Bridge bearings - Import export

Elastomeric bearings reinforced internally with one or more steel plates, chemically bonded during vulcanisation are called laminatid elastomeric bearings. Elastomeric bearings permit a smooth and uniform transfer of loads from beams to substructure and also allow beam rotations at the point of support due to deflection of beam under loading. They further allow lateral and longitudinal movement of beams caused by thermal forces. Elastomeric bearings have no moving parts and thermal expansion and contractions are supported by shear capacity of elastomers. There is no sliding motion between bearing and beam or between bearing and abutment.

Elastomeric bearings we have defined so far are the basic types, which constant feature is the fact that they allow all-ways movements and rotation. However, movements can be limited in one or all ways, thus obtaining guided or fixed bearings, respectively. In the first case -guided bearings- the restriction is obtained by means of guides parallel to the supporting axe that allows movement. To make friction as low as possible, PTFE and stainless steel sheets are welded to the guides.

If, on the contrary, a fixed bearing is desired, guides are added parallel to both axes, so that movement is completely blocked. Each elemental layer, subject to stresses and movements, deflects