Study On Performance Of Concrete-filled Steel Tubular Piers Under Vehicle Collision: Detailed Finite-element Model,Comparisons Of Current Design Specifications And Performance Evaluation Method

In recent years,accidents of vehicles hitting bridge piers have occurred from time to time.The bridge piers may be damaged or fail due to the collision of vehicles,which may cause serious consequences such as traffic interruption and bridge collapse.Therefore,studying the anti-vehicle impact performance of bridge piers has important engineering practical significance.At present,many scholars have conducted research on the anti-collision performance of reinforced concrete bridge piers.However,there are still few studies on concrete-filled steel tubular piers.Moreover,there are still the following problems in the research on the anti-collision performance of the existing bridge piers: the finite-element models of the used bridge piers have been simplified to varying degrees,but the accuracy is unknown;in the pier design before the finite element simulation study,the effect of vehicle collision load was not considered in accordance with the specifications;for the design review and post-disaster evaluation of the anti-collision performance of bridge piers,there is no applicable evaluation index and method at the same time.Therefore,this paper has carried out the following research on performance of concrete-filled steel tubular(CFST)piers under vehicle impact:(1)The detailed finiteelement model of the CFST pier impacted by the vehicle was established by ANSYS/LS-DYNA.The accuracy of the finite element model is verified by comparison with the existing drop weight test,and the rationality of the detailed finiteelement model is confirmed by comparison with seven simplified models;(2)With reference to the bridges and structural specifications of China,the United States,and Europe,the CFST piers under the same working condition were designed with and without consideration of the impact of vehicle crash loads.Then,based on the detailed finite element model,a comparative analysis of the anti-collision performance of the CFST bridge piers designed by the three rigions was carried out;(3)a method for evaluating the anti-collision performance of CFST bridge piers based on residual deformation is proposed.The residual rotation(the ratio of the residual deflection in the column to the height of the column)is used as the evaluation index,and the residual rotation prediction formula is given based on the simplified calculation model.Through the above research,the following main conclusions are obtained:(1)None of the simplified models can fully achieve the accuracy of the detailed model;(2)CFST piers designed in accordance with the bridge and structural specifications of China,the United States,and Europe have good performance under vehicle impact.The American specification is too conservative,and the European specification is safer and more economical.Whether the impact of vehicle crash load is considered The performance of the bridge pier after collision has little impact,so it can be ignored in the design;(3)The proposed CFST pier performance evaluation method under vehicle impact can accurately predict the results of numerical simulations.In engineering application,it can not only predict the performance of CFST piers in structural design,but also evaluate the performance of CFST piers after vehicle impact.