Experimental study of the mechanical behavior of steel staggered truss system under pool fire conditions

Experimental research has been conducted to study the mechanical behavior and failure mode of a 6-storey steel staggered truss system (SSTS) model made in 1/8 scale without fire-proof coating exposed to pool fire. The data of temperature distribution, displacements and strains of typical members were obtained. The results indicate that with the increase in temperature, local buckling appeared primarily on vertical web members of the Vierendeel panel of the truss directly exposed to fire, which contributed to the destruction of the original balance of the internal force. Afterwards, several joints of the truss exposed to fire, which connected diagonal web members with chords, were fractured. Catastrophic destruction of the truss exposed to fire was then observed. It can be inferred that the destruction of the truss exposed to fire may lead to the collapse of the two storeys supported by the truss, which would present a huge threat to the whole structure for the potential progressive collapse might be aroused.

► An experiment of a steel staggered truss system exposed to pool fire was conducted.
► Temperature evolution, strains and displacements of typical members were obtained.
► Catastrophic destruction of the truss in fire due to local buckling was observed.
► Structural behaviors and potential hazards for the system in fire were discovered.