Published: March 13, 2017
WHEN: 6 pm, Monday, March 20th
WHERE: Gym at Adele Harrison Middle School
1150 Broadway, Sonoma, CA 95476
- Condition of Watmaugh Bridge
- Brief History of the Project
- Approved Design
- Status Updates
- Next Steps
What is the proposed project?
The new bridge will be 32 feet wide, consisting of two 11
foot travel lanes and two 5 foot shoulders. To preserve the historical
aesthetics of the bridge, the trusses will be removed from the existing
structure and placed onto the new bridge, which will be built within the
approximate alignment of the existing bridge.
What are the recent highlights?
The engineering design for the bridge is substantially
developed, and construction could begin as early as 2019. The National
Environmental Protection Act (NEPA) process is close to completion, and
includes the recent designation of eligibility for Watmaugh Bridge on the
National Register of Historic Places. The California Environmental Quality Act
(CEQA) process was completed, including public hearings, and approved by the
Sonoma County Board of Supervisors in December of 2012.
Why must Watmaugh Bridge be replaced?
Watmaugh Bridge is seismically vulnerable and severely
structurally deficient. It does not meet modern seismic standards and could be
subject to collapse during moderate to severe earthquake. Additionally, the
bridge suffers from structural deficiencies, including:
- Rust in several joints has caused the concrete
to crumble away from the underlying steel.
- Inadequate footings are undermined by high creek
flows. Substantial erosion has been noted around the base of the shallow
- The truss has deteriorated and can no longer
support normal loads.
The Sufficiency Rating of the bridge, which is a federal
standard, rates the bridge at 4 out of 100.