homeWelcome, sign in or click here to subscribe.login
     


 

 

Architecture & Engineering


print  email to a friend  reprints add to mydjc  

2001 Awards

January 17, 2002

State Gold Award: Novelty Bridge replacement


Category: Complexity
Engineer: Parsons Brinckerhoff Quade & Douglas
General contractors: Wilder Construction
Owner: King County Department of Transportation
Description: The project replaced a substandard truss span and approaches with a steel tied arch bridge and precast concrete girder approach spans. The main span is 295 feet, flanked by two 82-foot approach spans on each side, for an overall structure length of 623 feet. The entire project length is 2,920 feet and includes improvements to the approach roadway on both sides.
 
The bridge strikes a balance between the divergent requirements for historic and environmental sensitivity, aesthetics, technical performance, construction impacts and project costs. The original or innovative application of techniques include the tied-arch design with a V-hangar arrangement; artistic blending with engineering design; effective use of materials that reduced waste, cost and time, and incorporated environmental recycling; and contractor incentives for early completion. Prior to contract award, the contractor had to submit a schedule that clearly showed how the work was to be executed.
 
Redundancy was a prime concern with the tied-arch structure. The tie beams were built up of two C-sections and though each half of the tie beam is capable of supporting the dead load of the span, it is still defined as fracture critical. The open configuration allows easier access for inspection. And using stone columns to densify the liquefiable soils was a cost-effective way to stabilize the banks.


Other Stories:



Email or user name:
Password:
 
Forgot password? Click here.