What are Bridge Bearings?

Bridge bearings are structural devices placed between the superstructure and substructure of a bridge. 

Bridge Bearings
Image Credits: www.dsbrown.com

Function of Bridge Bearings

The main function of bridge bearings is to:

1. Transmit the loads coming from the superstructure safely to the substructure

The loads coming on the bearings include self-weight, traffic loads, wind and earthquake loads.

2. Accommodate relative movements between the superstructure and the substructure

Bearings are designed to accommodate translational and rotational movements. The translation movements are created due to creep, shrinkage and temperature effects.  This can happen either in traverse or longitudinal directions.

Rotations are caused due to uneven settlement of the foundation, traffic loadings and construction tolerances.

Construction of Bearing in Bridges

Bearings in Steel Girder
Image Credits: www.dsbrown.com

• Usually bearings are connected to the superstructure using a steel sole plate. It rest on substructure through a steel masonry plate. 
• The sole plate used helps to distribute the concentrate bearing reactions to the superstructure, while the masonry plate distributes the reactions to the substructure.
• Steel sole plate in steel girders are connected using bolting or welding.
• Sole plate is embedded into the concreted using anchor studs.
• The masonry plate is typically connected to the substructure with the anchor bolts.

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