Improved design shear method of the bolted cold-formed steel clip-angle for serviceability

Abstract

This paper presents an experimental investigation on the three-bolted clip-angle (CA) connector under direct shear load. A total of 48 clip-angle connection tests were carried out with 27 different clip-angle configurations by varying the thickness, width and depth of the clip-angle. The present experimental results and the data from literature indicates that the existing design methods for the service limit state design of the clip-angle are inefficient. The present investigation proposes a novel and efficient design method for the service limit state after calibration against test data, for the low-grade steel clip-angle (fy=271MPa to 307 MPa) from the present research work and for the higher grade steel (fy=375MPa to 550 MPa) from the literature data. Hence the proposed design method has wider steel grade application from fy=271MPa to 550 MPa. Parametric studies were performed to evaluate the influence of the geometric variables on the service shear strength of the three bolted clip-angle. The proposed design method was also applied to the welded clip-angle configuration in the literature and corresponding design equations were developed. In addition, a comparative study between the present three-bolted and most recent welded clip-angle connection was conducted which indicated that the three-bolted clip-angle configuration has higher stiffness than that of the welded configuration. Reliability studies were performed and relevant design factors were determined according to the LRFD, LSD and ASD methods.