What are Simply Supported Slabs?
Before we discuss the technical design rules of Simply Supported slabs, lets just go through its definition and learn why they are named so…
As the name suggests, simply supported slabs are supported on columns or stanchions…
Simply Supported Slab
Simply supported slabs don’t give adequate provision to resist torsion at corner to prevent corner from lifting.
The maximum bending moment will be given if the slabs are restrained. But atleast 50% of the tension reinforcement provided at the mid span should extend to the support. The remaining 50% should extend to within 0.1Lx or Ly at the support as appropriate.
RCC Slab Design depends on the on the dimensions of the slab after which the slab is termed as a one-way slab or a two-way slab…
In the design of RCC structures, Column Design and Beam Design are to be done before we start with RCC Slab Design…
Basic Rules followed in the design of simply supported Slab
Thickness of slab
l/d ratio should be less than the following:
- Simply supported slab
- Continuous slab, l/d = 26
- Cantilever slab, l/d = 7
In any case of the above, the thickness should not be less than 100mm
Effective span
- Distance between centre to centre of support
- Clear span plus effective depth
Minimum main reinforcement
- 0.15% gross c/s of slab – for MS bars
- 0.12% gross c/s of slab – for HYSD bars
Spacing of main bars
The spacing or c/c distance of main bars shall not exceed following:
- Calculated value
- 3d
- 300mm
Distribution or Temperature reinforcement
This reinforcement runs perpendicular to the main reinforcement in order to distribute the load and to resist the temperature and shrinkage stresses.
It should be atleast equal to;
- 0.15% gross c/s of slab – for MS bars
- 0.12% gross c/s of slab – for HYSD bars
Spacing of distribution bars
The spacing or c/c distance of distribution bars shall not exceed the following
- Calculated area
- 5d
- 450mm
Diameter of bars
The diameter of the bars varies from 8mm to 14mm and should not exceed 1/8th of the overall depth of the slab.
For distribution steel, the diameter varies from 6mm to 8mm.
Cover
The bottom cover for reinforcement shall not be less than 15mm or less than the diameter of such bar.
Related posts:
- Guide to Design of RCC Columns RCC Column A column forms a very important component of a structure. Columns support beams which in turn support walls and slabs. It should be...
- Various types of RCC Slabs | Design of RCC Structures Reinforced Cement Concrete Slab A Reinforced Concrete Slab is the one of the most important component in a building. It is a structural element of...
- Design of Staircase | RCC Structures RCC Structures RCC Structures are nothing but reinforced concrete structures. RCC structure is composed of building components such as Footings, Columns, Beams, Slabs, Staircase etc....
- Guide to Foundation Design | Column Footings Foundation Design Foundation is the base of any structure. Without a firm foundation, the structure cannot stand. That is the reason why we have to...
- Types of Foundations | Design of RCC Structures Foundations Foundation of a structure is like the roots of a tree without which the tree cannot stand. The construction of any structure, be it...