Mammoet has installed a pedestrian bridge in Dallas, Texas in what was a complex overnight operation.
In Dallas, the Northaven Trail Bridge has been installed, providing a connection for multiple regional bicycle and pedestrian pathways. The s-curved bridge was set in an overnight operation led by Mammoet, which worked alongside building contractor Ragle and bridge designer HNTB
The 61 m-long, 357.1-tonne bridge connects the east and west sides of the US 75 highway. Beforehand, cyclists and pedestrians had to detour through an underpass.
Installation with a crane would prove risky and complex, with no suitable area to set the crane without causing a significant impact on area traffic and road closures. Additionally, the bridge’s design would require a complex bracing system if supported at mid-span, so the use of a jacking system was also ruled out.
Engineers utilised a gantry system with a jack and slide system on top, which would allow for directional movement to modify adjustments during setting whilst accounting for any misalignments.
The bridge was assembled away from its installation location. On the Friday evening of the installation weekend, it was jacked up and loaded onto a pair of double eight-line SPMTs and moved to the edge of the road. The length and width of the bridge required the use of turntables on top of the trailers for added manoeuverability.
On Saturday night, once the highway was fully closed to traffic, the bridge was transported to its installation position and the gantries were built around it. To ensure disruption was kept to an absolute minimum, at least one frontage road remained open, allowing traffic to move along U.S. 75 without a significant detour.
The bridge was then lifted off the trailers using the gantry/track combination. The bridge was raised above the road surface, skidded over, and set it on its piers at about 11:00 on Sunday morning.
