The Riverside Elementary Lateral Spreading Resistance Element (LSRE) Project (Project) involved constructing ground improvement to stabilize soil adjacent to Wildcat Creek in San Pablo, California. The Project was considered Critical Needs and was constructed through a design–build procurement for West Contra Costa Unified School District (School District). As part of the design–build team, ENGEO developed an LRSE design report and construction documents within the tight project schedule. The project was subject to an in-process review by the School District and State of California Division of State Architect (DSA)/California Geological Survey (CGS). Previous evaluation of the site by others identified a hazard of liquefaction within the alluvium and the potential of lateral movement of over 2 feet in the direction of the creek in a seismic event.
2022 ASCE San Francisco Section Outstanding Seismic Retrofit Award
2021-2022 CalGeo Outstanding Project Award, Public Medium-Budget Category
ENGEO performed geotechnical and seismic engineering design services for the design-build construction of ground improvement to mitigate the lateral spreading hazard. Ground improvement consisted of overlapping deep soil mix (DSM) columns to create shear panels in the ground parallel to the direction of possible soil movement. ENGEO performed analyses to design the DSM panels and prepared the construction drawings and specifications.
To avoid disruptions to the academic calendar, the project schedule was very aggressive and allowed for approximately five months to perform the design, achieve concurrence by the School District’s Geotechnical Engineer, and gain approval by the State of California in order to start construction in the School District’s required timeline. ENGEO led weekly meetings with the project review team to address questions as they arose. As a result, the LRSE Design Report and construction documents were approved by CGS on first review, which facilitated in meeting the project schedule.