1. What is Loss of Prestress due to Slip?

Definition: This calculator determines the loss of prestressing force that occurs when the anchorage system slips during the prestressing process.

Purpose: It helps structural engineers estimate the actual prestressing force after accounting for anchorage slip losses.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( F \) — Loss of prestress force (kN)
• \( A_{Tendon} \) — Cross-sectional area of tendon (m²)
• \( E_s \) — Modulus of elasticity of steel (MPa)
• \( \Delta \) — Slip of anchorage (mm)
• \( L_{Cable} \) — Length of prestressing cable (mm)

Explanation: The formula calculates the force loss based on the elastic shortening caused by the anchorage slip distributed over the cable length.

3. Importance of Prestress Loss Calculation

Details: Accurate estimation of prestress loss ensures structural safety and serviceability by accounting for all force reductions in the design.

4. Using the Calculator

Tips: Enter tendon area, modulus of elasticity (default 200,000 MPa), anchorage slip (default 5 mm), cable length, and tolerance percentage (default ±5%).

5. Frequently Asked Questions (FAQ)

Q1: What is typical anchorage slip value?
A: Most systems slip 3-6 mm during stressing, but consult manufacturer specifications for exact values.

Q2: Why include tolerance percentage?
A: The tolerance accounts for variations in material properties and installation conditions.

Q3: How does cable length affect prestress loss?
A: Longer cables experience less prestress loss per unit length as the slip is distributed over more material.

Q4: What's the typical modulus for prestressing steel?
A: Most prestressing steels have E ≈ 195-205 GPa (195,000-205,000 MPa).

Q5: How significant is slip-induced prestress loss?
A: It can account for 1-5% of total prestress force, making it an important consideration in design.

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