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September 2021

First New Truss installed at Merchants Bridge

St. Louis, Mo – Walsh Construction reached a significant milestone in the rehabilitation of the Terminal Railroad Association of St. Louis’ historic Merchants Bridge. The first new steel truss, measuring 520-feet-long and weighing 9,000,000 pounds, was floated, raised and put in place over the Mississippi River. The same technique will occur for the remaining two trusses which are scheduled to be installed in the winter and summer of 2022.

The Merchants Bridge rehabilitation focuses on the main span truss and east approach which will allow both tracks to become serviceable on the bridge at the same time. Previously, rail and maritime traffic had become congested due to outdated limitations, necessary repairs and continued maintenance. Doubling the capacity of the bridge will assist in meeting the projected future freight and passenger rail demand and reduce delays for motorists and emergency vehicles. With the improvements being made, the historic bridge can continue to be an important link between Illinois and Missouri for passengers and freight alike.

Rehabilitation of the existing river piers by seismically retrofitting the encasements and improving the elevated approach structures from the east is being undertaken in tandem with the three river-span truss replacements. Walsh’s major goal is to minimize the amount of necessary bridge maintenance while traffic continues around the site.

Removal and installation of the three new trusses require three separate 10-day rail outages, and three separate river channel outages. The first of these outages began on Sept. 13 in preparation for the first truss to be moved into position and floated into place on Sept. 17. The other two trusses will be installed in the winter and summer of 2022.

The replacement of the bridge had been an identified need going back to 2016. The Merchants Bridge is a vital rail artery that had been deemed the region’s top freight infrastructure priority by the St. Louis Regional Freightway for the last five years. The Freightway is nationally recognized for its innovative and collaborative approach to creating a Priority Projects List that identifies key infrastructure projects and advocates for funding for them.

Walsh Construction is the general contractor for the Merchants Bridge project, with TranSystems and Burns & McDonnell serving as the project engineers. Mammoet provided support to remove the original truss section and lift and place the new steel structure. The steel fabrication is being done by Veritas Steel in Eau Claire, Wisconsin.



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