Washington State Movable Bridges

Washington State Department of Transportation
Various Locations, WA

Mechanical Inspection, Rehabilitation Design, and Balance Testing

WJE staff have provided on-call mechanical and electrical engineering movable and floating bridge engineering services since April 2002 as part of two on-call servi­ce contracts. For the most recent contract (March 2006 – present), WJE has provided mechanical and electrical inspection services and mechanical and electrical construction support services on nine movable and floating bridges.


The Washington State Department of Transportation operates seventeen movable bridges on state routes throughout the state, including the I-5 Interstate Bridge, SR99; First Avenue South Bridge; SR101- Houquiam River Bridges; SR101 - Chehalis River Bridges,; SR104 - Hood Canal Bridge; SR513 - Montlake Bridge; SR529 - Snohomish River Bridges; US12 - Heron Street Bridge, US12 - Wishkah Street Bridge; US12 - Snake River Bridge; and several floating and retractable bridges, including the Lacey V. Murrow Memorial Bridge, Hood Canal Bridge, and the Homer M. Hadley Bridge.


WJE’s on-call services have included two random electrical inspections, three specialty inspections, and four in-depth mechanical and electrical inspections. The in-depth inspection of the Wishkah River Bridge included span balance testing using the strain gage method conducted by in-house personnel. Construction services provided under this contract included mechanical and electrical support during the rehabilitation of the Simpson Avenue and Heron Street bridges.

Simpson Avenue Bridge, a double-leaf Strauss trunnion bascule bridge, underwent a major rehabilitation including rehabilitation of counterweight trunnion machinery, span drive machinery span lock machinery, live load supports, and electrical power and control systems. WJE provided full-time on-site inspection of the mechanical and electrical work during critical closure periods and inspected manufactured components at the point of manufacture.

As part of the rehabilitation of SR99 - Duwamish River Bridge (First Avenue South), WJE provided trunnion stabilization, span lock mechanical and hydraulic rehabilitation, live load support rehabilitations, and minor electrical modifications for the double-leaf hydraulic cylinder drive bascule bridge.