Bridge Expansion Joint for Bridges with Expansion Joints in Utility Troughs

Expansion joints in bridge utility troughs must accommodate the movement of the bridge deck while maintaining the continuity of the utilities in the trough. The joint design must provide flexible connections for all utilities while maintaining the structural integrity of the trough. Utility trough continuity at expansion joints requires a flexible connection that allows the trough to move with the bridge deck while maintaining the utility function. The flexible connection must be watertight to prevent water from infiltrating the trough at the joint location. Flexible connections for different utility types at trough joints vary depending on the utility. Electrical cables require flexible conduit connections or cable loops. Water pipes require flexible couplings or expansion loops. Gas pipes require flexible metallic hoses or expansion joints designed for the operating pressure. Fiber optic cables require flexible conduit connections with sufficient slack to accommodate the movement. Trough cover design at expansion joints must allow the trough to be accessed for maintenance while accommodating the movement. A sliding cover plate that moves with the deck on one side and is fixed on the other side is the standard approach. The cover plate must maintain the utility protection function throughout the full movement range. Waterproofing at the trough joint must prevent water from infiltrating the trough and damaging the utilities. A flexible waterproofing membrane bridging the joint gap provides the primary waterproofing. The membrane must be bonded to the trough on both sides of the joint and must be flexible enough to accommodate the movement. Maintenance of utility trough joints requires annual inspection of the flexible connections, the trough cover, and the waterproofing membrane. Any damage to the connections or the membrane must be repaired promptly to maintain the utility function and prevent water damage.