长周期地震动作用下穿斗式木结构民居动力响应分析

Seismic response of column-and-tie timber structures under long-period ground motions

摘要:

为研究具有柔性受力机制的穿斗式木结构在长周期地震动作用下的动力响应规律,运用OpenSees软件建立带木板墙穿斗式木结构的有限元模型；在验证其合理性的基础上,探究穿斗式木结构民居在长周期地震动作用下的动力损伤演化机制。结果表明:通过合理简化关键节点和构件后,建立的有限元等效模型结构x向和y向的一阶平动频率与相应试验值的误差分别为6.5%和11.3%;等效模型的加速度放大系数沿结构层高方向的变化规律与试验结果相同。试验发现，长周期地震动TCU054、TCU102、ILA048和ILA056的傅里叶谱幅值主要集中在低频段,其加速度反应谱的长周期成分较Taft波更为丰富。在长周期地震动的作用下,结构的加速度放大系数、位移反应、层间剪力均大于相同峰值加速度Taft波作用下的动力响应。在峰值加速度为0.22g的长周期地震动作用下,结构屋脊x向和y向的最大相对位移分别是Taft波作用下的2.09~9.76倍和2.68~8.71倍；基底剪力分别是Taft波作用下的1.30~1.71倍和1.46~2.09倍。

Abstract:

A finite element (FE) analysis model was established in this paper to analyze the dynamic responses of column-and-tie timber structures with flexible mechanisms under long-period ground motions. The OpenSees was applied to verify the rationality of the FE model, after which the dynamic damage evolution mechanism of column-and-tie timber structures under long-period ground motions was explored. The results indicate that the errors between the first natural frequencies from the FE results and the corresponding shaking table test results are 6.5% and 11.3% in the x and y directions, respectively. The variation trend of the acceleration amplification factor along the structure's height direction based on the FE results is similar to that based on experiment results. Moreover, the Fourier spectral amplitudes of long-period ground motions TCU054, TCU102, ILA048, and ILA056 are mainly concentrated in low-frequency bands, while the long-period components of their acceleration response spectra are richer than Taft waves. Furthermore, the acceleration amplification factor, displacement response, and interlayer shear force of the structure under long-period ground motions are greater than those under the Taft wave with the same peak ground acceleration (PGA). Under the long-period ground motion with a PGA of 0.22g, the maximum relative displacement of the roof in the x and y directions are 2.09-9.76 times and 2.68-8.71 times of those under the Taft wave, respectively. Moreover, the corresponding shear forces in the x and y directions are 1.30-1.71 and 1.46-2.09 times those under the Taft wave.

Abstract:

A finite element (FE) analysis model was established in this paper to analyze the dynamic responses of column-and-tie timber structures with flexible mechanisms under long-period ground motions. The OpenSees was applied to verify the rationality of the FE model, after which the dynamic damage evolution mechanism of column-and-tie timber structures under long-period ground motions was explored. The results indicate that the errors between the first natural frequencies from the FE results and the corresponding shaking table test results are 6.5% and 11.3% in the x and y directions, respectively. The variation trend of the acceleration amplification factor along the structure's height direction based on the FE results is similar to that based on experiment results. Moreover, the Fourier spectral amplitudes of long-period ground motions TCU054, TCU102, ILA048, and ILA056 are mainly concentrated in low-frequency bands, while the long-period components of their acceleration response spectra are richer than Taft waves. Furthermore, the acceleration amplification factor, displacement response, and interlayer shear force of the structure under long-period ground motions are greater than those under the Taft wave with the same peak ground acceleration (PGA). Under the long-period ground motion with a PGA of 0.22g, the maximum relative displacement of the roof in the x and y directions are 2.09-9.76 times and 2.68-8.71 times of those under the Taft wave, respectively. Moreover, the corresponding shear forces in the x and y directions are 1.30-1.71 and 1.46-2.09 times those under the Taft wave.