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Home My WebLink About20191121_Geotechnical InvestigationPA2019-243 COAST GEOTECHNICAL, INC. Updated Geotechnical Engineering Investigation for Proposed New Residential Duplex at 494, 496 & 498 Seaward Road Newport Beach, California BY: COAST GEOTECHNICAL, INC. W. 0. 345107-03, dated July 23, 2019 FOR: Ms Marilyn Fox 980 Via Mirada Monterey, CA 93940 PA2019-243 COAST GEOTECHNICAL, INC. 1200 W. Commonwealth Avenue, Fullerton, CA 92833 • Ph: (714) 870-1211 • Fax: (714) 870-1222 • E-mail: coastgeotec@sbcglobal.net July 23, 2019 Ms. Marilyn Fox 980 Via Mirada Monterey, CA 93940 Dear Ms. Fox: Subject: w.o. 345107-03 Updated Geotechnical Engineering Investigation of Proposed Residential Duplex at 494, 496 & 498 Seaward, Newport Beach, California Pursuant to your request, a geotechnical engineering investigation has been performed at the subject site. The purposes of the investigation were to determine the general engineering characteristics of the near surface soils on and underlying the site and to provide recommendations for the design of foundations and underground improvements. The conclusions and recommendations contained in this report are based upon the understanding of the proposed development and the analyses of the data obtained from . our field and laboratory testing programs. This report completes our scope of geotechnical engineering services authorized by you in the April 24, 2019 proposal. SITE DEVELOPMENT It is our understanding that the existing residence will be demolished and that the site is to be redeveloped with a two-story residential structure over slabs-on-grade. Structural loads are anticipated to be light. Significant grade changes are not anticipated. The site was investigated by Coast Geotechnical in 2007 and information gathered during that investigation has been used to develop this updated report based on the proposed construction and current code requirements. PURPOSE AND SCOPE OF SERVICES The scope of the study was to obtain subsurface information within the project site area and to provide recommendations pertaining to the proposed development and included the following: 1. A cursory reconnaissance of the site and surrounding areas. 2. Excavation of two exploratory borings to determine the near subsurface soil conditions and groundwater conditions. 3. Collection of representative bulk and/or undisturbed soil samples for laboratory analysis. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 2 Updated Geotechnical Engineering Investigation w. 0. 345107-03 July 23, 2019 4. Laboratory analyses of soil samples including detennination of in-situ and maximum density, in- situ and optimum moisture content, shear strength characteristics, expansion potential, and sulfate content. 5. Preparation of this report presenting results of our investigation and recommendations of the proposed development. SITE CONDITIONS The site is located at 494, 496 and 498 Seaward Road in the Corona del Mar area of Newport Beach. The project is located on the Site Vicinity Map, Plate 1. The site is occupied by multi-unit residential structure. Physiographically, the parcel is bounded by Seaward Road to the north, Morning Canyon to the east and developed residential lots south and west of the property. The parcel is nearly rectangular in shape and gently descends to the south with about six to seven feet of topographic relief. Drainage of the site is by sheet flow towards the rear of the property. Site configuration is shown on a Site Plan, Plate 2. EXPLORATORY PROGRAM The on-site field investigation was performed on July 24, 2007, consisting of the excavation of two borings at the locations shown on the attached Site Plan. As excavations progressed, a representative from this office visually classified the earth materials encountered, and secured representative samples for laboratory testing. Earth material samples were obtained at various depth intervals within the excavations. Undisturbed earth samples were obtained by driving a thin-walled sampler lined with brass rings into the earth material. Bulk samples were taken of representative earth materials. Samples were placed in appropriate containers for transport. EARTH MATERIALS A representative of COAST GEOTECHNICAL, INC. visually logged earth materials encountered during placement of exploratory borings. The earth materials encountered were identified as artificial fill and native soils. The artificial fill encountered in the borings mantled the site and consisted of silty, clayey sand, medium dense. Native earth material consisted of silty sand, damp to moist with bedrock fragments, generally medium dense to maximum depth explored of 10 feet. Bedrock was not encountered within the exploratory excavations made. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 3 Updated Geotechnical Engineering Investigation Earth materials are further identified on the Boring Logs, Plates B and C. GROUNDWATER w. 0. 345107-03 July 23, 2019 Groundwater was not encountered to depths explored and is not expected to affect the proposed constrnction. SEISMICITY Southern California is located in an active seismic region. Moderate to strong earthquakes can occur on numerous faults. The United States Geological Survey, California Division of Mines and Geology, private consultants, and universities have been studying earthquakes in Southern California for several decades. Early studies were directed toward earthquake prediction estimation of the effects of strong ground shaking. Studies indicate that earthquake prediction is not practical and not sufficiently accurate to benefit the general public. Governmental agencies are shifting their focus to earthquake resistant strnctures as opposed to prediction. The purpose of the code seismic design parameters is to prevent collapse during strong ground shaking. Cosmetic damage should be expected. Within the past 48 years, Southern California and vicinity have experienced an increase in seismic activity beginning with the San Francisco earthquake in 1971. In 1987, a moderate earthquake strnck the Whittier area and was located on a previously unknown fault. Ground shaking from this event caused substantial damage to the City of Whittier, and surrounding cities. The January 17, 1994, Northridge earthquake was initiated along a previously unrecognized fault below the San Fernando Valley. The energy released by the earthquake propagated to the southeast, northwest, and northeast in the form of shear and compression waves, which caused the strong ground shaking in portions of the San Fernando Valley, Santa Monica Mountains, Simi Valley, City of Santa Clarita, and City of Santa Monica. Southern California faults are classified as: active, potentially active, or inactive. Faults from past geologic periods of mountain building, but do not display any evidence of recent offset, are considered "inactive" or "potentially active". Faults that have historically produced earthquakes or show evidence of movement within the past 11,000 years are known as "active faults". There are no known active faults within the subject property, with the nearest being the Newport Inglewood Fault Zone and the San Joaquin Blind Thrust Fault. • Newport-Inglewood Fault Zone: The Newport-Inglewood Fault Zone is a broad zone of left-stepping en echelon faults and folds striking southeastward from near Santa Monica across the Los Angeles basin to Newport Beach. Altogether these various faults constitute a system more than 150 miles long that extends into Baja California, Mexico. Faults having similar trends and projections occur offshore from San Clemente and San Diego (the Rose Canyon and La Nacion Faults). A near-shore portion of the Newport-Inglewood Fault Zone was the source of the destrnctive 1933 Long Beach earthquake. The reported PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 4 Updated Geotechnical Engineering Investigation w. 0. 345107-03 July 23, 2019 recurrence interval for a large event along this fault zone is 1,200 to 1,300 years with an expected slip of one meter. • San Joaquin Hills Blind Thrust Fault: The seismic hazards in Southern California have been further complicated with the recent realization that major earthquakes can occur on large thrust faults that are concealed at depths between 5 to 20 km, referred to as ''blind thrusts." The uplift of the San Joaquin Hills is produced by a southwest dipping blind thrust fault that extends at least 14 km from northwestern Huntington Mesa to Dana Point and comes to within 2 km of the ground surface. Work by Grant et al. (1997 and 1999) suggest that uplift of the San Joaquin Hills began in the Late Quaternary and continues during the Holocene. Uplift rates have been estimated between 0.25 and 0.5 mm/yr. If the entire length of the fault ruptured, the earthquake has been estimated to generate an Mw 6.8 event. We are of the opinion that the more active Newport Inglewood fault is the causative fault for the subject site. The site is located approximately 3.5 kilometer northeast of the Newport Inglewood fault. SEISMIC HAZARDS The potential hazards to be evaluated with regard to seismic conditions include fault rupture, landslides triggered by ground shaking, soil liquefaction, earthquake-induced vertical and lateral displacements, earthquake-induced flooding due to the failure of water containment structures, seiches, and tsunamis. Fault Rupture The project is not located within a currently designated Alquist-Priolo Earthquake Zone (Bryant and Hart, 2007). No known active faults are mapped on the site. Based on this consideration, the potential for surface fault rupture at the site is considered to be remote. Ground Shaking The site is located in a seismically active area that has historically been affected by moderate to occasionally high levels of ground motion, and the site lies in relatively close proximity to several active faults; therefore, during the life of the proposed development, the property will probably experience moderate to occasionally high ground shaking from these fault zones, as well as some backgrolmd shaking from other seismically active areas of the Southern California region. Design of residential structures is typically to maintain structural integrity not to prevent damage. Earthquake insurance is available where the damage risk is not acceptable to the client. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 5 Updated Geotechnical Engineering Investigation Seismic Induced Landslide w. 0. 345107-03 July 23, 2019 Earthquake-induced landslide zones were delineated by the State of California using criteria adopted by the California State Mining and Geology Board. Under those criteria, earthquake- induced landslide zones are areas meeting one or more of the following: 1. Areas known to have experienced earthquake-induced slope failure during historic earthquakes. 2. Areas identified as having past landslide movement, including both landslide deposits and source areas. 3. Areas where CDMG's analyses of geologic and geotechnical data indicate that the geologic materials are susceptible to earthquake-induced slope failure. Based on the Seismic Hazard Zone Map published by the State of California, Newport Beach Quadrangle, appended as Plate 3, the site is not mapped as being in an area subject to potential seismic induced landslides. Seismic Induced Liquefaction Liquefaction is a seismic phenomenon in which loose, saturated, non-cohesive granular soils exhibit severe reduction in strength and stability when subjected to high-intensity ground shaking. The mechanism by which liquefaction occurs is the progressive increase in excess pore pressure generated by the shaking associated with the seismic event and the tendency for loose non-cohesive soils to consolidate. As the excess pore fluid pressure approaches the in-situ overburden pressure, the soils exhibit behavior similar to a dense fluid with a corresponding significant decrease in shear strength and increase in compressibility. Liquefaction occurs when three general conditions exist: 1) shallow groundwater; 2) low density, non-cohesive sandy soils; and 3) high-intensity ground motion. Based on the Seismic Hazard Zone Map published by the State of California, Newport Beach Quadrangle, appended as Figure 3, the area is not mapped as being in an area subject to potential seismic induced liquefaction. Lateral Spreading The occurrence of liquefaction may cause lateral spreading. Lateral spreading is a phenomenon in which lateral displacement can occur on the ground surface due to movement of non-liquefied soils along zones of liquefied soils. For lateral spreading to occur, the liquefiable zone must be continuous, unconstrained laterally, and free to move along sloping ground toward an unconfined area. The area does not exhibit characteristics common to areas subject to seismic induced lateral spread. Our opinion is that the site is not subject to seismic induced lateral spread. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 6 Updated Geotechnical Engineering Investigation Earthquake Induced Settlements w. 0. 345107-03 July 23, 2019 Strong ground shaking can cause settlement by allowing sediment particles to become more tightly packed, thereby reducing pore space. Unconsolidated, loosely packed alluvium, beach/lake deposits are especially susceptible to this phenomenon. Poorly compacted artificial fills may also experience seismically induced settlement. The site is underlain by thin fills, stiff native soils and shallow bedrock. Seismic induced settlement will be negligible. Earthquake Induced Flooding The failure of dams or other water-retaining structures as a result of earthquakes and strong ground shaking could result in the inundation of adjacent areas. Due to the lack of a major dam or water-retaining structure located near the site, the potential of earthquake-induced flooding affecting the site is considered not to be present. Seiches Seiches are large waves generated in enclosed bodies of water in response to ground shaking. Based on the lack of nearby enclosed bodies of water the risk from a seiche event is not present. Tsunamis Tsunamis are waves generated in large bodies of water as a result of change of seafloor topography caused by tectonic displacement. Based on the elevation of the site the project has no potential to be affected by a tsunami. GEOTECHNICAL DISCUSSION Development of the site as proposed is considered feasible from a soil engineering standpoint, provided that the recommendations stated herein are incorporated in the design and are implemented in the field. General comments are as follows, and are subject to change based on review of final development plans and review of future grading plan: • Earthwork will be required to provide support for proposed foundations, interior/exterior slabs, and where determined needed by the soils engineer based on review of future plans and or field observations during construction. • Existing fills are unacceptable for support of new fills and or proposed improvements and shall be removed and replaced as compacted fill under the observation and testing of the soils engineer. • Grading limits shall be determined based on final site development plans, but for planning they shall encompass all areas proposed for development and fill placement. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 7 Updated Geotechnical Engineering Investigation w. 0. 345107-03 July 23, 2019 • Where structures are planned grading shall extend beneath the entire building and extend at least three feet outside the perimeter foundations. Depth of removal shall be adequate to remove all existing fill or unacceptable native materials, provide a minimum of one foot of compacted fill beneath the foundation bottoms, or to limit fill differences across the building pad to five feet over a horizontal distance of forty feet, whichever is deeper. • Where hardscape and driveway areas are proposed depth of removal shall be adequate to remove all existing fill or unacceptable native materials, or to provide a minimum of two feet of compacted fill beneath the finish subgrade elevation, whichever is deeper. • The proposed development is not anticipated to have an adverse affect, from a geotechnical perspective, on adjacent sites and vice versa provided our guidelines, building codes and construction standards are followed. • Foundations for the development may consist of conventional foundations. • Grading along property lines shall be in general accordance with the detail depicted on Figure 4. Based on field observations during grading modifications to this recommendation could be required. CONCLUSIONS AND RECOMMENDATIONS Development of the site as proposed is considered feasible from a soils engineering standpoint, provided that the recommendations stated herein are incorporated in the design and are implemented in the field. PROPOSED GRADING Grading plans were not available at the time this report was prepared; however, we anticipate that grading will be required to create designed pad elevations for the proposed residence, driveway construction, and hardscape and softscape areas. All recommendations within this report are subject to change based on review of final grading plans. The entire grading operation shall be done in accordance with the attached "Specifications for Grading". Any import fill materials to the site shall not have an expansion index greater than 25, and shall be tested and approved by our laboratory. Samples must be submitted 48 hours prior to import. The following are general grading recommendations, which shall be incorporated into the project where applicable. GRADING RECOMMENDATIONS Removal and recompaction of existing earth materials will be required to provide adequate support for foundations and site improvements. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 8 Updated Geotechnical Engineering Investigation w. 0. 345107-03 July 23, 2019 Earthwork for foundation support shall include the entire building pad and shall extend a minimum of three feet outside exterior footing lines. Existing artificial fill and unacceptable native earth materials shall be excavated down to competent native earth materials. Competent native earth material is determined by the project soil engineer based on physical testing of soil samples obtained during site exploration and experience in the area. Based on performed testing our opinion is that native earth materials found at three feet below existing grade and deeper have adequate capability of supporting proposed fills and foundation loads. The exposed excavation bottom shall be observed and approved by COAST GEOTECHNICAL, Inc. prior to processing. Dependent on field observations, removals may be adjusted up or down. Subsequent to approval of the excavation bottom, the area shall be scarified six inches, moisture conditioned as needed, and compacted to a minimum of 90% relative compaction. Fill soils shall be placed in six to eight inch loose lifts, moisture conditioned as needed, and compacted to a minimum of 90% relative compaction. This process shall be utilized to finish grade. During earthwork operations, a representative of COAST GEOTECHNICAL, Inc. shall be present to verify compliance with these recommendations. The grading contractor is advised that at the time of our investigation earth materials were well over optimum moisture content. Recompaction of existing soils may be difficult or not possible. Mitigation of wet conditions may be required to achieve compaction requirements. Replacement of wet soft soil conditions with selected import material or cement treating the soil may be necessary. Grading for hardscape areas shall consist of removal and recompaction of soft surficial soils. Removal depths are estimated at one to two feet. Earthwork shall be performed in accordance with previously specified methods. The project is in an area where usage of septic systems and or trash pit disposal was common. If encountered during site earth work the soil engineer shall be notified for recommendations. Typically septic tanks, leach fields, and trash pits are removed and the void backfilled with compacted soil. Seepage pits may require to be drilled-out and backfilled with minimum three sack cement slurry. If encountered additional removals may be necessary and will be field determined. The soil engineer shall review grading and/or foundation plans. All recommendations are subject to modification upon review of such plans. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 9 Updated Geotechnical Engineering Investigation CONSTRUCTION CUTS w. 0. 345107-03 July 23, 2019 Care shall be exercised when grading along property lines so as not to remove lateral support from public right of ways or to undermine adjacent foundations or hardscape. Along property lines 1: 1 cuts shall be made from the property line down to the excavation bottom. As fills are placed they shall be benched into the temporary cut. This shall be performed under the observation of the soils consultant. Details are shown on Plate 4. FOUNDATIONS ON COMPACTED FILL -RESIDENCE The residence may be supported by conventional foundations. Conventional foundations may consist of spread footings or isolated pads placed a minimum depth of 24 inches below lowest adjacent grade utilizing an allowable bearing value of 1,800 pounds per square foot. This value is for dead plus live load and may be increased 1/3 for total including seismic and wind loads where allowed by code. The footing width shall be at least 18 inches wide for the proposed three-story construction. Calculations are given on Plate F. Isolated pad footings shall be tied by grade beams to continuous footings. It is recommended that all footings be reinforced with a minimum of four #4 bars (two top and two bottom). The structural engineer's reinforcing requirements should be followed if more stringent. Footing excavations shall be observed by a representative of COAST GEOTECHNICAL, INC. prior to placement of steel or concrete to verify competent soil conditions. FOUNDATIONS ON NATIVE SOILS Property line walls may be supported by continuous spread footings bearing 12 inches into competent native soils and at least 24 inches below lowest adjacent grade, whichever is deeper, may utilize an allowable bearing value of 1,500 pounds per square foot. This value is for dead plus live load and may be increased 1/3 for total including seismic and wind loads where allowed by code. A representative of COAST GEOTECHNICAL, Inc. shall observe foundation excavations to verify that they comply with project geotechnical recommendations. It is recommended that all footings be reinforced with a minimum of four #5 bars (two top and two bottom). The structural engineer's reinforcing requirements should be followed if more stringent. LATERAL DESIGN Lateral restraint at the base of footings and on slabs may be assumed to be the product of the dead load and a coefficient of friction of .35. Passive pressure on the face of footings may also be used to PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 10 Updated Geotechnical Engineering Investigation w. 0. 345107-03 July 23, 2019 resist lateral forces. A passive pressure of zero increasing at the rate of 300 pounds per square foot of depth to a maximum value of 3,000 pounds per square foot may be used for competent native and compacted fill soils at this site. If passive pressure and friction are combined when evaluating the lateral resistance, the value of the passive pressure should be limited to 2/3 of the values given above. Calculations are given on Plate G. RETAINING WALLS Walls retaining drained earth under static loading may be designed for the following: Calculations for the stated equivalent fluid pressures are based on the Coulomb theory provided on Plate H. The point of resultant force under static loading is at H/3 above the base of the retaining wall. Walls are expected to be six feet or less, higher walls would need to be evaluated based on a site specific plan. Retaining walls should include subdrains consisting of four inch, SCH 40 or SDR 35 perforated pipe surrounded by one cubic foot per lineal foot of crushed rock, wrapped with geofabric cloth. All wall backfill should be compacted to a minimum of 90% relative compaction. All retaining structures should include appropriate allowances for anticipated surcharge loading, where applicable. Retaining walls with an ascending slope condition shall include a minimum one- foot free board and concrete swale in their design. Retaining walls shall be waterproofed to the degree desired by the client. SEISMIC DESIGN Based on the 2016 CBC the following seismic design parameters are provided. These seismic design values were determined utilizing latitude 33.592107 and longitude -117.862082 and calculations from the ATC Hazards seismic calculator. A printout of the data is attached. A conservative site class D was assigned to site earth materials. • Site Class = D • Mapped 0.2 Second Spectral Response Acceleration, Ss = 1.680g • Mapped One Second Spectral Response Acceleration S1 = 0.612g • Site Coefficient from Table 1613A.3.3(1), Fa= 1.0 • Site Coefficient from Table 1613A.3.3(2), Fv = 1.5 • Maximum Design Spectral Response Acceleration for short period, SMs = 1.680g • Maximum Design Spectral Response Acceleration for one-second period, SM 1 = 0.919g • 5 % Design Spectral Response Acceleration for short period, Sns = 1.120g • 5% Design Spectral Response Acceleration for one-second period, Sm= 0.612g PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 11 Updated Geotechnical Engineering Investigation SETTLEMENT w. 0. 345107-03 July 23, 2019 The maximum total post-construction settlement is anticipated to be on the order of one-half inch. Differential settlements are expected to be less than 1/2 inch, measured between adjacent structural elements over a distance of forty feet. EXPANSIVE SOILS Results of expansion tests indicate that the near surface soils have a very low expansion potential. FLOOR SLABS Where conventional foundation and slab on grade is utilized, the slab shall be supported on engineered fill compacted to a minimum of 90% relative compaction. Existing soil are non-plastic. Minimum geotechnical recommendations for on grade slab design are four inches actual thickness, with #3 bars at twelve inches on center each way. If the soils at grade become disturbed during construction, they shall be brought to optimum moisture content and compacted to a minimum of 90% relative compaction prior to placing concrete. COAST GEOTECHNICAL, Inc. will need to verify adequate mitigation. The capillary break material shall comply with the requirements of the local jurisdiction and shall be a minimum of four inches in thickness and consist of gravel (1/2-inch or larger clean aggregate). A heavy filter fabric should be placed over the gravels prior to placement of the recommended vapor retarder to minimize puncturing of the vapor retarder. Slab areas should be underlain by a vapor retarder consisting of an engineered plastic film ( as described by ASTM:E-1745). A vapor barrier with a permeance of less than 0.0lperms (consistent with ACI 302.2R-06) such as 15 mil. Stego Wrap Vapor Barrier or equivalent should be considered. The vapor barrier should be underlain by the above described capillary break material and filter cloth. The capillary break materials should be compacted to a uniform condition prior to placement of the recommended filter cloth and vapor barrier. The vapor barrier should be properly lapped and sealed and in contact with the slab bottom. SOLUBLE SULFATES Typical on-site soils showed a soluble sulfate content of 96 ppm. Based on the Table 4.3 .1 of ACI, concrete with Type II cement and a minimum compressive strength of 2,500 psi may be utilized. The structural engineers design criteria may be more stringent. Concrete shall be placed in accordance with appropriate codes. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 12 Updated Geotechnical Engineering Investigation UTILITY LINE BACKFILLS w. 0. 345107-03 July 23, 2019 All utility line, area drains, and other trench backfills, both interior and exterior, shall be compacted to a minimum of 90% relative compaction and shall require testing at a minimum of two-foot vertical intervals. Utility lines placed within expansive soils shall be shaded with clean sand. Where the utility line enters the structure a plug of three sack slurry shall be placed to minimize the potential of water intrusion into the structure, along the sand shading. HARDSCAPE SLABS Hardscape slabs may be supported by compacted fills a minimum of one foot in thickness. Deeper removal and recompaction may be required if unacceptable conditions are encountered. Hardscape slab subgrade areas shall exhibit a minimum of 90% relative compaction and a moisture content of 1-2% over optimum. These areas require testing just prior to placing concrete. Exterior hardscape slabs will be subject to stress from volume changes in expansive subgrade soils, which may lead to cracking, heaving, and horizontal separation from structures. The followings recommendations will minimize cracking, heaving and offsets, but will not eliminate them. Exterior hardscape slabs will be subject to volume changes in subgrade soils, which may lead to cracking. Movement of slabs adjacent to structures can be mitigated by doweling slabs to perimeter footings. Doweling should consist of No. 4 bars bent around exterior slabs. Doweling should be spaced no farther than 36 inches on centers. As an option to doweling, an architectural separation could be provided between the main structure and abutting appurtenance improvements. Presaturation of exterior slab areas is also desirable. At exterior edges of patios and other flatwork, a thickened edge containing reinforcement is highly recommended. If no significant load is associated with the edge of the slab, the depth and width of the thickened edge may be limited to eight inches. Reinforcement adopted for the main structure may be applied to the appurtenances. As an alternative to rigid hardscape or brickwork, flexible pavers may be utilized. DRAINAGE Positive drainage should be planned for the site. Drainage should be directed away from structures via non-erodible conduits to suitable disposal areas. The structure should utilize roof gutters and down spouts tied directly to yard drainage. Unlined flowerbeds, planters, and lawns should not be constructed against the perimeter of the structure. If such landscaping ( against the perimeter of a structure) is planned, it should be properly drained and lined or provided with an underground moisture barrier. Irrigation should be kept to a minimum. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 13 Updated Geotechnical Engineering Investigation w. 0. 345107-03 July 23, 2019 The current CBC recommends 5% slope away from structures for landscape areas and 2% slope away for hardscape areas, within ten feet of a residence. Minimum drainage shall be one percent for hardscape areas and two percent for landscape areas for all other areas. We do not recommend the use of bottomless trench drains to conform with infiltration best management practice (BMP) such as infiltration trenches, infiltration basins, dry wells, permeable pavements or similar systems designed primarily to percolate water into the subsurface soils within five feet of foundations. Due to the physical characteristics of the site earth materials, infiltration of waters into the subsurface earth materials has a risk of adversely affecting below grade structures, building foundations and slabs, and hardscape improvements. From a geotechnical viewpoint surface drainage should be directed to the street. The WQMP requirement shall be addressed by the Civil Engineer. SUPPLEMENTAL CONSUL TING During construction, a number of reviews by this office are recommended to verify site geotechnical conditions and conformance with the intentions of the recommendations for construction. Although not all possible geotechnical observation and testing services are required by the City of Newport Beach, the following site reviews are advised, some of which will probably be required by the City: • Site grading • Foundation excavation review for the all structures. • Slab subgrade compaction testing • Compaction of interior and exterior utility trench backfill • Hardscape subgrade testing AGENCY REVIEW All geotechnical and structural aspects of the proposed development are subject to the review and approval of the governing agency(s). It should be recognized that the governing agency(s) could dictate the manner in which the project proceeds. They could approve or deny any aspect of the proposed improvements and/or could dictate which foundation and grading options are acceptable. Supplemental geotechnical consulting in response to agency requests for additional information could be required and will be charged on a time and materials basis. LIMITATIONS This report presents recommendations pertaining to the subject site based on the assumption that the subsurface conditions do not deviate appreciably from those disclosed by our exploratory excavations. Our recommendations are based on the technical information, our understanding of the proposed construction, and our experience in the geotechnical field. We do not guarantee the performance of the project, only that our engineering work and judgments meet the standard of care of our profession at this time. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 14 Updated Geotechnical Engineering Investigation w. 0. 345107-03 July 23, 2019 In view of the general conditions in the area, the possibility of different local soil conditions may exist. Any deviation or unexpected condition observed during construction should be brought to the attention of the Geotechnical Engineer. In this way, any supplemental recommendations can be made with a minimum of delay necessary to the project. If the proposed construction will differ from our present understanding of the project, the existing information and possibly new factors may have to be evaluated. Any design changes and the finished plans should be reviewed by the Geotechnical Consultant. Of particular importance would be extending development to new areas, changes in structural loading conditions, postponed development for more than a year, or changes in ownership. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the information and recommendations contained herein are called to the attention of the Architects and Engineers for the project and incorporated into the plans and that the necessary steps are taken to see that the Contractors and Subcontractors carry out such recommendations in the field. This report is subject to review by the controlling authorities for this project. We appreciate this opportunity to be of service to you. Respectfully submitted: COAST GEOTECHNICAL, Inc ~:f" \Scd"--=-- Ming-Tarng Chen RCE54011 Staff Geologist I PA2019-243 COAST GEOTECHNICAL, INC. Ms.Fox 15 Updated Geotecbnical Engineering Investigation APPENDIXA w. 0. 345107-03 July 23. 2019 This appendix contains a description of the field investigation, laboratory testing procedures and results, site plan, and expansive soil recommendations. FIELD INVESTIGATION The field investigation was performed on July 24, 2007, and consisted of the excavation of two exploratory borings at locations shown on the attached Site Plan, Plate 2. As the excavations progressed, personnel from this office visually classified the soils encountered, and secured representative samples for laboratory testing. Descriptions of the soils encountered are presented on the attached Boring Logs, Plates B and C. The data presented on these logs is a simplification of actual subsurface conditions encountered and applies only at the specific boring locations and the date excavated. It is not warranted to be representative of subsurface conditions at other locations and times. LABORATORY TESTING Field samples were examined in the laboratory and a testing program was then established to develop data for preliminary evaluation of geotechnical conditions. Field moisture and dry densities were calculated for each undisturbed sample. The samples were obtained per ASTM:D-2937 and tested under ASTM:D-2216. Maximum density-optimum moisture relationships were established per ASTM:D-1557 for use in evaluation of in-situ conditions and for future use during grading operations. Direct shear tests were performed in accordance with ASTM:D-3080, on specimens at near saturation under various normal loads. The results of tests are based on an 80% peak strength or ultimate strength, whichever is lower, and are attached, Plates D and E. Expansion tests were performed on typical specimens of earth materials in accordance with the procedures outlined in ASTM D-4829. A consolidation test was performed on a representative sample based on ASTM:D-2435. The consolidation plot is presented on Plate F. PA2019-243 COAST GEOTECHNICAL, INC. Ms. Fox 16 Updated Geotecbnical Engineering Investigation TEST RES UL TS Maximum Density/Optimum Moisture Direct Shear 1 0-5.0 (remolded) 150 2 2.5 200 Expansion Index 1 0-5.0 12 2 5-8.0 Chemical Analysis {USEPA Method 375.4) 30 29 w. 0. 345107-03 July 23, 2019 Very Low Very Low PA2019-243 COAST GEOTECHNICAL, INC. SPECIFICATIONS FOR GRADING SITE CLEARING All existing vegetation shall be stripped and hauled from the site. PREPARATION After the foundation for the fill has been cleared, plowed or scarified, it shall be disced or bladed until it is uniform and free from large clods, brought to a proper moisture content and compacted to not less than ninety percent of the maximum dry density in accordance with ASTM:D-1557 (5 layers -25 blows per layer; 10 lb. hammer dropped 18"; 4" diameter mold). MATERIALS On-site materials may be used for fill, or fill materials shall consist of materials approved by the Soils Engineer and may be obtained from the excavation of banks, borrow pits or any other approved source. The materials used should be free of vegetable matter and other deleterious substances and shall not contain rocks or lumps greater than six inches in maximum dimension. PLACING, SPREADING AND COMPACTING FILL MATERIALS The selected fill material shall be placed in layers which, when compacted, shall not exceed six inches in thickness. Each layer shall be spread evenly and shall be thoroughly mixed during the spreading to ensure uniformity of material and moisture of each layer. Where moisture of the fill material is below the limits specified by the Soils Engineer, water shall be added until the moisture content is as required to ensure thorough bonding and thorough compaction. Where moisture content of the fill material is above the limits specified by the Soils Engineer, the fill materials shall be aerated by blading or other satisfactory methods until the moisture content is as specified. After each layer has been placed, mixed and spread evenly, it shall be thoroughly compacted to not less than 90 percent of the maximum dry density in accordance with ASTM:D-1557 (5 layers -25 blows per layer; 10 lbs. hammer dropped 18 inches; 4" diameter mold) or other density tests which will attain equivalent results. Compaction shall be by sheepfoot roller, multi-wheel pneumatic tire roller, track loader or other types of acceptable rollers. PA2019-243 COAST GEOTECHNICAL, INC. SPECIFICATIONS FOR GRADING PAGE2 Rollers shall be of such design that they will be able to compact the fill to the specified density. Rolling shall be accomplished while the fill material is at the specified moisture content. Rolling of each layer shall be continuous over the entire area and the roller shall make sufficient trips to ensure that the desired density has been obtained. The final surface of the lot areas to receive slabs on grade should be rolled to a dense, smooth surface. The outside of all fill slopes shall be compacted by means of sheepfoot rollers or other suitable equipment. Compaction operations shall be continued until the outer nine inches of the slope is at least 90 percent compacted. Compacting of the slopes may be progressively in increments of three feet to five feet of fill height as the fill is brought to grade, or after the fill is brought to its total height. Field density tests shall be made by the Soils Engineer of the compaction of each layer of fill. Density tests shall be made at intervals not to exceed two feet of fill height provided all layers are tested. Where the sheepfoot rollers are used, the soil may be disturbed to a depth of several inches and density readings shall be taken in the compacted material below the disturbed surface. When these readings indicate that the density of any layer of fill or portion there is below the required 90 percent density, the particular layer or portion shall be reworked until the required density has been obtained. The grading specifications should be a part of the project specifications. The Soil Engineer shall review the grading plans prior to grading. INSPECTION The Soil Engineer shall provide continuous supervision of the site clearing and grading operation so that he can verify the grading was done in accordance with the accepted plans and specifications. SEASONAL LIMITATIONS No fill material shall be placed, spread or rolled during unfavorable weather conditions. When heavy rains interrupt work, fill operations shall not be resumed until the field tests by the Soils Engineer indicate the moisture content and density of the fill are as previously specified. EXPANSIVE SOIL CONDITIONS Whenever expansive soil conditions are encountered, the moisture content of the fill or recompacted soil shall be as recommended in the expansive soil recommendations included herewith. PA2019-243 SITE VICINITY MAP .. NEWPORT BEACH QUADRANGLE CALIFORNIA -ORANGE CO. 7.5 MINUTE SERIES (TOPOGRAPHIC) UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGIC SURVEY Geotechnical Engineering Investigation 494, 496 & 498 Seaward Road Newport Beach, California Work Order 345107-03 Plate No. 1 COAST GEOTECHNICAL, INC. PA2019-243 SITE PLAN Scale: 1 "= 16' I II -/71 coNC, iii\ I / /1 Ii I / I _ .Boring #2-----_ l~===::iatl~-=='c;,;_~::JE;:i_ / coNc ---------------/ -------....____ _../ ----,.,,..----~--------~/ -2/,0 coNC, ----_ ,,,,,.- ----------...___ _-_ -----_..:.. ":---..__ -.. - Geotechnical Engineering Investigation 494, 496 & 498 Seaward Road Newport Beach, California Work Order 345107-03 Plate No. 2 COAST GEOTECHN/CAL, INC. PA2019-243 SEISMIC HAZARD ZONES MAP w ~-. -_.:Ai!T: :-."(#,/.~.:. ·-· ~ ·-·~ ~~ _ _ _STATI; OF CALIFORNIA. .. _ • )]1 SEISMI~,_!~~?!_ ZONES . Chaptlli-7,B.Dlvlllb!Zafth•Calfaml1Publlcllflau11:e1Clld. .. . fS-nJo 11-,,/a Mllpplng AatJ. .. ~ "! NEWPORT B!=ACH QUADRANGLE OFFICIAL MAP MAP EXPLANATION Zones of Required Investigation: Liquefaction . Areas where historic occurrence of liquefaollon, or local geological, geotechnical and groundwater conditions lndlcate·a potential for pennanent 9.round dispJacements such that mitigation es defined l'l Pubfic Resources Code Section 2693(0) would be required. E;arthquake-lnducod Landslides Areas where previous occurrence of landslide movenierit, or local topographic, geological, geotechnlcal and subsurface water condltlcins Indicate a potential 1or pennanent ground displacements such that mitigation es dellned In Public Resources Code Section 2693(0) would be required, ~ I /,.. '' , ~ ...._ ---~ •• _,,, :; ·: ·• .,. --_~ vi If { . STATE OF CALIFORNIA " "r EISMiC-HAZARD ZO-NE Dellnaawdlncomp,llancewith Chapter 7.8, Division z·of tha Caifomla Publk Resources C ___ ..,, GUNA BEACH QUADRANG · OFFICIAL MAP ·,.-.\rch. 42 ""'· . ·,, . ", __ ' \, Geotechnical Engineering Investigation 494, 496 & 498 Seaward Road Newport Beach, California Work Order 345107-03 Plate No. 3 COAST GEOTECHNICAL, INC. PA2019-243 Temporary Excavation Along Property Lines BLDG FACE NEW FTG (24*'). F.F. 3' ( . WALL OR P.L. ---ri ·--;) BENCH1NG . . OVER EXCAVATION_/ / 1:1 PROJECTION EXCAVATION DETAIL N.T.S. Geotechnical Engineering Investigation 494, 496 & 498 Seaward Road Newport Beach, California Work Order 345107-03 Plate No. 4 COAST GEOTECHNICAL, INC. PA2019-243 COAST GEOTECHNICAL, INC. (Text Supercedes) PLATEA 12" 12" 12" 15" 15" 15" 15" 15" 15" 15" 18" 18" 18" 18" 18" 24" 24" 24" 24" 30" 24" 24" 24" 24" 36" 24" 24" 24" 24" 30" 24" 24" 24" 24" 36" 4 #4 Bars 4 #4 Bars 4 #5 Bars 4 #5 Bars 4 #5 Bars 2 Top 2 Top 2 Top 2 Top 2 Top 2 Bottom 2 Bottom 2 Bottom 2 Bottom 2 Bottom 4"Nominal 4" Nominal 5" Nominal 5" Actual 5" Actual #3 Bars on #3Bars on #4 Bars on #4 Bars on #4 Bars on 12" 12" 12" 12" 12" Centers Both Centers Both Centers Both Centers Both Centers Both Ways Ways Ways Ways Ways 15 mil 15 mil 15 mil 15 mil 15 mil Membrane Membrane Membrane Membrane Membrane #3 Bars on #3 Bars on #4 Bars on #4 Bars on #4 Bars on 12" 12" 12" 12" Center 12" Center Centers Both Centers Both Centers Both Both Ways Both Ways Ways Ways Ways Free Floating Free Floating Same as Adj. Same as Adj. Same as Adj. Same as Adj. Same as Adj. Ext. Ftg. Ext. Ftg. Ext. Ftg. Ext. Ftg. Ext. Ftg. 4" Clean 4" Clean 4" Clean 4" Clean 4" Clean Aggregate Aggregate Aggregate Aggregate Aggregate Above Opt. 110% of Opt 130% of Opt 130% of Opt To M/Cto MIC to Depth M/Cto Depth Depth of Ftg. Depth Footing Footing (No Testing) Footing 1. Basement slabs shall have a minimum thickness of six inches. 2. Floor slab shall be constructed over a 15 mil plastic membrane. The membrane shall be properly lapped, sealed and may be in contact with the slab bottom. 3. Aggregate should be ½-inch or larger. PA2019-243 Date: ~ "cii c- CD D 0 0. ~ ---- 0 96.4 106.8 105.9 SUMMARY OF BORING NO. 1 7/24/2007 Elevation: E.G. -!/l -~ (I)...; CD ...; C :5s ci LL. ,._ CD ----0 ..... ti ~ E .c Description 0 !/l ·5 0 ro ..... () "cii (f) 0. C :?;?fl. CD 0 ----0 () FILL: SAND ---clayey, moist Orange Medium Brown 9.1 2 SAND ---silty, moist Tan Brown Medium Dense SAND ---silty, clayey, moist Dark Brown Medium Dense 4 17.8 SAND ---silty, clayey, moist with bedrock Dark Brown Medium fragments Dense 6 17.5 8 10----1:===================l=======l======I End of boring at 10 feet No Groundwater No Caving Geotechnical Engineering Investigation 494, 496, 498 Seaward Road Newport Beach, California Work Order 345107 Plate No. B COAST GEOTECHNICAL, INC. PA2019-243 SUMMARY OF BORING NO. 2 Date: 7/24/2007 109.0 15.3 94.2 21.1 106.5 17.9 lB c.. E ro CJ) U B -..... LL ----:§_ CD 0 2 4 - - - 6 - - 8 - Description FILL: SAND ---clayey, moist SAND ---silty, moist SAND ---silty, clayey, moist with bedrock fragments End of boring at 9 feet No Groundwater 10-No Caving Geotechnical Engineering Investigation 494, 496, 498 Seaward Road Newport Beach, California Elevation: E.G. L. 0 8 Orange Brown Tan Brown Dark Brown ~ C 2 Cl) "in C 0 0 Medium Medium Dense Medium Dense Work Order 345107 Plate No. C COAST GEOTECHNICAL, INC. PA2019-243 .---.. .:::: & C/l en 0. 32 -C/l C/l SHEAR TEST RESULT [ Boring No.1 @ 0 to 5 Feet (Remolded to 90%) ) 5 4 3 ~ 2 +-' Cl) 0 0 1 2 3 4 5 Confining Pressure (kips/sq. ft.) Remolded soil samples were tested at saturated conditions. The sample had a dry density of 113 lbs./cu.ft. and a moisture content of 18 %. Cohesion = 150 psf Friction Angle = 30 degrees Based on 80% peak strength or ultimate strength, whichever is lower Geotechnical Engineering Investigation 494, 496, 498 Seaward Road Newport Beach, California Work Order 345107 Plate No. D COAST GEOTECHNICAL, INC. PA2019-243 SHEAR TEST RESULT ( Boring No.1 @ 2.5 Feet ,,....., ¢:! (J) (J) 5 4 3 ~ 2 u5 0 0 1 2 3 4 Confining Pressure (kips/sq. ft.) Native soil samples were tested at saturated conditions. l 5 The sample had a dry density of 109 lbs./cu.ft. and a moisture content of 19.9 %. Cohesion = 200 psf Friction Angle = 29 degrees Based on 80% peak strength or ultimate strength, whichever is lower Geotechnical Engineering Investigation 494,496,498 Seaward Road Newport Beach, California Work Order 345107 Plate No. E COAST GEOTECHNICAL, INC. PA2019-243 ALLOWABLE BEARING CAPACITY Bearing Capacity Calculations are based on "Terzaghi's Bearing Capacity Theory" Bearing Material: Compacted Soil Properties: Wet Density (y) = 120 pcf Cohesion (C) = 150 psf Angle of Friction (</>) = 30 degrees Footing Depth (D) = 2 feet Footing Width (B) = 1.3 feet Factor of Safety = 3.0 Calculations -Ultimate Bearing Capacity from Table 3.1 on page 127 of "Foundation Engineering Handbook", 1975 Ne= 30.14 Nq = 18.4 Ny = 22.4 Ou = 1.3 C Ne + y D Nq + 0.4 y B Ny (Square Footing) = 1.3 * 150 * 30.14 + 120 * 2 * 18.4 + 0.4 * 120 * 1.25 * 22.4 = 5877 + 4416 + 1344 = 11637 psf Allowable Bearing Capacity for Square Footing 3879 psf Use 1800 psf Ou = 1.0 C Ne + y D Nq + 0.5 y B Ny (Continuous Footing) = 1.0 * 150 * 30.14 + 120 * 2 * 18.4 + 0.5 * 120 * 1.25 * 22.4 = 4521 + 4416 + 1680 = 10617 psf Allowable Bearing Capacity for Continuous Footing Oa11= Ou/ F.S. = Use 1800 psf 3539 psf Increases: 750 psf / ft in depth over 2 feet 400 psf / ft in width over 1.25 feet Geotechnical Engineering Investigation 494, 496 & 498 Seaward Road Newport Beach, California Work Order 345107-03 Plate F COAST GEOTECHNICAL, INC. PA2019-243 LATERAL EARTH PRESSURE CALCULATIONS Retaining structures such as retaining walls, basement walls, and bulk-heads are commonly used in foundation engineering, and they support almost vertical slopes of earth masses. Proper design and construction of these structures require a through knowledge of the lateral forces acting between the retaining structures and the soil masses being retained. These lateral forces are due to lateral earth pressure. Properties of earth material: Wet Density (y) Cohesion (C) = = 120 pcf 150 psf Angle of Friction(¢) = 30 degrees Coefficient of Friction = tan <I> Therefore, Coefficient of Friction = tan <I> = tan¢ = 0.577 Assumed H = 2 feet Use 0.35 Pp = 0.5 y H2 tan 2 ( 45° + ¢ I 2 ) + 2 C H tan ( 45° + ¢ I 2 ) = 0.5*120*4*3+2*150*2*1.732 = 720 + 1039 = 1759 lbs/ LF 1/2 EFP H2 = 1759 EFP: passive pressure EFP = 880 psf / LF Allowable Passive Pressure= 300 psf / LF ( with F.S. = 2.93) Geotechnical Engineering Investigation 494, $96 & 498 Seaward Road Newport Beach, California Work Order 345107-03 Plate G COAST GEOTECHNICAL, INC. PA2019-243 ACTIVE EARTH PRESSURE BY COULOMB THEORY Compacted Fill The total active thrust can be expressed as PA= 0.5 KA y H2 where the active earth pressure coefficient, KA, is given by cos 20 cos(o + 0) { 1 + [ Where: cos 2 (</> -0) sin(o + <P) sin(</> -/J) cos(o + 0) cos(/J -0) 0 = slope of the back of the wall with respect to the vertical o = angle of friction between the wall and the soil /3 = slope of the backfill with respect to the horizontal Properties of earth material: Wet Density (y) Cohesion (C) Angle of Friction(¢) 0 0 = = = = = Caculate KA based on slope of the backfill Surface Slope Slope Angle (/J) KA Level 0.0 0.297 5:1 (H:V) 11.3 0.347 4:1 (H:V) 14.0 0.364 3:1 (H:V) 18.4 0.399 2:1 (H:V) 26.6 0.524 1.5:1 (H:V) 33.7 0.798 Geotechnical Engineering Investigation 494, 496 & 498 Seashore Road Newport Beach, California 120 pcf 150 psf 30 degrees 0 20 EFP [ = y * KA ], pcf 35.7 41.7 43.7 47.8 62.9 95.8 Work Order 345107-03 Plate H COAST GEOTECHNICAL, INC. PA2019-243 7/23/2019 ATC Hazards by Location L\TC Hazards by Location Search Information Address: Coordinates: Elevation: Timestamp: Hazard Type: Reference Document: 494 Seaward Rd, Corona Del Mar, CA 92625, USA 33.592107, -117.86208199999999 129 ft 2019-07-23T17:42:39.761 Z Seismic ASCE7-10 Risk Category: Ill Site Class: D MCER Horizontal Response Spectrum Sa(g) 1.50 1.00 0.50 0.00 0 2 Basic Parameters """'"'"=•,--=·"'"'"'" ·-·~·¥ Name Value Ss 1.68 S1 0.612 SMs 1.68 SM1 0.919 Sos 1.12 So1 0.612 ,~,m=w=,mm,,,,= 4 6 8 Period (s) Description MCER ground motion (period=0.2s) MCER ground motion (period=1.0s) Site-modified spectral acceleration value Site-modified spectral acceleration value Numeric seismic design value at 0.2s SA Numeric seismic design value at 1.0s SA .... Additional Information r::~--Value Description soc D Seismic design category : Fa 1 Site amplification factor at 0.2s l Fv 1.5 Site amplification factor at 1.0s 0.902 Coefficient of risk (0.2s) Design Horizontal Response Spectrum Sa(g) 1.00 0.80 0.60 0.40 0.20 0.00 0 2 4 6 8 Period (s) https://hazards.atcouncil.org/#/seismic?lat=33.592107 &lng=-117 .86208199999999&address=494 Seaward Rd%2C Corona Del Mar%2C CA 92625%2... 1/2 PA2019-2437/23/2019 ATC Hazards by Location CRs CR1 0.921 Coefficient of risk (1.0s) PGA 0.689 MCEG peak ground acceleration FPGA 1 Site amplification factor at PGA PGAM 0.689 Site modified peak ground acceleration TL 8 Long-period transition period (s) SsRT 1.68 Probabilistic risk-targeted ground motion (0.2s) SsUH 1.861 Factored uniform-hazard spectral acceleration (2% probability of exceedance in 50 years) SsD 3.221 Factored deterministic acceleration value (0.2s) S1RT 0.612 Probabilistic risk-targeted ground motion (1.0s) S1UH 0.665 Factored uniform-hazard spectral acceleration (2% probability of exceedance in 50 years) S1D 1.08 Factored deterministic acceleration value (1.0s) PGAd 1.177 Factored deterministic acceleration value (PGA) The results indicated here DO NOT reflect any state or local amendments to the values or any delineation lines made during the building code adoption process. Users should confirm any output obtained from this tool with the local Authority Having Jurisdiction before proceeding with design. Disclaimer Hazard loads are provided by the U.S. Geological Survey Seismic Design Web Services. While the information presented on this website is believed to be correct, ATC and its sponsors and contributors assume no responsibility or liability for its accuracy. The material presented in the report should not be used or relied upon for any specific application without competent examination and verification of its accuracy, suitability and applicability by engineers or other licensed professionals. ATC does not intend that the use of this information replace the sound judgment of such competent professionals, having experience and knowledge in the field of practice, nor to substitute for the standard of care required of such professionals in interpreting and applying the results of the report provided by this website. Users of the information from this website assume all liability arising from such use. Use of the output of this website does not imply approval by the governing building code bodies responsible for building code approval and interpretation for the building site described by latitude/longitude location in the report. https://hazards.atcouncil.org/#/seismic?lat=33.592107 &lng=-117 .86208199999999&address=494 Seaward Rd%2C Corona Del Mar%2C CA 92625%2... 2/2