Expansion Joints
Bridge expansion joints are critical components of bridge design and construction, allowing the structure to accommodate movements caused by factors such as temperature fluctuations, traffic loads, seismic activity, and settlement. These joints are essential for preventing the buildup of stress within the bridge structure, which could lead to cracks, distortions, or even failure if left unchecked.
Single Strip Seal Expansion Joints
Single strip/box seal expansion joint consists of two edge beams with anchorages and an elastomeric sealing element held firmly in the housings of edge beams that guarantee the water tightness of the joint. The maximum gap between the edge beams at road surface when the joint fully opens due to maximum contraction of deck shall be limited to 80 mm for comfortable passage of the traffic. The edge beams protect the adjacent bridge deck concrete from damage due to vehicular impact and also transfer the vehicular load to the deck structure through robust anchorage system.
Modular Expansion Joints
The modular strip/box seal expansion joint divides the total movement capacity into several smaller gaps. The joint consists of two edge beams, one or more central/separation beams or lamellas oriented transversely to the traffic direction forming the load carrying elements, and cross beams supporting individual or multiple central beams to transfer the loads to the bridge deck through the anchorage system. Centre beams and transverse support/ cross beams are connected by resilient or shock absorption system to dampen dynamic loading, thus reducing the forces transmitted to the structure and anchorages. The shock absorption system accommodates vertical and transverse movements apart from longitudinal movement. The joint also contains gap control system, which allows closing and opening of the joint and ensures that all modules open or close equally. The joint is made watertight through mechanically locked sealing system of elastomeric strip seals connected between the lamellas. The gap width between the consecutive centre beams at the joint surface shall be limited to 80 mm when the joint opens fully due to maximum contraction of deck.