According to different structural forms and stress characteristics, bridge expansion joints can also be subdivided into five categories:
1.Docking type. According to its different structural forms and stress characteristics, butt expansion joints can be divided into two types: plug-in type and embedded type. Filling butt expansion joints are generally used in conventional bridge engineering, and the expansion and contraction amount is less than 40mm;Embedded docking extension devices are widely used in bridge projects of 80mm and below.
2.Steel support type. A steel expansion joint is a structure made of steel that can directly withstand the load of the wheel. In the past, this type of telescopic device was mostly used for steel bridges, but now it is also used for concrete beams.
3.Plate. Plate rubber expansion joint is a kind of rigid and flexible expansion device. It has a certain vertical stiffness after bearing the load, so it has the advantages of large span headroom capacity (i.e., large expansion and contraction) and smooth driving.
4.Modular support type. The expansion joint of the module support bridge is a combination of rubber material with good shock absorption and cushioning performance, easy sealing and special-shaped steel with high strength and good stiffness, which can withstand vehicle loads under large displacement.
5.Seamless. Seamless bridge expansion joint is a kind of expansion joint product with a joint structure that does not extend out of the bridge deck, also known as TST bridge expansion joint. The expansion joint at the end of the bridge is filled with elastic material and waterproof material is laid, and then the viscoelastic composite material is laid on the bridge deck pavement, so that the bridge deck pavement at the expansion joint forms a continuum with other pavement parts, and the expansion is supported by the deformation of materials such as asphalt concrete at the joint. However, the most common ones in practical use are modular expansion joints and comb plate expansion joints. Regardless of the form of bridge expansion joint, the key technology lies in the design of the force transmission support system and the displacement control system.