ABSTRACT
Tubular members with intermediate to high slenderness ratios are normally used in space frame structures. When the space frame structure is subjected to localized fire, only part of the structure is subjected to heating and the heated members are restrained by the adjacent members which are not heated. In this study, a novel experimental set-up has been proposed to test an end restrained axially loaded member subjected to fire. In the experiment, the axial end restraint is simulated by a series of pre-compressed springs. These pre-compressed springs can provide a constant axial end restraint stiffness during the fire test. When subjected to heating, the member tends to expand due to thermal effect, but it is restrained by the axial springs which provide a constant end-restraint stiffness through the entire heating process. This novel test set-up can simulate the actual behavior of compression chord member in a space frame structure when subjected to localized fire. The axial end restraint stiffness can be adjusted by changing the number of springs or by using springs with different stiffness. This paper describes the novel test set-up and the test load deflection curve of the heated member before and after buckling. The second part of the companion paper presents the test results including parameter studies investigating the important factors such as end restraint stiffness, member slenderness ratio, load ratio and initial imperfection on the fire resistance of axially compressed members.
