When designing seismic spherical bearings, you must fully understand the entire bridge abutment in the role. Important bridge connecting the upper part and the lower part of the structure when the structure of the bridge supports. Therefore, you must have the following main bridge support role and function requirements. 1. You must be able to support lateral load transfer from the upper structure of the dead load and live load, such as the vertical load and seismic and wind, and securely transmitted to the substructure (piers, and Taiwan). 2. The upper part of the structure must be adapted by the horizontal displacement of live load and temperature variations generated and produced by the deflection angle displacement fulcrum. 3. In order to improve the entire bridge during an earthquake seismic performance, bearing should have a damping and isolation of performance, that is, under seismic and wind (such as typhoons) role has to adapt to the instantaneous displacement effect. 4. With the installation, maintenance and replacement of convenience. 5. With a buffer role in the vehicle. In order to achieve these functions bearing, we should really grasp bridge static characteristics and dynamic characteristics, and proper form bearing on the obvious choice is very important. Depending on the size and form of the bridge, to support methods and safety levels of load force, should take full account of the beam due to the size and direction of the temperature change amount of stretching, and produce live load deflection and rotation reverse generated. Meanwhile, there is a negative bearing reaction force appears to be focused on selecting a seat in the form of anti-negative reaction force performance. 

keywords: Spherical bearings, seismic ball bearings, spherical bearings unidirectional earthquake,