Marsh Drive Bridge Replacement Project

10.1 Million Marsh Drive Bridge Replacement over Walnut Creek Project replaced the existing reinforced concrete slab bridge originally constructed in 1938 as a 6-span bridge, and subsequently lengthened in 1965 by adding 4 additional reinforced concrete spans, creating a 10-span bridge. The existing bridge was 325 feet long by 34 feet wide.
The new bridge was designed to correct all the existing bridge deficiencies and meet traffic needs for traveling public. Funding for this project was provided by six sources, including Federal Highway Bridge Program Funds.
The project replaced an existing structurally deficient and geometrically obsolete bridge with a new 340 feet long and 55 feet wide 5-span bridge, pre-stressed, voided concrete slab structure bridge supported by 36-inch diameter drilled hole cast-in-place concrete piles. The new bridge elevation was raised approximately seven feet with fewer supports in the channel to improve hydraulic capacity and meet hydraulic standards. The roadway approaches to the bridge re-aligned Marsh Drive slightly to the north utilizing a larger horizontal curve on the east in order to improve safety. To improve the roadway alignment and horizontal curve at the bridge, there was approximately 350 to 500 linear feet of roadway approach work at each end of the bridge. In its final configuration, the bridge can accommodate two lanes of vehicular traffic (one in each direction) with pedestrian facilities on each side of the road.
In addition to the project’s goal of replacing the existing bridge with one that meets current design standards and allows for safe public access, as part of the design of the bridge, this project focused its project initiative and goals towards a comprehensive transportation solution, including sustainable modes of transportation. The County partnered with East Bay Regional Park District (EBRPD) to design and construct a pedestrian access across Marsh Drive bridge to provide connectivity to the future extension of the Iron Horse Trail (IHT). The Iron Horse Trail Corridor in Contra Costa County stretches 18.5 miles from the Alameda County line northward to Marsh Drive. The new bridge provides a long-awaited connection across the bridge for a future extension of the trail to the north. Connecting to the west side of Walnut Creek is the first crucial step to connecting the IHT westward to Martinez and the San Francisco Bay Trail across the Benicia Bridge.
The project also included upgrades to the sidewalks and drainage, roadway resurfacing, new crosswalks with increased visibility, and a designated bike lane.