Patch-loading resistance performance of stainless-clad bimetallic steel plate girders: Numerical investigations and design methods

Abstract

Compared with stainless steel, stainless-clad bimetallic steel (SCBS), which comprises a stainless steel cladding layer and a carbon steel base layer, requires a lower project cost and can maintain the same corrosion resistance, thus allowing the corrosion weakening of steel structures to be solved effectively. Investigations regarding SCBS plate girders, which can be widely used in bridge and industrial structure servicing in corrosive environments, are few. In this study, the patch-loading resistance performance of SCBS plate girders is investigated systematically, and the effects of cladding ratios are considered. A finite element modelling method is proposed to predict the patch-loading resistance performance of SCBS plate girders, which is validated using 33 experimental results regarding conventional structural steel and bimetallic steel plate girders. A comparison of the ultimate strength, load–deflection curve, and failure mode shows that the proposed finite element modelling method can be used to effectively clarify the patch-loading resistance performance of SCBS plate girders. A comprehensive parameter study involving 288 numerical models is conducted. Based on numerical results, the basis for design recommendations is presented. The relationship among the ultimate strength of the plate girders corresponding to SCBS, stainless steel (cladding layer), and HSS (base layer) is determined, and a linear equation is proposed. The applicability of Chinese, American, and European codes in determining the ultimate strength of SCBS plate girders is verified. The verification results show that the existing codes cannot be directly used to determine the ultimate strength of SCBS plate girders. Therefore, two strength reduction functions are proposed to modify the design equations in European codes. The undetermined constants in the proposed strength reduction functions for SCBS plate girders with different cladding ratios are statistically calibrated. Additionally, a predictive equation for determining the undetermined constants in function-I is proposed. When these proposed strength reduction functions are employed, the calculation accuracy of the European codes is significantly improved. The basis for design recommendations presented in this study is valid for the SCBS plate girders with specific geometric dimensions and material properties included in the parametric study.