Mechanical properties of HRB400E/316L stainless steel clad rebar under low-cycle fatigue

Abstract

Under severe disasters, the longitudinal rebars in the plastic hinge areas of concrete structures are prone to sustain significant buckling and then suffer low-cycle fatigue, due to the cracking and detachment of covering concrete. Based on a novel type of stainless steel clad rebar with HRB400E hot rolled ribbed carbon steel core covered by 316L stainless steel clad (HRBSC), this paper conducted experimental studies to investigate the mechanical properties of HRBSC under low-cycle fatigue with buckling, considering strain amplitude, strain rate and nominal diameter. Based on the test results, the ultimate strength, strength degradation and fatigue life evaluation methods of HRBSC are discussed and proposed. It is validated that HRBSC possesses desirable material properties and can be used as longitudinal load carrying rebar in seismic designed structures. The elastic modulus of HRBSC is proved to be affected by the clad ratio. It is found that the strain rate and nominal diameter have limited effects on the ultimate strength and strength degradation of HRBSC during low-cycle fatigue, while the key factor is strain amplitude. Test results show that the increase of strain rate influences the low-cycle fatigue mechanism and reduces the fatigue life of HRBSC under small strain amplitude, while the growth of nominal diameter brings positive effects on the fatigue life.