Located near State Route 237 in Milpitas, California, Bridge Point Silicon Valley is an industrial complex comprised a ground-up, 328,240 s.f., concrete tilt-up structure on a 34.52-acre site. The project is near big employment hubs such as San Jose, Oakland, and San Francisco, and close to major Fortune 100 operations within the Bay Area.
Greg Woolway, vice president and Bay Area officer for Bridge Development, shared about the project, â€śWe didnâ€™t want this to be a traditional warehouse. We have really cool wood features on these buildings. They have a lot of glass and glazing. You normally donâ€™t see that with industrial.â€ť
Existing Soil Conditions
Due to the projectâ€™s close proximity to the San Francisco Bay, just north of San Jose, the existing project site contained high levels of alluvial soil, making it too insufficiently dense to support the loads of new construction. To remedy this, Oltmans worked with the Keller Group to propose an effective ground-improvement method in lieu of traditional drilled piles. The team opted for dynamic compaction.
Ground improvements consisted of wick drain installation beneath the building pad followed by deep dynamic compaction (DDC), which entailed dropping a 27-ton weight repeatedly from 60â€™ to 70â€™ high onto a 15â€™ x 15â€™ grid during two passes, then followed by an ironing pass onto a 7â€™ x 7â€™ grid using a 10-ton weight to densify and settle the loose granular soils. Following this, the site was then surcharged finalizing the settlement process. Piezometers and settlement plates were installed to track the progress.
January 2020 Construction Video
In the video linked below, two rigs are completing a wick-drain installation across the proposed site for Building 2, prior to moving west towards Building 1. They are followed by DDC rigs which drop 27 tons of weight repeatedly onto a 15-foot-by-15-foot grid during two passes. Next is an ironing pass, using a 10-ton weight, spaced out among a seven-foot by seven-foot grid. Upon completion, the site elevation is anticipated to settle approximately two feet by densifying the loose granular soils up to 15 to 20 feet deep. Following this process, the site will be surcharged, anticipating another three to four inches of settlement. Piezometers and settlement plates will be installed to track the progress.