Behaviour of Restrained Steel Components in Fire

Behaviour of Restrained Steel Components in Fire

Abstract

Fire is one of the disastrous effects on steel structures. To understand the behavior of components in a steel structure subjected to fire is essential to the structural safety against fire. Considering that the component in a structure is normally restrained by the other neighbor components, the behavior of restrained steel compo-nents in fire is more meaningful than that of isolated steel components in fire. Comparing with the un-restrained or independent components, the thermal expansion effect have to be considered on the behavior of restrained components, which is in general harmful to the fire-resistance of steel components. However, the restrain is beneficial to pertain the capacity of restrained components with some deflection developed, which can release the thermal expansion effect. Obviously, the behavior of restrained steel components may be complicated. It is founded that the catenary action may be developed in a restrained beam and the bowing effect may be developed in a restrained column. In addition, the membrane action can also be regarded as a kind of restrained effect being able to develop in a slab. The theoretical models to simulate the behavior of restrained steel beams, steel columns and steel-concrete composite slabs in fire are proposed and the experi-mental verifications are presented.