Earthquake is one of the terrible natural calamities,although we can not prevent earthquakes, but we can reduce the damage caused by earthquakes by using seismic isolation, lead rubber bearings are widely used on bridge construction, as well as building construction, now we have Mature production processes of LRB, from rubber formulation,= vulcanization,to product testing and type testing, we can production seismic isolation with displacement large up to 450%.
The structure characteristic and capacities of lead rubber bearing
The seismic isolators are installed between the base and buildings or beam and bridge. Lead rubber bearing structure is add lead core inside the elastomeric seismic isolation to Increase energy absorption. When there is a loading on the bearings , the laminated steel plates prevent the rubber deformation, then there will be Horizontal and vertical stiffness performance of the lead rubber bearing.The vertical stiffness is the performance to make the lead rubber bearing to have vertical loading capacity to bear heavy loading on the top. Horizontal stiffness to make the seismic isolation has Lateral deformation capacity, and Play a role in absorbing seismic energy during earthquakes.
Our elastomeric seismic isolation also has good working life, as the designing life of the building and bridge.
Vertical mechanical performance requirements: When laminated rubber bearings are under vertical loads, due to the lateral extension of the steel plate restraining the rubber, the rubber layer is in a state of three-dimensional compressive stress, resulting in an increase in vertical stiffness and a greater utilization of its bearing capacity.
The most basic performance requirement for laminated lead rubber bearings is to have long-term bearing capacity. If the total thickness of the support is the same, the thinner the thickness of each layer of rubber sheet, the more layers, the greater the vertical stiffness, On the contrary, the thicker the rubber sheets in each layer, the fewer layers, the smaller the vertical stiffness, and the smaller the bearing capacity. If the rubber bearing is equipped with a lead core, it does not bear the load and does not affect the loading capacity.
But for a lead rubber bearing, loading capacity is not the only important capacity, we have to consider displacement, damping ratio, and horizontal performance, so once the vertical loading is meeting the request of buildings or bridge, on the designing process, we should consider other performances of the lead rubber bearing, to make sure the isolation not only has good loading capacity, also have good energy absorb capacity and good service life. So we also do tests before production, to make sure the rubber formula and structure are perfectly matched to meet all the parameter standards required by the design of rubber seismic isolation.
