Reinforcement schemes for cold-formed steel joists with a large web opening in shear zone-An experimental investigation

摘要

The floor joists of cold-formed steel (CFS) structures often require large web openings. Reinforcement of such openings may mitigate the detrimental effects arising from such web openings. This paper is based on an experimental investigation conducted to establish reinforcement schemes for CFS joists with a large web opening located in high shear zones. The investigation considered a large web opening cut out in the middle of the web of a lipped channel section. Circular and square large web openings of about 65% web depth were considered. The shear tests involved short span specimens, simply supported at the ends, and subjected to a mid-span point load. This paper presents the experimental set-up, and the test results associated with 27 individual tests consisting of nine sets of three identical tests. These test sets consist of cold-formed steel joists sections with (a) no web opening, (b) webs having circular or square openings, (c) webs having reinforced openings. Three different reinforcement schemes were investigated, however, the test results indicated that the proposed "Vierendeel truss type reinforcement scheme" can restore the original shear strength of such sections having circular or square openings. Overall, this study establishes a cost-effective reinforcement scheme for cold-formed steel joists having a large web opening in high shear zone.