大型梁式渡槽竖向地震作用估计

应用流体势流理论与结构的振动理论 ,通过流 固耦合简化分析 ,导得了渡槽承重简支梁的湿频率及湿振型估算公式 ,导得了结构竖向地震响应的时程计算公式 ,应用反应谱法 ,导得了作用于结构的等效竖向地震荷载估算公式 ,做了几项数值算例 ,分析结果表明 :(1)由于附连水质量的影响 ,梁的湿频率比其干频率要低 ,但湿振型与其干振型完全相同 ;(2 )水质量在结构竖向地震响应中起着重要的作用 ,竖向响应的幅值随着不同的场地而发生改变 ,一般水越深 ,结构的响应越大 ;(3 )在 7度设防时应考虑竖向地震的作用。

ESTIMATION OF VERTICAL SEISMIC ACTION FOR LARGE-SCALE BEAM AQUEDUCT

A formula for the vertical seismic load of the large?scale beam aqueduct is proposed in the paper It is based on the theory of potential flow and structural vibration Firstly,the wet frequencies and wet mode shapes are got through the simplified fluid?structure interaction The time?history response of the structure under the vertical seismic load is obtained At last,applying the response spectrum,the equivalent seismic load of the large?scale beam aqueduct is appeared Some useful conclusions are obtained through the study It is found that the wet frequencies are lower than the dry frequencies,but the wet mode shapes are identical to the dry one The water mass plays an important role in the vertical seismic response,which varies with the different geological sites.The vertical seismic action should be considered in the structural design.