摘要
在对钢筋沥青隔震层的实验和研究中我们发现,由于重力二阶效应的影响,隔震层的实测刚度往往小于结构力学中的计算刚度,而实测自振周期则大于计算周期。对钢筋沥青隔震层来说隔震层侧向刚度取决于隔震钢筋的侧向刚度,为研究分析这一问题,本文采用如下方法:(1)建立了重力荷载作用下隔震钢筋的平衡微分方程,并求得了刚度的解,在分析了它的适用性后,提出了考虑上部重力荷载作用的隔震层修正侧向刚度;(2)将修正后的侧向刚度与实验结果拟合,发现修正后侧向刚度与实验值拟合较好,线性相关系数为0.81;(3)以实验模型为算例分析了同一工程中,修正前与后两种刚度计算方法对隔震性能评价的差别。结果表明,按修正后刚度分析的隔震效果更好,两种方法计算结果的差距随隔震层刚度的减小而增大。值得注意的是,重力荷载导致的侧向刚度减小效应是普遍存在的,这一点在目前对结构振动特性分析时往往被忽略了。
The steel-asphalt isolation layer is a new kind of isolation structure,which is mainly composed of isolated steel bar and asphalt ointment.It depends on the small lateral stiffness of steel bar and the damping of asphalt ointment to achieve the purpose of isolation.In a large number of experiments and studies,it is found that the measured stiffness of the isolation layer is usually smaller than the calculated stiffness in structural mechanics,and the measured natural vibration period is larger than the calculated period.Considering the large gravity load on the top of the isolation layer,we believe that this phenomenon is caused by the second-order effect of gravity.For the steel-asphalt isolation layer,the lateral stiffness of the isolation layer depends on the lateral stiffness of the isolation steel bar.To study and analyze this problem,the main methods adopted in this paper are as follows:Firstly,establishing the equilibrium differential equation of the isolation steel bar under gravity load and get the theoretical solution,after analyzing its applicability,the modified lateral stiffness of isolation layer considering the upper gravity load is proposed.Secondly,fitting the corrected lateral stiffness with the experimental results,and we found that the corrected lateral stiffness fitted well with the experimental values,with a linear correlation coefficient of 0.81.Finally,the experimental model is taken as an example to analyze the difference between the two stiffness calculation methods(before and after the modification)in evaluating the isolation performance in the same project,the results show that the isolation effect calculated by the modified stiffness is better,and the difference between the calculation result of two methods increases with the decrease of the stiffness of the isolation layer.This also indicates that the method of stiffness analysis before modification is conservative,and the reduction of stiffness caused by gravity load is beneficial to the safety of the structure from the perspective
作者
尚守平
肖逸夫
SHANG Shouping;XIAO Yifu(College of Civil Engineering,Hunan University,Changsha 410082,China)
出处
《地震工程与工程振动》
CSCD
北大核心
2020年第6期16-24,共9页
Earthquake Engineering and Engineering Dynamics
基金
国家“十二五”科技支撑计划(2015BAL03B01)。
关键词
钢筋沥青隔震层
侧向刚度
平衡微分方程
自振周期
隔震效果
steel-asphalt isolation layer
lateral stiffness
equilibrium differential equation
natural vibration period
isolation effect
