Abstract
This paper first investigates the material ductility effect on the bearing strength of bolted connections in mild steel (S275), high strength steel (G550) and ultra-high strength steel (S1150), the latter having never been tested in the literature. Importantly, it also investigates the effects of different cooling methods on the post-fire bearing strength of ultra-high strength steel specimens. The specimens were cooled in either air or water from temperatures as high as 1000 °C, resulting in a very wide range of material ductility. It was found that material ductility (and therefore the cooling methods for particular exposure temperatures) had a significant effect on the bearing strength, namely the bearing coefficient increased considerably with a particular combination of exposure temperature and cooling method. Either air or water cooling may lead to the higher material ductility, depending on the exposure temperature. An additional finding is that the elongation at fr