What are Bridge Bearings?

 The bridge bearing is an important structural component connecting the upper structure and the lower structure of the bridge. It is located between the bridge and the pad. It can reliably transfer the load and deformation (displacement and rotation) of the upper structure of the bridge to the lower structure of the bridge. important force transmission device. There are two types of fixed supports and movable supports. Commonly used bearing forms in bridge engineering include: linoleum or flat bearing,lead rubber bearing, spherical bearing, steel bearing and special bearing, etc.

The role of bridge supports

The main functions of bridge bearings are:

1. Safely transfer loads from the superstructure to the substructure

Loads on bearings include self-weight, traffic loads, wind loads and seismic loads.

2. To accommodate the relative movement between the superstructure and the substructure

Bearings are designed to accommodate translational and rotational motion. The translational motion is due to creep, shrinkage and temperature effects. This can happen in landscape or portrait orientation.

The rotation is caused by uneven settlement of the foundation, traffic loads and construction tolerances.

Bridge bearing construction

Typically, the bearings are attached to the superstructure using a steel base plate. It rests on the substructure by means of a steel masonry slab.

The base plate used helps distribute the concentrate bearing reaction to the superstructure, while the masonry slab distributes the reaction to the substructure.

The steel base plate in the steel beam is bolted or welded.

The base plate is embedded in the concrete using anchors.

Masonry panels are usually attached to the substructure with anchor bolts.

TYPES OF BRIDGE BEARINGS:

Bridge Bearing Manufacturers have introduced multiple forms of bridge bearings, some basic types of bearings are listed below:

Rocker and pin bearings

Sliding bearings

Roller bearings

Curved bearings

Elastomeric bearings

Disk bearings

Pot bearings

Precautions for construction of bridge bearing replacement

(1) Different jacking methods should be adopted for different types of bridges. For the section form composed of T beam or I-beam, generally, the backing plate can be placed under the beam body to be directly lifted with a jack; however, when jacking up hollow slabs and box beams, attention must be paid to the lifting position to avoid The bottom of the beam body is directly jacked up, and it is easy to select the two ribs and the web of the box girder to prevent damage to the beam body.

(2) Due to the influence of the self-weight of the side beam itself and the auxiliary facilities of the bridge deck (such as guardrails and connectors at the branch), the jacking force of the side beam is quite different from that of the middle beam. During jacking, both pressure and stroke must be controlled, and Take the stroke as the final control. Avoid shear damage to the bridge deck due to uneven roofing.

(3) Strictly control the jacking height of the beam body to avoid damage to the bridge deck and ancillary facilities caused by excessive jacking.

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