Axial-compression performance and numerical-simulation analysis of steel tube coal gangue concrete column

Coal gangue is a solid waste produced in the process of coal mining, excessive accumulation will occupy land and pollute the environment. It is one of the most effective means to realize comprehensive utilization of coal gangue by replacing some aggregates in concrete and applying it to engineering structures. In this paper, based on C30 concrete, by changing the replacement rate of coal gangue, slenderness ratio, and steel pipe wall thickness, 17 Coal gangue concrete-filled steel tubular (CGC-FST) columns were designed and made, and the axial compression tests were carried out. The results show that the failure mode of the CGC-FST column is similar to that of CFST, and the annular band shear buckling occurs on the wall of the steel pipe, and the higher the slenderness ratio, the more the number of buckling in the middle. With the increase of coal gangue substitution rate, the ultimate bearing capacity of the CGC-FST column decreases gradually, and the ductility of the specimen decreases slightly. The increase in slenderness ratio reduces the ultimate bearing capacity of the member, the failure form changes from material failure to stable failure, and the material properties are not fully utilized. The most obvious way to improve the bearing capacity and ductility of gangue steel tube members is to increase the steel content. Through the finite element simulation analysis of more working conditions of the CGC-FST column, the calculation formula of the bearing capacity of the CGC-FST column is fitted, which can effectively predict the bearing capacity of the CGC-FST column in a certain range. •Axial compression performance of CGC-FST.•Finite element analysis of CGC-FST.•The bearing capacity formula was established.