Thursday, September 14, 2017
Different types of bearings used in bridge structures
Bridge bearings stand for structural equipment or devices which are set up among bridge substructure and superstructure with the purpose of transmitting the functional load together with earthquake loads; wind loads; traffic loads; and superstructure self-weight.
Bridge bearings also allow for relative movements among superstructure and substructure, as for example, rotation movements and translational movements in horizontal and transverse direction.
Bearing is employed in building up the bridge structure. It is categorized as expansion bearings and fixed bearings. The first one allows for both translational and rotational movements while the second one allows for rotational and limited translational movements.
A friction force is produced in sliding bearing and it is enforced on substructure, superstructure and sliding bearing itself. So, it is necessary to arrange lubricant like polytetrafluoroethylene (PTFE) to reject generated friction.
While using sliding bearing, this span limitation can be avoided if it is employed in conjunction with other bearing types.
Both rocker and pin bearings are vital parts of steel bridge structure. Rocker and pin bearing are taken into account when the bridge movement is suitably known and defined, because such bearings can allow for both translational and rotational movements in one direction only.