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HomeMy WebLinkAboutX2020-2722 - Soils9AV,2(16 wood. Wood Environment & Infrastructure Solutions, Inc. 6001 Rickenbacker Road Los Angeles, CA 90040-3031 USA T: +1 323.889.5300 www.woodplc.com November 13, 2020 Project 4953-20-0781 Mr. Cary Brooks Senior Project Manager Real Estate Construction Operations (REFCO) Hoag Memorial Hospital Presbyterian 510 Superior Avenue, Suite 290 Newport Beach, California 92663 Subject: Report of Geotechnical Consultation Proposed Temporary Modular Building Hoag Memorial Hospital Presbyterian Newport Beach, California Dear Mr. Brooks: This letter presents the results of our geotechnical consultation in support of the proposed temporary modular building on the lower campus of Hoag Memorial Hospital Presbyterian in Newport Beach, California. Our services have been provided in general accordance with our proposal dated October 13, 2020, as authorized by your Purchase Order No. 1706634CAP, dated November 4, 2020. Mr. Roger Paul Young of Solid Rock Structural Solutions, Inc. and Mr. Barry Paxson of Howe Bonney & Associates have provided us with details and plans for the project. Our professional services have been performed using that degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical consultants practicing in this or similar localities. No other warranty, express or implied, is made as to the professional advice included in this report. 1.0 SCOPE We previously performed geotechnical investigations for numerous projects at the existing hospital campus, including for the existing Advanced Technology Pavilion (ATP, originally known as the Employee Child Care Center) which is located immediately south of the proposed project site. The results of this nearby investigation were submitted in a report dated April 20, 1990 (our Job No. LCA 089083.AEB). We also provided inspection and testing services during grading and construction for the existing ATP Building, the results of which were documented in a report dated December 17, 1990 (our Job No. LCA 090038.6). Our services have been authorizedto review our prior data and evaluate the applicability of the foundation recommendations provided in our prior report for the ATP building. We were also to provide the mapped seismic design parameters in accordance with the 2019 California Building Code (CBC) and ASCE 7-16. The Wood' is a trading name for John Wood Group PLC and its subsidiaries • i Hoag Memorial Hospital Presbyterian Report of Geotechnical Consultation — Proposed Temporary Modular Building Project 4953-20-0781 Page 2 November 13, 2020 assessment of general site environmental conditions for the presence of contaminants in the soils and groundwater of the site was beyond the scope of our current services. 2.0 PROJECT INFORMATION The proposed project is to consist of a new temporary modular building located approximately 80 feet north of northernmost portion of the existing ATP Building and 10 feet south of the base of an existing retaining wall, which is approximately 28 feet in height. The modular building will be 2 stories in height with a total height of approximately 28 feet above grade. New paving/hardscape is also planned around the building. The new modular building will consist of 6 trailers per level and will measure approximately 120 feet in length and 35 feet in width. An approximately 5-foot high landscaped slope is located immediately south of the proposed modular building; the slope descends at inclinations of between approximately 3:1 (horizontal:vertical) and 6:1 toward the site. An approximately 15-foot high ascending slope (inclination of approximately 21/2:1) is located behind the retaining wall to the north. 3.0 CONCLUSIONS AND RECOMMENDATIONS 3.1 General Our previous exploration boring for the existing ATP Building encountered approximately 4 feet of undocumented fill soil which would not be considered suitable for support of the proposed modular building on conventional spread/continuous footings. The proposed modular building site is located outside of the limits of grading performed and observed by our firm during the original construction of the existing ATP Building. However, the grade at the location of the proposed modular building site has been lowered significantly since the time of our investigation for the existing ATP Building as part of that construction and/or as part of the subsequent grading and construction of the existing retaining wall north of the site. Therefore, a lesser thickness of undocumented fill soils should be expected beneath the footprint of the proposed modular building. The foundation recommendations contained in our report for the existing ATP Building may be used for the design of the foundations for the proposed modular building. Updated recommendations for seismic design parameters and for paving for the proposed modular building project are presented below. Our report for the existing ATP Building is attached to this letter for reference. 3.2 Seismic Design Parameters We have determined the mapped seismic design parameters in accordance with the 2019 CBC and ASCE 7-16 Standard (ASCE, 2017) using the SEAOC/OSHPD Seismic Design Map Tool. The CBC Site Class was determined to be Site Class "D" based on the results of our prior explorations and a review of the local soil and geologic conditions. The mapped seismic parameters may be taken as presented in the table on the following page: Hoag Memorial Hospital Presbyterian Report of Geotechnical Consultation — Proposed Temporary Modular Building Project 4953-20-0781 Page 3 Parameter SS Mapped Value 1.39g* Si 0.49g* Project Site Class D Fa 1.0 Fv 1.7 SMs = FaSs (0.2 second period) 1.39g* SM1 = FvS1(1.0 second period) 0.84g* Sips = 2/3 x SMs (0.2 second period) 0.92g* So1 = 2/3 x SMi (1.0 second period) 0.56g* By: MM 11/12/2020 Checked: LT 11/13/2020 November 13, 2020 *It should be noted that, based on the project Site Class and the Si value, per Section 11.4.8 of ASCE 7-16, a site - specific ground motion hazard analysis would be required unless one of the three exceptions listed under Section 11.4.8 of ASCE 7-16 is utilized. Based on the nature of the proposed structure, we have assumed that one of the three exceptions listed under Section 11.4.8 of ASCE 7-16 could be applied without overly burdensome cost impacts so that a site -specific ground motion hazard analysis will not be required. 3.3 Paving To provide support for paving, the subgrade soils should be prepared as recommended in the grading section of our previous report. Compaction of the subgrade, including trench backfills, to at least 90%, and achieving a firm, hard, and unyielding surface will be important for paving support. The preparation of the paving area subgrade should be performed immediately prior to placement of the base course. Proper drainage of the paved areas should be provided since this will reduce moisture infiltration into the subgrade and increase the life of the paving. Based on our prior nearby test data, an R-value of 40 was assumed for design. The R-value should be confirmed during grading. Asphalt Concrete Paving The required paving and base thicknesses will depend on the expected wheel loads and volume of traffic (Traffic Index or TI). Assuming that the paving subgrade will consist of the on -site or comparable soils compacted to at least 90%, the minimum recommended paving thicknesses are presented in the following table. Assumed Traffic Index Asphalt Concrete Base Course (Inches) (Inches) 4 (Automobile Parking) 3 4 5 (Driveways with Light Truck Traffic) 3 4 6 (Driveways with Heavy/Fire Truck Traffic) 4 4 The asphalt paving sections were determined using the Caltrans design method. We can determine the recommended paving and base course thicknesses for other Traffic Indices if required. Careful inspection is recommended to verify that the recommended thicknesses or greater are achieved, and that proper construction procedures are followed. Hoag Memorial Hospital Presbyterian Report of Geotechnical Consultation — Proposed Temporary Modular Building Project 4953-20-0781 Page 4 November 13, 2020 Portland Cement Concrete Paving Portland cement concrete paving sections were determined in accordance with procedures developed by the Portland Cement Association. Concrete paving sections for a range of Traffic Indices are presented in the following table. We have assumed that the portland cement concrete will have a compressive strength of at least 3,000 pounds per square inch and that the paving subgrade will consist of the on -site or comparable soils compacted to at least 90% as recommended. Assumed Traffic Index Concrete Paving I Base Course (Inches) (Inches) 4 (Automobile Parking) 5 (Driveways with Light Truck Traffic) 6 (Driveways with Heavy/Fire Truck Traffic) 61h 7 71/2 4 4 4 The paving should be provided with joints at regular intervals no more than 15 feet in each direction. Load transfer devices, such as dowels or keys, are recommended at joints in the paving to reduce possible offsets. The paving sections in the above table have been developed based on the strength of unreinforced concrete. Steel reinforcing may be added to the paving to reduce cracking and to prolong the life of the paving. Base Course The base course for both asphaltic and concrete paving should meet the specifications for Class 2 Aggregate Base as defined in Section 26 of the latest edition of the State of California, Department of Transportation, Standard Specifications. Alternatively, the base course could meet the specifications for untreated base as defined in Section 200-2 of the latest edition of the Standard Specifications for Public Works Construction. The base course should be compacted to at least 95%. It has been a pleasure to be of professional service to you. Please contact us if there are any questions or if we can be of further assistance. Sincerely, Wood Environment & Infrastructure Solutions, Inc. i/ Lan Anh Tran Senior Enginee, Reviewed by: Mark A. Murphy ��e 0�, Principal Geotechnical Engineer Project Manager \LAX-FS1lprojects14953 Geotech12020-proj1200781 Hoag Lower Campus Modular Building103 DocCtrl\Final Report14953-20-0781101.doc\MM:mm (submitted electronically) Attachment: Report of Geotechnical Investigation, dated April 20, 1990 • REPORT OF GEOTECHNICAL INVESTIGATION PROPOSED EMPLOYEE CHILD CARE CENTER 4050 WEST COAST HIGHWAY NEWPORT BEACH, CALIFORNIA FOR HOAG MEMORIAL HOSPITAL PRESBYTERIAN (LCA O89083.AEB) APRIL 20, 1990 • • • April 20, 1990 Hoag Memorial Hospital Presbyterian 301 Newport Boulevard Box Y GPC No. 445G-90 Newport Beach, California 92658-8912 (LCA O89083.AEB) Attention: Mr. Leif Thompson Project Manager Gentlemen: Our "Report of Geotechnical Investigation, Proposed Employee Child Care Center, 4050 West Coast Highway, Newport Beach, California, for Hoag Memorial Hospital Presbyterian" is herewith submitted. The scope of the investigation was planned in collaboration with Mssrs. F. W. Evins and Leif Thompson. The investigation, which supplements prior work at the site, was authorized to provide design recommendations for the proposed building and to comply with a March 21, 1990 City of Newport Beach Review letter. The results of our investigation and design recommendations are presented in the report. We appreciate this opportunity to be of professional service. Please contact us if you should have any questions or require additional information. Respectfully submitted, LeROY CRANDALL AND ASSOCIATES Mervin E. Johnson, C.E.G. 26 Director of Geological Services Vice President Mark M. Kirkga kJ, Ph.D. Senior Engineer R15/mae (6 copies submitted) cc: (4) Kennith Clark Associates (1) Merrill E. Wright • • • TABLE OF CONTENTS Text Page No. Summary 1 Scope 3 Prior Studies 4 Project Description 5 Site Conditions 5 Explorations and Tests 6 Field Investigation 6 Laboratory Testing 6 Geology 6 General 6 Geologic Materials 7 Geologic Structure 7 Ground Water 8 Geologic Hazards 9 Faults 9 Seismicity 12 Flooding, Tsunamis and Seiches 13 Liquefaction 14 Seismic Settlement, Differential Compaction and Subsidence 14 Slope Stability 14 Expansive Soils 15 Slope Stability Analyses 15 Gross 15 Surficial 16 Conclusions and Recommendations 16 Geologic -Seismic Evaluation 16 Foundations 17 General 17 Bearing Value 17 Lateral Loads 18 Footing Observation 18 Backfill 18 Grading 19 General 19 Excavation 19 Compaction 19 Material for Fill 20 Grading Observation 20 Subdrain 21 • • • TABLE OF CONTENTS (Continued) Text Conclusions and Recommendations (continued) Floor Slab Support Paving Gas Protection System Basis for Recommendations References Appendix - Explorations and Laboratory Tests Plates Site Plan Geologic Map/Plot Plan Geologic Section Slope Stability Analysis Surficial Stability Analysis Log of Boring Unified Soil Classification System Direct Shear Test Data Consolidation Test Data Compaction Test Data Expansion Index Test Data "R" Value Test Data Page No. 22 23 24 24 26 Plate No. 1 2 3 4 5 A-1.1 and A-1.2 A-2 A-3 A-4.1 and A-4.2 A-5 A-6 A-7.1 through A-7.4 • • • REPORT OF GEOTECHNICAL INVESTIGATION PROPOSED EMPLOYEE CHILD CARE CENTER 4050 WEST COAST HIGHWAY NEWPORT BEACH, CALIFORNIA FOR HOAG MEMORIAL HOSPITAL PRESBYTERIAN LCA O89083.AEB Page 1 • • • SUMMARY A geotcchnical investigation has been performed for a proposed child care center at the Hoag Memorial Hospital Presbyterian campus. The proposed building will be a modular structure with a slab -on -grade floor. The site is located in an area currently being used as a soil stockpile area for the adjacent Hoag Cancer Center. Fill soils, four feet in thickness, were encountered in one of the two current borings. Based on our previous investigations, other portions of the site are also mantled by artificial fill materials of varying thickness. The majority of the site is underlain by marine terrace deposits consisting of interbedded clay, silt, and sand. These materials are typical of the poorly -indurated materials that blanket the mesas of the Orange County Coastal Plain. In general, the terrace deposits on -site are present at elevations greater than about 20 feet above sea level (USGS datum) and are exposed in the slope along Pacific Coast Highway and Newport Boulevard. The terrace deposits are underlain by siltstone and claystone of the Miocene age Monterey Formation_ The on -site marine terrace deposits consist of granular materials and are generally horizontally stratified. The claystone and siltstone of the Monterey Formation exposed on -site generally strikes N60W to N80E and dips between 9 to 50 degrees to the north. The claystone and siltstone exhibit undulatory folding with some beds striking northeasterly and dipping gently to the south. Based on our investigation, the site is stable and the development is considered feasible from a geologic and soils standpoint. The planned construction will not affect the geologic stability of the site or of the area outside of the building site. With respect to geologic and seismic hazards, the site is considered as safe as any within the general area. Based on the geologic findings, no faults are known to exist within the site; accordingly, the possibility of surface rupture of the site due to faulting is remote. LCA O89083.AEB Page 2 • The natural soils are generally medium firm to firm, and the proposed child care center may be supported on spread footings. If any existing fill soils are excavated and replaced as properly compacted fill, and any required additional fill is properly compacted, footings may be established in the resulting compacted fill and/or the natural soils or bedrock. • • LCA 089083.AEB Page 3 • • • SCOPE This report presents the results of a geotechnical investigation of the site of the proposed child care center. The locations of the proposed building and our exploration borings are shown on Plate 1, Site Plan and on Plate 2, Geologic Map/Plot Plan. Also shown on Plate 2 are the locations of borings drilled during our prior investigations for other facilities at the site. This investigation was authorized to determine the physical characteristics of the soils at selected locations, and to provide recommendations for foundation design and floor slab support for the proposed building. More specifically, the scope of the investigation included the foIIowing objectives: • To evaluate the existing surface and subsurface conditions, including the soil and ground water conditions within the area of proposed construc- tion. • To define the geologic environment and evaluate geologic/seismic hazards that may affect the project. • To recommend appropriate foundation systems along with the necessary design parameters. • To provide recommendations for handling ground water and for mitigating gas. • To provide recommendations concerning construction procedures and quality control measures relating to earthwork. • To provide recommendations for floor slab and paving support. Our recommendations are based on the results of our field explorations and laboratory tests and appropriate engineering analyses. The results of the field explorations and laboratory tests which together with the prior data form the basis of our recommendations, are presented in the attached Appendix. LCA 089083.AEB Page 4 • • • Our professional services have been performed using that degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical consultants practicing in this or similar localities. No other warranty, expressed or implied, is made as to the professional advice included in this report. This report has been prepared for Hoag Memorial Hospital Presbyterian and their design consultants to be used solely in the design of the proposed child care center. The report has not been prepared for use by other parties, and may not contain sufficient information for purposes of other parties or other uses. PRIOR STUDIES We have performed numerous foundation and soil investigations for prior projects. Our prior work included: • Consultation, Proposed Child Care Center (LCA 089083.AO) • Geotechnical Evaluation, Hoag Memorial Hospital Campus (LCA 089034.AE). • Geotechnical Investigation, Proposed Hoag Cancer Center (LCA AE- 87147). • Ground Motion Studies, Proposed Hoag Cancer Center (LCA D-87147). • Foundation Investigation, Proposed Parking Structure (LCA A-88260-A). • Foundation Investigation, Proposed Sewer and Storm Drain Relocation (LCA A-88260-B). • Geotechnical Investigation, Proposed South Tower Addition (LCA AE- 84159). • Foundation Investigation, Proposed Magnetic Resonance Imaging Center (LCA A-84364). • Geologic Study, Proposed Hospital Additions (LCA E-79369). LCA O89083.AEB Page 5 • • • • Foundation Investigation, Proposed Entrance Building (LCA A-79239). • Foundation Investigation, Proposed Super Energy Addition (LCA A-73069). • Foundation Investigation, Proposed Parking Structure (LCA A-71235). • Foundation Investigation, Proposed Nursing Wing and Power Plant (LCA A-69080). We also reviewed reports by Foundation Engineering Co., Inc., and Omnibus Environmental Services prepared for the Cancer Center currently being constructed at the site. PROJECT DESCRIPTION We understand that the 8,400-square-foot center will be constructed in modular units that are clustered around a service core. The building will have a slab -on -grade floor established at Elevation 21.0. Foundation loads will be relatively light. Due to site grades, cuts on the order of ten feet and compacted fill up to about four feet in thickness will be required to achieve the desired floor grade. SITE CONDITIONS The site is located in an area currently being used as a soil stockpile area for the adjacent Hoag Cancer Center. LCA 089083.AEB Page 6 • EXPLORATIONS AND TESTS FIELD INVESTIGATION The site was recently explored by drilling two borings at the locations shown on Plate 1. Data were also available from our prior investigations. The borings were drilled to depths of about 15 and 41 feet below the existing grade. Further details of the explorations and logs of the borings are presented in the Appendix. LABORATORY TESTING Laboratory tests were performed on selected samples obtained from the borings to aid in the classification of the soils and to determine their engineering properties. The following tests were performed: moisture content and dry density determinations, direct shear, consolidation, Expansion Index, and compaction. Details of the laboratory testing program and test results are presented in the Appendix. • GEOLOGY GENERAL The site is situated at the base of Newport Mesa, about one-third mile from the Pacific Ocean and one-half mile northwest of Lido Isle in Newport Bay at an elevation of about 14 to 64 feet above sea level (U.S. Geological Survey datum). Newport Mesa is one of several physiographic features that comprise the Orange County Coastal Plain. The hills and mesas of the Newport Area are separated from each other by gaps which were incised into the late Pleistocene land surface. Two such features are Santa Ana Gap, which is occupied by the Santa Ana River northwest of Newport Mesa, and Upper Newport Bay, which separates Newport Mesa from the San Joaquin Hills to the east. The site is near the southern end of the Los Angeles Basin, a structural depression that contains a great thickness of sedimentary rocks. • LCA 089083.AEB Page 7 • The geologic conditions and locations of borings drilled on the property are depicted on Plate 2. Subsurface geologic conditions are shown on Plate 3, Geologic Section. GEOLOGIC MATERIALS Artificial fill mantles the pad area of the site. The fill was observed to a depth of 4 feet in Boring 2, located in the vicinity of the proposed child care center. The artificial fill within the planned building area is underlain by marine terrace deposits composed of interbedded clay, silt, and sand. These deposits are typical of the poorly - indurated materials that blanket the mesas of the Orange County Coastal Plain. In general, the terrace deposits on -site are present at elevations greater than 20 feet above sea level (U.S. Geological Survey datum) and are exposed in the cut slope north of the pad area. The terrace deposits are underlain by clayey siltstone and shale of the Miocene age Monterey Formation, as depicted on Plate 3. • GEOLOGIC STRUCTURE The on -site marine terrace deposits consist of granular materials and are generally horizontally stratified. The shale and siltstone of the Monterey Formation, exposed during our previous investigations, generally strikes N6OW to N80E and dips between 9 to 50 degrees to the north. The shale and siltstone exhibit undulatory folding with some beds striking northeasterly and dipping gently to the south. The Monterey Formation, together with other underlying Tertiary age sedimentary rocks, are estimated to be about 10,000 feet thick beneath Newport Mesa and are underlain by igneous and metamorphic basement complex rocks. • LCA 089083.AEB Page 8 • • • GROUND WATER The site is located outside the main ground water basin of the Orange County Coastal Plain. Perched water is present locally within the terrace deposits capping Newport Mesa and at the contact between the terrace deposits and the • less permeable Monterey Formation. The underlying bedrock is considered to be non-waterbearing; however, due to the proximity of the site to the Pacific Ocean, the formation would be saturated at or near sea level. Seepage was encountered locally within the terrace deposits in both of our current exploratory borings. Water was measured in Boring 1 at depths of 26 and 32 feet and in Boring 2 at depths of 7 to 11 feet below the existing grade. During a site visit on January 29, 1990, we observed a seepage condition near the westernmost portion of the proposed access drive, south of the proposed child care center. A shallow trench excavation had been created in an attempt to divert the seepage away from the proposed construction area. The seepage appeared to be occurring along the contact between the existing fill soils at this location and the underlying claystone. The seepage has resulted in the ponding of water and a soft subgrade. A field reconnaissance of the site of the proposed child care center was also performed on April 9, 1990. No seepage was observed along the bluff face at this time. However, during our previous field investigation (LCA 089034.AEO), a seepage condition was observed along the bluff face at the contact between the terrace deposits and the Monterey Formation. The seepage resulted in the ponding of water along the toe of the slope in the area northeast and west of the proposed child care center. No ponding of water was observed during our recent site reconnaissance. LCA O89083.AEB Page 9 • GEOLOGIC HAZARDS The geologic hazards at the site are essentially limited to those caused by earthquakes. The major damage from earthquakes is the result of violent shaking from earthquake waves; damage due to actual displacement or fault movement beneath a structure is much less frequent. The violent shaking would occur not only immediately adjacent to the earthquake epicenter, but within areas for many miles in all directions. Faults The numerous faults in Southern California are categorized as active, potentially active, and inactive. An active fault, as defined by the California Division of Mines and Geology (Hart, 1988), is one that has "had surface displacement within Holocene time (about the last 11,000 years)." A potentially active fault has moved in the last two million years but not in the last 11,000 years. Faults which have not moved in the last two million years are considered inactive. • No faults or fault -associated features were observed on the subject property during our field investigation. No known active or potentially active faults pass beneath the proposed child care center site. The closest trace of the Newport -Inglewood fault zone is located approximately 1,500 feet to the west of the proposed child care center. The site is not within an Alquist-Priolo Special Studies zone for fault rupture hazard. The possibility of fault rupture occurring beneath the building site is judged to be low. Active Faults: The active fault nearest the site is the North Branch of the Newport - Inglewood Fault. The position of the actual fault trace through the Newport Peninsula has not been firmly established; however, the California Division of Mines and Geology (1986) projects the fault passing about 1,500 feet southwest of the site trending northwest. This portion of the fault has not been zoned by the state. • LCA O89083.AEB Page 10 • • • Available information on the North Branch and other faults of the Newport -Inglewood System indicates that there has been no displacement of the Holocene age Talbert aquifer underlying Santa Ana Gap, which is estimated to be less than 10,000 years old. The Pleistocene and older formations, however, have been affected by the Newport -Inglewood zone. There is some evidence in Bolsa and Sunset Gaps (farther to the northwest) that Holocene deposits have been disturbed by movement on the North and South Branches of the Newport -Inglewood fault zone. The active Whittier fault is a southeast -trending fault along the south edge of the Puente Hills, 21 miles north-northeast of the site. The 1929 Whittier earthquake may have originated on this fault, although some geologists believe that movement on the Norwalk fault was the cause. The active Elsinore fault is located on the northeast side of the Santa Ana Mountains. Several earthquakes have originated along this fault system. The largest was in 1910 with a magnitude of about 6.0. The northern terminus of the Elsinore fault is about 26 miles northeast of the site. The historically active San Andreas fault is the best known and most significant fault in California. This fault is about 51 miles northeast of the site at the nearest point on the fault. Potentially Active Faults: A discontinuity believed to be a fault is exposed in the cut slope adjacent to Pacific Coast Highway, approximately 1,300 feet west of the proposed child care facility. The fault appears to offset the Miocene age Monterey Formation and possibly the Pleistocene age terrace deposits. By definition, this would be considered a potentially active fault. Faults of this nature are not considered unusual and are commonly associated with zones of deformation such as the Newport -Inglewood fault zone. LCA O89083.AEB Page 11 • The Pelican Hill fault is a probable branch of the Newport -Inglewood fault zone located about 3 miles east of the site. A branch of the fault has displaced higher marine terrace deposits in the San Joaquin Hills, indicating upper Pleistocene or younger activity. Holocene activity has not been established; therefore, the fault is considered potentially active. The El Modeno fault is located about 15 miles north of the site. The fault is a steeply - dipping normal fault about 9 miles in length that has about 2,000 feet of uplift on its eastern side. Movement on the fault has been inferred during Holocene time, suggesting the fault is active; however, further study is needed to confirm this. The fault is presently classified as potentially active. The Peralta Hills fault is located approximately 15 miles north of the site. This potentially active reverse fault trends east -west and dips to the north. The fault is approximately 5 miles in length and has a sinuous surface trace across the southern Peralta Hills, which lie northeast of the City of Orange. Pleistocene age offsets are known along this fault; on this basis, this fault is classified as potentially active. Some geologists believe that the Peralta Hills fault may be active, based upon recent Carbon 14 dating of known offsets estimated to be 3,000 to 3,500 years old (Fife and Bryant, 1983). Geologic mapping of the bluff within the undeveloped portion of the property, north and west of the proposed child care center, was performed as part of a previous investigation. The contact between the Pleistocene age terrace deposits and the Miocene age Monterey Formation is exposed there in the bluff face and could be traced for nearly the entire length of the bluff in areas to the northwest. The materials exposed in the bluff face were observed to be stratigraphically continuous and the contact was not disrupted; no faults or fault -associated features were observed on the site during our field investigation. • LCA O89083.AEB Page 12 • • • Seismicity The Southern California area has been subjected to numerous earthquakes of varying magnitudes. Among the historic damaging earthquakes which have directly affected the Los Angeles Basin are the Long Beach earthquake, the San Fernando Earthquake, and the Whittier Narrows earthquake. The earliest of these three earthquakes was the March 11, 1933 (Greenwich Civil Time) Long Beach earthquake. The epicenter of this earthquake, magnitude 6.3, was located approximately 2.5 miles southwest of the site. This earthquake, although of only moderate magnitude, ranks as one of the major disasters in Southern California. The majority of the damage was suffered by structures which are now considered substandard construction and/or were located on filled or saturated ground. The epicenter of the February 9, 1971, San Fernando earthquake, magnitude 6.4, was about 61 miles north-northwest of the site. Surface rupture occurred on various strands of the San Fernando fault zone as a result of this earthquake. The large amount of damage caused to existing buildings by this earthquake led to the adoption of more stringent building codes. The magnitude 5.9 Whittier Narrows earthquake occurred on October 1, 1987, on a previously unrecognized fault. The earthquake epicenter was located approximately 31 miles north-northwest of the site. The majority of structural damage resulting from this earthquake occurred in buildings constructed prior to the establishment of the building codes which were developed after the 1971 San Fernando earthquake. More recently, six minor earthquakes have occurred in the metropolitan Los Angeles - Orange County area. The first earthquake was centered in the Pasadena area, approximately 37 miles to the north. The earthquake occurred on December 4, 1988 and registered a magnitude of 5.0. The second earthquake was in the Malibu area, approximately 43 miles to the northwest, and occurred on January 18, 1989, registering a LCA O89083.AEB Page 13 • • • magnitude of 5.0. On April 7, 1989, a 4.6 magnitude earthquake occurred in the Newport Beach area, approximately 1.8 miles southwest of the site. On June 12, 1989, two earthquakes were centered in the southern Repetto Hills near Montebello, approximately 30 miles to the north. These two earthquakes occurred about one-half hour apart and registered magnitudes of 4.5 and 4.3, respectively. The sixth earthquake occurred on February 28, 1990, registering a magnitude of 5.5, centered approximately 3 miles northwest of Upland, about 40 miles north of the site. The earthquakes cited are remote from the site but are representative of some of the moderate earthquakes that can occur on the active (or potentially active) faults of Southern California. The location of the site in relation to the Newport -Inglewood fault zone indicates that the immediate area may be exposed to greater than normal seismic risk for the Orange County Coastal Plain. Flooding, Tsunamis and Seiches The site is in a "Zone C" flood hazard area as established by the Federal Insurance Administration. As defined, "Zone C" is an area of minimal flooding. According to the U.S. Army Engineer Waterways Experiment Station (Houston and Garcia, 1974), the Newport Beach area (in the vicinity of the site) could experience run- up from a 100-year tsunami (seismic sea wave) to an approximate elevation of 6.1 feet above sea level. Run-up from a tsunami with a return interval of 500 years would reach an elevation of about 10.8 feet. The site elevation, including the upslope area, varies from 14 to 64 feet above sea level. Accordingly, there is little risk that lower portions of the site could be inundated by a 100-year or a 500-year tsunami. The site is not located downslope of any large bodies of water that would adversely affect the site in an event of an earthquake -induced failure or seiches (wave oscillations in a body of water due to earthquake shaking). LCA O89083.AEB Page 14 • • • Liquefaction Liquefaction potential has been found to be the greatest where the ground water level is shallow and loose fine sands occur within a depth of about 50 feet or less. Liquefaction potential decreases with increasing grain size and clay and gravel content, but increases as the ground acceleration and duration of shaking increase. The sands and silty sands encountered in our exploratory borings are generally dense to very dense. The claystone and siltstone of the underlying Monterey Formation are also very dense. Due to the density and nature of the underlying geologic materials, the potential for liquefaction is judged to be low. Seismic Settlement, Differential Compaction and Subsidence Seismic settlement often occurs when loose to medium -dense granular soils densify during ground shaking. The granular soils encountered in our exploration borings are not in the loose to medium -dense category. As mentioned previously, the sands and silty sands are generally dense to very dense. As a result, the probability of such settlement is considered to be very low. The site is not located in an area of known ground subsidence due to the extraction of fluids or as a result of peat oxidation. Accordingly, the potential for subsidence occurring beneath the site is considered remote. Slope Stability The property is located adjacent to Pacific Coast Highway near the base of a 21:1 to 2:1 (horizontal to vertical) 30-foot-high cut slope. The topography is relatively level at the top and the toe of the slope. The cut will be heightened by about 10 feet during proposed grading at the site. Terrace materials exposed in the slope are composed of LCA 089083.AEB Page 15 • • • predominantly granular materials that are horizontally stratified. This condition is considered favorable for gross stability from a geologic standpoint. However, the slope is prone to surficial instability as evidenced by surficial sloughing and erosion gullies observed on the slope face, immediately north and west of the proposed child care facility. Such surficial instability is not considered a serious problem and can be mitigated by planting the slope with erosion -resistant vegetation and by providing proper drainage. Expansive Soils Expansive clayey siltstone and shale bedrock were identified in the vicinity of the site during prior geotechnical investigations. The on -site bedrock materials are also considered expansive. SLOPE STABILITY ANALYSES GROSS The stability of the existing and proposed slope has been analyzed by using a stability chart. The analysis considers the most critical circular assumed failure surface that passes through the toe of the slope. The shear strength parameters adopted in the analysis are based on direct shear tests performed on undisturbed samples of the terrace deposit. Based on the analysis, a calculated factor -of -safety in excess of 1.5 was obtained. Calculations are presented on Plate 4, Slope Stability Analysis. The calculated factor -of - safety is conservative, since the existing slope is generally flatter than assumed in the analysis, and the beneficial effect of the terrace located near midslope was ignored. LCA O89083.AEB Page 16 • • SURFICIAL The stability of the existing and proposed slope surface has been analyzed. The following assumptions have been made: A. The slip surface is four feet from the slope surface and parallel to the slope. B. The saturation is to extend four feet below the slope surface. C. There is sufficient permeability to establish water flow and the flow lines are parallel to the slope surface. (This assumption is considered highly conservative due to the granular and highly permeable nature of the soil deposits. However, the assumption is generally required by controlling governmental agencies.) Based on this analysis, the slope exhibits a calculated factor of safety in excess of 1.50. Calculations are included on Plate 5, Surficial Stability Analysis. CONCLUSIONS AND RECOMMENDATIONS GEOLOGIC -SEISMIC EVALUATION With respect to geologic and seismic hazards, the site is considered as safe as any within the general area. No faults or fault -associated features were observed in the vicinity of the proposed child care facility, and no known active or potentially active faults pass beneath the site. Accordingly, the possibility of surface rupture due to faulting beneath the site is considered low. Although the site could be subject to severe ground shaking in the event of a major earthquake, this hazard is common to Southern California and the effects of the shaking can be minimized by proper structural design and construction. The cut slope is prone to surficial instability as evidenced by erosion gullies. Such surficial instability is not considered a serious problem and can be easily mitigated. Geologic hazards associated with flooding, seiches, tsunamis, subsidence, landsliding, or seismically- LCA O89083.AEB Page 17 • • • induced settlement will not impact the site. Expansive soil conditions can be mitigated with proper grading and construction. FOUNDATIONS General The natural soils beneath the site are generally medium firm to firm, and the proposed child care center may be supported on spread footings. If any existing fill soils are excavated and replaced as properly compacted fill, and any required additional fill is properly compacted, footings may be established in the resulting compacted fill and/or the natural soils or bedrock. Recommendations for grading are presented in a following section. The reworking of the upper soils and the compaction of all required fill should be observed and tested by personnel of our firm. Bearing Value Conventional spread footings established in properly compacted fill and/or the undisturbed natural soils or bedrock may be designed to impose a net dead plus live load pressure of 2,000 pounds per square foot. A one-third increase in the bearing value may be used for wind or seismic loads. For the above bearing value, footings should extend to a depth of at least two feet below the adjacent final grade. Since the recommended bearing value is a net value, the weight of concrete in the footings may be taken as equal to 50 pounds per cubic foot, and the weight of soil backfill may be neglected. While the actual bearing value of the compacted fill will depend on the material used and the compaction methods employed, the quoted value will be applicable if acceptable soils are used and are compacted as recommended. The bearing value of the fill should be confirmed after completion of the grading. LCA O89083.AEB Page 18 • • • The settlement of the proposed center, supported on spread footings in the manner recommended, should be less than about one-half inch. Lateral Loads Lateral loads may be resisted by soil friction and by the passive resistance of the soils. A coefficient of friction of 0.4 may be used between footings and the supporting soils. For embedded footings, the passive resistance of the compacted fill and/or natural soil against footings may be assumed to be equal to the pressure developed by a fluid with a density of 250 pounds per cubic foot. A one-third increase in the passive value may be used for wind or seismic loads. The frictional resistance and the passive resistance of the soils may be combined without reduction in determining the total lateral resistance. Footing Observation To verify the presence of satisfactory soils at design elevations, all footing excavations should be observed by personnel of our firm. Footing excavations should be cleaned of any loosened soils and debris before placing steel or concrete. Some difficulty in excavation may be encountered due to water. Inspection of footing excavations may also be required by the appropriate reviewing governmental agencies. The contractor should familiarize himself with the inspection requirements of the reviewing agencies. Backfill All required footing backfill and utility trench backfill within the building area should be mechanically compacted; flooding should not be permitted. The exterior grades should be sloped to drain away from the building to minimize ponding of water adjacent to foundations. LCA O89083.AEB Page 19 • GRADING General Due to site grades, cuts on the order of ten feet and compacted fill up to about four feet in thickness will be required to achieve the desired floor grade. Permanent cut slopes should be made no steeper than 2:1 (horizontal to vertical). To provide support for the building footings and for adjacent walks and slabs, any existing fill soils should be excavated and replaced as properly compacted fill. Any required additional fill should be properly compacted. Excavation After removing the existing soil stockpile, any existing fill soils and disturbed natural soils within the proposed building area and beneath its adjacent walks and slabs should be excavated. Where possible, the excavation of the existing fill should extend at least five feet beyond the building in plan. The soils and the underlying bedrock may be excavated with conventional earthmoving equipment. Temporary unsurcharged excavations may be made at 3/4:1 (horizontal to vertical). Storage loads should be kept back at least five feet from the top of temporary cut slopes. The soils at the excavated level may be wet and spongy. To provide a working base for workers and equipment, a layer of select granular material at least one foot in thickness may be required over the excavated surface. Preferably, this layer should consist of coarse gravel. Compaction Prior to placing fill, all vegetation and debris should be cleared from the site and all existing fill and disturbed soils should be excavated. The soils should be carefully inspected to verify the removal of all unsuitable deposits. Next, the exposed natural soils should be scarified to a depth of at least six inches, brought to optimum moisture content, and rolled with heavy compaction equipment. The upper six inches of exposed natural • LCA 089083.AEB Page 20 • • • soils should be compacted to at least 90% of the maximum dry density obtainable by the ASTM Designation D1557-78 method of compaction. All required fill should be placed in loose lifts not more than eight inches in thickness and compacted to at least 90%. The moisture content of the on -site soils at the time of compaction should vary no more than 2% below or above optimum moisture content. Material for Fill The on -site soils, less any debris or organic matter within any existing fill, may be used in required fills. Any required imported fill should consist of relatively non -expansive soils with an Expansion Index of less than 35. Imported fill should contain sufficient fines (binder material) so as to be relatively impermeable when compacted and result in a stable subgrade. Imported fill material should be approved for use prior to importing. Grading Observation The excavation of the existing fill and the compaction of all required fill should be observed and tested by a representative of our firm. This representative should have at least the following duties: • Observe the clearing and grubbing operations to ensure that all unsuitable materials have been properly removed. • Observe the exposed subgrade in areas to receive fill and in areas where excavation has resulted in the desired finished subgrade, observe proofrolling, and delineate areas requiring overexcavation. • Perform visual observations to evaluate the suitability of on -site and import soils for fill placement; collect and submit soil samples for required or recommended laboratory testing where necessary. • Perform field density and compaction testing to determine the degree of compaction achieved during fill placement. • Observe and probe foundation bearing materials to confirm that suitable bearing materials are present at the design grades. LCA O89083.AEB Page 21 • • The governmental agencies having jurisdiction over the project should be notified prior to commencement of grading so that the necessary grading permits may be obtained and arrangements may be made for the required inspection(s). SUBDRAIN As discussed before, water is perched above the bedrock at the site. Since the water could fluctuate in the future, a subdrain system should be installed beneath the floor slab of the structure to maintain the water below the lower level floor. A permit from the Regional Water Quality Control Board will have to be obtained to discharge the subdrain water into the storm drain system. To obtain such a permit, chemical tests may have to be performed on ground water samples obtained at the site at the time of development to verify that chemicals or pollutants within the water do not exceed the allowable limits for discharging into the storm drain. It may also be possible to resubmit the results of tests performed for the adjacent Cancer Center. For a subdrain system, we recommend that the lower floor of the structure be underlain by a layer of filter material approximately on foot in thickness. The filter material should be drained by subdrain pipes leading to a sump area equipped with automatic pumping units or to the storm drain. We suggest that the filter material meet the requirements of Class 2 Permeable Material as defined in section 68 of the State of California, Department of Transportation, Standard Specifications, dated July 1984. The drain lines should consist of perforated pipe placed, with the perforations down, in trenches extending at least one foot below the filter material. The trenches should be backfilled with material meeting the requirements of the Class 2 Permeable Material. Alternatively, the filter material could consist of gravel surrounded by a suitable filter geofabric. The drain lines should extend around the perimeter of the building and one drain line should extend each way LCA 089083.AEB Page 22 • • • beneath the interior of the building. A slope of at least 2 inches per 100 feet should be used for the drain lines. We could provide additional data for design of the subdrain system as the features of the system and building plans are developed. In addition, we suggest that the design be reviewed after the excavation has been completed. If necessary, the system could be modified as indicated by the observed conditions. FLOOR SLAB SUPPORT If the subgrade is prepared as recommended, the building floor slab may be supported on grade. Construction activities and exposure to the environment can cause deterioration of prepared subgrades. Therefore, we recommend that our field representative observe the condition of the final subgrade soils immediately prior to slab on grade construction and, if necessary, perform further field density and moisture content tests to determine the suitability of the final prepared subgrade. Expansive soils should not be used in the upper one foot of subgrade beneath the building floor slab or adjacent walks. If a floor covering that would be critically affected by moisture, such as vinyl, is to be used, we suggest that the floor slab be supported on a four -inch -thick layer of gravel or on an impermeable membrane as a capillary break. A suggested gradation for the gravel layer would be as follows: Sieve Size Percent Passing 3/4" 90 - 100 No. 4 0 - 10 No. 100 0 - 3 If a membrane is used, a low -slump concrete should be used to minimize possible curling of the slabs. The concrete slabs should be allowed to cure properly before placing vinyl or other moisture -sensitive floor covering. LCA O89083.AEB Page 23 • • • PAVING To provide data for design of paving, stabilimetcr tests ("R" value tests) were performed during prior studies on samples of the upper silty sand soils. The tests indicated "R" values of 57 and 72. Compaction of the subgrade, including trench backfills, to at least 90% and achieving a firm, hard and unyielding surface will be important for paving support. The preparation of the parking area subgrade should be done immediately prior to the placement of the base course. Proper drainage of the paved areas should be provided since this will reduce moisture infiltration into the subgrade and increase the life of the paving. Assuming that the paving subgrade will consist of the on -site soils or a suitable import with an R value of at least 57, compacted to at least 90% as recommended, parking areas subject to automobile traffic (assumed Traffic Index of 4.5) may be paved with four inches of asphaltic paving placed on the compacted subgrade. Driveways and areas subject to truck traffic (assumed Traffic Index of 5) may be paved with three inches of asphaltic paving and four inches of base course placed on the compacted subgrade. We can provide the recommended paving sections for other Traffic Indices, if needed. Careful inspection is recommended to verify that the recommended thicknesses or greater are achieved and that proper construction procedures are used. The base course should meet the specifications for Class 2 Aggregate Base as defined in Section 26 of the State of California, Department of Transportation, Standard Specifi- cations, dated January 1988. Alternatively, the base course could meet the specifications for untreated base as defined in Section 200-2 of the 1988 edition of the Standard Speci- fications for Public Works Construction. The base course should be compacted to at least 95%. LCA 089083.AEB Page 24 • • GAS PROTECTION SYSTEM Gas monitoring wells were installed in some of our previous exploration borings to permit measurement of any gases. Gas vapor concentrations were also measured in our current borings by representatives of M. E. Wright, Geological and Petroleum Consultant. Previous studies of surface gas were performed by Omnibus Environmental Services, and by M. E. Wright, as covered in reports dated January 9, 1986 and June 12, 1989, respectively. We recommend that the gas mitigation and safety measures currently being installed for the adjacent Cancer Center also be implemented for the child care center. The building should be protected by an impermeable membrane underlain by gravel -filled trenches containing perforated vent pipe. Riser vents should be installed to the high points of the building. BASIS FOR RECOMMENDATIONS The recommendations provided in this report are based upon our understanding of the described project information and on our interpretation of the data collected during the subsurface exploration. We have made our recommendations based upon experience with similar subsurface conditions under similar loading conditions. The recommendations apply to the specific project discussed in this report; therefore, any change in building loads, building location, or site grades should be provided to us so that we may review our conclusions and recommendations and make any necessary modifications. The recommendations provided in this report are also based upon the assumption that the necessary geotechnical observations and testing during construction will be performed by representatives of our firm. The field observation services are considered a continua- tion of the geotechnical investigation and essential to verify that the actual soil conditions are as anticipated. This also provides for the procedure whereby the Client can be advised of unanticipated or changed conditions that would require modifications of our LCA O89083.AEB Page 25 • original recommendations. In addition, the presence of our representative at the site provides the Client with an independent professional opinion regarding the geotechnic- ally related construction procedures. If another firm is retained for the geotechnical observation services, our professional responsibility and liability would be impaired. • • LCA 089083.AEB Page 26 • • REFERENCES Alfors, J.T. Burnett, J. L., and Gay, T.E., Jr., "Urban Geology Master Plan for California," California Division of Mines and Geology, Bulletin 198. Association of Engineering Geologists, Special Publication, 1973, "Geology and Earthquake Hazards, Planners Guide to the Seismic Safety Element." Bolt, B.A., 1973, "Duration of Strong Ground Motion," in Proceedings, Fifth World Conference on Earthquake Engineering. California Department of Water Resources, 1967, "Progress Report on Ground Water Geology of the Coastal Plain of Orange County." City of Newport Beach General Plan, 1972, "Geologic -Seismic Study, Phase I," by Woodward -McNeill and Associates. Fife, D.L., and Bryant, M.E., 1983, Association of Engineering Geologists, Abstract: "The Peralta Hills Fault, A Transverse Range Structure in the Northern Peninsular Ranges, Orange County, California," 26th Annual Meeting, San Diego, California. Greensfelder, R.W., 1974, "Maximum Credible Rock Acceleration from Earthquakes in California," California Division of Mines and Geology, Map Sheet 23. Hart, E.W., 1972 (revised 1985), "Fault -Rupture Hazard Zones in California, Alquist- Priolo Special Studies Zones Act of 1972," California Division of Mines and Geology, Special Publication 42. Houston, J.R., and Garcia, A.E., 1974, "Type 16 Flood Insurance Study: Tsunami Predictions for Pacific Coastal Communities," United States Army Waterways Experiment Station Technical Report H1-74-3. Mark, R.K., 1977, "Application of Linear Statistical Models of Earthquake Magnitude Versus Fault Length in Estimating Maximum Expectable Earthquakes," Geology, Vol. 5, No. 2 pp. 464-466. Miller, R.V., and Tan, S.S., 1976, "Geology and Engineering Geologic Aspects of the South Half of the Tustin Quadrangle, Orange County, California," California Division of Mines and Geology Special Report 126. Morton, P.K., Miller, R.V., and Fife, D.L., 1979, "Environmental Geology of Orange County, California," California Division of Mines and Geology, Open File Report 79- 8LA. LCA O89083.AEB Page 27 • Orange County General Plan Safety Element, 1975, Environmental Management Agency. Slemmons, D.B., 1979, "Evaluation of Geomorphic Features of Active Faults for Engineering Design and Siting Studies," Association of Engineering Geologists Short Course. -oOo- • • x-kvvv-Z�yy wood. Wood Environment & Infrastructure Solutions, Inc. 6001 Rickenbacker Road Los Angeles, CA 90040-3031 USA T: +1 323.889.5300 www.woodplc.com December 18, 2020 Project 4953-20-0781 Mr. Cary Brooks Senior Project Manager Real Estate Construction Operations (REFCO) Hoag Memorial Hospital Presbyterian 510 Superior Avenue, Suite 290 Newport Beach, California 92663 Subject: Supplemental Geotechnical Consultation - Response to Comments Proposed Temporary Modular Building Hoag Memorial Hospital Presbyterian Newport Beach, California Dear Mr. Brooks: This letter presents our response to comments received from the Building Division of the Community Development Department of the City of Newport Beach, California based on their review of our report dated November 13, 2020. The comments were provided in a Geotechnical Report Review Checklist, dated December 2, 2020; the checklist is attached to this letter for ease of reference. Our professional services have been performed using that degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical consultants practicing in this or similar localities. No other warranty, express or implied, is made as to the professional advice included in this letter. Our itemized responses are given below. Comment No. 1: Please provide final recommendations for subgrade remedial grading along with updated seismic soil parameters consistent with 2019 CBC. Response to Comment No. 1: Final recommendations for subgrade remedial grading were provided in Section 3.1 of our November 13, 2020 report. As stated in our report, a maximum of 4 feet of undocumented fill is anticipated at the site and the recommendations contained in our report for the existing Advanced Technology Pavilion, which we stated were applicable to the temporary modular building project, required that all existing fill soils be excavated and replaced as properly compacted fill so that footings could be established in compacted fill and/or the natural soils. 'Wood' is a trading name for John Wood Group PLC and its subsidiaries Hoag Memorial Hospital Presbyterian Supplemental Geotechnical Consultation — Response to Comments Project 4953-20-0781 Page 2 December 18, 2020 Updated seismic parameters and Site Class were provided in Section 3.2 of our report, in conformance with the 2019 California Building Code (CBC). Comment No. 2: Please provide adequate foundation set -back from the toe of the slope per 2019CBC Chapter 18 Section 1808.7.2. Response to Comment No. 2: The setback requirements from the ascending slopes adjacent to the project site are addressed in Section 1808.7.1 of the 2019 CBC. As described in our report, the ascending slope south of the site is approximately 5 feet in height with inclinations between approximately 3:1 and 6:1 (horizontal:vertical); this slope is exempt from CBC setback requirements because its inclination is not steeper than 3:1. As described in our report, the retaining wall and ascending slope north of the site have heights of approximately 28 feet and 15 feet, respectively, and the slope has an inclination of approximately 21/2:1. The setback required by Section 1808.7.1 of the 2019 CBC from this slope (or the base of the retaining wall) is approximately 71/2 feet (half of the height of the slope above the top of the wall). Therefore, the 10-foot setback provided between the proposed temporary modular building and the retaining wall is in compliance with the 2019 CBC setback requirements. Comment No. 3: The Asphalt Concrete paving section of the report will need to be revise to clearly indicate "temporary design only" or design with a minimum TI = 5 and for Emergency Fire Driveways TI = 7. Response to Comment No. 3: As required, the traffic index used in our report for automobile parking areas, and the corresponding asphalt concrete paving section thicknesses provided in our report should be considered for temporary design only. For long-term design of asphalt concrete paving, the minimum Traffic Index used should be 5.0 and a minimum Traffic Index of 6.5 should be used for areas of fire truck traffic, as required. For a Traffic Index of 6.5, we recommend that the asphalt concrete paving sections consist of 4 inches of asphalt concrete underlain by 6 inches of base course. The remainder of the paving recommendation in our report remain applicable. Comment No. 4: Please review the Grading, Foundation and Landscape Plans for compliance with geotechnical recommendations of this report. Response to Comment No. 4: We will review the Grading, Foundation, and Landscape Plans for conformance with our recommendations, as required. Hoag Memorial Hospital Presbyterian Supplemental Geotechnical Consultation — Response to Comments Project 4953-20-0781 Page 3 December 18, 2020 It has been a pleasure to be of professional service to you. We trust that the above satisfies your current needs. Please contact us if there are any questions or if we can be of further assistance. Sincerely, Wood Environment & Infrastructure Solutions, Inc. Lan Anh Tran Senior Enginee. Reviewed by: Mark A. Murphy Principal Geotechnical Engineer Project Manager 11lax-fsllprojects14953 Geotech\2020-proj\200781 Hoag Lower Campus Modular Building\03 DocCtrl\Final Report14953-20-0781102.doc1MM:lt (submitted electronically) Attachment: Geotechnical Report Review Checklist, dated December 2, 2020 CITY OF NEWPORT BEACH COMMUNITY DEVELOPMENT DEPARTMENT BUILDING DIVISION 100 Civic Center Drive I P.O. Box 1768 I Newport Beach, CA 92658-8915 www.newportbeachca.gov I (949) 644-3200 Project Description: Title & Date of Report Project Address: Permit App. Date: CY Cut/Fill: 175/10 Consultant: Applicant/Contact: Plan Check Engineer: Engineer email: X GEOTECHNICAL REPORT REVIEW CHECKLIST COMM - FOUNDATION & GRADING FOR MODULAR TRAILERS (12) (LOCATED NEXT TO NURSE EDUCATION CENTER) Geotechnical consultation report, proposed temporary modular building Hoag Memorial Hospital dated November 13, 2020 1 HOAG DRIVE 11/23/2020 Permit Valuation: $150,000 WEIS,INC. BROOKS CARY Sergio Gutierrez sgutierrez@newportbeachca.gov 1st Review: 12/2/2020 2nd Review: Italic comments Plan Check No.: 2161-2020 Permit App. Expires: 5/22/2021 Adjusted Valuation: Phone: 323-889-5300 Phone: Phone: 949-644-3213 3rd Review: By Appointment The project plans were reviewed for compliance with the following codes and standards: 2019 CRC; 2019 CBC; 2019 CPC; 2019 CEC; 2019 CMC; 2019 California Energy Code; 2019 California Green Building Standards Code (CG); & Chapter 15 of the Newport Beach Municipal Code (NBMC). The code section references are from the 2019 CBC, unless otherwise stated. • TO EXPEDITE PROJECT APPROVAL: Please provide a written response indicating how and where each comment was resolved on the plans. • Resubmit all previously reviewed plans, updated plans and supporting documents with each subsequent review. • AFTER 2nd PLAN REVIEW: Please call the geologist listed above to schedule a plan review appointment, to expedite project approval. • For clarification of any plan review comment, please call the plan check engineer listed above. • Plan review status is available online at www.newportbeachca._gov. Project status is also available using the interactive voice response system at 949-644-3255, or by speaking with a permit technician at 949-718-1888 during business hours. CorrLists\GeotechnicalReportReviewChecklist 12/02/2020 1 PRIOR TO APPROVAL OF THE REPORT, ATTEND TO THE ITEMS BELOW: 1. Please provide final recommendation for subgrade remedial grading along with updated seismic soil parameters consistent with 2019 CBC. 2. Please provide adequate foundation set -back from toe of slope per 2019CBC Chapter 18 Section 1808.7.2 3. The Asphalt Concrete paving section of the report will need to be revise to clearly indicate "temporary design only" or design with a minimum TI = 5 and for Emergency Fire Driveways TI = 7. 4. Please review the Grading, Foundation and Landscape Plans for compliance with geotechnical recommendations of this report. Limitations of Review: Our review is intended to determine if the submitted report(s) comply with City Codes and generally accepted geotechnical practices within the local area. The scope of our services for this third party review has been limited to a brief site visit and a review of the above -referenced report and associated documents, as supplied by this City of Newport Beach. Re -analysis of reported data and/or calculations and preparation of amended construction or design recommendations are specifically not included within our scope of services. Our review should not be considered as a certification, approval or acceptance previous consultant's work, or is meant ad an acceptance of liability for final design or construction. CorrLists\GeotechnicalReportReviewChecklist 12/02/2020 2