人行钢箱梁桥模态试验研究

Experimental Modal Anlysis of Pedestrian Steel Box Girder Bridge

为了了解人行钢桥的自振特性,运用东华测试系统对某人行钢箱梁桥进行模态测试,得到桥梁的动力特性参数,并将试验测得的固有频率、模态振型与ANSYS有限元模型中的模态数据进行对比分析。分析结果表明:该人行钢箱梁桥的基频的试验值与理论值的误差为3.8%,行人的附加模态质量是对试验产生误差的原因之一,但对结构基频的影响不大,这也就证明了采用峰值拾取法处理时域数据是合理的,同时结合模态判定准则所得模态数据也是可信的,通过该模态测试系统可有效地测得模态参数(固有频率、模态振型及阻尼比)。

In order to study the natural vibration characteristics of the pedestrian bridge steel,a pedestrian steel box girder bridge’s model experiment is carried out with Donghua Test System to get the dynamic characteristics of bridge,and comparing Natural frequency and mode shapes with modal data analysis of ANSYS finite element model. The analysis results indicate that the error between the fundamental frequency experiment value and the theoretical value of the pedestrian steel box girder bridge is 3. 8%. And the additional modal mass of pedestrian is one of the reasons why the experiment have error,it’s influence is little. What proved that using the Peak Picking Method to manipulation time domain data is reasonable. At the same time,the modal date that obtained by combining with the modal criterion is credible. That modal parameters（ natural frequency,modal vibration mode and damping ratio） can be measured effectively by the modal testing system.