【摘要】 多塔长跨斜拉桥受力复杂,采用轻质结合梁时结构地震响应更具特点。本文以某主跨为616m的三塔结合梁斜拉桥为工程背景,制作动力缩尺模型进行三台阵振动台试验。在单向一致激励振动台试验的基础上,进行多维激励、多点激励振动台试验,并与数值分析结果进行比较验证。试验结果表明:此结构的基本振型为中塔纵弯与主梁竖弯的耦合振动。纵向一致地震作用下,主塔及主梁均会有较大的地震响应;横向一致地震激励下,中塔地震响应较边塔更为不利。多点激励振动台试验表明,行波效应使得各构件地震响应不同程度增大;最后,通过多维地震激励下试验结果验证了规范中方向组合计算方法的准确性。更多还原

【Abstract】 As long-span cable-stayed bridge with multi-tower has complex mechanical characteristics,the seismic responses are quite different when the lightweight composite girder is adopted.In this paper,a practical project is taken as research background and the scaled test specimen is made,which is three towers cable-stayed bridge with span of 616m.The shaking table tests under uniform excitation,multi-support excitation and multi-dimensional earthquake excitation are carried out respectively.Results show the fundamental mode shape is coupled vibration of middle tower in longitudinal direction and girder in vertical direction.Under the uniform earthquake excitation in longitudinal direction,the seismic responses of towers and girder are significant.And the seismic responses of middle tower are more disadvantageous than side tower under earthquake excitation in transverse direction.The tests under multi-support and multi-dimensional earthquake excitations indicate that wave propagation effects on seismic response can not be ignored and the combination method for different direction effect recommended by seismic specification is verified.更多还原