Design And Damage Static & Dynamic Analysis Of A Concrete-Filled Steel Tube Arch Bridge Model

The adaptability and advantages of concrete-filled steel tube (CFST) arch bridges has led to a boom in their construction in China during the last decade. However, some bridges were found different damages and some bridges collapsed during the operation of these bridges. So it is necessary to develop an effective method to make sure the safety of these bridges and avoid the collapses.In this paper, the author took the GuangHua Bridge which is a through tied arch bridge in Shantou as the prototype, built the plane finite element models of GuangHua Bridge and bridge model using ANSYS and implemented static and transient analyses, designed and built a CFST arch bridge model in their laboratory. Then 3-D finite element models of GuangHua Bridge and bridge model were built and the natural frequencies and modes were obtained using ANSYS modal analysis.Damage to the vertical link is one of the most common and dangerous causes of failure in both half-through and through CFST arch bridges. Influences of different vertical link damage cases on static and dynamic characteristics were studied. Analysis indicated that the self-axial force of the damaged vertical link decreases and the tension forces of neighboring links increase when a vertical link is damaged, but the tension forces in the other links change very little. Damage to any link causes little changes to the natural frequencies of the model with the greatest change occurring in the natural frequency corresponding to the third vertical bending mode. The curvatures of the mode shapes of the longitudinal girders, particularly of the second vertical bending mode, are sensitive to damage in the vertical links. Using the change of mode shape curvature, the location of the damaged vertical links can be reliably identified. At last, this paper proposes a static and dynamic integrative analysis method for identifying the damage location in the vertical links. This method identifies the damage location by analyzing the changes in the natural frequencies, the modal curvatures of the longitudinal girders, and the axial forces in the vertical links.Finally, calm-loading,move-loading and dynamic experiments were done in the lab. The calm-loading test showed that the stiffness of the bridge model is big and the intensities of concrete beam and arch rib accord with the requirement of the design. Natural frequencies gained by dynamic test are different with the theoretic values, so it is needed to next test and update the ANSYS finite element model.