SCH Number 2020040312
- Marsh Creek Road Bridge Replacement, Bridges #28C-0143 and #28C-0145
- The purpose of this project is to replace two existing bridges (Bridges #28C-0143 and #28C-0145) on Marsh Creek Road that carry traffic over Marsh Creek. The improvements are necessary to meet current design standards. The proposed replacement for Bridge #28C-0143 would be a single span bridge. The bridge deck would be approximately 19.7 feet wider than the existing bridge and provide a curb-to-curb width of 40 feet, with two 12-foot travel lanes, eight-foot shoulders, and one and a half-foot wide concrete barriers, for a total width of approximately 43 feet. The length of the bridge would be approximately 40 feet longer (total length of 80 feet) to decrease the new bridge abutment heights and bridge skew. The west and east roadway approaches to the bridge would be reconstructed and would be approximately 680 feet and 1,040 feet in length, respectively. Bridge #28C- 0143 would be replaced on a shifted alignment (approximately 45 feet to the northwest) to provide a single stage construction approach that would allow traffic to use the existing bridge during most of the construction duration while the new bridge and roadway approaches are built. Toward the end of the construction, project traffic would be shifted to the new structure and the old bridge would be demolished, and remaining creek and roadway connection work completed. Retaining walls would be required on both ends of the bridge. The proposed replacement for Bridge #28C-0145 would be a single span bridge. The bridge deck would be approximately 18 feet wider than the existing bridge and provide a curb–to-curb width of 40 feet, with two 12-foot travel lanes, eight-foot shoulders and one and a half-foot wide concrete barriers for a total width of approximately 43 feet. The length of the new bridge would be approximately 80 feet. The west and east roadway approaches would be reconstructed by approximately 775 feet and 620 feet in length, respectively, each direction from the new bridge. Retaining walls would be required on both ends of the bridge. Bridge 145 would be replaced on a shifted alignment (approximately 48 feet to the north) to provide a single stage construction approach, similar to the approach described above for Bridge #28C-0143. Work would occur in Marsh Creek. If creek flows are present, dewatering would be required according to regulatory permit conditions. Dewatering is expected to consist of a bypass pipe to ensure downstream flows are maintained and pumping of seepage from the work area if necessary. Ground disturbance would be necessary. Construction depth would vary between project elements. The maximum depth of excavation for the project work would be approximately 75 feet for the installation of bridge foundation piles (using drilling), approximately 10 to 15 feet of excavation for bridge abutments, and approximately five feet for general roadway work and utility relocations. Disturbed areas would be stabilized as necessary following construction. Existing earthen ditches would be reconstructed and additional ditches may be constructed as necessary to intercept runoff from the roadway. Bioretention facilities would be constructed to receive water from the ditches. Water dissipation pads, culverts, and inlets may be constructed. Drainage patterns in the project area would be maintained. Utility relocation would be necessary. Right-of-way acquisition near the existing road right-of-way would likely be required at both bridge locations. Temporary construction easements would also be required for access to the creek, driveway conforms, proposed staging areas, and for other construction access. Tree removal (approximately 30 total) and vegetation removal would be necessary throughout the project area. No full detours are anticipated. Temporary traffic controls may be necessary for certain operations but a minimum of two 10-foot wide traffic lanes, one for each direction, would be maintained during construction with only brief lane closures. Standard traffic control measures would be employed, and emergency vehicles and private property owners will have access at all times. Portable construction trailers (portable office structure) would also be placed at each site. It is anticipated that both bridges would be constructed at the same time. Construction is expected to begin in May of 2022 and take approximately 18 months to complete. The Project is a covered activity under the East Contra Costa Habitat Conservation Plan.
2 documents in project