Different Types of Bearings in Bridges are described below-Sliding steel plate bearing, Pin bearing, elastomeric bearing, Rocker bearing, Roller bearing, Roller cum rocker bearing, Pot-PTFE bearing, Metallic guide bearing, Metallic plunger head hinge bearing, Central hinge bearing, etc.

Type Of Bridge Bearing AND Function Of Bridge Bearing.

Image-1: Type Of Bearings In Bridge

Types Of Bearing In Bridge | Function Of Bearing In Bridge

What is Bridge Bearing:

Bearing is the main component of a bridge Which transmits the load coming from the superstructure to the substructure and allows transition movement and rotational movement due to dead loads, live loads, wind loads and seismic loads, etc.

The bearing selection process is dependent on certain parameters. The parameters are loads acting, the geometry, the extent of maintenance, the clearance available, the displacement, rotation, and deflection policy, availability, preference of the designer, the construction tolerances, and the cost criteria, etc.

For the bridge design, all the above-mentioned aspect is considered for the design and the choice of bearings. The designer must consider the bearing arrangement in the bridge construction as a separate system. In most of the construction practices, the bearing is selected or the decision for the bearing is done at the last moment.

Types Of Bearing In Bridge | Function Of Bearing In Bridge

Different Types of Bearing in Bridges are-

1. Pin bearing,

2. Sliding Steel Plaet Bearing,

3. Rocker Bearing,

4. Roller Bearing,

5. Rocker Cum Roller Bearing,

6. Elastomeric Pad or Laminated Elastomeric Bearing,

7. Pot Bearing,

8. Metallic Guided Bearing,

9. Metallic Plunger Head Hinge Bearing,

10. Central Hinge Bearing

The above bridge bearings have been briefly described here-

1. Pin Bearings for Bridges:

Picture-Pin_Bearing_For_Bridge

This is one type of fixed bearing. This bearing consists of a metal pin within a metal cylinder. Pin bearing bears and transmits horizontal forces in any direction in horizontal plane. Its allow rotational movement only and restrains translation movement. Pin bearings can not bear or transmit any vertical loads. A steel pin plays a key role to allow rotational movement. Therefore this bridge bearing is called pin bearing. This type of bearing is commonly used in steel structures.

2. Sliding Steel Plate Bearings for Bridges :

Picture-Sliding_Plate_Type_Bridge_Bearing

There are two steel plates. It's can slide to each other. The top steel plate is called a sole plate which is connected with the deck slab or bottom of the girder. The Bottom Steel plate is called a masonry plate. Sliding steel plate bearing allows longitudinal movement. This type of bearing restrains rotational movement. This type of bearing had been used in old design bridges (in the case of minor bridges-T beam-type girder).

3. Rocker Bearings for Bridges:

Picture-Rocker-Type_Bridge_Bearing

Rocker bearing consists of two steel plates. Type types of bearing allow the rotational movement only and restrain the transition movement. In this bearing, the rocker pin plays a vital role. Rocker pin prevents the relative movement of both plates without interrupting the rotational movement. Rocker bearing is mainly provided in long-span bridges. If rocker cum roller is provided at one side then rocker bearing will provide at another side to maintain one side fixed and another side free. Now a day, using of rocker bearings has been reduced.

4. Segmental Metallic Roller Bearing

5. Rocker cum Roller Bearing For Bridges

Pin cum roller bearing, Type of bridge bearings

6. Elastomeric Bearing For Bridges

Pictire-Elastomeric pad bearing.

Picture-Laminated elastomeric bearing

This type of bearing is commonly used in wide rage. Now a days either elastomeric bearing or Pot-PTFE bearing is used in the case of deck slab-girders systems or simply supported box girder superstructures. Elastomeric pad bearings consist of premium quality neoprene or natural rubber. A plain elastomeric pad is the weakest bearing to transfer a huge amount of vertical loads. It's easily compressed and bulged due to vertical loads. To get more strength, it's modified and laminated with steel reinforcements, fiberglass reinforcements or cotton duck reinforcements. Steel-reinforced elastomeric bearing is the strongest bearing among of them. Its transfers the rotational and transition movement. Elastomeric bearing selects to make it economical for bridge construction. It's easy to install and maintain.

7. Pot Bearing For Bridges

Pot Bearings consist of a metal piston, Sliding disc, PTFE, Elastomeric pad, brass sealing ring, top plate, and bottom plate. The minimum theoretical clearance between top edge of cylindrical pot and bottom edge of piston at design rotation should not be less than 5 mm.

There are three types of pot bearings.

A. Fixed Type Pot Bearing: Sliding disc does not provide in this bearing. This type Pot Bearing bears vertical load and transmits horizontal forces in any direction and allows rotation about any axis in horizontal plate without permitting horizontal movement.

B. Free Sliding Type Pot Cum PTFE Bearing: A sliding disc and PTFE provide in this type bearing. This type bearing bears and transmits vertical load and allows horizontal movement in any direction along with rotation about any axis in horizontal plane.

C. Guided Sliding Type Pot Cum PTFE Bearing: A sliding disc and PTFE provide in this type bearing. A type of Pot Bearing along with vertical load bears and transmits horizontal forces in one direction only and allow horizontal movement perpendicular of that direction. This type of Pot Bearing allow rotation about any axis in horizontal plane.

8. Metallic Guided Bearing

A bearing consisting of a sliding assembly with restrain along a desire direction to bear and transmit horizontal force in one direction only and allow horizontal movement in a direction perpendicular of horizontal force. Metallic guided bearing is capable of allowing rotation only about an axis perpendicular to the plane of sliding. This type of bearing can not bear or transmit any vertical loads.

9. Metallic Plunger Head Hinge Bearing

Nowadays, this type of bridge bearing is not available. Metallic plunger-type hinge bridge bearings had been provided in old pattern bridges. This type of bridge bearing is mainly provided in box girder-balanced cantilever Bridges. It had seen in Mahatma Gandhi Setu in Patna, Bihar State (Across the Ganga River) and Old Narmada Bridge which is known as Sardar Vallabhai Patel Bridge in Bharuch, Gujarat State (Across the Narmada River). Mahatma Gandhi Setu had been constructed from 1972 to 1982 and Old Narmada Bridge had been opened in 1977.
But nowadays, It is observed that the bridge design does not seem to take present-day loading patterns and making distress in bridge articulation zones due to moving present days loading vehicles. The distressed superstructure of Mahatma Gandhi Setu has been replaced in the recent past year 2020 to 2021.

10. Central Hinge Bridge Bearing

Maintenance of bridge bearings:

1. Surrounding of all bearings shall be cleaned out from silt and debris.

2. In the case of POT-PTFE bearings, I have noticed in some cases that the temporary clamp did not disconnect after the installation of the bearing. Fixed temporary clamp interrupts the bearing function. So after the installation of Pot-PTFE bearings, You need to pay attention to disconnecting the temporary clamp.

3. In the case of metal bearings, dirt, rust, and corrosion are common remedies due to weather effects.

For Bearing rust removal and Cleaning / repainting:

The following stepwise treatment is to be followed:

A. The area around the bearings and their pedestals shall be cleared of all debris,
vegetation, dust, etc. And cleaned for proper inspection.
B. Fresh graphite grease as approved by the Engineer shall be applied to the surfaces which are siding, rotating, or moving due to movement in bearings.
C. All other surfaces of the metallic bearing shall be cleaned of all rusts, corrosion and a coat of anticorrosive oil paint applied.

1. Sitemap || Direct Links of All Posts

2. Special Types Of Bridge Bearings || Bridge Articulation

2. Function and Type Of Expansion joints In Bridges

4. Components Of Bridge | Basic Parts of A Bridge

5. Bridge Foundation | Type-Of-Bridge-Foundation

6. Classification-Of-Bridges | Type-Of Bridges

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