Experimental Shear Study of Rivet-Fastened Rectangular Hollow Flange Channel Beams with Web Openings

Abstract

The rivet-fastened rectangular hollow flange channel beam (RHFCB) is a new cold-formed steel section and is considered to be a substitute for welded hollow flange channel beams. This monosymmetric channel section is made from two torsionally rigid rectangular hollow flanges connected to a web plate using rivets at intermittent spacing. This fabrication process allows great flexibility in selecting different combinations of web and flange element sizes to attain optimum design capacities. Although the shear behavior of the commonly used lipped channel beam (LCB) and welded hollow flange beam (HFB) sections, with and without web openings, has been investigated previously, the shear strength and behavior of rivet-fastened RHFCBs with web openings have not been investigated yet. Therefore a series of shear tests was conducted to investigate the shear behavior and strength of rivet-fastened RHFCBs with circular web openings. Simply supported test specimens with aspect ratios of 1. and 1.5 were loaded at midspan until failure. The shear capacities determined from the tests were compared with those predicted by current cold-formed steel design standards. The results revealed that the existing design equations were not able to accurately predict the shear capacities of rivet-fastened RHFCBs with circular web openings. This is mainly due to the shear buckling capacity improvements provided by the rectangular hollow flanges and associated postbuckling strength. Hence the shear strength capacity results were used to propose improved design equations for rivet-fastened RHFCBs with circular web openings. This paper presents the details of the shear tests, observations, design capacity comparison, and proposed design equations.