Doubly Reinforced Beam is described as the beam reinforced with steel both in tension and compression zone. When the depth of the beam is constrained, this type of beam is mostly effective.
If a beam having limited depth on the Tension side the reinforced to adequate resistance capacity for resist the bending moment does not prevail.
On satisfying the following condition the doubly reinforced beams are applicable.
- If the outside load is fluctuating, i.e. the load is functioning on the face of the member.
- The load is eccentric which varying on its axis from one side to another.
- Shock or impact or accidental lateral thrust are the dependent factors of the member.
- Requirement doubly reinforced beam, if architectural constraints exist on the beam size and the Moment to be defended is very big that a singly-reinforced.
Large moments are defended by means of doubly Reinforcing the beam essentially enlarges it’s compression area which sequentially facilitates to expand area of tension reinforcement whereas control it under-reinforced.
Due to under wind load or earthquake load, if the reversal of load occurs the same can result in creating tension in both part of the beam i.e lower and upper part which should be reinforced with tensile reinforcements.
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