地震波斜入射下土-单层柱面网壳结构振动台试验研究

Experimental Investigation for Soil-single-layer Cylindrical Reticulated Shell Interaction System Considering Oblique Incidence of Earthquake Wave

现阶段有关地震波斜入射下大跨空间网格结构地震响应的试验研究未见报道.基于设计的7.7m×3.2m×1.2m大型刚性模型箱和1.8m×1.8m的单层柱面网壳结构,并实测土体参数,通过4台阵体系设计实现自由场振动台试验和土-单层柱面网壳结构振动台试验.通过自由场振动台试验结果与数值模拟结果的对比验证了试验设计的正确性,并研究了土-单层柱面网壳结构体系的地震响应.试验结果表明：土-结构相互作用下网壳屋盖的地震响应随着地震波入射角度的增大呈现明显的非线性变化,当以30°~60°角度输入时,网壳地震响应剧烈;不同地震波输入下,网壳柱底两个水平方向加速度最大值比值在1∶0.3~1∶3之间.进行抗震计算时,柱底两水平方向的加速度输入比例与地震波的入射角度有关,宜考虑地震波斜入射的空间效应.

The experimental investigation about oblique incidence of earthquake wave on seismic response of large span spatial grid structure was lack at the present stage. Based on a model box of 7. 7 m length,3. 2 m width and 1. 2 m depth,and a single-layer cylindrical reticulated shell of1. 8 m length and 1. 8 m span,at the same time,the soil parameters were measured,a free field shaking test and a shaking table test of soil-single-layer reticulated cylindrical shell interaction were realized by four array shaking table system. The correctness of the shaking test design was verified by comparing the results of free field shaking table test and numerical simulation,then the seismic response of the soil-single-layer cylindrical reticulated shell system subjected to oblique incidence wave was studied. Experimental investigation showed that the seismic response of the reticulated shell presents obvious nonlinear variation with the increase of the incident angle of seismic wave. Especially when the seismic wave was input from 30° to 60°,the seismic response of the reticulated shell was violent. The maximum ratio of the horizontal acceleration at the bottom of the reticulated shell column was between 1 ∶ 0. 3 and 1 ∶ 3. When the seismic calculation was carried out,the acceleration input ratio of the two horizontal direction of the column base was related to the incident angle of the seismic wave,and the spatial effect of oblique incidence of earthquake wave should be considered carefully.