BNSF Bridge 24.8 Fallbridge Subdivision
This complex accelerated bridge construction (ABC) project was an active rail slide-in-bridge replacement. Complete removal of the old bridge and the installation of a fully assembled new bridge and was completed within one 30-hour period.
The existing structure was replaced with one 202-foot-long through-truss span, two through-plate girder spans and two 41-foot-long precast box girder approach spans, one 60-foot deck plate girder, one 90-foot deck plate girder, and a new 203-foot-long truss span. The entire substructure of the new bridge was built under the existing bridge – just outboard of it. Drilled shafts, columns, and caps were all completed while the existing bridge continued to serve trains.
Hamilton developed a lateral translation system used for the bridge change-out. Temporary falsework and translation system members were also built under the existing structure. This was made possible by the two work bridges that were built on either side of the active bridge. A new truss and two through plate girder spans were erected on the work bridge.
Hamilton was responsible for stakeholder management and collaborating with the Washington Department of Transportation (WSDOT), which had an adjacent bridge, and a Georgia Pacific line, which had utilities and pumps within the project limits. After extensive planning and coordination with BNSF, the change-out involved a shutdown of a BNSF mainline, the complete removal of the old bridge, and the installation of a fully assembled new bridge – all within one 30-hour work period – successfully limiting the overall impact to the BNSF rail network.
Time lapse video for the BNSF 24.8 Bridge Replacement project.
Major Project Elements: