The characteristics of seismic isolation products for bridges mainly include the following aspects:
Vertical bearing performance: Seismic isolation rubber bearings mainly bear vertical loads in bridge structures, including bridge deadweight, vehicle loads, and possible live loads. The stability and reliability of its vertical bearing performance are the basis for ensuring the safe use of bridges. Seismic isolation rubber bearings are made of rubber and sandwich steel plates layered and bonded by high-temperature vulcanization. This structure enables the rubber bearings to produce a certain degree of compression deformation when bearing vertical loads, thereby absorbing and dispersing load energy and improving the overall stability of the bridge.
Deformation performance: Bridges will undergo various deformations under the action of earthquakes, including horizontal displacement, vertical displacement, and torsion. Seismic isolation rubber bearings can adapt to these deformations due to their moderate flexibility, thereby protecting bridge structures from damage. When the bearings are subjected to horizontal loads, the relative lateral displacement of the rubber layer is greatly reduced, allowing the rubber pads to achieve a large overall lateral displacement without instability, while maintaining a small horizontal stiffness. This characteristic enables the bridge to produce a certain "swaying" effect during an earthquake, effectively reducing the impact of earthquake energy on the bridge structure.
Damping characteristics : Damping is one of the important properties of seismic isolation rubber bearings, which can effectively control the seismic response of the seismic isolation structure, especially reducing the horizontal displacement of the superstructure. The damping of the seismic isolation rubber bearing mainly comes from the viscoelasticity of the rubber material and the friction between the sandwich steel plate and the rubber layer. Under the action of an earthquake, the rubber material will undergo elastic-plastic deformation, thereby consuming seismic energy; at the same time, the friction between the sandwich steel plate and the rubber layer will also produce a damping effect. This damping characteristic enables the bridge to return to a balanced state faster during an earthquake, reducing the damage to the bridge structure caused by the earthquake.
Durability : The durability of the seismic isolation rubber bearing of the bridge is an important guarantee for its long-term safe use. It is usually made of high-quality rubber and steel plates, which have good weather resistance and corrosion resistance. However, the use environment of the bridge is complex and changeable, and harsh conditions such as high temperature, low temperature, humidity, and salt spray may affect the performance of the bearing. Therefore, when designing and selecting seismic isolation rubber bearings, it is necessary to fully consider their durability to ensure that the bearings can maintain stable performance throughout the life cycle of the bridge.
Other characteristics: High-damping seismic isolation rubber bearings also have the characteristics of full hysteresis characteristics and significant energy consumption. This means that under the action of an earthquake, the bearings can absorb and consume a large amount of vibration energy, thereby reducing the seismic force borne by the building. In addition, high-damping seismic isolation rubber bearings have low temperature dependence, can be widely used in different climatic regions, and are pollution-free and environmentally friendly.