Flexural testing of cold-formed steel members with reinforced web openings

The floor joists of Cold-Formed Steel (CFS) structures may require large web openings. Providing appropriate reinforcements for such openings may mitigate the detrimental effects of such large web openings. This paper is based on a recent experimental investigation which considered 203mm deep 14 gauge (thickness 1.91mm) galvanized lipped channel sections having circular, square, and rectangular openings, and two associated reinforcement schemes. The test specimen was simply supported at its ends, and was subjected to two equal point loads acting at equal distance from the supports. Two lipped channel sections with a length of 2743 mm were set face-to-face to form the test specimen. Based on these limited tests, it was determined that [a] it may not be necessary to reinforce the tension zones of the web having a large opening, [b] it is desirable to have closely spaced screws to reduce the possibility of compression edge of the large opening from crippling, and [c] it is desirable to screw fasten the reinforcements as close as possible to the compression edges of the opening, in order to minimize crippling. Overall, it is evident from the test results that it is possible to establish cost-effective reinforcement schemes for cold-formed steel sections having large web openings.