Laminated Rubber Bearing

A laminated rubber bearing has a multilayer stiffening plate and a steel plate. They are commonly used type of bridge bearings. They wrap both in elastic rubber material on the inside and outside. The bearing is stiff enough to handle the bridge’s internal forces. It can reliably transfer these forces to the pier. Rubber materials provide good elasticity and shear deformation. This helps meet the angle and displacement needs of the upper structure. Rubber dampens dynamic loads. This reduces their impact on the superstructure and pier. It acts as a buffer and provides isolation.

Laminated rubber bearings are easier to install than other bridge bearings. Plus, they require no maintenance. They are a practical and cheap seismic isolation option. Neoprene is different from most elastomers. When the bridge deck shrinks the most, neoprene doesn’t harden much, even in low temperatures.

Laminated rubber bearings work well in steel and precast concrete structures. They also suit standard concrete slabs and any place that needs vibration isolation. This bearing works well with camber and rotation. These factors create high-stress loads on it. This bearing is a budget-friendly option for uses with minimal structural movement. It works well for both side-to-side and forward-backward motion, plus rotation. It also provides vibration isolation and is often easy to install.

The vulcanization and molding process sandwiches reinforced steel plates between rubber layers. This creates a uniform unit in the laminated elastomeric bearing. These embedded steel plates not only limit excessive expansion but also boost strength. They boost transverse, longitudinal, and compressive strength. They also improve rotational ability compared to regular elastomeric bearings.

Features of Laminated Rubber Bearings

• Strong in the vertical direction but flexible in the horizontal direction.

• High durability and maintenance-free.

• Excellent vertical load capacity, ranging from 5 tons to 2,000 tons.

• Easy to install without a separate damper.

• Simple structure, easy manufacturing, low cost, saving steel.

• The rubber is elastic and dampens well. The rubber bearing absorbs shocks effectively. This reduces the dynamic load on the bridge span and lessens the impact on the pile body. As a result, the bridge’s stress improves.

Applications of Laminated Rubber Bearing

It has a wide range of applications and can adapt to wider bridges, curved bridges and slanted bridges, but it is usually used for short-span cast concrete slabs in bridges or precast concrete slabs used in multi-story stadiums.

Different plane shapes are suitable for different span structures: orthogonal bridges are suitable for rectangular bearings; curved bridges, skew bridges and cylindrical pier bridges are suitable for circular bearings.

Although elastic bearings are designed to accommodate shear motion, they should not be used to provide permanent resistance to continuously applied external shear forces.

Working Principle of Laminated Rubber Bearing

In an earthquake, unisolated buildings vibrate back and forth in different directions due to inertial forces, resulting in building deformation and damage. In contrast, a foundation-isolated building will also shift but maintain its original shape and avoid damage – this is because the lead rubber bearing effectively dissipates the inertial forces on the building, extending the building’s vibration period and reducing the building’s acceleration.