Mammoet tackles Texas transport

Aiding construction on the “Signature Bridge” project in Irving, TX, Mammoet set four precast box-girder bridge units into place for the Texas Department of Transportation and its general contractor Webber, LLC. Once complete, the bridge will stretch 500 feet long over State Highway 114 and will connect the former Texas Stadium site to a planned, mixed-use development, which is set to include a new Dallas Area Rapid Transit light rail station. 

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

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

In order to execute as planned, a trench was dug underneath each 120-foot long section to allow for installation of a beam under each end of the bridge unit. The sections were then lifted using a 700-ton capacity gantry system and once elevated, Mammoet’s crew drove SPMTs underneath to load each piece before carefully delivering to the abutments.

The route from construction site to final setting location provided some challenges for the team, including steep grades and tight spaces to negotiate. Thorough coordination with Webber LLC and careful engineering ensured that the team was able to successfully set all four bridge units in the allotted traffic outage period. Since the start of the project in 2017, there have been over 170,000 hours with zero recordable incidents.