Axial restraint Effects on Fire Resistance of Statically Indeterminate RC Beams
Journal
Structural Fire Engineering
Date Issued
2013-03
Author(s)
Lazarov, Ljupco
Abstract
The non uniform temperature fields in the cross section of the structural elements
exposed to fire cause thermal dilatations which induce internal forces. In same time
temperature changes cause longitudinal elongations and if these elongations are
restricted, additional axial stresses will be induced. In this case the various support
conditions can have a significant influence on fire resistance of reinforced concrete
elements. In this paper three different support conditions as: pin-pin, pin-fixed and fully
fixed were used to model RC beams with various level of axial restraint. The beams were
exposed to the ISO-fire curve. The numerically obtained results are presented and based
on these results it can be concluded that increasing of axial spring stiffness increases the
induced axial forces and the fire resistance of the beams.
exposed to fire cause thermal dilatations which induce internal forces. In same time
temperature changes cause longitudinal elongations and if these elongations are
restricted, additional axial stresses will be induced. In this case the various support
conditions can have a significant influence on fire resistance of reinforced concrete
elements. In this paper three different support conditions as: pin-pin, pin-fixed and fully
fixed were used to model RC beams with various level of axial restraint. The beams were
exposed to the ISO-fire curve. The numerically obtained results are presented and based
on these results it can be concluded that increasing of axial spring stiffness increases the
induced axial forces and the fire resistance of the beams.
Subjects