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GEOTECHNICAL

URS Corporation
North Property Line Residential Remediation

Project Background
ERRG was selected by URS to perform remediation activities for 12 residential yards in Oakland, CA. The yards in question were adjacent to a former manufacturing facility. The scope of work included demolition of various structures, underpinning of two structures, excavation of approximately 350 cubic yards PCB impacted soil, off-site disposal of the contaminated soil, and backfill and reconstruction of demolished and removed structures. Prior to site mobilization, ERRG provided a Health & Safety Plan, a Detailed Work Plan and a Detailed Underpinning Plan.

The excavation trench was approximately 450 feet in length, 4 feet wide and 10 feet in depth and impacted the property lines of 12 houses. Two structures along the trench required underpinning. ERRG designed, permitted and installed a beam and jack approach so that the structures could remain during excavation.

The top 3 feet of soil in the trench was clean fill from prior site activities, and this material was excavated and stored on 10-mil visqueen for use as backfill. The soil excavation between 3-10 feet was placed into 10-cubic yard bins as material was being removed. The PCB impacted soils were ultimately taken to an off-site, Class I disposal facility. Excavation activities were hindered by the unexpected identification of a storm drain that ran along the bottom of the trench and into the residential yards. ERRG removed the old storm drain and installed new piping under a URS approved change order. Additionally, an early season rain caused infiltration into the trench and the subsequent storage and treatment of stormwater. ERRG collected the stormwater in temporary tanks for off-site treatment and disposal.

Once the excavation activities were completed, the site was backfilled and ERRG labor crews reconstructed property line fencing and various concrete patio repairs.