.L.LW. (E) BLOCK WALL ... ;, ' :.. (E) CONC COPING (E) DREDGE LINE 1000.0 GROSS PASSIVE=5· x 200 PASSIVE EARTH PRESSURE T YPICAL SEA WALL LOADING (N) fiNISH GRADE ~...--- 668.0 ACTIVE (N) OY'MOAG iHR(AOBAR PER PLAN NP 666 PLF•580+4.41' x 20 PCf 20 PLF" ;.., "N -----~- ! , I 1 ----- DESIGN LEVEL ELEV ON LAND SIDE •+2.00'± M.L.LW. STATIC ACTIVE EARTH PRESSURE SURCHARGE SEISMIC EARTH PRESSURE __________________ =r_------N r_s. _l_l z <::::s: ~ ~ ~ ~ ~ ""'<: :t $ ' \:,..- ~ ......... ~ """ "" ~ ~ ~ PA2017-019 GEOTECHNICAL INVESTIGATION FORPROPOSEDPOOLHOUSE LOCATED AT 2772 BAYSHORE DRIVE NEWPORT BEACH, CALIFORNIA Presented to: KEVIN MORIARTY 2782 Bayshore Drive Newport Beach, CA 92661 c/o: ian Harrison, AlA Prepared by: EGA CONSULTANTS, LLC 375-C Monte Vista Avenue Costa Mesa, California 92627 ph (949) 642-9309 fax (949) 642-1290 August 30, 2016 Project No. IH971.1 PA2017-019 Site: Proposed 2-Story Pool House -2772 Bayshore Drive Newport Beach . California Executive Summary August30,2016 Project No. IH971. 1 Based on our geotechnical study of the site, our review of available reports and literature and our experience, it is our opinion that the proposed residential development is feasible from a geotechnical standpoint. There appear to be no significant geotechnical constraints on-site that cannot be mitigated by proper planning, design, and utilization of sound construction practices. The engineering properties of the soil and native materials, and surface drainage offer favorable conditions for site re-development. The following key elements are conclusions confirmed from this investigation: A review of available geologic records indicates that no active faults cross the subject property. The site is located in the seismically active Southern California area, and within 2 kilometers of the Type B Newport-Inglewood Fault. As such, the proposed development shall be designed in accordance with seismic considerations specified in the 2013 California Building Code (CBC) and the City of Newport Beach requirements. Foundation specifications herein include added provisions for potential liquefaction on-site per City policy CBC 1803.11-12. SUMMARY OF RECOMMENDATIONS Design Item Foundations: Footing Bearing Pressure Passive Lateral Resistance Perimeter Footing Widths: Perimeter Footing Depths: Coefficient of Friction Soil Expansion Soil Sulfate Content Building Pad Removals: Sandy Soil Max. Density: Building Slab: Recommendations 1, 750 psf-building, continuous; 2,250 psf column 250 psf per foot min. 15 inches with two No. 5 bars top and bottom min. 24 inches below lowest adjacent grade 0.30 Non-Expansive Beach Sands Negligible min. 2Y, ft. overexcavation, with 2Y, ft. envelope. 121 .0 pcf@ 11 .5 % Opt. Moisture * Concrete slabs cast against properly compacted fill materials shall be a minimum of 5 inches thick (actual) and reinforced with No.4 rebar at 12 inches on center in both directions. * Dowel all footings to slabs with No. 4 bars at 24 inches on center. * Concrete building slabs shall be underlain by 2" clean sand, underlain by a min. 15 mil thick moisture barrier, with all laps sealed, underlain by 4" of %-inch gravel (capillary break). Seismic Values : Site Class Definition (Table 1613.5.2) Mapped Spectral Response Acceleration at 0.2s Period, S, Mapped Spectral Response Acceleration at 1s Period, S1 Short Period Site Coefficient at 0.2 Period, F, Long Period Site Coefficient at 1s Period, F, Adjusted Spectral Response Acceleration at 0.2s Period, SMs Adjusted Spectral Response Acceleration at 1s Period, SM1 Design Spectral Response Acceleration at 0.2s Period, S08 Design Spectral Response Acceleration at 1 s Period, S01 D 1.720 g 0.635 g 1.00 1.50 1.720 g 0.952 g 1.147 g 0.635 g PGAm= 0.715 g PA2017-019 KEVIN MORIARTY 2782 Bayshore Drive Newport Beach, CA 92661 c/o: Subject: Jan Harrison, AlA GEOTECHNICAL INVESTIGATION FORPROPOSEDPOOLHOUSE LOCATED AT 2772 BAYSHORE DRIVE NEWPORT BEACH, CALIFORNIA Dear Mr. Moriarty, August30,2016 Project No. IH971.1 In accordance with your request we have completed our Geotechnical Investigation of the above referenced site. This investigation was performed to determine the site soil conditions and to provide geotechnical parameters for the proposed re-grading and construction at the subject site. Based on our discussions with the project architect, ian Harrison, AlA, the proposed residential re-development shall include the demolition of the existing structures, and the construction of a new residential dwelling and associated improvements. This opportunity to be of service is appreciated. If you have any questions, please call. Very truly yours, EGA Consultants, LLC DAVID A. WORTHINGTON CEG 2124 Principal Engineering Geologist Copies: {4) ian Harrison, AlA (1) Kevin Moriarty PAUL DURAND RCE 58364 Sr. Project Engineer PA2017-019 INTRODUCTION GEOTECHNICAL INVESTIGATION FORPROPOSEDPOOLHOUSE LOCATED AT 2772 BAYSHORE DRIVE NEWPORT BEACH, CALIFORNIA August 30, 2016 Project No. IH971.1 In response to your request and in accordance with the City of Newport Beach Building Department requirements, we have completed a preliminary geotechnical investigation at the subject site located at 2772 Bay shore Drive (within the "Bayshore Community"), in the City of Newport Beach, State of California (see Site Location Map, Figure 1 ). The purpose of our investigation was to evaluate the existing geotechnical conditions at the subject site and provide recommendations and geotechnical parameters for site re- development, earthwork, and foundation design for the proposed re-construction. We were also requested to evaluate the potential for on-site geotechnical hazards. This report presents the results of our findings, as well as our conclusions and recommendations. SCOPE OF STUDY The scope of our investigation included the following tasks: • Review of readily available published and unpublished reports; • Geologic reconnaissance and mapping; • Excavation and sampling of one exploratory boring to a total depth of 11 feet below existing grade (b.g.); • Continuous Cone Penetration Test (CPT) soundings to a depth of 50% feet below grade (results of the CPT soundings are included herein); • Laboratory testing of representative samples obtained from the exploratory boring; • Engineering and geologic analysis including seismicity coefficients in accordance with the 2013 California Building Code (CBC); 2 PA2017-019 • Seismic and Liquefaction analysis and settlement computations (in accordance with California Geological Survey, SP 117 A); • Preparation of this report presenting our findings, conclusions, and recommendations. GENERAL SITE CONDITIONS The subject property is an approximate 40ft. by 99ft. rectangular shaped lot located at 2772 Bayshore Drive in the City of Newport Beach, County of Orange, California (see Site Location Map, Figure 1 ). For the purpose of clarity in this report, the lot is bound by Bayshore Drive to the west, by a rear bulkhead/boat dock and Newport Harbor to the west, and by similar single family dwellings to the north and south. The lot is legally described as Lot 2 of Tract 1014 (APN 049-191-28). The bayside property consists of a relatively flat, planar lot with no significant slopes on or adjacent to the site. Currently, the lot is occupied by a single family, two-story residence situated on a graded level pad. An existing attached garage is located in the front portion of the property and is accessed by Bayshore Drive. The residence is supported on continuous perimeter footings with slab-on-grade floors. PROPOSED RESIDENTIAL RE-DEVELOPMENT Based on the preliminary site plan, the proposed residential re-development shall include the demolition of the existing structures, and the construction of a new pool house dwelling with an approximate 4-feet deep lap pool and an attached two-car garage. The garage will be accessed by Bayshore Drive. No basement or retaining walls are planned. The limits of proposed construction are shown in Figure 2, herein. We assume that the proposed building will consist of wood-frame and masonry block construction or building materials of similar type and load. The building foundations will consist of a combination of isolated and continuous spread footings. Loads on the footings are unknown, but are expected to be less than 2,250 and 1,750 pounds per square foot on the isolated and continuous footings, respectively. If actual loads exceed these assumed values, we should be contacted to evaluate whether revisions of this report are necessary. It is our understanding that the grade of the site is not expected to vary significantly, with maximum regrades consisting of approximately 1 to Moriarty Poolhouse-2772 Baysbore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30, 2016 3 PA2017-019 2 feet in the building areas. Based on NAVD88, the site elevation is approximately 13ft. above MSL. Based on the preliminary plans, the proposed finish floor elevation shall be 9+ ft. above mean sea level (MSL) to conform with City and United States FEMA flood elevation requirements. Note: The precise determination, measuring, and documenting of the site elevations, hub locations, property boundaries, etc., is the responsibility of the project licensed land surveyor. SUBSURFACE EXPLORATION Our subsurface exploration consisted of the excavation of one exploratory boring (B-1) to a maximum depth of 11 feet below grade (b.g.) and one CPT probe (CPT-1) to a depth of 50Y, ft b.g. (continuous soil profile). Prior to drilling, the underground detection and markup service (Underground Service Alert of Southern California) was ordered and completed under DigAiert Confirmation No. A62180571-00A. Representative bulk and relatively undisturbed soil samples were obtained for labora- tory testing. Geologic/CPT logs of the soil boring/probes are included in Appendix A. The borings were continuously logged by a registered geologist from our firm who obtained soil samples for geotechnical laboratory analysis. The approximate locations of the borings are shown on Figure 2, Plot Plan. Geotechnical soil samples were obtained using a modified California sampler filled with 2% inch diameter, 1-inch tall brass rings. Bulk samples were obtained by collecting representative bore hole cuttings. Locations of geotechnical samples and other data are presented on the boring logs in Appendix A. The soils were visually classified according to the Unified Soil Classification System. Classifications are shown on the boring logs included in Appendix A. LABORATORY TESTING Laboratory testing was performed on representative soil samples obtained during our subsurface exploration. The following tests were performed: * * Dry Density and Moisture Content (ASTM: D 2216) Maximum Dry Density and Optimum Moisture Content (ASTM: D 1557) Moriarty Poorhouse~ 2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. lli971.1 August 30, 2016 4 PA2017-019 * * * * Wet (Submerged) Density (ASTM: D 1557) Direct Shear (ASTM D 3080) Sulfate Content (CA417) Soil Classification (ASTM D 2487) All laboratory testing was performed by our sub-contractor, G3Soi1Works, Inc., of Costa Mesa, California. Geotechnical test results are included in Appendix B, herein. SOIL AND GEOLOGIC CONDITIONS The site soil and geologic conditions are as follows: Seepage and Groundwater Seepage or surface water ponding was not noted on the subject site at the time of our study. Groundwater was encountered in our test excavations at a depth of approximately 10 feet b.g .. According to the Orange County Water District (OCWD), there are no water wells located within the general vicinity of the subject property. Our data indicates that the perched groundwater encountered is subject to tidal fluctuations. A seawall bulkhead and channel waters of the Newport Bay are located along the east end of the dock-side property. Based on our review of nearby piezometric data, the groundwater highs approach the tidal highs in the bay, and groundwater lows drop slightly below mean sea level. For a comparative illustration, a tidal chart for the area at the time of our subsurface investigation, is included as Figure 4, herein. Bayside Topography and Bathymetry Elevations across the Bayshore Community sites range from 11 to 14 feet along Moriarty Poolhouse" 2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30,2016 5 PA2017-019 the bulkhead lines at the seawall perimeters. A common area sandy beach is located 9 lots southwest of the site. The beach grade has been groomed with import sands which feather gently to the bay waters. From the bulkhead shorelines, the nearshore bay floor slopes descends at an inclination of approximately 10:1 (horizontal to vertical), down to approximate elevations of -10 to -15 feet along the channel limit line (depending on tidal fluctuations). Bayshore Community Geologic History Unlike the surrounding, man-made Islands (e.g. Lido, Balboa, Linda Isle}, Bayshore area is a naturally-formed, back-barrier coastal landmass. It is situated on the landward side of a coastal bar formed by a transgressive sea and littoral currents at the seaward edge of a stream delta or lagoon. The Newport Bay coastal estuary was originally formed as the lower reach of the Santa Ana River. However, in 1915, due to severe silting that resulted from flooding of the Santa Ana River (and also the construction of man-made channel), the Santa Ana River was structurally realigned. Consequently, the Newport Bay is currently fed only by the San Diego Creek which drains a comparatively small area. The mouth of the San Diego Creek is located at the Jamboree Road bridge roughly 5% kilometers northeast of the subject site (Upper Back Bay). Geologic Setting Regionally, the site is located within the western boundary of the Coastal Plain of Orange County. The Coastal Plain lies within the southwest portion of the Los Angeles Basin and consists of semi-consolidated marine and non-marine deposits ranging in age from Miocene to recent. The western boundary of the Coastal Plain, in which the site is located, is referred to as the Tustin Plain. It is bound by the Santa Ana Mountains to the northeast and the San Joaquin Hills to the southeast. Based on available geologic maps the site is underlain by a thin mantle of estuarine (Qes}/hydraulic sands and/or engineered fill. The shallow soil layer is underlain by Quaternary-age old paralic deposits (Qop) which are described as medium dense to very dense, oxidized, fine to medium grained, moderately to well-cemented sand and silty sand (see reference No. 2). The old paralic deposits are underlain by massive bedrock of the Monterey Formation (Tm). Roadside exposures of massive bedrock of the Monterey Formation (Tm) are visible on the inland side of East Pacific Coast Highway Moriarty Poolhouse-2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30,2016 E PA2017-019 less than Y, kilometers north of the site (Dover Shores bluffs). A Geologic Map is presented as Figure 3, herein (reference: Morton, D.M., and Miller, F.K., 2006). Based on the geologic map (Figure 3) correlation with the on-site CPT probe advanced on August 10, 2016, bedrock of the Monterey Formation (Tm) was likely encountered approximately 14 feet below grade. Faulting A review of available geologic records indicates that no active faults cross the subject property (reference No. 2). Seismicity The seismic hazards most likely to impact the subject site is ground shaking following a large earthquake on the Newport-Inglewood (onshore), Palos Verdes (offshore), Whittier-Elsinore, or Cucamonga. The fault distances, probable magnitudes, and horizontal accelerations are listed as follows: Newport-2 kilometers southwest 7.2 0.69 g's Inglewood (B) Palos Verdes 16 kilometers 7.1 0.38 g's (B) southwest Chino-Cental 40 kilometers northeast 6.7 0.14 g's Avenue (B) Elsinore (B) 37 kilometers northeast 6.8 0.16g's Cucamonga 50 kilometers north-7.0 0.14 g's northeast The maximum anticipated bedrock acceleration on the site is estimated to be less than 0.69, based on a maximum probable earthquake on the Newport- Inglewood Fault. The site is underlain by fill and estuarine sands. For design purposes, two-thirds of the maximum anticipated bedrock acceleration may be assumed for the repeatable ground acceleration. The effects of seismic shaking can be mitigated by adhering to the 2013 California Building Code or Moriarty Poolbouse-2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 AUI:,'llSt 30,2016 7 PA2017-019 the standards of care established by the Structural Engineers Association of California. With respect to this hazard, the site is comparable to others in this general area in similar geologic settings. The grading specifications and guidelines outlined in Appendix C of the referenced report are in part, intended to mitigate seismic shaking. These guidelines conform to the industry standard of care and from a geotechnical standpoint, no additional measures are warranted. Based on our review of the "Seismic Zone Map," published by the California Department of Mines and Geology in conjunction with Special Publication 117, there are no earthquake landslide zones on or adjacent to the site. The proposed development shall be designed in accordance with seismic considerations contained in the 2013 CBC and the City of Newport Beach requirements. Based on Chapter 16 of the 2013 CBC and on Maps of Known Active Near- Source Zones in California and Adjacent Portions of Nevada (ASCE 7 Standard), the following parameters may be considered: 2013 CBC Seismic Design Parameters ITE DDRE : 2772 Bavs ore Dr., Newnort Beac , S A SS h h C A Site Longitude (Decimal Degrees) -117.9073 Site Latitude (Decimal Degrees) 33.6142 Site Class Definition D Mapped Spectral Response Acceleration at 0.2s Period, S8 1.720 g Mapped Spectral Response Acceleration at 1 s Period, S1 0.635 g Short Period Site Coefficient at 0.2 Period, Fa 1.00 Long Period Site Coefficient at Is Period, Fv 1.50 Adjusted Spectral Response Acceleration at 0.2s Period, SMs 1.720 g Adjusted Spectral Response Acceleration at 1 s Period, SM1 0.952 g Design Spectral Response Acceleration at 0.2s Period, Sns 1.147 g Design Spectral Response Acceleration at 1 s Period SDI 0.635 g In accordance with the USGS Design Maps, and assuming Site Class "D", the mean peak ground acceleration (PGAm) per USGS is 0.715 g. The stated PGAm is based on a 2% probability of exceedance in a 50 year span (see Moriarty Poolhouse" 2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30,2016 PA2017-019 copies of the USGS Design Maps Detailed Report, Appendix D, herein). Other Geologic Hazards Other geologic hazards such as landsliding, or expansive soils, do not appear to be evident at the subject site. FINDINGS Subsurface Soils As encountered in our test borings, the site is underlain by, fill and native materials as follows: Fill (Af) Fill soils were encountered in each of the borings to a depth of approximately 2% feet b.g. The fill soils consist generally of dark to medium brown, moist, loose to medium dense, silty sand. The expansion potential of the fill soils was judged to be very low (E.I. = 0) when exposed to an increase in moisture content. Hydraulic-Native Sands (Qes), Paralic Deposits (Qop) and Bedrock (Tm) Underlying the fill materials are hydraulic and native sands as encountered in each of the test borings (B-1 and CPT-1 ). The native sands consist generally of light-to medium-brown, dry to saturated, medium dense to dense, non-cemented, fine-to medium-grained, micaceous sand and silty sand. The native sands are underlain by estuarine (Qes) and old paralic (Qop) deposits, which are underlain by very dense Monterey Formation (Tm) bedrock consisting of medium dense to very dense, oxidized, fine to medium grained, moderately to well-cemented sand and siltstone to the maximum depths explored (50% ft b.g.). Based on the geologic map (Figure 3) correlation with the on-site CPT probe advanced on August 10, 2016, bedrock of the Monterey Formation (Tm) was likely encountered approximately 14 feet below grade. Based on the laboratory results dated August, 2016, the site maximum dry density is 121.0 pcf at an optimum moisture content of 11.5% (per ASTM D 1557) and the wet (submerged) density of the native sands is 124.3 pcf (the complete laboratory reports are presented in Appendix B, herein). Moriarty Poolhouse-2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30,2016 9 PA2017-019 LIQUEFACTION ANALYSIS (Per SP117 A) Liquefaction of soils can be caused by strong vibratory motion in response to earthquakes. Both research and historical data indicate that loose, granular sandy soils are susceptible to liquefaction, while the stability of rock, gravels, clays, and silts are not significantly affected by vibratory motion. Liquefaction is generally known to occur only in saturated or near saturated granular soils. The site is underlain by fill/estuarine sands, old paralic deposits, and bedrock of the Monterey Formation. It is our understanding that the current City policy, has assigned a seismic settlement potential of one (1.0) inch in the upper ten feet, and three (3.0) inches for soil depths of ten to fifty feet. In the event settlement values exceed these threshold values, then additional analysis and/or additional mitigation is required. The CPT testing was performed in accordance with the "Standard Test Method for Performing Electronic Friction Cone and Piezocone Penetration Testing of Soils," (ASTM 05778-12). The seismically induced settlement for the proposed structure was evaluated based on the "Soil Liquefaction During Earthquakes" by I.M. ldriss and R.W. Boulanger, dated September 8, 2008. The analysis was provided by the 10-feet deep 4" diameter hand-auger boring, and a 50+ feet deep 1.7" diameter CPT probe advanced on August 10, 2016. The exploratory boring and probe locations are shown in the Plot Plan, Figure 2, herein. The soil borings were continuously logged by a certified engineering geologist of our firm. The computations and results of our Liquefaction Analysis, based on CPT blow counts of Boring CPT-1, are attached in Appendix E, herein. The seismically induced settlement analysis was evaluated based on methods published in the references Nos. "a" through "j" (see "Associated References", herein). The liquefaction and seismic settlement calculations indicate seismic settlement (includes dry and saturated sands) in the upper 50 feet is less than 2.0 inches, and hence shallow mitigation methods for liquefaction may be implemented per City Code Policy (No. CBC 1803.5.11-2 last revised 7/3/2014). Based on our liquefaction analysis, and in accordance with the City of Newport Beach Policy No. CBC 1803.5.11-12 (NBMC, Chapter 15), we recommend the following mitigative methods to minimize the effects of shallow liquefaction: 1. Tie all pad footings with grade beams. Moriarty Poolhouse" 2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30,2016 10 PA2017-019 2. All footings should be a minimum of 24 inches deep, below grade. 3. Continuous footings should be reinforced with two No.5 rebar (two at the top and two at the bottom). 4. Concrete slabs cast against properly compacted fill materials shall be a minimum of 5 inches thick (actual) and reinforced with No.4 rebar at 12 inches on center in both directions. The reinforcement shall be supported on chairs to insure positioning of the reinforcement at mid-center in the slab. 5. Dowel all footings to slabs with No. 4 bars at 24 inches on center. 6. Additionally, to further reduce the effects of the thin shallow zones of potentially liquefiable, cohesionless sand fills; soil-cement shall be used in the upper two to three feet. To achieve this, during grading -dry bags of Portland Cement shall be mixed in the scarified over-excavation bottoms and into each of the overlying fill lifts. The foundation specifications outlined above will act to decrease the potential settlement due to liquefaction and/or seismically induced lateral deformation to tolerable amounts. The above specifications eliminate the use of piles and associated construction vibrations and groundwater displacement induced by caisson drilling or pile-driving. If the above specifications are incorporated, the proposed structure shall be stable and adequate for the intended uses and the proposed construction will not adversely impact the subject or adjacent properties. Other Geologic Hazards Other geologic hazards such as landsliding, or expansive soils, do not appear to be evident at the subject site. CONCLUSIONS Based on our geotechnical study of the site, our review of available reports and literature and our experience, it is our opinion that the proposed improvements at the site are feasible from a geotechnical standpoint. There appear to be no significant geotechnical constraints on-site that cannot be mitigated by proper planning, design, and utilization of sound construction practices. The engineering properties of the soil and native materials, and the surface drainage offer favorable conditions for site re- development. RECOMMENDATIONS The following sections discuss the pr"1nciple geotechnical concerns which should be considered for proper site re-development. Moriarty Poolhouse ~ 2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30,2016 11 PA2017-019 Earthwork Grading and earthwork should be performed in accordance with the following recommendations and the General Earthwork and Grading Guidelines included in Appendix C. It is our understanding that the majority of grading will be limited to the re-grading of the building pad for the proposed construction. In general, it is anticipated that the removal of the upper 2Yz feet within the building footprint (slab-on-grade portion) will require removal and recompaction to prepare the site for construction. The removals should be accomplished so that all fill and backfill existing as part of the previous site use and demolition operations are removed. As stated above, for cohesion treatment of the site sand fills; soil-cement shall be used. To achieve this, during grading-dry bags of Portland Cement shall be mixed in the scarified over-excavation bottoms and into the overlying fill lifts. Where feasible, the limits of the pad fill shall be defined by a three (3) feet envelope encompassing the building footprint. Care should be taken to protect the adjacent property improvements. A minimum one foot thick fill blanket should be placed throughout the exterior improvements (approaches, hardscape, etc.). The fill blanket will be achieved by re-working (scarifying) the upper 12 inches of the existing grade. A general cross-section showing the limits of the temporary pad overexcavation in the side yard condition is presented as Figure 5, herein. Site Preparation Prior to earthwork or construction operations, the site should be cleared of surface structures and subsurface obstructions and stripped of any vegetation in the areas proposed for development. Removed vegetation and debris should then be disposed of off-site. A minimum of 2Yz feet of the soils below existing grade will require removal and recompaction in the areas to receive building pad fill. Following removal, the excavated surface should be inspected by the soils engineer or his designated representative prior to the placement of any fill in footing trenches. Holes or pockets of undocumented fill resulting from removal of buried obstructions discovered during this inspection should be filled with suitable compacted fill. The on-site soils are suitable for reuse as compacted fill, provided they are free Moriarty Poolhouse-2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30,2016 12 PA2017-019 of organic materials, debris, and materials larger than six (6) inches in diameter. After removal of any loose, compressible soils, all areas to receive fill and/or other surface improvements should be scarified to a minimum depth of 12 inches, brought to at least 2 percent over optimum moisture conditions and compacted to at least 90 percent relative compaction (based on ASTM: D 1557). If necessary, import soils for near-surface fills should be predominately granular, possess a very low expansion potential, and be approved by the geotechnical engineer. Due to the granular, dry nature of the site sands, vigorous soaking (via a 2-inch diameter fire hose) shall be employed during the pad grading operations. For pad grading, lift thicknesses will be dependent on the size and type of equipment used. In general, fill should be placed in uniform lifts not exceeding 6 inches. Placement and compaction of fill should be in accordance with local grading ordinances under the observation and testing of the geotechnical consultant. We recommend that fill soils be placed at moisture contents at least 2 percent over optimum (based on ASTM: D 1557). We recommend that oversize materials (materials over 6 inches) should they be encountered, be stockpiled and removed from the site. Trench Backfill The on-site soils may be used as trench backfill provided they are screened of rock sizes over 6 inches in dimension and organic matter. Trench backfill should be compacted in uniform lifts (not exceeding 8 inches in compacted thickness) by mechanical means to at least 90 percent relative compaction (ASTM: D 1557). Geotechnical Parameters The following Geotechnical parameters may used in the design of the proposed structure (also, see "Liquefaction Analysis" section, above): Foundation Design Structures on properly compacted fill may be supported by conventional, continuous or isolated spread footings. All footings should be a minimum of 24 inches deep (measured in the field below lowest adjacent grade). Footing widths shall me an minimum 15 inches and 18 inches for interior cross beams and perimeter footings respectively. At this depth (24 inches) footings founded in fill materials may be designed for Moriarty Poolhouse-2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 August 30,2016 13 PA2017-019 an allowable bearing value of 1, 750 and 2,250 psf (for dead-plus-live load) for continuous wall and isolated spread footings, respectively. These values may be increased by one-third for loads of short duration, including wind or seismic forces. Reinforcement requirements may be increased if recommended by the project structural engineer. In no case should they be decreased from the previous recommendations. Cement Type for Concrete in Contact with On-Site Earth Materials Concrete mix design should be based on sulfate testing with Section 1904.2 of the 2013 CBC. Preliminary laboratory testing indicates the site soils possess negligible sulfate exposure. In the event import soils are used, the soils shall be tested for sulfate content and the associated recommendation shall be implemented as follows: ACI 318 BUILDING CODE Table 4.3.1-REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE-CONTAINING SOLUTIONS Sulfate Water soluble Sulfate (S04) in Cement Type Maximum water~ Minimum fc' , Exposure sulfate (804) in soil water, ppm cementitious material normal-weight percent by weight ratio, by weight, normal and light weight weight concrete concrete, psi Negligible 0.00 ~ 804 < 0.10 0 s; 804 <:150 ---------------- Moderate 0.10 < S04< 0.20 150 < so4 < 1500 II,IP(MS), 0.50 4000 IS(MS),P(MS) I(PM)(MS), I(SM)(MS) Severe 0.20 ~ so4 < 2.00 1500 < 804 < v 0.45 4500 10,000 Very Severe so4 > 2.00 S04> 10,000 V plus 0.45 4500 pozzalan As a conservative approach, we recommend cement with a minimum strength f'c of 3,000 psi be used for concrete in contact with on-site earth materials. Settlement Utilizing the design recommendations presented herein, we anticipate that the majority of any post-grading settlement will occur during construction activities. We estimate that the total settlement for the proposed structure will be on the order of 1 inch. Differential settlement is not expected to exceed 1 inch in 30 feet. These settlement values are expected to be within tolerable limits for properly designed and constructed foundations. Moriarty Poolhouse-2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH971.1 Augu,t30, 2016 14 PA2017-019 Lateral Load Resistance Footings founded in fill materials may be designed for a passive lateral bearing pressure of 250 pounds per square foot per foot of depth. A coefficient of friction against sliding between concrete and soil of 0.30 may be assumed. Capillary Break Below Interior Slabs In accordance with the 2013 Californ·la Green Building Standards Code Section 4.505.2.1, we provide the following building specification for the subject site (living area and garages slabs): Concrete building slabs shall be directly underlain by a min. 2 inches of clean/washed sand, underlain by a min.15 mil-thick moisture barrier (e.g. "Stego Wrap"), with all laps sealed, underlain by 4 inches of% -inch gravel. The above specification meets or exceeds the Section 5.505.2.1 requirement. Exterior Slabs-on-grade (Hardscape) Concrete slabs cast against properly compacted fill materials shall be a minimum of 4 inches thick (actual) and reinforced with No. 3 rebar at 18 inches on center in both directions. The reinforcement shall be supported on chairs to insure positioning of the reinforcement at mid-center in the slab. Control joints should be provided at a maximum spacing of 8 feet on center in two directions for slabs and at 6 feet on center for sidewalks. Control joints are intended to direct cracking. Expansion or felt joints should be used at the interface of exterior slabs on grade and any fixed structures to permit relative movement. Some slab cracking due to shrinkage should be anticipated. The potential for the slab cracking may be reduced by careful control of water/cement ratios. The contractor should take appropriate curing precautions during the pouring of concrete in hot weather to minimize cracking of slabs. Surface Drainage Surface drainage shall be controlled at all times. Positive surface drainage should be provided to direct surface water away from structures and toward the street or suitable drainage facilities. Ponding of water should be avoided adjacent to the structures. Recommended minimum gradient is 2 percent for unpaved areas and one percent for concrete/paved areas. Roof gutter Moriarty Poolhouse-2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. 11-1971.1 August 30,2016 15 PA2017-019 discharge should be directed away from the building areas through solid PVC pipes to suitable discharge points. Area drains should be provided for planter areas and drainage shall be directed away from the top of slopes. Proposed Lap Pool The following additional recommendations should be incorporated for the swimming pool design: a. Maximum, net allowable soil bearing pressure: 2,250 lbs/ff. b. Minimum pool shell thickness: 6inches. c. Swimming pool bond beam minimum longitudinal steel reinforcement: (4) No. 3 rebars (3 top, and 1 bottom). The actual design of the swimming pool should be completed by the structural engineer. Pool Excavation Based on the proposed pool depths, and accounting for the shell thickness, no over-excavation of the pool is necessary. Hence, we anticipate the swimming pool excavation and the deep end shall be approximately 4'h below existing grade. Based on our review of the preliminary plans, the pool shell radius will mean "shaping" of the excavation bottom, which favors the sidewall stability (similar to benching). Pool Shell Wall Design A minimum lateral earth pressure of 100 pcf (equivalent earth pressure) is recommended for the design of the pool walls. The following additional equivalent fluid pressures may be used as necessary: Condition Active Pressures Passive Pressures At-Rest Pressures Coefficient of Friction Footing Bearing Pressure Hydrostatic Pressure Equivalent Fluid Pressure Level 40 pel 250 pel 65 pel 0.30 2,000 psf The pool shell (walls) may be designed for an additional 50 pcf to provide for hydrostatic pressure based on the following equation: Moriarty Poolhouse ~ 2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. 11-1971.1 August 30,2016 16 PA2017-019 1 -sin (29. 0 degrees) x dry density = 50 pcf The actual design of the swimming pool should be eompleteEI-I:Jy-tl"le-stFuetuFall-- engineer. New Swimming Pool The above-recommended geotechnical parameters can be used for structural design of the proposed swimming pool, as needed. In addition the following are recommended. a) The plumbing system of the swimming pool should be properly designed and constructed to minimize potential leaking, which produce additional local high pressures to the swimming pool shell and/or differential settlement. b) Installation of a moisture pressure release valve system beneath the swimming pool bottom is recommended in order to release any potential water pressure accumulated beneath the swimming pool, which may produce additional pressure on the swimming pool shell. c) The contractor should provide a sufficient level of inspection and control to assure that approved plans and specifications are implemented during construction. PRE-CONSTRUCTION MEETING It is recommended that no clearing of the site or any grading operation be performed without the presence of a representative of this office. An on site pre-grading meeting should be arranged between the soils engineer and the grading contractor prior to any construction. GEOTECHNICAL OBSERVATION AND TESTING DURING CONSTRUCTION We recommend that a qualified geotechnical consultant be retained to provide geotechnical engineering services, including geotechnical observation/testing, during the construction phase of the project. This is to verify the compliance with the design, specifications and or recommendations, and to allow design changes in the event that subsurface conditions differ from those anticipated. Geotechnical observations/testing should be performed at the following stages: During ANY grading operations, including excavation, removal, filling, compaction, and backfilling, etc. After excavations for footings (or thickened edges) and/or grade beams verify the adequacy of underlying materials. After pre-soaking of new slab sub-grade earth materials and placement of capillary break, plastic membrane, prior to pouring concrete. During backfill of drainage and utility line trenches, to verify proper compaction. When/if any unusual geotechnical conditions are encountered. Moriarty Poolhouse-2772 Bayshore Dr., Ne"Wport Beach, CA Soils Report Project No. IH971.1 August 30,2016 17 PA2017-019 Prior to slab pours to ensure proper subgrade compaction and moisture barriers. Please schedule an inspection with the geotechnical consultant prior to the pouring of interior and exterior slabs. LIMITATIONS The geotechnical services described herein have been conducted in a manner consistent with the level of care and skill ordinarily exercised by members of the geotechnical engineering profession practicing contemporaneously under similar conditions in the subject locality. Under no circumstance is any warranty, expressed or implied, made in connection with the providing of services described herein. Data, interpretations, and recommendations presented herein are based solely on information available to this office at the time work was-f)efformed~EGA-Gonsultants-will· not-be-responsible-for· other·parties' --· interpretations or use of the information developed in this report. The interpolated subsurface conditions should be checked in the field during construction by a representative of EGA Consultants. We recommend that all foundation excavations and grading operations be observed by a representative of this firm to ensure that construction is performed in accordance with the specifications outlined in this report. We do not direct the contractor's operations, and we cannot be responsible for the safety of others. The contractor should notify the owner if he considers any of the recommended actions presented herein to be unsafe. Moriarty Poolhouse-2772 Bayshore Dr., Newport Beach, CA Soils Report Project No. IH97I.l August 30,2016 18 PA2017-019 Associated References re: Liquefaction Analvsis a. "Special Publication 117 A: Guidelines for Evaluating and Mitigating Seismic Hazards in California," by the California Department of Conservation, California Geological Survey, dated March 13, 1997; Revised September 11, 2008. b. "Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and Mitigating Liquefaction Hazards in California," by G.R. Martin and M. Lew, University of Southern California Earthquake Center dated March, 1999. c. "Soil Liquefaction During Earthquakes" by I.M. ldriss and R.W. Boulanger, dated September 8, 2008. d. "Soils and Foundations, 8'h Edition," by Cheng Liu and Jack B. Evett, dated August 4, 2013. e. "Evaluation of Settlement in Sands due to Earthquake Shaking" by Kahaji Tokimatsu and H Bolton Seed, Dated August 1987. f. "Guidelines for Estimation of Shear Wave Velocity Profiles" By Bernard R. Wair, Jason T. Jong, Thomas Shantz Pacific Earthquake Engineering Research Center, Dated December, 2012. g. "Subsurface Exploration Using the Standard Penetration Test and the Cone Penetrometer Test," by J. David Rogers, Environmental & Engineering Geoscience, pp. 161-179, dated May, 2006. h. "Handbook of Geotechnical Investigation and Design Tables" By Burt G. Look, Dated 2007. I. "Use of SPT Blow Counts to Estimate Shear Strength Properties of Soils: Energy Balance Approach," by Hiroshan Hettiarachi and Timothy Brown, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, pp. 830-834, dated June, 2009. j. "Standard Test Method for Performing Electronic Friction Cone and Piezocone Penetration Testing of Soils," (ASTM D5778-12), dated 2012. REFERENCES 1. "USGS Topographic Map, 7.5 minute Quadrangle, Newport Beach, California Quadrangle," dated 1965, Photorevised 1981. 2. "Geologic Map of the San Bernardino and Santa Ana 30' X 60' Quadrangles, California," Version 1.0, compiled by Douglas M. Morton and Fred K. Miller, dated 2006. 3. "Maximum Credible Rock Acceleration from Earthquakes in California," by RogerW. Reensfelder, dated 1974. 4. Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada," prepared by California Department of Conservation Division of Mines and Geology, published by International Conference of Building Officials, dated February, 1998. 5. "Guide for Concrete Floor and Slab Construction," by American Concrete Institute, ACI 302.1 R-04, dated 2004. 6. "California Building Code, California Code of Regulations, Title 24, Part 2," by California Building Standards Commission, 2013. 7. "Seismic Hazard Zone Report for the Newport Beach 7.5-Minute Quadrangles, Orange County, California," by the California Department of Conservation, 1997. 8. "20151nternational Building Code," by the International Code Council, dated June 5, 2014. 9. "Geologic Map of California, Santa Ana Sheet," Compilation by Thomas H. Rogers, 1965, fifth printing 1985. PA2017-019