88% Federal Highway Bridge Program, 12% Local Road Funds

The purpose of this Project is to replace an existing bridge along Marsh Creek Road that carries traffic over Marsh Creek. The Project consists of bridge replacement; The proposed bridge would be an approximately 90-foot-long, single-span bridge. The bridge deck would be approximately 43 feet, 12-foot-wide travel lanes, 8-foot-wide shoulders, and an approximately 1.5-foot-wide concrete barrier on each side of the new bridge.   
  
The proposed bridge would be constructed of reinforced concrete on pre-cast and pre-stressed I-girders. The reinforced concrete bridge abutments would be supported by spread footings. The existing structure includes tall, reinforced concrete walls that restrict the flows of Marsh Creek under the bridge. These existing walls would be removed as part of the project to open up the channel where Marsh Creek flows under the bridge. The channel work would require that Marsh Creek be dewatered in accordance with regulatory permits. Dewatering would likely be accomplished using coffer dams according to methods acceptable to the California Department of Fish and Wildlife (CDFW). Water would be routed around the work area to maintain downstream flows. Dewatering would occur in the work area extending approximately 150 feet upstream and 200 feet downstream of the existing bridge. Along with replacing the bridge, the horizontal alignment of Marsh Creek Road would be shifted north on a parallel alignment to accommodate the wider bridge structure, and earthwork would be required along both sides of the existing roadway. In order to meet the hydraulic design standards, the vertical profile of the bridge would be slightly raised. The changes in both the horizontal and vertical alignments require reconstruction of Marsh Creek Road on both sides of the bridge (900 feet total). Two retaining walls may also be necessary: the first retaining wall would be along the north side of the roadway (west of the bridge), would have an average approximate height of 10 feet, and would be 183 feet long; the second smaller retaining wall would be set back from the roadway on the north side of the road (west of the bridge) and would be approximately 7 feet high and 90 feet long. The final design of these walls will be determined prior to construction.   
  
The widening and realignment of Marsh Creek Road to construct the new bridge may require right-of-way or temporary easements from several adjacent parcels. Staging of construction materials and equipment would occur in two potential locations north and south of the road in the center of the project site. The northern staging area would occur within an undeveloped vegetated area, and the southern staging would occur entirely within paved parking areas. Standard construction equipment would be used for constructing the proposed project, including but not limited to: excavators, graders, scrapers, loaders, sweepers/scrubbers, compactors, rollers, backhoes, cranes and paver's. The proposed project has been designed so that existing traffic can be accommodated during construction, while minimizing impacts to the surrounding right-of-way, including existing buildings. Construction would be sequenced in a manner to minimize traffic impacts during construction. Two phases of bridge construction are expected: The first phase would partially construct the new bridge with traffic using the existing bridge; The second phase shifts both directions of traffic onto the new bridge so the existing bridge can be demolished and the new bridge can be built to full width. During construction, the project is expected to accommodate one 12-foot-wide travel lane in each direction on Marsh Creek Road through the project site throughout construction, with short, infrequent periods of one lane traffic controls. Construction would take up to two seasons, likely starting in the summer of 2017 and finishing by the fall of 2018, pending Cal-trans and Federal approvals. Utility relocation and right-of-way transaction will be necessary in support of the project. Tree and shrubbery removal and trimming will be necessary.  

Delay in approving the project may result in a delay of design and construction, and may jeopardize funding.  

Speakers: Linda Dortzbach-Hudlin on behalf of property owners Richard & Wrenatta Dortzbach; James Gray, P.E, resident of Concord (handout attached).