基于动应变测量在桥梁动挠度识别应用研究

Study on the Application of Dynamic Strain Measurement in the Dynamic Deflection Bridge

针对传统桥梁挠度监测过程中精度不足,应用范围局限于小跨度桥梁结构,提出了一种基于应变模态的动应变识别方式。通过动应变互相关函数求得振动梁结构的应变模态振型,利用应变—位移转化关系获得结构的位移模态振型,进而获得应变模型的位移模态坐标。将位移坐标与位移模态振型进行关系叠加获取整个梁结构的动应变实时曲线。以天津外环津静收费站高速路段简支梁段为对象,对动应变识别方法进行了验证,结果表明:在脉冲激励作用下,动挠度识别法能够有效控制不同位置节点动挠度误差持在7%的误差范围内,在移动荷载下的梁结构动挠度识别最大误差在2%以内,满足工程实际需求。

In view of the shortcomings of traditional bridge deflection monitoring process,the application scope is limited to small span bridge structure.A dynamic strain identification method based on strain mode is proposed.Cross-correlation function is obtained by dynamic strain beam vibration strain modal vibration mode of the structure,strain,displacement transformation method was used to get displacement modal vibration mode of the structure,to obtain the strain displacement modal coordinates of the model.The dynamic strain real time curve of the whole beam structure is obtained by the relationship between displacement coordinate and displacement mode.Based on the tianjin outer ring beam static high-speed toll road section as an object,dynamic strain identification methods are verified and the results show that under the effect of pulse excitation,this paper provides the dynamic deflection of identification method can effectively control different node position dynamic deflection error with in 7%of the error range,dynamic deflection of beam structure under moving load identification error within 2%,the biggest meet the demand of practical engineering.