Experimental research on steel-concrete-steel sandwich panels subjected to biaxial tension compression

This paper described the experimental results of 9 steel-concrete-steel (SCS1) sandwich panels subjected to biaxial tension compression. Specific specimens and loading modes were designed to simulate uniform loading in SCS panels. 8 LVDTs were used to measure the biaxial averaged principal strains. The test parameters were compression to tension ratio (C/T), steel plate ratio (rho(s)) and tie bar space to steel plate thickness ratio (Bt/t). Test results show that SCS panels feature high strength and good ductility even under high C/T. The ultimate strengths of SCS panels are compared with previously established failure criteria. It was found that, in the principal tension direction, for SCS panel elements under high C/T, the averaged concrete stress between cracks may turned from tension to compression, which is supposed to be caused by the rapid enlargement of Poisson's effects of the concrete subjected to combined tension and compression. According to the test results, confinement effect and compression softening effect coexist in the principal compression direction: tension weakening effect rather than tension stiffening effect happens in the principal tension direction. These two new findings will help us further understand the mechanical behavior of concrete in SCS panels in the future research. (C) 2019 Elsevier Ltd. All rights reserved.