1. What is Radial Thickness of Element given Rotation due to Twist?

Definition: This calculator determines the radial thickness of an arch dam element based on the rotation caused by twisting moments.

Purpose: It helps civil engineers design arch dams by calculating the required thickness to resist twisting forces.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( t \) — Radial thickness (meters)
• \( M \) — Cantilever twisting moment (N·m)
• \( K4 \) — Constant depending on b/a ratio and Poisson ratio (±5%)
• \( E \) — Elastic modulus of rock (GPa)
• \( \Phi \) — Angle of rotation (radians)

Explanation: The formula calculates the thickness needed to resist the twisting moment while considering material properties and deformation.

3. Importance of Radial Thickness Calculation

Details: Proper thickness calculation ensures structural integrity of arch dams against twisting forces, preventing failures.

4. Using the Calculator

Tips: Enter the twisting moment, constant K4 (default 10.02 ±5%), elastic modulus (default 10.2 GPa), and rotation angle (default 35 radians). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for constant K4?
A: K4 typically ranges between 9-11 (±5%) depending on the arch dam geometry and material properties.

Q2: How is the angle of rotation measured?
A: The angle is measured in radians from the original position due to the twisting moment.

Q3: What affects the elastic modulus of rock?
A: Rock type, weathering, and confinement pressure significantly affect the elastic modulus.

Q4: How accurate is this calculation?
A: The calculation provides an estimate with ±5% accuracy for K4; other factors may affect actual performance.

Q5: Can this be used for other structures?
A: The formula is specifically developed for arch dams; use with caution for other applications.

Radial Thickness of Element given Rotation due to Twist on Arch Dam Calculator© - All Rights Reserved 2025