Minimum reinforcement on slabs

[A.Bugajski]

Can someone explain the weird pattern of minimum reinforcement, as per attached rebar map. I have also attached the required reinforcement map, which is partially governed by crack width limit.

The slab is ground bearing i.e. elastic coefficient has been defined and of constant depth and has no stress concentartions.

The design is done to EC2 with UK N.A. Expected min reinforcement would be 3417, calculated on the basis of 0.26fctm/fyc*b*d (slab is 2m deep).

I am not sure where the value of 8873 came from.

Will appreciate any feedback.

Thanks,

Adrian

[Artur.Kosakowski · Accepted solution]

My assumption is that this may be caused by the code provisions for elements under pure tension (areas of zero bending). If you calculated these slabs for bending = tension/compression try to run calculations again for bending only (my assumption is that axial forces are negligible). 

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[A.Bugajski]

Artur,

Yes, just checked it and those values were exactly at the point of contraflexure. Do you know the exact reference to the code?

Many thanks and regards,

Adrian

[Artur.Kosakowski]

I hope for the UK NAD the numbers are the same as for general EC.

in 7.3.2 check the formula (7.1). 

for pure tension kc = 1

for pure bending kc = 0.4

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