预应力混凝土部分斜拉桥的阻尼特性

以塔梁固结、墩梁分离的预应力混凝土部分斜拉桥为对象,通过桥梁的振动试验分析这类结构的阻尼特性,在此基础上应用非正交阻尼理论研究构件阻尼与振型阻尼比之间的关系,验证在小阻尼条件下结构振型阻尼比可以通过构件阻尼效果线性叠加得到的假定.讨论应变能比例阻尼理论计算结构振型阻尼比的特性,并利用实测和理论结果的对比探讨这类结构的构件阻尼比.结果表明,预应力混凝土部分斜拉桥的竖弯和扭转振型的阻尼比约为1%,小于普通预应力混凝土连续梁桥；应变能比例阻尼理论可近似估算结构的振型阻尼比,预应力混凝土主梁、混凝土墩塔、钢拉索和场地的材料阻尼比建议分别在1.0%、1.2%、0.1%、4.0%附近取值．

Damping characteristics of PC partial cable-stayed bridge

Taking a PC partial cable-stayed bridge with tower beam consolidation and pier beam separation system as an example,the damping characteristics of such structures was investigated in bridge vibration test.Based on non-orthogonal damping theory,the relationship between component damping and modal damping ratio was studied,and the assumption that the modal damping ratio can be obtained by superposition of component damping under small damping condition was verified.The characteristics of damping ratio which was calculated by strain energy proportional damping theory was discussed,and the component damping ratio was talked over by comparison of experimental and theoretical results.The results show that the damping ratios of vertical bending mode and torsional mode are about 1%,which is less than that of ordinary PC continuous beam bridge.The damping ratio can be obtained by linear superposition of component damping according to non-orthogonal damping theory.It also can be approximately estimated with strain energy proportional damping theory,while the material damping ratios of PC beam,concrete pier and tower and steel cable are around 1.0%,1.2%,0.1% and 4.0% respectively.