Anchorage Slip given Settling Length Calculator

Anchorage Slip Formula:

\[ \Delta = \frac{0.5 \times \Delta f_p \times l_{set}}{A_p \times E_s} \]

Prestress Drop (Δfp):

MPa

Settling Length (lset):

Steel Area (Ap):

mm²

Modulus of Elasticity (Es):

MPa

Tolerance:

Anchorage Slip (Δ): mm

1. What is Anchorage Slip?

Definition: Anchorage slip is the distance by which the anchorage gets displaced when the force is transmitted from anchorage to tendon.

Purpose: It helps engineers account for the loss of prestress due to anchorage setting in post-tensioned concrete members.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \Delta = \frac{0.5 \times \Delta f_p \times l_{set}}{A_p \times E_s} \]

Where:

\( \Delta \) — Slip of Anchorage (mm)
\( \Delta f_p \) — Prestress Drop (MPa)
\( l_{set} \) — Settling Length (mm)
\( A_p \) — Steel Area in Prestress (mm²)
\( E_s \) — Modulus of Elasticity of Steel (MPa)

Explanation: The formula calculates the slip based on the force drop, affected length, tendon properties, and steel modulus.

3. Importance of Anchorage Slip Calculation

Details: Proper calculation ensures accurate prestress force estimation, preventing under-design of concrete members and potential structural issues.

4. Using the Calculator

Tips: Enter the prestress drop, settling length, steel area, and modulus of elasticity. The default steel modulus is 200,000 MPa. Tolerance can be set (default ±5%).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical settling length?
A: Settling length varies but is typically 100-500 mm depending on anchorage type and tendon configuration.

Q2: Why is the formula multiplied by 0.5?
A: The factor accounts for the triangular stress distribution along the settling length.

Q3: How does anchorage slip affect prestress?
A: Slip causes loss of prestress force, which must be accounted for in design to ensure adequate capacity.

Q4: What's the typical modulus for prestressing steel?
A: Most prestressing steel has a modulus of about 195-200 GPa (195,000-200,000 MPa).

Q5: When would I adjust the tolerance?
A: Adjust for specific project requirements or when using non-standard materials with higher variability.