Bailey Bridge Jack Usage Skills And How To Assemble Bailey Bridge Trusses

The stringer jacks of the Bailey Bridge are only used when installing the upper truss. After the first layer is installed, due to the self-weight of the structure and the gap between the pins and pin holes, the bridge may bend downward or arch upward, causing the joints of the upper truss to be misaligned. At this time, the stringer jacks must be used to push or pull the upper truss into position before the pins can be inserted.

1. When the bridge bends downward and the second layer of trusses is to be installed, the upper pin holes of the front and rear trusses can be aligned without difficulty and the pins inserted. However, the lower pin holes of the trusses will be misaligned due to the sagging of the upper chord of the lower layer of the bridge. For a Bailey bridge, external force is required to align them. At this time, fix one of the trusses with truss bolts (without tightening), and place a seat frame on the upper chord of the lower layer of the bridge behind the other truss. The seat frame is connected to the lower truss by bolts passing through the bolt holes at its head.
2. Place a rhombic jack between the seat frame and the truss of the Bailey bridge, and turn the screw of the jack with a wrench (if necessary, insert a steel pipe over the wrench handle to increase the turning radius and reduce the force required). Gradually open the rhombic jack from its original closed position.