Arch was engaged under immense pressure to resolve a critical issue on a highly complex bridge launch project. The project involved a 7-girder, 9-segment steel bridge that was curved, cambered, inclined, and super-elevated. During the launch, the bridge had been partially advanced to 4000mm over Pier 1 when it became apparent that the structure would not align with the Pier 2 rollers, instead conflicting with the pier cap. With much of the bridge already assembled and counterweights in place, the project was brought to a halt, and a stop-work order was issued until a solution could be developed.
Faced with this urgency, Arch mobilized two independent teams to model potential solutions in parallel. This dual-team approach was critical for rapidly verifying outcomes, performing independent checks, and fostering innovation by allowing each team to explore unique solutions that the other might not have considered. The teams developed sophisticated models that could accurately simulate the behavior of the complicated bridge structure, which involved multiple iterations of segment and girder configurations, each affecting the deflection of the dynamically loaded structure during the launch.
The complexity of the bridge’s design required meticulous attention to detail. Variations in assemblies and counterweights were evaluated, and modifications to the launch nose were considered while the bridge was mid-span. These efforts were crucial in preventing permanent deformation and ensuring the safe continuation of the launch.
One of the most innovative solutions developed was the use of a tower-crane assisted launch method. Given the unique nature of the problem, this method was meticulously planned and executed, with the final launch landing within 5mm of Arch Engineers’ design calculations—a testament to the precision and effectiveness of the solution.