Typical diseases of a long-span concrete-filled steel tubular arch bridge and their effects on vehicle-induced dynamic response

A long-span concrete-filled steel tubular (CFST) arch bridge suffers severe vehicle-induced dynamic responses during its service life. However, few quantitative studies have been reported on the typical diseases suffered by such bridges and their effects on vehicle-induced dynamic response. Thus, a series of field tests and theoretical analyses were conducted to study the effects of typical diseases on the vehicle-induced dynamic response of a typical CFST arch bridge. The results show that a support void results in a height difference between both sides of the expansion joint, thus increasing the effect of vehicle impact on the main girder and suspenders. The impact factor of the displacement response of the main girder exceeds the design value. The variation of the suspender force is significant, and the diseases are found to have a greater effect on a shorter suspender. The theoretical analysis results also show that the support void causes an obvious longitudinal displacement of the main girder that is almost as large as the vertical displacement. The support void can also cause significant changes in the vehicle-induced acceleration response, particularly when the supports and steel box girder continue to collide with each other under the vehicle load.