Simply Supported Slab Design
The following process of Design of Simply Supported Slab.
- First of all suitable bearings required to be assume. After that span of the slab determined between centre of bearings.
- The thickness of the slab must be finalize .(It may be 100 mm or 125mm etc.)
- Now effective span of the slab required to be design by calculating the lesser value of the following two items,
- Clear span + effective depth of the simply supported slab.(effective depth is calculated by considering clear cover)
- Centre to centre distance of bearings.
- Determination of Dead Load and Live Load of slab
i)Dead Load of the slab ,
=(1 m X overall depth X 2400 kg/m2) /10
ii) Live Load is considered as per design data consideration as per site situation.
5.Determination of Maximum Bending Moment (B.M) for one Metre of the Simply Supported slab.
The maximum bending moment per metre width = Wl2/8 kg.m = Wl2/8 X 100 kg.m
I = effective span length of the ,
W = total load on square metre.
- Now determine balanced moment of resistance of Qbd2 (Q x b X d2) to find out maximum bending moment, to find out the effective depth.
- At this stage the value of effective depth found from item no (6) and (2) is compared and realistic value is adopted.
- Calculation of requirement of steel of per metre width of the slab.
A(t)= Maximum Bending moment/permissible stress in steel X lever arm
- Selection of suitable diameter of reinforcement as a main reinforcement bar and spacing can be find out from the formula.
= Area of one bar X 100 /Area of steel required per metre width
- As Shear and bond stress value is very much low , in case of bridges slab, shear and bond stresses are also verified.