ABSTRACT
Up to the middle of this century bridges relied on roller, rocker or metal sliding bearings to permit movement. With more advanced designs to make better use of the materials employed and the increased use of skewed and curved bridges to carry modern high speed roads over obstructions, the need arose for bearings to take movement in more than one direction. New types of bearings have been developed taking advantage of the new materials arising from improved technology. No doubt others will be developed in the future, but it will be necessary to ensure that they are at least as reliable as those already in service.
