BEHAVIOUR OF FIBRE REINFORCE CONCRETE BEAM IN COMBINED BENDING AND TORSION

Abstract

In structures where equilibrium torsion occurs, in addition to shear and flexure, torsion should be calculated and designed for torsional strength of sections. The phenomenon of torsion seldom occurs by itself. It is almost invariably combined with other actions such as flexure and shear. Hence it is combined torsion and bending which is of real practical interest. In this work combined bending and torsion has been considered for the fibre reinforced concrete beams by taking the different percentage of fibre volume. The glass fibres are used for the investigation. This would seem to justify large number of investigations dealing with pure torsion of concrete members. In present research, an attempt is made to study the following aspects: Behaviour of reinforced concrete beam under. 1)Combined bending and torsion, (a)Without glass fibres (b)With glass fibres 2)The effect of increase of fibre percentage on torsional resistance of beam. 3) To develop torque. Vs. twist relation of the beams. The experimental program consists of casting 4 reinforced concrete beams of size 150mm X150 mm and length 2m. Two of them were cast without fibres to make a comparative study with the remaining 3 beams; one beam is cast with 0.5% fibre by weight, one beam 1.0% fibre by weight in the rest one beam 1.5% fibre by weight added. The longitudinal reinforcement, spacing of shear stirrups is kept constant.