Bridge Panel Cart
IQE was approached to design a unique one-off precast concrete panel transfer system for a highway bridge project. The system had to operate on the bridge steel beams after the concrete decking had been removed and shear studs were welded in place. The schedule was aggressive to accommodate the construction time frame. To accomplish the task, IQE designed a panel transfer cart as well as an unloading and placing frame to unload the 16,000 lb panels from the cart and lower them into position on the bridge beams. The shear studs being welded in place on the beam top surfaces introduced a tight restriction on the available beam surface for the cart to run on as well as limiting room for mechanical drive components. Further complicating matters was the fact that the bridge beams the cart would run on were set at different elevations to achieve the proper road camber, meaning that the wheels could not be connected with a solid axle and required two independent but synchronized drives. The cart also had to be able to operate on both sides of the camber meaning that it had to be easily reconfigured to accommodate the opposite camber slope. Additionally, the cart had to be able to side shift the panels into the proper location for the frame to pick and drop the panels into their position on the deck while maintaining the allowable loading on the bridge beams. The client requested that IQE design the cart to utilize mechanical and hydraulic components available from their used spare components. The cart was designed to accommodate an existing hydraulic power unit and two used winches were selected from spare stock and modified to become chain drives which drove the cart. The engineering was completed within the timeframe allotted, and the cart and lifting assembly were fabricated, tested, and put into service successfully.