Wind Load Calculation for PEB Building as per IS 875(Part 3):2015

Wind load is one of the most critical forces acting on steel structures, especially Pre-Engineered Buildings (PEB). Proper estimation of wind pressure ensures structural safety, serviceability, and economy.

In this article, we will explain a example of wind load calculation for a PEB building at Noida, using IS 875 (Part 3): 2015.

This guide is especially useful for:

• Structural engineers
• ETABS/STAAD users
• Civil engineering students

Project Details

The project involves the design of a PEB industrial-type structure with the following parameters:

• Location: Noida
• Basic Wind Speed: 47 m/s
• Building Length: 26 m
• Building Width: 20 m
• Eave Height: 5 m
• Roof Type: Pitched roof
• Roof Angle: 5.71°
• No. of Bays: 4

Types of Loads Considered

1. Dead Load (DL)

Dead load includes self-weight of structure and permanent components.

• Roof Load: 20 kg/m²
• Main Frame: 1.26 kN/m
• End Wall: 0.63 kN/m

2. Live Load (LL)

Live load represents temporary loads like maintenance or workers.

• Roof Live Load: 57.5 kg/m²
• Main Frame: 3.58 kN/m
• End Wall: 1.79 kN/m

3. Collateral Load (CL)

Includes services like ducts, lighting, and piping.

• Roof Collateral Load: 25 kg/m²
• Main Frame: 1.57 kN/m
• End Wall: 0.78 kN/m

4. Other Loads

• Solar Load: 0
• Mezzanine Load: 0

Step-by-Step Wind Load Calculation (IS 875:2015)

Step 1: Basic Wind Speed (Vb)

From IS 875 wind map:$$V_b = 47 \, m/s$$

Step 2: Wind Speed Factors

According to IS 875:

• k₁ (Probability Factor) = 1.0
• k₂ (Terrain Factor) = Category 2
• k₃ (Topography Factor) = 1.0
• k₄ (Cyclonic Factor) = 1.0

Step 3: Design Wind Speed (Vz)

$V_z = k_1 \cdot k_2 \cdot k_3 \cdot k_4 \cdot V_b$$$V_z = 47 \, m/s$$

Step 4: Wind Pressure (Pz)

$P_z = 0.6 \cdot V_z^2$ $$P_z = 1325.4 \, N/m^2$$

Step 5: Design Wind Pressure

Considering reduction factors:

• Area Averaging Factor = 0.9
• Combination Factor = 0.9
• Directionality Factor = 0.9

Final:$$P_d = 0.97 \, kN/m^2$$Pressure Coefficients

Internal Pressure Coefficient (Cpi)

• Building Type: Enclosed
• Value:

$$C_{pi} = \pm 0.20$$

External Pressure Coefficient (Cpe)

From IS 875 (Part-3) Table-5 External Pressure Coefficients For Walls of Rectangular Clad Buildings.

For 0 degree

Walls

• Left Wall: +0.70
• Right Wall: -0.20
• Windward Wall: -0.50
• Leeward Wall: -0.50

For 90 degree

Walls

From IS 875 (Part-3) Table-6 External Pressure Coefficients For Pitched Roofs of Rectangular Clad Buildings. By interpolrate our angle is 5.17

For 0 degree, fist we take Roof (-0.2)

For 90 degree, fist we take Roof (-0.2)

For 0 degree, fist we take Roof (0.2)

For 90 degree, fist we take Roof (0.2)

Final Wind Load Application

Wind load is calculated using:$$F = (C_{pe} – C_{pi}) \cdot P_d \cdot A$$Where:

• A = area of surface
• $P_d$​ = design wind pressure

Now appling wind load forces to PEB Building

Wind Load Calculation

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