Oregon Gulch Road Bridge Replacement across Morris Ravine

Location

Oregon Gulch Road, 0.1 miles east of Cherokee Road

City or County Responsible for Project

Butte County

Category

Bridge: Efficient and Sustainable Bridge Maintenance, Construction and Reconstruction Projects

Author

Raymond Cooper

Organization

Butte County Public Works

Address

7 County Center Drive, Oroville, CA 95965

Phone

530-538-7681

Project Description

Butte County Oregon Gulch Road Bridge Replacement across Morris Ravine This project is a bridge replacement funded through the Federal Highway Bridge Program (HBP) in conjunction with the Off Federal-aid System (OFS) Highway Bridge Program. In general, the project involved the replacement and the subsequent removal of an existing bridge. The new bridge, completed in the fall of 2017 was constructed on a new alignment immediately adjacent and just downstream of the previous crossing. This allowed local traffic to be preserved throughout construction. The new bridge is a single-span pre-stressed cast-in-place reinforced concrete slab type highway bridge approximately 70 feet in length accommodating two 12 foot lanes with 4 foot shoulders for an overall width of 32 feet between bridge railing and approach guardrail. The former bridge, constructed in 1930, did not meet current design standards and had been determined to be structurally deficient. It was made up of two short spans totaling just under 37 feet positioned on a tangent alignment between short radius curves. This alignment, combined with a narrow width of 18 feet, made it difficult for vehicles, particularly large trucks such as lowbed transports responding to wildland fire incidents, to maneuver safely and efficiently across the structure thus causing repeated damage to the existing guard railing. The project included the construction of a soil-nail wall on the westerly approach which accommodated a larger turning radius required for the larger vehicles. The wall was finished with sculpted rock concrete facing that allowed it to blend into the environment and provide an aesthetically pleasing result. Construction of the new bridge was facilitated by the use of falsework supported off of brackets bolted through small diameter holes cast in one abutment and clear spanning the ravine to a small bent and series of pads placed on the opposite bank and other abutment. This method allowed the contractor to perform the work without impacting the water-way below and allowed construction to be continued into the winter months. Rock excavated on site was sized and placed as slope protection and used to stabilize pipe outlets and newly constructed roadside drainage paths. This project adhered to the mitigations as required in the associated environmental documents and subsequent regulatory agency permits and produced a result that greatly improved the functionality of the facility and at the same time enhanced the public safety of the area.