Structural Bearings and Expansion Joints for Bridges, edited by Günter Ramberger, ISBN 3-85748-105-6, published in 2002.
Bridge superstructures have to be designed to permit thermal and live load strains to occur without unintended restraints. Bridge bearings have to transfer forces from the superstructure to the substructure, allowing all movements in directions defined by the designer. The two functions transfer the loads and allow movements only in the required directions for a long service time with little maintenance must be fulfilled. Different bearings for different purposes and requirements have been developed so, that the bridge designer can choose the most suitable bearing.