低温对天然橡胶支座力学性能与隔震结构地震反应的影响

Effect of low temperature on mechanical properties of linear natural rubber bearing and seismic response of isolated structures

为研究在低温条件下温度对天然橡胶支座性能的影响,通过设置-40℃、-30℃、-20℃和23℃不同温度工况对直径为500 mm和600 mm的天然橡胶支座进行了拟静力试验。试验表明,随着温度降低,支座的力学性能也随之变化。在-40℃条件下,直径为500 mm的天然橡胶支座的竖向压缩刚度和水平等效刚度与常温23℃时相比分别增加了29.9%、11.4%,直径为600 mm的天然橡胶支座的竖向压缩刚度和水平等效刚度与常温23℃时相比分别增加了42.3%、49.1%。结合低温下隔震支座的相关参数,对隔震结构进行了地震反应分析。分析表明,考虑低温影响后,随着温度降低,隔震结构中震下的层剪力和水平向减震系数随之增大,大震下的层位移角随之增大。

In order to study the influence of low temperature on linear natural rubber bearing,quasi static tests were carried out on linear natural rubber bearing with diameters of 500 mm and 600 mm by setting different temperature conditions of-40℃,-30℃,-20℃and 23℃.The results show that the mechanical properties of the bearings change with the decrease of temperature.Under the condition of-40℃,the vertical compression stiffness and horizontal equivalent stiffness of linear natural rubber bearing with diameter of 500 mm increase by 29.9%and 11.4%respectively compared with normal temperature 23℃,and the vertical compression stiffness and horizontal stiffness of linear natural rubber bearing with diameter of 600 mm increase by 42.3%and 49.1%respectively compared with normal temperature 23℃.Combined with the relevant parameters of the isolation bearing at low temperature,the seismic response of the isolated structure was analyzed.The analysis shows that considering the influence of low temperature,the story shear force and damping coefficient of the isolated structure increase with the decrease of temperature under moderate earthquake,and the story displacement increases with the decrease of temperature under large earthquake.