Research On The Effect Of Debonding On Dynamic Characteristics Of CFST Arch Bridge

In the practical engineering,CFST arch bridge debonding is relatively common problem. In order to know about that debond has impacted on the dynamic property of concrete filled steel tube truss rib,the paper,based on complete debonding hypothesis,choose the reasonable finite element applying ANSYS software,and established the complete debonding model or bonding model of the Zongxi river bridge. The paper study different debonding positions and scope of debonding effect on the dynamic characteristics of the CFST arch bridge. Finally,the paper analyzed dynamic characteristics of the CFST arch bridge in all across under the condition of complete debond which considered different debonding height,different steel ratio,the effect of the inner flange,and different axial stiffness. The following are main research contents anda chievements:(1) Changes in the main arch rib of first-order symmetric and antisymmetric vertical bending vibration mode is given priority to in advance. first ten modes basic shape will not change after bridge debonding only the order of the main arch rib-related mode has changes. Changes in the main arch rib of first-order symmetric and antisymmetric vertical bending vibration mode is given priority to in advance.The main reason is that the main arch rib after debonding to cause a decline in in-plane stiffness of arch rib.(2) After Debonding occurs the frequency of the vibration mode of the arch rib by corresponding drop will happen,and with the increase of debonding range, the bigger the drop also.Debonding for in-plane antisymmetric vibration mode corresponding to the frequency effect is particularly obvious.The same range of debonding at different positions of debonding of the main arch rib of the the influence of the frequency of the corresponding mode shapes,the impact of double side arch foot debonding is greater than single side,which is greater than the middle of arch rib.(3) All across complete debonding, debonding simulation unit considering the axial strength at 0.05 MPa to 0.3 MPa,With the increase of bond strength, vibration frequency of the whole bridge has increased,but small. In-plane vibration modecorresponding to the frequency is very sensitive to the change of bond strength.Debonding height in the range of 0.5 mm to 3.5 mm,each corresponding mode frequency is not sensitive to the change of height of debonding. Compared with outside surface modal frequency,the in-plane vibration mode frequency is more sensitive the changes of. Steel ratio in the range of 5% ~ 13.3%,with the increase of steel ratio, debonding of the influence of vibration frequency of the concrete-filled steel tube arch bridge will be reduced.Inner flange can improve the dynamic performance after CFST arch bridge debonding.