A less noticed bridge across the Willamette

From ODOT- When the original Interstate 5 bridge was built in 1962, the contractor filled part of the river with rock, providing a platform to drive onto and build the bridge. We have since learned a great deal about the effects of construction on waterways and wildlife since then. Now, we strive to prevent or limit impacts.



This time, we built a work bridge across the river. It is more than two acres in size. The deck of the work bridge is 10 feet above the high water mark, protecting it from spring runoff. A drainage system catches all rain runoff and treats it before it is discharged into the river.

The work bridge supporting construction work and the new arches.



The bridge allows large cranes and other construction equipment to be positioned over the river during construction and demolition. During demolition of the original Willamette River Bridge, the work bridge captured all the debris, keeping it out of the river. The work bridge is also a platform in which to build the supports and falsework necessary to pour the arches and other bridge parts. Construction activity continues at all times with no affect on the river and wildlife.



Approximately 1.3 million board feet of lumber and 15 million pounds of steel were used to build the work bridge. Construction of the work bridge required driving 24-inch steel piles into the ground, connecting the piles with 36-inch steel beams, building a deck on top of the beams with large wooden 12-inch by 12-inch timbers, sealing with a plastic material, and covering with 1 1/8-inch thick plywood creating a smooth work surface. All the material will be recycled when the project is complete.