Post-Fire Response of S235 Steel Plates Considering Different Bolt Hole-Making Processes

Abstract

This study aims at investigating the effect of bolt hole-making processes on the post-fire behavior of S235 steel plates. To address this issue, a total of nine steel plates with a single bolt hole are tested in this study. The single bolt holes are fabricated using three different hole-making processes: drilling, waterjet, and plasma. Among the nine steel plates, three fabricated specimens are control specimens and are tested at ambient temperature. The six remaining steel plates with a single bolt hole are subjected to a complete heating-cooling cycle and then monotonically loaded until failure. The six fabricated specimens are first heated up to two different temperatures 800°Cand 925°C and then cooled back to the ambient prior to loading. The residual responses are characterized as load-displacement characteristics after being exposed to a complete heating and cooling cycle. The results show that after being exposed to post-fire temperatures (800°C and 925°C), the maximum decrease in strength of the S235 steel plate was 6% (at 925°C), 14% (at 925°C), and 22% (at 800°C) when compared to the results of ambient specimens for waterjet, drilled, and plasma bolt holes, respectively. In addition, for post-fire temperature tests, drilled and waterjet bolt hole-making processes result in having approximately the same load-displacement response and both have larger strength and ductility than those obtained using plasma cutting. This study provides preliminary data to guide the steel designers and fabricators in choosing the most suitable hole-making process for fire applications and to quantify the reduction in capacity of the S235 steel plates after fire exposure.