TYPICAL APPLICATIONS

 

Pot-style bearing assemblies are suitable at locations where low-profile, high-load bearing devices are suitable at locations where low-profile, high-load bearing devices are required.  Our bearing assemblies are especially suited for curved or skewed bridges and other complex structures where the direction of rotation varies or cannot be precisely determined. 

 

DESIGN CRITERIA

 

Required information for the proper design of a bearing assembly includes:

 

Vertical Load

 

Horizontal Load

 

Rotation

 

Translational Movements

 

The plan area of a bearing assembly is usually controlled by the average vertical stress on the elastomeric disc.

 

 

 

Rotations of up to ±0.03 radians can be accommodated by bearing assemblies.  Design rotation is a combination of the effects of live load and construction tolerances. 

 

The use of polytetrafluoroethylene (PTFE) as the low-friction sliding surface in bearing guide systems was previously the standard.  With the increased use of seismic design in the bridge industry, larger horizontal loads must pass through the bearing assembly’s guide system.  Alternative low-friction materials, which provide much higher allowable bearing pressures than PTFE, are recommended for cases where horizontal loads exceed 50 percent of the vertical design load. 

 

For curved bridge structures, the theoretical direction of movement is a chord projected from the mid-point of the deck at the expansion bearing line to the mid-point of the deck at a fixed bearing line.  Finite element analysis may also be used to determine a more precise movement direction.  All bearing assemblies at any pier or abutment line must be oriented in the same direction.