The mass timber structure at Contra Costa County’s East County Service Center began rising in August with the installation of the project’s first two timber columns -- an intentionally measured start before erection shifts into full production.
The project is the first mass timber effort for Webcor Builders.
Rather than bring a steady stream of timber onto the site while the crew was still working through the installation process, the project team scheduled just two columns for the first day. The balance of the columns was scheduled to begin arriving on August 24.
“The first one is always difficult,” said Project Director Alec Bangs. “We want to use these two with a learning curve and make sure that we know what we’re doing before we go nuts on production.”
In fact, it took a while to bolt the first column to its base as workers figured out how to align the pre-drilled holes in the column to the holes on the bracket to which it would be attached.
The full mass timber effort will involve considerably more than a handful of exposed wood columns. Mass timber is a major component of the Service Center’s structural system, with the design calling for 24 timber columns per deck. The project also incorporates mass timber beams and decks, elevator shaft walls, and stair cores. Unlike Webcor's previous mass timber project, completed by Webcor Concrete in Oakland, the timber will remain visible in the finished county building.
Prefabrication is central to the system. The timber components arrive pre-drilled and fabricated for their specific locations, allowing crews to set and connect pieces in sequence rather than fabricate them on-site.
The stair cores take that concept several steps further. They are entirely timber, and the first stair assemblies were scheduled to arrive in early September as prefabricated modules. “It’s walls, stairs, lighting, everything,” Alec says. “It's all pre-assembled.”
By the time the stair cores arrive, Alec expects column erection to be well underway. Once the timber decking is installed through Level 2 and tied together, the team can proceed to form and pour the remaining concrete shear walls, integrating the mass timber structure with the building’s concrete structural elements.
Mass timber is only one part of an unusually broad sustainability strategy at the East County Service Center. The project also features an extensive geothermal system consisting of 70 approximately 300-foot-deep bores organized into five loops. Rather than generating electricity, the system uses the earth as a giant heat exchanger, circulating water underground to reject heat from the building. On the hottest day of the year, the geothermal system is designed to provide about 70 percent of the building’s cooling capacity; for much of the year, Alec says, it should essentially handle the entire cooling load.
The site will also incorporate an overhead solar array installed under a separate owner contract, with the Webcor project team providing the underground infrastructure.
