Dry Creek Bridge Replacement on Burrough Valley Road
The former 98-year-old, 65-foot-long bridge consisted of a three-span timber stringer superstructure with a reinforced concrete deck and thin asphalt concrete wearing surface. The former bridge was flagged as being functionally obsolete due to its narrow width and was hydraulically deficient; the bridge could not pass the 100-year storm flow of Dry Creek. Due to pressure flow events, both bridge abutments were suffering from routine scour and the road approaches were beginning to be undermined. The bridge was greatly in need of replacement.
Replacement Bridge and Culvert:
The replacement bridge consists of a two-span, 114-foot-long cast-in-place post-tensioned slab with two 12-foot lanes and two 4-foot shoulders. The increase in the bridge length was required to allow the passage of the 100-year storm event and provide 2 feet of freeboard. The slab superstructure was used to keep the bridge thin and maintain the lowest possible vertical profile. The replacement culvert consists of a two-cell concrete box culvert with each cell being 12 feet wide by 6 feet tall. To meet fish passage requirements for the Dry Creek tributary, the invert of the culvert was buried 2 feet to allow for a natural invert through the culvert structure.
Construction Staging:
The remoteness of the project site did not afford the use a detour route to divert public traffic around the site during construction. As a result, an on-site temporary detour road was constructed to reroute traffic around the bridge on Burrough Valley Road during the removal of the old bridge and construction of the replacement bridge. In addition, to replace the box culvert structure on Tollhouse Road, a temporary traffic signal system was installed to control one way traffic through the construction site while the box culvert was removed, and the replacement structure built. This allowed the replacement culvert to be built in two stages: half of the structure at a time. The temporary traffic signal system also included a leg on the Burrough Valley Road temporary detour to control traffic entering Tollhouse Road so that traffic was entering Tollhouse Road at right time for the correct direction of traffic. Detailed construction staging and traffic handling plans, and specifications were provided in the construction documents to ensure the project could be constructed while maintain public traffic safely through the project site during construction.
Construction was completed in June 2024 with a final construction cost of $4,995,240.
