Determine the moment of resistance of the flitched beam:
A flitched beam consists of a wooden beam of width 120 mm & depth 250 mm & mild steel plates of thickness 10 mm & width 120 mm one on each of side of the wooden beam. The maximum bending stress in wood is equal to7 N/mm2 and the modular ratio between steel & wood is 20. Determine the moment of resistance of the flitched beam section.
Moment of resistance of the wooden beam = (1/6) σ w bd 2
= (1/6) × 7 × 120 × (250)2
= 8759 × 103 N-mm = 8750 Nm
Moment of resistance of the steel plates is following,
= 29167 Nm
Moment of resistance of flitched beam = Moment of resistance of wooden beam + Moment of resistance of steel plates.
= 8750 + 29167
= 37917 Nm