냉간성형강 볼트접합부의 파단모드 및 최대하중 고찰

Abstract

Cold-formed steel design standards such as AIK, AISI, CSA, EC3, AIJ etc. which were suggested through experimental and numerical research with many parameters to estimate the failure mode and ultimate strength of bolted connections were summarized according to four failure modes of bolted connections ; net section fracture, end shear out fracture, bearing fracture and block shear rupture. These design equations which have been revised until recently were classified into some expressions based on types of shear connections, use of washer, requirements of ductility, shear lag effect, ratio of bolt diameter to thickness etc. In this study, it is shown that there are differences between the standards with respect to same failure mode and, in order to verify their applicability in predicting ultimate behavior of connections, the comparisons among current design codes and two existing test results of connection specimens fabricated from common steel and low ductility steel were made. It is recommended that AISI specification for bolted connections governed by net section fracture, end shear out fracture and bearing fracture, and CSA design code for block shear rupture within limited edge distance be used. In addition, revised formula for block shear rupture considering bearing fracture is suggested.