地震作用下高位层间隔震体系参数优化设计

Parameter optimization design of high position story isolated structure subjected to earthquake

对地震作用下高位层间隔震体系中隔震支座参数的优化设计进行了研究。通过两自由度体系近似模拟多自由度结构层间隔震体系,将地震波简化为白噪声,优化目标为使层间隔震上部与下部结构频域振动能量和最小,推导了隔震支座优化参数的理论表达式,隔震支座的优化刚度系数和阻尼系数与上部和下部结构的质量比密切相关。在数值算例中,通过比较过滤白噪声激励下多自由度体系中的隔震支座参数化研究结果和两自由度体系理论结果,发现二者吻合良好;实际地震波记录激励下多自由度结构体系的响应与两自由度体系的响应规律一致。研究结果表明,多自由度结构高位层间隔震体系的隔震支座优化参数可基于理论表达式得出,可为高位层间隔震体系的初步设计提供参考。

Optimizations are made for the parameters of the isolator used in the high-position story isolated structure that is subjected to earthquakes. The multi-degree-of-freedom system is approximately modeled by the two-degree-of-freedom system for the story-isolated structure, while the ground motion is represented by white-noise excitation. The optimization target is to minimize the sum of vibration energy in frequency domain for the upper and the lower structures in the structure model. The explicit analytical expressions for the optimal stiffness coefficient and the damping coefficient of the isolator are derived, which demonstrates both of the two coefficients are closely related to the mass ratio of the upper structure to the lower one. In the nu- merical study, using the Kanai-Tajimi filtered white-noise ground motion model, the appropriate parameters of the isolator are achieved through extensive parametric studies firstly. Then, it is found that the parameter values of the isolator obtained through the parametric study agree well with the optimal theoretical values obtained by means of analytical expressions. Struc- ture being excited by actual earthquake records, the seismic responses also agree well between the multi degree-of-freedom sys- tem and the two-degree-of-freedom system. The results show that the analytical formulas for the isolator can provide usuful in formation for the preliminary design of the high-position story-isolated structures.