空间钢网格盒式结构的随机地震响应研究

Random seismic response of spatial steel-grid box-structure

给出了空间钢网格盒式结构地震反应运动方程,利用复模态理论推导了盒式结构体系的时域闭合解和随机响应闭合解。假定随机响应符合极值Ⅰ型分布,给出了结构响应的可靠度计算公式。利用随机响应的峰值因子和变异系数,构建了随机响应给定概率的置信区间。以南京多功能展厅为工程背景,以KANAI-TAJIMI功率谱作为随机激励,计算了空间钢网格盒式结构的随机响应峰值和方差;同时选用14条强震记录作为确定性激励,得到盒式结构复模态时程响应峰值。计算结果表明,两种方法所得结果具有一致性。随机地震响应方法可作为盒式结构这一新型结构体系的补充计算方法,也可用于估计和校核确定性时程响应的可靠程度。

The differential motion equation of a steel grid box-structure under ground excitation was given. The close form solutions of time domain response and random seismic response were obtained based on the complex mode theory. A formula for the structure reliability was obtained with a hypothesis of probability distribution of extreme value type I and the confidence interval with a specific probability was derived based on the mean value and variance of random seismic response peaks. Taking the Nanjing multi-function exhibition hall as an example,the mean value and variance of random seismic response peaks were calculated. Meanwhile, 14 complex-mode deterministic displacements were calculated under 14 records of seismic wave excitations. The results indicate that the results of the two methods are consistent. The random response analysis method is an effective assistant calculation method in the design of spatial steelgrid box-structure,and based on that,the reliability of structures＇ responses can be estimated.