Effect of Structural Parameters on Dynamic Characteristics of Through Concrete-Filled Steel Tube Arch Bridges

To study the effect of structural parameters on the dynamic characteristics of through concrete-filled steel tube(CFST) arch bridges,a through CFST arch bridge with span arrangement 2×125 m was cited as an example and analyzed,the model of the bridge was set up by the software ANSYS and the first 6 orders of natural vibration frequency and the corresponding vibration modes of the bridge were calculated.The results of the calculation show that the vibration of the bridge has both the individual in-plane and out-of-plane vibration and also the in-plane and out-of plane vibration coupling.The effect of the structural parameters,such as the steel content ratio of the main arch rings,sectional area and arrangement of the wind bracings,in-plane initial deflection of the arch ribs,deck width and rise-to-span ratio,on the dynamic characteristics was analyzed.The results of the analysis show that the increase of the steel content ratio,the rational arrangement of the wind bracings and the appropriate decrease of the rise-to-span ratio can effectively increase the structural rigidity of the bridge,the effect of the in-plane initial deflection of the arch ribs on the dynamic characteristics of the structure can be ignored and the excessive width of the deck will decrease the rigidity of the structure,which requires that the cross ties should be appropriately reinforced.