Post-fire residual capacity of protected and unprotected concrete filled steel hollow columns.

Concrete filled steel hollow structural (CFS) sections are an increasingly popular means to support large compressive loads in buildings. Whilst the response of unprotected CFS sections during a fire is reasonably well researched, their post-fire residual structural performance is less well established. The results of 19 post-fire residual eccentric axial compression tests on unprotected and protected CFS columns is presented, along with six unheated control tests. The tests confirm that as the maximum exposed temperature within the cross-section increases, the residual strength capacity, ductility and axial-flexural stiffness decrease. The data presented herein can be used to assess the ability to predict the residual capacity of CFS columns after fires using available post-fire structural and material models.