Research on axial compression performance of concrete columns with angle steel embedded in BMSCC stay-in-place formwork

Abstract

A new type of stay-in-place formwork column (SFC) was proposed. The square prefabricated shell was made of basic magnesium sulfate cement based composite (BMSCC) and reinforced by angle steel frame. The SFC can be formed after ordinary concrete is poured. The optimum mix ratio of BMSCC was obtained by physical and mechanical tests. The axial compression tests were conducted on 5 SFCs and 3 reinforced concrete (RC) contrast columns, to investigate the effects of the amount of angle steel and the batten plate spacing on the axial compression performance of the SFCs. The results show that the axial compression capacity, cracking load and ductility of the SFC are improved compared with the RC column under the same conditions. The bearing capacity increased by about 13 % and the cracking load increased by more than 54 %. The axial compression capacity increases with the increase of the section area of the angle steel and the decrease of the spacing between the batten plates. According to the theoretical analysis and test results, by introducing the reduction coefficient of angle steel strength and the reduction coefficient of cement strength, the calculation expression of axial compression capacity of short column with BMSCC stay-in-place (SIP) formwork reinforced by angle steel was established.