GEOTECHNICAL AND GEOLOGIC HAZARD INVESTIGATION NEW STADIUM CONCESSION STAND BUILDING ANDREW HILL HIGH SCHOOL 3200 SENTER ROAD SAN JOSE, CALIFORNIA for East Side Union High School District Mr. Julio Lucas, Director of Construction 830 North Capitol Avenue San Jose, California 95133 by Cleary Consultants, Inc. 560 Division Street Campbell, California 95008 August 2019 ^CLEARY CONSULTANTS, DNC. Christophe A. Ciechanowski, President, GE Grant F. Foster, Vice-President, GE Geotechnical Engineers and Geologists J. Michael Cleary, Principal, CEG, GE August 12, 2019 Project No. 978.13F Ser. 6316 Mr. Julio Lucas, Director of Construction East Side Union High School District 830 North Capitol Avenue San Jose, California 95133 RE: GEOTECHNICAL AND GEOLOGIC HAZARD INVESTIGATION NEW STADIUM CONCESSION STAND BUILDING ANDREW HILL HIGH SCHOOL 3200 SENTER ROAD SAN JOSE, CALIFORNIA Dear Mr. Lucas: As requested, we have performed a geotechnical and geologic hazard investigation for the planned Stadium Concession Stand Building project at Andrew Hill High School in San Jose, California. The accompanying report presents the results of our field investigation, laboratory testing and engineering analyses. The site and subsurface conditions are discussed, recommendations for the soil and foundation engineering aspects of the project design are presented and potential geologic hazards are evaluated. The recommendations presented in this report are contingent upon our review of the grading and foundation plans for the proposed new construction and observation/testing of the earthwork and foundation installation phases of the project. We refer you to the text of the report for detailed recommendations. If you have any concerning our findings or the report, please call. 3 CD <&> %m Yours very tmly, Ql rn 2662 3D CLEARY CONSULTANTS, INC. o€ Dustin Lettenberger Grant Foster Of 'o/v Staff Engineer Geotechnical Engineer 2662Uj A , CLfy £'k Or <?. -,7- CMj go m Mo. 222 U'« 3 lil Chris Ciechanowski J. Michael Cleary U- ■h Geotechnical Engineer 2584 Engineering Geologist Geotechnical Engineer 2: A. Op DL/GF/JMC/CC:cs e,1 Copies: Addressee (email) /^yj.UL CLEr U \ : Gilbane Building Company (email) Attn: Alex Morrison, Kwan ChoJ 1 No. 352 \ * CERTIFIED ENGINEERING 560 DIVISION STREET • CAMPBELL, CALIFORNIA 95008 ■ (650) 948-05, www.clearyconsultantsinc.com \ V GEOLOGIST ---- :U OF Ci-.W. TABLE OF CONTENTS Page No. Letter of Transmittal INTRODUCTION 1 SCOPE 2 A. Geotechnical Investigation......................... 2 B. Geologic and Seismic Hazards Assessment 3 METHOD OF INVESTIGATION 4 SITE CONDITIONS.. 5 A. Surface........ 5 B. Subsurface... 6 C. Groundwater 7 GEOLOGIC AND SEISMICITY 7 GEOLOGIC AND SEISMIC HAZARDS EVALUATION 11 A. Fault Offset Hazards................................................ 11 B. Ground Shaking Hazards......................................... 12 1. Strong Ground Shaking...................................... 12 2. Soil Liquefaction................................................ 12 3. Soil Densification............................................... 14 4. Other Seismic Hazards....................................... 15 C. Flooding................................................................... 15 CONCLUSIONS AND RECOMMENDATIONS.............................. 16 A. Earthwork............................................................................... 17 1. Stripping and Site Preparation........................................... 17 2. Stadium Concession Stand Building Pad Overexcavation and Recompaction............................................................. 18 3. Recompaction of Surface Soils Outside Building Area .... 19 4. Fill Placement and Compaction......................................... 19 5. Utility Trenches................................................................. 20 6. Surface Drainage............................................................... 21 7. Construction Observation.................................................. 21 B. Stadium Concession Stand Building Foundations.................. 21 C. Seismic Design Parameters..................................................... 22 D. Slabs-on-Grade and AC Hardscape........................................ 23 E. Soil Corrosivity....................................................................... 24 PLAN REVIEW AND CONSTRUCTION OBSERVATION 25 LIST OF REFERENCES TABLES Page No. TABLE 1 - Summary of Significant Earthquake Faults Capable of Generating Strong Ground Shaking at the Andrew Hill High School New Stadium Concession Stand Building Project Site, San Jose, CA........................... 9 TABLE 2 - Correlation Between Resistivity and Corrosion Potential 24 DRAWINGS Drawing No. SITE VICINITY MAP 1 LOCAL GEOLOGIC MAP 2 REGIONAL FAULT MAP 3 REGIONAL EARTHQUAKE EPICENTER MAP 4 SITE PLAN 5 KEY TO EXPLORATORY BORING LOGS 6 SUMMARY OF FIELD SAMPLING PROCEDURES 7 LABORATORY TESTING PROCEDURES 8 LOG OF EXPLORATORY BORINGS ONE AND TWO 9-12 PLASTICITY CHART 13 R-VALUE TEST RESULTS 14-15 CORROSIVITY TEST SUMMARY 16 APPENDICES APPENDIX A- Andrew Hill High School, New Stadium Concession Stand Building, Liquefaction and Dry Settlement Analyses and Calculations, EB-2, Drilled May 20, 2019 INTRODUCTION This report presents the results of our geotechnical and geologic hazards investigation for the planned Stadium Concession Stand Building project at Andrew Hill High School in San Jose, California (see Drawing 1, Site Vicinity and Earthquake Zones of Required Investigation Map for location). The purpose of this investigation was to explore the soil and foundation conditions in the general location of the planned concession stand and to develop recommendations for the geotechnical engineering aspects of the project design. We have also performed an evaluation of potential geologic/seismic hazards at the site. We understand that the project will include the construction of a new stadium concession stand building on the southwest side of the existing stadium/running track which is located on the northeast side of the campus. The approximate planned location of the new building is shown on Drawing 5, Site Plan. We understand that the approximately 30 foot by 45 foot stadium concession stand building will be of modular construction with a crawlspace and conventional concrete spread footings. Building loads are expected to be typical for one-story modular building construction. The project will also include the installation of new exterior slabs-on-grade, asphalt hardscape and associated underground utilities. We have previously performed geotechnical/geologic investigations, including associated construction observation and testing services, for a number of projects at Andrew Hill High School beginning in 1994 (see List of References). Relevant information from our prior investigations was used in the current study. 1 CLEARY CONSULTANTS, INC. Preliminary geotechnical findings and recommendations were transmitted to the District and their representatives on June 28, 2019. SCOPE As presented in our proposal letter dated March 29, 2019, the scope of our services for this investigation has included: A. Geotechnical Investigation 1. A review of relevant published and unpublished geologic literature, maps and geotechnical information for the area. 2. Several reconnaissances of the site by our staff. 3. A field subsurface investigation consisting of two (2) exploratory boring drilled at the project site. 4. Laboratory testing of samples obtained from the boring. 5. Engineering analysis of the field and laboratory data. 6. Preparation of this geotechnical investigation and geologic and seismic hazards assessment report for use in the project design and construction. The report includes findings and recommendations for the following: a. Geologic and seismic setting of the site and surrounding area, including research and review of available geologic/seismic reports and maps. 2 CLEARY CONSULTANTS, INC. b. 2016 CBC seismic design criteria. c. Grading including site preparation and fill placement. d. Stadium concession stand building soil and foundation engineering design criteria. e.Estimated foundation settlements. f. Support of exterior concrete slabs-on-grade and asphalt hardscape. g- Treatment of expansive soils (as required). h.Backfilling and compaction of utility trenches. 1. Surface and subsurface drainage. J- Any other unusual design or construction conditions encountered in the investigation. B.Geologic and Seismic Hazards Assessment 1. Discussion of geologic and seismic conditions and data on the nature of the site and potential earthquake damage including: a. Regional geology and seismic conditions and historical information on the seismicity of the local and regional area. 3 CLEARY CONSULTANTS, INC. b. Location of known active and potentially active faults in the vicinity of the site, as well as nearby inactive faults. 2. Earthquake ground motion acceleration design parameters and geologic site classification in accordance with the 2016 California Building Code study requirements. 3. Potential site impacts related to faulting, liquefaction, lateral spreading, seismic settlement and differential compaction, landsliding, flooding and dam failure inundation with recommended mitigation measures, where appropriate. This report has been prepared for the specific use of the East Side Union High School District and their consultants in accordance with generally accepted geotechnical engineering principles and practices. No other warranty, either expressed or implied, is made. In