For a ribbed span, the minimum thickness of the ribs & that of the in-situ ribs are respectively?
Anonymous Quiz
54 mm & 65 mm
65 mm & 54 mm
40 mm & 25 mm
25 mm & 40 mm

1 comment

For a ribbed slab (ribbed span), the minimum thickness of the ribs and the minimum thickness of the in-situ topping are typically:


Rib width (thickness): 65 mm
In-situ topping thickness: 54 mm

✅ Correct answer: 65 mm & 54 mm

The trap in this question is that many people reverse the values. In practice, the rib must be thicker than the topping because it acts as the primary load-carrying beam element.