Design of Simply Supported Roof Slab (Inside Dimension 7x3 m)

Design a roof slab inside dimension 7x3 m if supporting brick walls are 300 mm thick. The Slab will have to carry 75 mm thick additional material as the rooftop finishing, Whose Unit weight 20 KN/m³, service load 2 HYSD Steel bar Fe415, Rec slab simply supported

1. Given Data:

• Slab Dimension (inside): $7\text{m}\times 3\text{m}$
• Supporting Wall Thickness: 300 mm
• Rooftop Finishing Thickness: 75 mm
• Rooftop Finishing Unit Weight: 20 kN/m³
• Service Load: 2 kN/m²
• Steel Reinforcement: Fe415 HYSD bars
• Slab Type: Simply supported

2. Calculation of Load

a) Self-weight of the Slab

Assume Slab Thickness: Generally, for a simply supported slab, the thickness $t$ is chosen as:

$$t = \frac{L_{\text{short}}}{20} \approx \frac{3}{20} = 0.15 \, \text{m (or 150 mm)}$$