Steel Hollow Columns filled with self compacting Concrete under Fire Conditions

Concrete filled steel hollow section (CFSHS) columns can carry important loads and therefore are used extensively in the construction of high-rise buildings. Steel hollow sections are filled usually with ordinary concrete, but filling problems may arise with small cross sections and dense reinforcement or hollow sections (tubes) surrounding another profile (tube or H section) when the distance between the two profiles is small. For such a configuration, self-compacting concrete can be recommended. Ten columns filled with self-compacting concrete embedding another steel profile have been tested in the Fire Engineering Laboratory of the University of Liege - Belgium. The non linear finite element software SAFIR developed at the University of Liege has been used to simulate the thermal and structural behavior under fire conditions. A good agreement between numerical and experimental results has been obtained. This shows that SAFIR code can predict well the behavior of CFSHS columns and that the properties of self-compacting concrete at high temperatures can be considered to be the same as those of ordinary concrete. Another purpose of this study was to give practical tools to consulting engineers.