Statics: Bending

Reducing bending moments using overhangs

Fig. 4-6: Overhangs used to reduce bending moments and deflections (courtesy of Mr. J Calverley)

Fig. 4-6 shows a steel-framed multi-storey carpark where cellular beams are used. The vertical loads from floors are transmitted to the beams and then from the beams through bending to the supporting columns. Overhangs are used in the structure which can reduce the bending moments and deflections of the beams. Examining the first overhang, two steel wires are placed to link the free end of the overhang and the concrete support. A downward force on the free end of the overhang is provided by tensions induced in the pair of steel wires. This force will generate a negative bending moment over the column support which will partly off-set the positive moments induced in the beam by applied loading.