Challenge

Our client was attempting to develop a 9-acre former lumber yard into a public Mill District and needed assistance with geotechnical engineering services through several phases of development. The area intended for development is located within a zone of high liquefaction potential during strong earthquake ground motion.

Solutions

The client hired RGH to provide geotechnical engineering services for development and public infrastructure improvements. GLA wholly owned subsidiary RGH Consultants began by developing recommendations for site preparation and grading, foundation designs, settlement and liquefaction potential, retaining walls, concrete slabs on grade, excavation dewatering, utility trench backfill, and geotechnical engineering drainage improvements. Our team developed recommendations through geotechnical studies, utilizing the drilling and sampling of soil borings, pushing of cone penetrometer tests (CPT) to evaluate subsurface soil and groundwater conditions, and liquefaction analysis with data collected using CLiq – CPT Liquefaction Assessment Software.

Following our recommendations, our team continued to provide geotechnical consultation through multiple design and construction phases. Our recommendations and continuing consultation were used for a wide variety of developments, including public frontage roadway and utility improvements, a four-story low-income housing condominium building, a concrete and steel framed, four-story high-end condominium building with underground parking, an amenities and support building, and a four-story hotel. We also provided assistance on public infrastructure improvements, including roadways, sidewalks, sanitary sewer, storm drain, water, and joint trench utility installation which formed an access loop around the Mill District. Our team provided on-site services during construction to ensure all developments and improvements were geotechnically feasible, providing field observation and testing as well as special inspection services to support our geotechnical consultation.

Results

RGH provided geotechnical consultation through the various phases of design for the Mill District project and was also on-site during various phase of construction to provide field observation and testing, and special inspection services. Our technically-feasible recommendations and subsequent geotechnical consultation throughout construction have provided the client with cost-effective solutions to the liquefaction potential of the area, ensuring long-lasting developments and infrastructure over the entire property.