Mammoet Helps Place Bridge Sections Using Accelerated Method

 August 5, 2020 - Mammoet’s crew set four precast box-girder bridge units into place as part of the construction of the “Signature Bridge” in Irving, Texas, for the Texas Department of Transportation and its general contractor Webber, LLC.

The completed bridge will stretch 500’ over State Highway 114 and will connect the former Texas Stadium site to a planned mixed-use development that will include a new Dallas Area Rapid Transit light rail station.

Each bridge unit weighed about 792 U.S. tons and was transported and set using Self-Propelled Modular Transporters (SPMTs), during specific overnight traffic outages to ensure minimal disruption to the public.

The original plan was to use jacking and skidding equipment so the bridge could be built on top of the existing bridge and skidded to its new foundation. Upon review of engineering, Mammoet devised a specialized solution in which each unit would be built directly on the ground off-site, then picked up and self-loaded using SPMTs. The method is known as Accelerated Bridge Construction, or ABC.

The ABC method avoided the need for work to be done at height, eliminating many safety concerns and allowing quicker loading time than originally expected. The method eliminated the need for two overnight shifts.

In order to execute the plan, a trench was dug beneath each 120’ long section to allow installation of a beam under each end of the bridge section. The sections were then lifted  using a 700-U.S.-ton capacity gantry system. Once the section was elevated, Mammoet drove SPMTs beneath to load each piece before carefully for delivery to the abutments.

The route from construction site to final setting location provided some challenges, including steep grades and tight spaces to negotiate. Thorough coordination with Webber LLC and careful engineering let the team set all four bridge units in the allotted traffic outage periods.

Since the start of the project in 2017, there have been more than 170,000 hours with no recordable incidents.

Mammoet has extensive experience in executing bridge replacements around the globe, including an upgrade to the Shaler Street Bridge in Pennsylvania and the recent installation of a pedestrian bridge at the Seattle-Tacoma airport.