Oregon Map of Hamilton project

Union Pacific Railroad Bridge Harrisburg

Mid Willamette Valley, Oregon

Start Date: Spring 2013
End Date: October 2014

Hamilton was selected by the Union Pacific Railroad to replace a 908 ft. steel truss bridge crossing the Willamette River in the mid-Valley. The challenges of replacing of an aging, speed restricted 100-year-old railroad bridge while keeping it operational for Union Pacific and Amtrak train schedules required the best efforts of the delivery team. The most challenging aspect of the project was the task of marrying up incremental change-outs between the old bridge and its new replacement. In advance of closures, Hamilton worked in close proximity to the live rail lines (without interrupting service) to remove significant portions of the old substructure, drill shafts, build columns and caps, and stage the new UPRR-supplied Deck Plate Girders (DPG's). The instability of the old trusses was a concern so Hamilton reinforced them before each move.

Then, during only five bridge closures of less than 30 hours each during an 18 month period, Hamilton incrementally removed the remaining portions of the old substructure. Using a vertical jacking and horizontal slide system Hamilton developed in collaboration with McGee Engineering, Hamilton crews slid segments of the old trusses out of the alignment for eventual removal and slid into place new 126 ft. steel spans. UPRR then tied into the existing lines at the conclusion of each closure. During each of the five bridge slides, Hamilton actually performed the work in almost half of the allotted closure time; trains kept moving and fish were protected in the river below. Work on the new 908 ft. bridge was completed on time and at budget.