【摘要】 建立了哪吒大桥———钢桁加劲梁悬索桥的三维有限元计算模型,对该桥进行了振动特性和地震响应研究,对比分析了一致激励下和考虑局部场地效应、行波效应非一致激励下的桥梁地震时程响应的差异。计算结果表明,由于悬索桥的钢桁加劲梁采用半飘浮体系,纵向约束较弱,桥梁第1阶振型为钢桁加劲梁的纵飘;各阶振型的频率呈现出密集分布的形态;考虑地震波传播速度产生的行波效应的影响,桥梁的地震响应与一致激励下的地震响应有一定差异;局部场地效应对哪吒大桥的地震响应影响较大,特别是对大缆应力及结构变形影响很大;哪吒大桥在7度设防(地震波峰值加速度不超过0.15g)时,大桥的抗震安全性是可以得到保证的。更多还原

【Abstract】 Introducing 3D model and free vibration of Nazha suspension bridge in detail,the paper analyzes seismic time-history response under uniform excitation and considering traveling wave effect and local site effect non-uniform excitation.According to analytical result,longitudinal stiffness is weaker than vertical stiffness because of half-floating system,and the first vibration mode is longitudinal floating.Traveling wave effect is non-significant to seismic response of the bridge,and local site effect is distinct to cable’s stress and structural stress of seismic response of the bridge.When seismic wave acceleration is no more than 0.15g according design document’s 7 degree seismic zone,the bridge is secure.更多还原