The Twin Cities Road Bridge at Snodgrass Slough is a two-span steel through truss bridge that swings about its center pier to allow for the passage of boat traffic. The truss spans were built in 1931. The bridge also has approach trestles consisting of several concrete slab spans of that have been more recently constructed at either end of the truss spans.
In September of 2004 a hay truck traveling at high speeds struck the bridge, badly damaging several elements of the north truss. Damage was also done to the railing and timber wheel guards. The damage was severe enough to reduce the capacity of the bridge to carry heavy truck traffic.
NRV made the initial evaluation and post-accident load limit rating of the bridge. Because only incomplete as-built drawings were available, it was necessary for NRV to perform a detailed field inspection of the structure in order to develop plans and specifications for its repair. At the request of the owner, NRV selected a group of qualified bidders for the work, oversaw the advertisement and bidding of the project, reviewed and approved contractor submittals, inspected both the shop and fieldwork for the job, and administered the construction contract.
 
Repair methods included construction of a temporary support system that did not include any new structural elements in the bridge waterway, strict geometric control to assure proper operation of the bridge after repair, removing and replacing members that were damaged beyond repair, in-place flame straightening of less severely damaged members, field welding of torn members, removal of gouges and nicks in the existing steel, straightening of damaged rail, cleaning and painting of the new and repaired steel members, and replacement of the timber wheel guards.
Twin Cities Road Bridge
Snodgrass Slough
in Sacramento County, CA
 
Services Rendered
PS&E & Construction Administration
Current Project Status
Completed 2005
Client/Owner
Sacramento County, California
Client/Owner Contact
Michael Meshei