POST-FIRE DAMAGE ASSESSMENT OF SLIP-CRITICAL CONNECTIONS

Abstract

Steel buildings may encounter fire events during their life cycle. There is a necessity of exploring the ways of assessing the remaining capacity of steel structures after exposure to high temperature. In this study, the post-fire mechanical properties of slip-critical connections and the adopted high strength bolts are experimentally studied using an electronic furnace, an electronic torsion wrench, strain gauges and a universal testing machine. Each of the slip-critical connections is composed of a single JIS F10T high strength bolt and an A36 steel PL-70x70x18 (mm) with a standard hole in the center. The test parameters are elevated temperature (400°C, 600°C and 800°C) and exposure time (60 min, 90 min and 120 min). The test items include: (1) torque strength, (2) torque coefficient, and (3) bolt pretension. The tests are made before and after the connections are exposed to high temperature. The results obtained from the above tests can be used as an important reference for judging whether a steel structure continues to be used after fire damage.