Abstract:To study the dynamic response and damage characteristics of the super-wide concrete self-anchored suspension bridge under the blast loading,a real bridge with these characteristics was selected as the background,and the numerical simulation was used to analyze the dynamic response of the top surface crack shape and the vertical displacement of the bottom plate of the super-wide box girder under the close blast of the bridge deck.Firstly,the refined finite element model of the whole bridge was established by using SolidWorks and HyperMesh.Secondly,the blast loading was applied by Ansys/LS-DYNA and *LOAD_BLAST_ENHANCED (LBE ) method,and the reliability of the calculation method was verified by combining the blast test results of concrete members in the literature.Finally,the dynamic response of the bridge under different explosive equivalents and different lateral and longitudinal blast positions was analyzed parametrically.The results show that when the TNT equivalent is 300 kg,the stress of the concrete unit right below the blast center reaches the limit value and fails,forming an elliptical crack.With the increase of TNT charge,the peak value of vertical displacement at the center of the bottom plate directly below the blast center increases continuously,with the vertical displacement reaching 135.9 mm after 50 ms of blast under 1000 kg charge.With the increase of the distance to the explosion center,the vertical displacement of the bottom plate decreases,and the increase speed of the vertical displacement slows down.The internal force change of the suspender correlates with the vertical displacement of the bottom plate of the connected box girder.The larger the vertical displacement of the bottom plate of the box girder,the higher the first peak value of the internal force change of the suspender.Under the same explosive equivalent,when the explosion center is at different positions in the lateral and longitudinal directions of the bridge,the difference in the dynamic response and crack shape of the super-wide box girder is mainly caused by the different support and restraint effects of the cross diaphragm and web.The research results can provide important references for anti-blast protection and reinforcement of self-anchored concrete suspension bridges.
