What is HDRB?

High Damping Rubber Bearing (HDRB) have been practically applied in structures for more than 20 years. The excellent isolation effect and reliability have been globally verified and examined by several actual cases. Therefore, they have been widely used in bridges, buildings, factories and many kinds of structures and provided structures excellent protection against the damages of earthquake.

Characteristics：
# Reduce the seismic loading transiting into structures (Isolation).
# Dissipate the vibration energy and decrease displacement into structures (Dissipation)
# Uniformly distribute the loads to main supports of structures.
# Decrease the stresses in structure caused by creep, shrinkage and thermal expansion/contraction.
# It is capable of all the functions of normal bearings
# Reduce the construction cost
# Enable the bridge being designed as multiple continuous spans and minimum the numbers of joints.
# Maintenance free and the longevity are longer than 60 years.

Combination of isolators system:
# The period Shift Effect: reduce the horizontal stiffness of structure and shift the period of structure to be a longer period.
# Energy Dissipation: the damping characteristic decrease both acceleration and displacement.

The most popular isolator systems are the elastomeric pad combined with damper or viscous materials, or sliding damping. Lead Rubber Bearings are the combination of elastomeric pad and damper. High Damping Rubber Bearings are the combination of elastomeric pad and viscous materials.

Structures without Isolators VS. Structures with Isolators
When the earthquake occurs, the structures without isolators will move severely together with ground acceleration and the structures with isolators will parallel move slowly.

Building without isolators VS Building with isolators

Multiple continuous span bridge VS Bridge with isolators

Functions of Seismically Isolated Bearing Components
High Damping Rubber Bearings are manufactured in the way as laminated elastomeric bearings, except that a special formula of rubber are used to obtain a higher damping characteristic to dissipate the energy and decrease the displacement during the horizontal deformation.

Behavior of HDRB in the shaking table test

Ref: http://www.lienfoo.com/eindex1-3.asp