Clark County Public Works manages a comprehensive bridge program that includes regular inspection and maintenance of county-owned bridges.
Federal and state standards require the county to inspect and document the condition of its bridges at least once every two years.
Clark County owns and maintains 79 bridges, of which three are pedestrian bridges. The county also inspects 27 other bridges owned by cities and six owned by railroads.
Washington Administrative Code 136-20-060 requires the county to produce a written report on its bridge inspection program.
Bridge engineers use two terms for deficient bridges:
Structurally deficient means the bridge’s condition or design has affected its ability to carry traffic. The bridge is not unsafe or likely to collapse – Clark County would immediately close an unsafe bridge – but it does indicate the bridge will require significant maintenance and repair and ultimately will require replacement or major rehabilitation.
Clark County has two bridges that are listed as structurally deficient: Davis Bridge and Salmon Creek Bridge. Both bridges were downgraded in 2016 and are structurally deficient due to substructure scour damage, a type of water erosion that can can undermine bridge piers and abutments.
Functionally obsolete means the bridge's deck geometry, load carrying capacity, clearance or approach roadway alignment does not meet accepted design standards.
While structural deficiencies are generally the result of deterioration of bridge components, functional obsolescence typically results from older bridge configurations that are subject to increased traffic demands and are substandard structures as defined by the current bridge design codes.
In 2016-2017, the county replaced Cedar Creek Bridge, on Northeast Etna Road just south of the North Fork Lewis River in north Clark County. Cedar Creek Bridge was one of two weight-restricted bridges owned by the county. The replacement bridge opened on March 27, 2017.
During 2015-2016, the county replaced Fifth Plain Creek Bridge, on Northeast 88th Street about one-half mile east of Northeast Ward Road. Fifth Plain Creek Bridge was the last wood support bridge owned by the county. A replacement bridge opened on Jan. 21, 2016.
In 2012, Clark County replaced Cougar Creek Bridge, on Northeast Washougal River Road.
Clark County's next major bridge project will replace Davis Bridge, which spans Fifth Plain Creek on Northeast Davis Road about a half mile east of Northeast Ward Road. Construction is scheduled for 2019.
The bridge program also includes projects to:
- Seismically retrofit bridges so they will be better able to withstand earthquakes.
- Repair scour damage and reduce the potential for future scour.
The county aggressively seeks outside funding to help pay for bridge projects. In 2012, the county was selected to receive $4.1 million in federal grants to replace one bridge, Fifth Plain Creek Bridge, and to upgrade four other crossings.
For more information on those bridge grants, watch this January 2013 CVTV video: