铅芯橡胶支座剪切性能的压力相关性试验研究

Experimental study on vertical pressure dependency about shear properties of lead rubber bearing

由于在地震中橡胶支座承受的竖向压力会产生较大变化,因而有必要对橡胶支座剪切性能的压力相关性进行研究。采用低周反复循环加载试验方法对铅芯橡胶支座进行了剪切性能试验,研究了支座压应力和剪应变对支座屈服力、屈服后刚度、水平等效刚度和等效阻尼比的影响,结果表明,随着支座压应力的增大,支座的滞回曲线越来越饱满,支座的耗能能力近似呈线性增大;支座的屈服力和等效阻尼比随着压应力的增大而近似呈线性增大,随着支座剪应变的增大,压应力对屈服力和等效阻尼比的影响逐渐减小;支座的屈服后刚度随着压应力的增大而减小,随着剪应变的增大,压应力对屈服后刚度的影响逐渐减小;支座的水平等效刚度随着压应力的增大而近似呈线性减小,随着剪应变的增大,压应力对水平等效刚度的影响略有增大。根据试验结果给出了支座剪切性能的压力相关性经验公式,可供工程设计人员使用。

In earthquake, the vertical pressure of the rubber bearing would have great change, so it is necessary tostudy the pressure dependency about the shear properties of the rubber bearing. The cyclic loading method wasadopted to study the shear properties of the lead rubber bearing, and the influence of the vertical pressure and shearstrain on the shear properties of LRB was studied. The results show that with the increase of compressive stress, thehysteresic loops of LRB become more full, and the energy dissipation of LRB increases. The yield force and theequivalent damping ratio of LRB increases with the increase of compressive stress, and the effect of compressivestress on the yield force and the equivalent damping ratio decreases with the increase of the shear strain. The postyield stiffness of LRB decreases with the increase of compressive stress, and the effect of compressive stress on thepost yield stiffness decreases with the increase of shear strain. The horizontal equivalent stiffness of LRB decreaseswith the increase of compressive stress, and the effect of the compressive stress on the horizontal equivalent stiffnessslightly increases with the increase of shear strain. According to the test results, the empirical formula on the pres-sure dependency of the bearing shear properties is given, which can be used by the engineering designers.