SSome people have eyes that don't see or see only what they choose to see. And worse still even though they may be looking at objects their brains don't register and connect with their vision at all.
On checking the drawings I found the cause of the cracks appearing in the beam. The cracks are due to insufficient shear reinforcement in the beam. In my design calculation sheet I specified clearly with the aid of a sketch R10 links spaced at 250 mm c/c. However in the beam construction drawing the draftsman detailed R6 links spaced at 250 mm c/c. For the same spacing the difference in steel areas between R6 and R10 links is a whopping 64% deficit! I suspect the mistake is due to the common practice of draftsmen mindlessly cutting and pasting CAD drawing objects from one part of a drawing to another.
Since the building work has been completed I am now scratching my head on how to rectify the defect without demolishing and then rebuilding the beam.
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