Block shear capacity in cold-formed lean duplex stainless steel double-shear bolted connections

Abstract

Since stainless steel has many advantages such as excellent durability, ductility and corrosion resistance, the use of stainless steel has been increased in a variety of structural members and industrial fields. Even if stainless steels are included as structural materials of the Korean Design Standard, the corresponding design standards for stainless steel structural members are not specified in Korea. Recently, lean duplex stainless steel, STS329FLD with less nickel (reduced to 0.5%~1.5%) has been developed as a substitute for austenitic stainless steel (8%~10.5% nickel in STS304) and included in the Korean Industrial Standards. In this paper, experimental studies on double-shear bolted connections fabricated with the lean duplex stainless steel were conducted and the validation of finite element analysis model was verified in the field of ultimate strength and fracture mode through the comparison with test results. Parametric studies were also performed with extended end distances and edge distances. Analysis strengths were compared with block shear predictions by the current design equations and suggested equations by previous researchers. A modified block shear strength equation was recommended considering the material properties of lean duplex stainless steel and the shear stress distribution in the critical shear section of block shear. Moreover, additional tests for seven specimens were performed and the feasibility of the recommended block shear equations in this study was also verified.