Final answer:
An elastomeric bearing is used to support a bridge girder and provide flexibility during earthquakes, with a maximum allowable displacement determined by engineering standards. The bearing absorbs seismic forces and restrains the bridge girder's movement within a specified limit to ensure structural safety.
Step-by-step explanation:
An elastomeric bearing is used to support a bridge girder and provide flexibility during earthquakes. The bearing has a shear modulus (G) of 130 psi. The purpose of the bearing is to absorb the seismic forces and allow the bridge to move without causing structural damage. The displacement of the bridge girder should be limited to a specific value determined by engineering standards and regulations.
For example, if the maximum allowable displacement is 2 inches, the elastomeric bearing should be designed to restrict the movement of the bridge girder to within this limit during an earthquake. This ensures the safety and stability of the structure.
It is important to note that the specific maximum displacement requirement may vary depending on the location, size, and complexity of the bridge. Engineering experts and seismic design codes provide guidelines for determining the appropriate displacement limits for different types of bridges.