Dynamic Analysis of a Cable-Stayed Concrete-Filled Steel Tube Arch Bridge under Vehicle Loading

This paper presents the results from a dynamic analysis of a cable-stayed concrete-filled steel tube arch bridge under vehicle loading. The study is carried out based on a three-dimensional vehicle-bridge coupled model. A finite-element model for the bridge is first developed and validated based on field measurement data. A truck specified by industry standards is adopted for vehicle loading in the analysis and is simulated as a multidegree-of-freedom vehicle model. Three important indexes, including the dynamic impact factor, perceptible level of vibration, and ride comfort of the bridge, are investigated. A parametric study is conducted to investigate the effects of a few important parameters, including the vehicle loading condition, vehicle speed, and road surface condition, on the three indexes. Results from the analysis show the following: (1) the dynamic impact factors, which vary between different bridge components/locations, are significantly affected by the three parameters; the impact factors of key structural components of the bridge studied are generally below the value of 0.33 specified in previous design specifications; (2) the perceptible level of bridge vibration is greatly affected by the road surface condition and vehicle loading condition; pedestrians can feel it to be slightly hard to walk on the bridge when two trucks move side by side under poor road surface conditions; and (3) the ride comfort of the bridge decreases as the road surface condition becomes worse, and drivers can feel a little uncomfortable under poor road surface conditions. Because all three indexes studied are found to be greatly affected by the road surface condition, establishing and maintaining a regular program of maintenance is very important to assure both the safety and serviceability of the bridge studied.