The following picture is taken at a construction site and it shows the beam reinforcement. In any beam reinforcement, two things should always be kept in mind. These are Proper Lap and Ld
In case these are not properly provided as per the design the entire beam purpose is lost and beam loses its required strength. It has been found that if the beam is not properly reinforced, the entire structure is bound to collapse
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ld = 41*dia of bar