STRUCTURAL SAFETY OF ULTRA-TWIST BLIND FASTENERS IN TENSION

Ultra-twist blind fasteners were developed for connecting tube members where access for installation is from one side of the connection only . They offer many advantages, including strengths and sizes comparable to A325 bolts, potential use in tension as well as in moment-resistin g connections, and ease of installation. Reliability-based analyses ar e conducted to develop resistance factors for blind bolts designed acc ording to the principles underlying specifications for steel construct ion (CAN/CSA-S16.1-94). The limit state considered here is the direct tensile strength. The applied loading consists of dead load, live load , and wind. Probabilistic resistance models are developed for the ultr a-twist fasteners based on experimental test results. The study consid ers a wide spectrum of live-to-dead load ratios and a range of wind lo ad intensities. The results of the reliability analysis indicate that a resistance factor of the order of 0.55 is appropriate for applicatio ns employing ultra-twist blind fasteners.