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Re: Two way slab designed as one way

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You may or may not see a collapse.  By designing a two-way slab as a
one-way slab, you are providing more reinforcement in the short
direction than required.  By definition, a two-way slab has significant
bending moment in both directions.  Therefore, along the longer
direction (16') the reinforcement will be less (or much less) than
required to resist the moment that will occur in that direction.  This
will cause cracks perpendicular to long direction leading to increased
deformation.  However, the increasing deformation will tend to get
resisted by the excessive reinforcement along short direction (hopefully
tied together with shrinkage or some minimum reinforcement in the long
direction).  The severity of cracking will depend on the amount of
reinforcement provided in the long direction.  In the extreme
theoretical case, where no reinforcement is provided in the long
direction, collapse of the slab will be inevitable, if the slab does see
the design load.  Also, remember that a two-way slab requires adequate
reinforcement in the corners to take care of "corner uplift".  


Alex C. Nacionales wrote:
> I would like your opinion on designing two way slabs as one way.
> Ex.   12 ft x   16 ft  slab designed as one way  on the 12' direction.
> My opinion is that it  is possible but it would be more economical to design
> it as two way slab.
> Alex C. Nacionales
> A.C. Nacionales Construction