Civil Engineering - RCC Structures Design - Discussion

Above answer is right.

But as per cl 24.1, cl 23. 2.1 IS456 2000,

Basic values of~span to effective depth ratios for spans up to 10 m.
Cantilever 7.
Simply supported 20.
Continuous 26.
For spans above 10 m, the values in (a) may be.

Multiplied by lo/span in metres, except for cantilever in which case deflection calculations should be made.

For two-way slabs of short spans (up to 3. 5 m) with mild steel reinforcement, the span to overall depth ratios given below may generally be assumed to satisfy vertical deflection limits for loading class up to 3 kN/m.

Simply supported slabs 35.

Continuous slabs 40.

For high strength deformed bars of grade Fe 415. The values given above should be multiplied by 0.8.

Simply supported and spanning in one direction 30.
Continuous and spanning in one direction 35.
Simply supported and spanning in two directions 35.
Continuous and spanning in two directions 40.
Cantilever slabs 12.

As per I.S 456:2000, L/D ration is mentioned below.

For Cantilever Beam - 7, Simply supported Beam - 20, Continuous Beam - 26.

Maximum in case Span/depth ratio in;

Cantilever - 12.
SSB- 30.
Continues beam- 35.

It should be 20 as per code.

How is the correct answer 30? Anybody explain.

It will be 35 as per IS 456: 2000 clause 24.1.

@Vipin.

That is for 2 way spanning slab, for 1way it is 30 and for 1way spanning continuous slab it is 35.