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Civil Engineering/reinforcement of slab of load bearing structure

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description:room is 15x25 ft made up of 14 inches brickwork, beams on top are to be casted with slab and 1.5ft is projected on every side (cantilever).now a cross beam  is also to be laid parallel to 15 ft side and resting on beam on wall of 25 ft side  so that two panels of 12.5x15 ft are formed now if we have to used reinforcement cranked or bent up bars in slab please help me understand answers to following questions
a . whether the bars at bottom of main slab be parallel to  25 or 15 ft side. and in cantilevered portion whether bottom bars will be parallel to (15or 25) or 1.5ft.
b.whether we have to give crank to bars at one side near end beam or also at cross beam please clarify in detail
c whether we have to give crank to other main reinforcement above bottom bars or not
d where have to we use holdong bars and extra bars
e whether we have to extend same bar we use in main slab to cantilever portion or use separate bar.
f where will be the double mesh formed in slab if any
g also when we give a crank at what distance.

Answer
Dear Aamir

a - You need to provide the slab with reinforcement i both way, unless you aim to force the slab to transfer load in one way. Actually the slab has the tendency to transfer load in shory span.

b , c and g  - you are not obligated to have crank unless you need to have a special economical view regarding the steel materials.

d- to keep the reinforcement bars in place you need sometimes to construct supports out of steel bars to lay the reinforcement on it.

e- The extension if main bar is essential but you can make an extra extension from main slab into cantilever part. If you dont have an extension the cantilever will not work.

f- When the reinforcement for a specific moment is greater than  the maximum  ( 14.1/fy for instance) , increasing the amount of reinforcement more than maximum needs to have compressive bars equal to the amount of extra reinforcemnt you have provided.


Regards
BEH

Civil Engineering

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