Rc slab Punching verification (by maps and rc slab provided reinforcement )

[Anonymous]

Dear sir 

Is the punhing shear verfication by checking the principal shear strees in  maps  gives the same results of verfication punching  by rc slab provided reinforcement .

regards

[Artur.Kosakowski]

These results are different mainly because the design code tells you how to determine the critical perimeter whereas the stress is displayed in a selected position within a slab.

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[Anonymous]

Dear sir 

What i was mean by my Question is 

if we take the reading of shear stresses after check the reduced forces above columns support at  the same distance from the face of the column permitted in the code is this value from the maps will be the same or closed to the value calculated in rc slab provided reinforcement in the punching check .

What i know : in the calculation of shear stresses in the map 

the formula is ;

T= Q*S/B*I      which is mean the the unbalanced moment which is going to the columns is not considered .

But for the calculation of shear stresses in rc slab provided reinforcement  whis is according to the used code is ;

T = Q/b*d + Mux*y/Jx +Muy * x/Jy

which is mean the unbalanced moment taken in consideration Of the shear stress as per code parametes but didnt taken in consideration in the map result .

kindly confirm if this understanding is correct .

[Artur.Kosakowski · Accepted solution]

The valued on the map are calculated based on the shear force only with no influence of bending.

[Anonymous]

Why Mr Artur ?

[Artur.Kosakowski]

Because these maps are intended for shear rather than punching and are displayed on the entire slab rather than over the supports only not mentioning the fact that given design code may have different rules for calculations of actual punching force which is addressed in the RC Slab Required reinforcement module.

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