LNR抗震橡胶支座

Among various base isolation systems, through extensive experiments and research, and according to international evaluation standards for isolation systems, the laminated rubber pad isolation system exhibits the following performance advantages:

1) The system has a high vertical bearing capacity. The design value of a single shock absorber's vertical bearing capacity can reach thousands of tons, with the ultimate bearing capacity up to tens of thousands of tons.

2) The isolation layer of this system features a stable elastic reset function, capable of automatically resetting instantly during multiple earthquakes. This is something that the friction sliding isolation system cannot compare to at all.

3) The shock absorber exhibits excellent durability, with good resistance to low-cycle fatigue, thermal air aging, ozone aging, acidity, and water resistance. Performance tests on the product samples indicate a lifespan of 60 to 80 years. Japan once replaced the shock absorbers from a multi-layered rubber pad foundation isolation building that had been in use for 10 years to conduct various performance tests. The results showed that the performance indicators were almost unchanged compared to 10 years prior.

4) The shock isolation effect is significant, with the acceleration response much lower than that of non-isolated structures. The theoretical analysis results are in good agreement with the experimental results. For instance, a 22.8-meter-high reinforced concrete foundation isolated building in Tokyo, Japan, experienced a 6.7-magnitude earthquake off the coast of Chiba on December 17, 1987. The measured ground acceleration was 43.8 cm/s², while the acceleration at the top of the building was only 11.9 cm/s². During the research on the layered rubber pad foundation isolation system, through the analysis and calculation of four different types of structural isolation systems, it can be observed that in areas with an earthquake-resistant fortification intensity of 8 degrees, if a layered rubber pad foundation isolation system is adopted, the fortification intensity of the upper structure can be reduced by 1 to 2 degrees, with a considerable safety reserve.

5) Compared to other shock-absorbing systems, isolators are less affected by uneven settlement of the foundation, and they are structurally simple, easy to install, and have a straightforward transmission method.

Although the layered rubber pad isolation structure has many obvious advantages, it was found during the research process that the system has quite strict requirements for dynamic performance, which is significantly different from traditional non-isolation structures, both in design and construction. To ensure the reliability of the analysis and calculation results, four different types of structural systems were analyzed for their dynamic responses through four separate approaches, and it was discovered:

1) The dynamic characteristics of the base isolation structure with layered rubber pads not only vary with the type of structural system but also greatly depend on the installation position of the isolation devices. Therefore, during the design process, not only should a specialized conceptual design be conducted, but a multi-angle dynamic analysis should also be performed to reasonably and accurately grasp its dynamic response, ensuring a safe and reliable design.

2) In seismic isolation structures, to truly achieve the "isolation" of the upper structure from the ground, attention must be paid to the construction of some key areas. This includes the isolation treatment of the ground floor staircase from the main structure, as well as the flexibility issues of water, gas, heating, and power distribution pipelines when crossing the seismic isolation layer. Neglect in any of these aspects could lead to catastrophic disasters during an earthquake.

3) In addition, the base isolation system with layered rubber pads has stringent requirements for construction. The displacement of the isolation layer must not be interfered with or constrained by any cause, and the construction must not damage the isolators and their accessories. It is also required that the isolators be installed with a high level of horizontality to ensure that the isolation layer can undergo horizontal displacement and instantly reset during an earthquake.

1) Due to the performance advantages of the layered rubber pad isolation system, such as high vertical bearing capacity, strong elastic reset function, and significant vibration isolation effect, these limitations, such as the height limit and safety distance of traditional buildings in design, can be appropriately relaxed.

2) The research results indicate that the seismic fortification intensity of the upper structure in the layered rubber pad base isolation system can be reduced by 1 to 2 degrees, while still retaining a considerable safety reserve.

3) Although the seismic isolation system requires an additional isolation layer, which might seem to increase the cost, the savings in cost from reducing the fortification intensity of the upper structure can be allocated for constructing the isolation layer. Therefore, for the overall construction cost of the seismic isolation building, compared to similar non-isolated buildings, the cost fluctuates between -5% to +5%. When considering the total lifespan of the building, the damage to the building structure during earthquakes, losses of internal property, casualties, and the economic losses due to work stoppage caused by building damage, the economic and social benefits of this basic seismic isolation system are extremely significant. It is a new technology that is highly promotable and applicable.