Fire behaviour of hollow structural section steel columns filled with high strength concrete

The use of hollow structural section (HSS) steel columns filled with high strength concrete (HSC) is becoming popular due to many advantages they offer. However, whereas the design rules for HSS columns filled with normal strength concrete are well established, there are many uncertainties for HSS columns filled with HSC. Results from numerical studies on the behaviour of HSS columns filled with HSC are presented. The studies were carried out based on both North American and European material properties for HSC and steel. Results show that required fire resistance in HSS columns can be obtained through the use of bar- or steel fibre-reinforcement in HSC.