Design Considerations for Spherical Bridge Bearings Under Horizontal Loads
T. Ivan Campbell
Appears on pages(s):
bearings; bridge bearings; bridges (structures); load transfer; stresses; Design
The mechanics of load transfer in the curved sliding compression- only surface of a spherical bearing, containing a layer of polytetrafluoroethylene (PTFE), under external applied horizontal load and the implications for design of such a bearing are the topic of this paper. Relevant literature indicates that the critical parameters are the ratio of horizontal to vertical load and the ratio of the radius of curvature to the plan diameter of the interfacing spherical surfaces. An experimental program to measure the stress-displacement relationship of confined PTFE discs, under uniaxial and eccentric compressive loading, is described and a bilinear stress-displacement relationship is proposed. This stress- displacement relationship is incorporated into a displacement model to predict the stress distribution in the PTFE in the curved interface; this model is used to develop design charts for spherical bearings under combined vertical and horizontal loads.