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An expansion joint may be defined as a device to support the surfacing, or provide a running surface, across the expansion gap, i.e. the area between adjacent bridge deck spans or the bridge deck and abutment(1).
Types of bridge expansion joint (specified in BD33/94(2)
Type 1: Buried joint
An in-situ joint consisting of an elastomeric pad or flashing placed across the expansion gap to support the surfacing laid continuously over the joint (see Figure 1). Sub-types are buried flashing (BF) and buried pad (BP). Movement range ± 10mm.
Type 2: Asphaltic plug joint (APJ)
An in-situ joint comprising a band of specially formulated binder plus aggregate, typically 500mm wide and 100mm deep (see Figure 2)(3). This runs across the road, above the expansion gap. These joints accommodate movements of ±20mm without cracking at low temperatures. They resist rutting under wheel loading at high temperatures.
Types 3 and 4: Nosing joint (N)
A section of nosing material is bonded to the deck on both sides of the expansion gap, bridged by a compression seal (see Figure 3). The nosing material is to support the adjacent surfacing, providing an edge which will resist the impact of vehicle wheel loads. Movement range is ±20mm, as the maximum joint gap specified in BD33/94(2) may not exceed 65mm.
Type 5: Reinforced elastomeric joint (RE)
A sectional prefabricated joint where an elastomer bonded to metal plates is bolted to the deck. Additional metal reinforcing plates are embedded in the elastomer (see Figure 4). Movement range ±165mm.
Type 6: Elastomeric joint in metal runners (EMR)
A prefabricated joint, where an elastomeric seal is fixed between metal rails or runners. There are two types of EMR joint, determined by the method by which metal runners are attached to the deck. The two methods are either...