17 Sep Building from the Ground Up on the Estudillo Canal Tidegate Structure
Replacing an aging bridge and tide gate starts long before the new structure takes shape.
At Estudillo Canal in San Leandro, California, Shimmick is working with the Alameda County Flood Control and Water Conservation District to replace an existing bridge and tide gate structure that had deteriorated over time. Severe scour had developed around the tide gate, while the bridge itself had deteriorated to the point that it could no longer be used.
The work will ultimately provide a new bridge and tide gate structure while contributing to greater climate resilience for the surrounding watershed.
But first, the team had to create a way to build it.
Driving concrete piles
Pouring the footing for the new tide gate structure
Building the Access
One of the first major activities was constructing a 130-foot temporary trestle, providing access for the work ahead.
Working within an active waterway added another layer of complexity. To isolate the work zone, the team installed two 145-foot sheet pile cutoff walls perpendicular to the canal, shutting off tidal flow from San Francisco Bay and outflow from the San Leandro Watershed. The team then installed a design-build gravity bypass, allowing the watershed to maintain its natural connection with the Bay while construction moved forward.
With the trestle and bypass system in place, crews moved into demolition of the existing bridge and tide gate structure while installing permanent sheet pile.
The work came with another challenge beneath the surface. Remnants of timber piles dating back to the 1970s remained within the project footprint, requiring the team to work around existing infrastructure as construction progressed.
Building a New Foundation
Following demolition, work shifted to the foundation of the new structure.
Crews installed 132 concrete piles to support the new bridge and tide gate. Completing pile driving marked an important milestone for the project, allowing the team to move forward with the work that depended on the new foundation.
With the piles in place, crews moved into concrete construction, including placement of the footing for the new tide gate structure.
Each phase has transformed the site — from temporary access and demolition to a new foundation beginning to take shape within the canal.
Building for What Comes Next
The work extends beyond the tide gate itself. Approximately one mile away, Shimmick is also lowering a section of levee to create a spillway intended to help protect the surrounding community during major rain events.
Together, the improvements are part of a broader effort to strengthen climate resilience within the watershed and replace infrastructure that has reached the end of its useful life.
For Shimmick’s team, reaching the concrete phase represents another step toward delivering infrastructure designed to serve the community for years to come.