对具有摩擦型接触面的经典Newmark双滑块系统进行分析,给出单周期简谐激励下最大相对滑移量的近似解析式,进一步分析发现,接触面最大相对滑移量对应的能量传递系数e/(ky/ka)与ky/ka存在近似线性关系;拟合86条地震波作用下的338个地震永久位移计算结果,得到e/(ky/ka)与ky/ka的线性表达式,给出地震永久位移的简化计算公式.公式基于较严格的理论推导,同时考虑了地震波的随机特性,是发展经典Newmark理论的新思路;与其他学者建议的公式对比表明,本文公式计算结果合理、形式简单而便于工程应用.
Classic Newmark double-sliding block system with friction interface was analyzed and an approximate analytical solution was given for the maximum relative sliding displacement under a single harmonic excitation.It was found by further analysis that there was an approximate linear relationship between the earthquake input energy coefficient e/(ky/ka) and(ky/ka) when the relative displacement in the interface became the maximum.86 curve fitting was performed for 338 earthquake-induced permanent displacement data,so that the linear expression of e/(ky/ka) with respect to(ky/ka) was obtained,and a simplified formula was given for predicting the earthquake-induced permanent displacement.The formula was derived on a relatively strict theoretical basis and the stochastic characteristics of seismic wave was taken into account so that it is a new idea to develop the classic Newmark theory.Compared with other earthquake-induced permanent displacement formulas in literature,the calculation results using the proposed formula was reasonable and could be easily used in practice.