IRC:58 Some Important Calculations

IRC 58:2015 Concrete Pavement Design Calculator

1. Cumulative Axle Load Repetitions

AADT of Commercial Vehicles: Growth Rate (%): Design Period (Years):

N =

2. Equivalent Single Wheel Load (ESWL)

Total Wheel Load (kN): Distance Between Wheels (mm): Slab Thickness h (mm):

ESWL =

kN

3. Contact Area (Circular Footprint)

Wheel Load P (N): Tyre Pressure p (MPa):

Contact Radius a =

mm

4. Radius of Relative Stiffness (l)

Modulus of Elasticity E (MPa): Slab Thickness h (mm): Poisson's Ratio μ: Modulus of Subgrade Reaction k (MPa/m):

l =

mm

5. Spacing of Contraction Joints

Slab Thickness h (mm): Are dowel bars provided? Yes No Type of Base: Stabilized (Good Base) Granular (Poor Base) Traffic Category: Low Medium High

6. Flexural Stress - Interior Loading

Wheel Load P (kN): Slab Thickness h (mm): Radius of Contact Area a (mm): Radius of Relative Stiffness l (mm): Characteristic Compressive Strength fck (MPa):

Edge Stress =

MPa

Corner Stress =

MPa

Interior Stress =

MPa

Modulus of Rupture (MR) =

MPa

7. Temperature Warping Stress

ΔT (Temperature Differential °C): Coefficient of Thermal Expansion (1/°C): Modulus of Elasticity E (MPa): Poisson's Ratio μ:

Warping Stress =

MPa

8. Fatigue Life of Concrete

Flexural Stress σ (MPa): Modulus of Rupture MR (MPa): Traffic Repetitions (n):

Stress Ratio (SR) =

Allowable Repetitions to Failure (Nf) =

Cumulative Fatigue Damage (CFD = n/Nf) =

9. Load Transfer Efficiency (LTE)

Deflection of Loaded Slab (Δ_loaded) in mm: Deflection of Unloaded Slab (Δ_unloaded) in mm:

LTE > 90%: Excellent, 70–90%: Good, 50–70%: Marginal, < 50%: Poor

10. Area of Tie Bar Steel

Slab Width b (mm): Coefficient of Friction f: Unit Weight of Concrete w (kN/m³): Working Stress in Steel S (N/mm²): Bar Diameter (mm): Permissible Bond Stress τ (N/mm²):