世博轴阳光谷大型钢结构风致线性和非线性响应比较

Comparison of linear and nonlinear wind-induced responses of a structure of Expo Axis

以世博轴阳光谷结构为研究对象,基于刚性模型风洞试验获得的表面风压分布结果,研究了时域内考虑几何非线性和不考虑几何非线性两种条件下计算得到的位移响应分布及位移和轴力响应的差别。结果表明,结构非线性效应相对较强的长悬挑边在大位移下出现刚度软化,使其刚度减小,竖向位移增加,非线性方法获得的响应值大于线性方法,但是差别在可接受范围之内;两种条件下计算的响应功率谱曲线反映了类似的能量分布。

Based on the wind pressure data from the wind tunnel test,the distributions of displacements of a structure of Expo Axis and the differences between the displacements and the responses under axial forces were analysed in time domain in the two cases of with or without consideration of geometrical nonlinearities in structure.The results indicate that the cantilevered part,which is of high nonlinear behavior,appears stiffness softening.Because of that,the total stiffness of structure decreases and the displacement increases.The displacement RMS values computed nonlinearly are greater than those computed linearly,but the differences are acceptable from the viewpoint of engineering application.The power spectral density curves computed in both cases show the similar energy distributions.