Plate Girder Stress Reduction Factor Calculator

Plate Girder Strength Reduction Factor Formula:

\[ R_{pg} = \left(1 - 0.0005 \times \left(\frac{A_{web}}{A_f}\right) \times \left(\frac{h}{t} - \frac{760}{\sqrt{F_b}}\right)\right) \]

Web Area (A_web):

mm²

Area of Flange (A_f):

mm²

Depth to Thickness Ratio (h/t):

Allowable Bending Stress (F_b):

Plate Girder Strength Reduction Factor (R_pg):

1. What is Plate Girder Strength Reduction Factor?

Definition: The Plate Girder Strength Reduction Factor accounts for the strength reduction due to elastic web buckling in plate girders.

Purpose: It helps structural engineers determine the reduced capacity of plate girders considering web slenderness effects.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ R_{pg} = \left(1 - 0.0005 \times \left(\frac{A_{web}}{A_f}\right) \times \left(\frac{h}{t} - \frac{760}{\sqrt{F_b}}\right)\right) \]

Where:

\( R_{pg} \) — Plate girder strength reduction factor
\( A_{web} \) — Web area (mm²)
\( A_f \) — Area of flange (mm²)
\( h/t \) — Depth to thickness ratio
\( F_b \) — Allowable bending stress (Pa)

Explanation: The formula accounts for the interaction between web slenderness and flange strength in determining the overall girder capacity.

3. Importance of Reduction Factor Calculation

Details: Proper calculation ensures safe design of plate girders by considering potential web buckling effects that could reduce the overall strength.

4. Using the Calculator

Tips: Enter the web area, flange area, depth-to-thickness ratio, and allowable bending stress. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical range for R_pg?
A: The reduction factor typically ranges between 0.5 and 1.0, with 1.0 representing no reduction.

Q2: When is this reduction factor most important?
A: It's most critical for slender webs (high h/t ratios) where buckling is a concern.

Q3: What's the significance of the 760 value in the formula?
A: This is a constant derived from empirical data and theoretical analysis of web buckling behavior.

Q4: How accurate is this calculation?
A: The calculation has an accuracy of approximately ±5% for typical plate girder configurations.

Q5: Does this apply to all types of plate girders?
A: This formula is specifically for welded plate girders with slender webs.