| Concrete-filled steel tube(CFST)members are widely used in modern high-rise buildings and transportation projects.In practical projects,CFST members will inevitably suffer accidental loads such as impact loads.With the development of science and technology,the advancement of urbanization and the acceleration of transportation,CFST members pose great threats and losses to people’s lives and social property.Deflection is an important index for evaluating the damage and destructive performance of force components.In this paper,the deflection calculation of concrete filled circular steel tubular members subjected to transverse impact at any impact point is studied.The main research contents are as follows:1.The drop hammer impact test data of 55 concrete filled circular steel tubular members under three kinds of constraints,i.e.,two-end fixed support,two-end simple support and two-end fixed simple support,were collected and summarized.Statistical results show that the experimental parameters information of previous scholars covers a very wide range of structural factors.It includes the parameters of impact body,component,material and impact site.At the same time,this wide range of parameters also means the extensive application of the revised formula.2.Assuming that the material is ideal rigid-plastic,based on the theory of plastic transition hinge and considering the constraints at both ends,the deflection calculation of component impact point under any transverse impact point is deduced theoretically,and the deflection calculation formulas of component impact point under the constraints of fixed support at both ends,simple support at both ends and simple support at both ends are given.3.Considering energy loss and local deformation,based on the statistical analysis of impact test data,the theoretical calculation formula of impact point deflection of concrete filled steel tubular members is revised and reduced.The deflection correction formulas of concrete filled circular steel tubular members with two ends fixed,two ends simply supported,two ends simply supported and unified constraints are given respectively.Through error analysis and comparison with test results,the accuracy of the revised formula is good,which can provide reference for engineering design and research. |
