Bridge Expansion Joint for Bridges with Movable Barriers

Bridges equipped with movable median barriers allow the traffic lane configuration to be changed to meet varying traffic demands. The expansion joint must be designed to accommodate the barrier movement across the joint location while maintaining waterproofing and structural integrity. Movable barrier systems use a barrier transfer machine to move the median barrier from one position to another, changing the number of lanes available in each direction. The barrier must cross the expansion joint during the transfer operation, requiring the joint to be designed to accommodate the barrier wheels and the barrier weight. Joint surface requirements for movable barrier bridges must ensure that the barrier transfer machine can cross the joint without damage to the joint or the machine. The joint surface must be flush with the adjacent road surface, with no steps or gaps that could catch the barrier wheels. The joint must be strong enough to support the weight of the barrier transfer machine. Barrier restraint at the expansion joint requires special design to prevent the barrier from moving longitudinally with the bridge deck. The barrier is typically anchored to the bridge deck on one side of the joint and allowed to slide on the other side. The sliding connection must accommodate the full thermal movement of the bridge deck. Waterproofing at the barrier anchor locations must be maintained despite the penetrations required for the anchor bolts. Waterproof sleeves around the anchor bolts prevent water infiltration at the penetration locations. The sleeves must be flexible enough to accommodate the movement of the anchor bolts relative to the joint. Maintenance of movable barrier bridge joints requires coordination between the bridge maintenance team and the barrier operator. The joint must be inspected after each barrier transfer operation to verify that the joint has not been damaged. Any damage must be repaired before the next barrier transfer operation.