While designing the slabs, which are built up on
ground, the crack control factors should be taken into account. Given below,
reinforcement details for slabs-on-ground.
The density and the design of the slabs-on-ground
are dependent on the cracks which are developed because of the external
loading. The calculation for slab thickness is made on the basis of the
suppositions of a slab being unreinforced and un-cracked.
For specific situations of slabs on ground, the steel
reinforcement can offer a great solution. The characteristics of this method
contains the following :-
1. The limiting of cracks occur because of shrinkage
2. Apply bigger joint spacing that is larger than the unreinforced slabs
3. The possibilities for cracks development may be avoided by provision for moment capacity and constancy for those areas.
4. Cracking can’t be resisted with the integration of reinforcement. These elements allow in minimizing or adjusting the produced crack width by genuinely raising the frequency of cracks that is created.
2. Apply bigger joint spacing that is larger than the unreinforced slabs
3. The possibilities for cracks development may be avoided by provision for moment capacity and constancy for those areas.
4. Cracking can’t be resisted with the integration of reinforcement. These elements allow in minimizing or adjusting the produced crack width by genuinely raising the frequency of cracks that is created.
If
a reinforcement design is proportioned and arranged perfectly, it can allow to
restrain the width of the crack significantly and therefore the serviceability
period of the slab is not impacted.
Thickness Design Methods for Slabs-on-Ground Construction
When
reinforcement in the slab design is applied increasingly, the un-cracked
strength of the slab is slightly affected. The various methods for thickness
design like Pickett’s Analysis Method (PCA), WRI (Wire Reinforcement Institute)
Design Method and COE methods can be employed for creating the design of slabs
on ground with reinforcement.
Reinforcement for Slabs-on ground for Crack Width Control Only
The
width of crack can be restrained by reinforcement on the basis of the two
factors like the joint spacing and the thickness of the slab. Otherwise we can
define the crack width control as a function of joint space and slab thickness.
There should be a minimum steel ratio of 0.5% of the slab cross
section to facilitate the saw cut of contraction joints to be removed.
When
the reinforcement is arranged, it is suggested to set the reinforcement bars
nearer to the surface of the slab top surface devoid of compromising the
minimum concrete coverage over the reinforcement.
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