Mt Murphy Bridge Project

The Transportation Division of the El Dorado County Community Development Agency is beginning the process of looking into various alternatives to improve the Mt. Murphy Road Bridge, crossing the South Fork of the American River in the town of Coloma. The County is evaluating consultant proposals to prepare a Project Study Report (PSR). The purpose of the PSR is to identify possible alternatives and recommend an alternative to repair or replace the existing bridge.

The current steel truss bridge was built in 1915 and is nearly 100 years old. The main span is 160-feet long with two concrete approach structures of 140-feet and 60-feet long, which were rebuilt in 1931. The bridge approaches are narrow (10.5-feet) with no separation of vehicles from pedestrians. Average Daily Traffic is 280 (both directions, per 2009 traffic counts). The bridge is classified as structurally deficient and functionally obsolete. The structure qualifies for in-depth steel investigations because it has fracture critical (FC) members. Several indications of cracking and missing rivets were identified in the last FC inspection in 2011.

The bridge is routinely inspected by Caltrans every two years and is given a Sufficiency Rating (SR) from 0 to 100 based on 140 elements. If the SR is less than 80, the bridge is eligible for rehabilitation. If it is less than 50, the bridge is eligible for replacement. In 2006, the SR was 2.0 and in 2011, Caltrans reported an SR of 0.00, the lowest rating of all the County maintained bridges.

Annual routine maintenance is performed by the County’s bridge crew. In September 2007, the crew noticed one of the bridge decks had slipped about four inches from the bridge stringers, creating a critical safety issue that needed immediate repair. Maintenance workers moved the bridge deck back into place by jacking the concrete slab from the bottom stringers. The emergency repair cost an estimated $90,000 and took about 3 weeks of 530 man hours to complete.

The Mt. Murphy Road Bridge meets federal criteria for replacement and funding under the HBP Off Federal Aid System 100% Reimbursement Program. In August 2011, the County received federal authorization to complete the planning and environmental phase and scope the project.

An initial public scoping meeting is being held on February 7, 2013 at the Gold Trail Grange Hall in Coloma to present the Project’s goals and objectives, review existing conditions of the bridge, and solicit public input/participation. Follow-up public workshops will be held later this year to seek community input in establishing the evaluation criteria and alternatives to include in the Draft PSR. There will be a pubic review period of the Draft PSR to provide opportunities to submit comments prior to finalizing the report. The public is also encouraged to voice their opinions and offer ideas to County Transportation Division staff throughout the entire planning process. A County website for this project is being developed to provide interested individuals and groups with project updates, notices of upcoming public meetings and informational documents as they become available.

Award Consultant Contract Spring 2013
Draft PSR Fall 2013
Final PSR Spring 2014

Environmental Studies - (2016 - 2022)

Geotechnical Studies - (2017)

Right of Way - (2023 - 2024)

Design - (2016 - 2024)

Construction - (2025 - 2026/2027)