Nearly impossible to achieve without the strength of steel, the new Wittpenn Bridge’s main lift span measures 324 feet long and 110 feet wide and weighs in at nearly 2500 Tons. Fabricated by Vigor, the bridge design features a unique orthotropic deck system, with integrated floor beams and box girders, where the ¾” thick deck serves as the top flange to the U-ribs, transverse floor beams and primary box girders. This integrated system not only makes the bridge more efficient for such a long span but also allows the deck to directly bear vehicular traffic loads, with only a thin wearing surface for texture. This system reduces the overall weight, improves construction schedule and minimizes long-term maintenance.
McLaren Engineering Group’s construction team
was contracted by CCA Civil to serve as the project’s erection engineers and tasked with helping meet the strict contract tolerances, of which included erecting the bridge within a 16th
of an inch over 324 feet in the longitudinal deck joints. The challenge required innovative engineering solutions in the development of erection sequences and means and methods, temporary works, crane plans and custom rigging solutions. All of this was closely coordinated with Vigor who used state-of-the-art fabrication technology/equipment, like 3D scanners, CNC plasma cutters and Robotic welders, to ensure the highest level of accuracy in fabrication. Vigor also mimicked the proposed erection sequence in their yard, not only to ensure contract tolerances were met, but also to vet the proposed sequence/procedures, work out any kinks, and ensure seamless erection in the field.