Effects of shape factor on the behaviour of elastomeric roadway bridge bearings and benefits of circular bearing cross section

Elastomeric bearings can support steel and concrete bridge girders. Layered bearings with steel plates are typical and they provide the lateral flexibility to accommodate longitudinal girder movement and the necessary vertical stiffness to vertical support reactions. Elastomeric bearings also replace existing roadway bridge girder supports. Mechanical behaviour of elastomeric bearings strongly relates to the incompressible character of the elastomer material. Incompressible character of elastomers, allows elastomer-bearing design through confining unbound surfaces and limiting surface deformations. A particular character of elastomeric bearings known as the shape factor (S) represents the difference in stiffness of two elastomeric bearings that have same cross sectional areas but different cross sectional shapes. Through an advanced finite element-modeling program, this study evaluates and compares the behaviours of rectangular and circular steel layered elastomeric bridge bearings under the application of vertical and lateral loads.