This project is the replacement of three Forest Service bridges near Salmon Idaho, two located over the Salmon River and one is a small bridge over Pine Creek as well as the re-graveling of 11.5 miles of roadway..
The two main bridges are 240 foot single span steel girder bridges. This segment of the Salmon River is classified as Wild and Scenic, so there are significant environmental and aesthetic requirements as well as being located in a canyon that experiences extreme fire conditions each year, adding significant restrictions and care required in doing many tasks.
The bridges presented a unique challenge for deep foundation for the bridges. The site is located where driving piles was not feasible as the sub-surface consisted of sand, gravel, cobbles, boulders and bedrock. As per the design the 16” round pile needed to be embedded 2’ in the bedrock. The unique situation was resolved by installing the round piles using the down the hole hammer utilizing the round piles as casing. Upon reaching the depth the pile was left in place retrieving the hammer and drill steel. Girder erection was also extremely challenging due to restricted access to the river, load limits on bridges requiring cranes to be brought in over the mountain on back roads, and very long, tall girders.
All bridges are now complete, we are working on approach slabs, PCCP, road grade, re-graveling of the 11.5 miles. Remaining items are bridge removal, guardrail, landscaping, staining abutments, and final signing. Project is scheduled to be complete by mid Novemeber.
Project Owner – Western Federal Lands, Vancouver, Washington.
Project Manager – Betty Purdie-Alvez
Project Engineers – Clint Wiscombe and Daniel Ruiz
Project Superintendents – Paul Christiansen and Bud Shumway