Myths on Beam construction – Challenge to overcome

With natural hazards like earthquake or high speed storms hitting various parts of country more frequently, such load bearing wall construction are no longer safe for withstanding horizontal drifts unless retrofitted. Also such construction is suitable upto G+2 storied building in general.

With high storied construction trend now-a-days coupled with natural hazards, it is advisable to opt for RCC (Reinforced Cement Concrete) framed construction (Fig 2). Basically, RCC framed construction consists of a series of columns provided suitably in the house which are interconnected by beams to form a frame.The beams carry the load from slab/building and transfer to columns, and therefrom the building load is transferred to underneath soil through RCC footings.Beams span between one or more supports, and are reinforced by means of main longitudinal bars to resist bending moment; and transverse steel (closed ties) to resist shear force.

Beams are meant for supporting load of brick walls also (slab couldn’t carry brick wall load in general), hence width of beams shouldn’t be less than width of walls. In general, beams have minimum width of 230 to 250 mm.

Typical Loads to be considered for Beam Design

(i) Dead Load: Any permanent load acting on the beam, e.g. self-weight of beam, dead load/super-imposed dead load of slab/staircase, weight of brick wall.

(ii) Live Load: Any non-permanent or moving load on slab.

(iii) Earthquake Load: Depends on the seismic zone where building is located, also upon dead weight (seismic weight) of building, soil site type.

(iv) Wind Load: Depends upon the wind speed, height & location of building. Also terrain and adjacent structures play a role in determination of this load.