Pressure Drop when Anchorage Slip and Settling Length are Considered Calculator

Prestress Drop Formula:

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

Slip of Anchorage (Δ):

Steel Area in Prestress (Aₚ):

mm²

Modulus of Elasticity (Eₛ):

MPa

Settling Length (lₛₑₜ):

Prestress Drop (Δfₚ): MPa

1. What is Prestress Drop Calculation?

Definition: This calculator estimates the pressure drop in prestressed concrete due to anchorage slip and settling length.

Purpose: It helps structural engineers determine the loss of prestress force when considering anchorage slip effects.

2. How Does the Calculator Work?

The calculator uses the formula:

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

Where:

\( \Delta f_p \) — Prestress drop (MPa)
\( \Delta \) — Slip of anchorage (mm)
\( A_p \) — Steel area in prestress (mm²)
\( E_s \) — Modulus of elasticity of steel (MPa)
\( l_{set} \) — Settling length (mm)

Explanation: The formula calculates the stress loss due to anchorage slip over the settling length where friction effects are absent.

3. Importance of Prestress Drop Calculation

Details: Accurate calculation ensures proper design of prestressed concrete members by accounting for force losses that affect structural performance.

4. Using the Calculator

Tips: Enter anchorage slip, steel area, modulus of elasticity (default 200,000 MPa), and settling length. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is typical anchorage slip value?
A: Typically 3-6mm for wedge-type anchorages, but varies by manufacturer and system.

Q2: Why is the modulus of elasticity important?
A: It determines how much the tendon will stretch under load, affecting the force loss calculation.

Q3: What is settling length?
A: The length over which the anchorage slip affects the tendon, typically 30-60 times the tendon diameter.

Q4: Does this include other prestress losses?
A: No, this only calculates losses due to anchorage slip. Other losses (elastic shortening, creep, etc.) must be calculated separately.

Q5: Why is there a 0.5 factor in the formula?
A: The factor accounts for the triangular stress distribution over the settling length.