High – Damping Rubber Bearing: A Promising Solution for Seismic Isolation

High – Damping Rubber Bearing: A Promising Solution for Seismic Isolation

Abstract: This article provides a comprehensive introduction to high – damping rubber bearings, including their working principles, structural characteristics, advantages, and applications. High – damping rubber bearings play a crucial role in enhancing the seismic performance of structures, offering effective protection against earthquake – induced damage.

1. Introduction

High – damping rubber bearing (HDRB for short) is a type of seismic isolation bearing that has been widely used in recent years. It is developed based on natural rubber bearings by improving the rubber formula and adding various additives. HDRB combines the advantages of high – strength natural rubber and excellent damping materials, which can effectively absorb and dissipate seismic energy, thus reducing the seismic response of structures.

2. Working Principle

The working principle of HDRB is mainly based on the following aspects:

• Creating a Soft Seismic Isolation Layer: By introducing HDRBs in the structure, a soft seismic isolation layer is formed to separate the superstructure from the lower foundation. This lowers the overall stiffness of the structure, prolongs its natural vibration period, and reduces its natural vibration frequency. As a result, it can avoid the highest – frequency range of energy in the earthquake and reduce the input of seismic energy.
• Absorbing and Dissipating Seismic Energy: The high – damping characteristics of the seismic isolation layer ensure the absorption and dissipation of seismic energy. When an earthquake occurs, the vibration energy of the lower foundation is transferred to the high – damping rubber bearing first. When the bearing is subjected to horizontal deformation, it provides certain resistances that can effectively convert the seismic energy into heat and dissipate it, thereby reducing the transmission of seismic energy to the upper structure. After the earthquake, the bearing will restore to its original position through the recovery force of the rubber.

3. Structure and Characteristics

• Structure: HDRB usually consists of top and bottom connecting steel plates, internal high – damping rubber layers, internal steel plates, a rubber cover, and top and bottom sealing plates. The internal steel plate layers provide high vertical load – bearing capacity, while the internal high – damping rubber layers offer excellent horizontal deformation capacity, horizontal restoring force, and seismic energy absorption and dissipation capacity. The rubber cover protects the inner rubber from ozone and UV damage and provides good aging resistance.
• Characteristics:

• High Strength and Vertical Stiffness: It can withstand higher vertical loads and stably support buildings.
• Excellent Horizontal Deformation Capacity: It has great horizontal deformation capacity, horizontal restoring force, and amazing seismic energy absorption and dissipation capacity.
• High Damping Ratio: The designed maximum damping ratio can reach up to 25%, and it can provide the damping required in seismic isolation design without adding additional dampers, with low maintenance and management costs.
• Smooth Hysteresis Characteristics: It can reduce both the seismic response and high – frequency vibration of the superstructure during an earthquake.
• Good Wind – Resistance Performance: Its higher initial horizontal stiffness provides excellent resistance to wind – induced vibration.
• Minimal Residual Deformation: It has minimal residual deformation after severe earthquakes and does not require replacement, being economical and durable with a long service life, typically up to 60 years and above.

4. Applications

HDRB is widely used in various fields of civil engineering, mainly in the following aspects2:

• Buildings: It is used in the seismic isolation design of new buildings and the seismic reinforcement and renovation of existing buildings. It can effectively reduce the seismic force acting on the building structure, protect the safety of the structure and the people and equipment inside, and improve the seismic performance of the building.
• Bridges: It is an important component of bridge seismic isolation systems. It can not only reduce the seismic response of the bridge during an earthquake but also ensure the normal use of the bridge after the earthquake, facilitating rapid repair and restoration of traffic.
• Hydropower Projects: In hydropower projects such as dams and power stations, HDRBs are used to improve the seismic resistance of structures, ensuring the safety and stability of the project during an earthquake and reducing the risk of damage to the project.

5. Development Trends

With the continuous development of seismic isolation technology and the increasing demand for structural seismic safety, the development trends of high – damping rubber bearings are as follows:

• Improvement of Damping Performance: Researchers are constantly working on improving the damping performance of rubber materials to further increase the damping ratio of HDRBs and improve their ability to absorb and dissipate seismic energy.
• Enhancement of Environmental Adaptability: In order to adapt to different working environments, such as high – temperature, low – temperature, and humid environments, the research and development of HDRBs with better environmental adaptability is being strengthened.
• Intelligent Monitoring and Diagnosis: With the development of sensor technology and data processing technology, the intelligent monitoring and diagnosis of HDRBs are becoming more and more important. By installing sensors on HDRBs, real – time monitoring of their working status can be carried out, and timely diagnosis and treatment of potential problems can be carried out to ensure the safe operation of structures.

6. Conclusion

High – damping rubber bearings have excellent seismic isolation performance and a series of outstanding characteristics. They have been widely used in the seismic isolation of buildings, bridges, and other structures and have achieved good results. With the continuous progress of technology, high – damping rubber bearings are expected to be further improved and developed in the future, providing more reliable protection for the seismic safety of structures.

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