1. What is Short Term Deflection at Transfer?

Definition: Short Term Deflection refers to the immediate deflection after casting and application of partial or full-service loads.

Purpose: It helps engineers evaluate the structural behavior immediately after prestress transfer and self-weight application.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \Delta_{st} \) — Short Term Deflection (%)
• \( \Delta_{po} \) — Deflection due to Prestressing Force (%)
• \( \Delta_{sw} \) — Deflection due to Self Weight (%)

Explanation: The formula accounts for the upward deflection from prestressing (negative sign) and the downward deflection from self-weight (positive sign).

3. Importance of Short Term Deflection Calculation

Details: Proper deflection estimation ensures structural integrity, serviceability, and meets design requirements immediately after transfer.

4. Using the Calculator

Tips: Enter deflection values in percentage. The calculator accounts for the ±5% variation common in prestressed concrete applications.

5. Frequently Asked Questions (FAQ)

Q1: Why is prestress deflection negative?
A: Prestressing typically causes upward deflection (camber), which is opposite to the downward deflection from loads, hence the negative sign.

Q2: What's the typical range for short term deflection?
A: Most designs aim for deflections within ±5% of calculated values to account for material and construction variations.

Q3: When is this deflection most critical?
A: Immediately after prestress transfer when the member is most vulnerable to excessive camber or deflection.

Q4: How do I measure these deflections?
A: Use surveying equipment or deflection gauges immediately after prestress transfer and before additional loading.

Q5: Does this include long-term effects?
A: No, this is only for immediate deflection. Creep and shrinkage effects require separate calculations.

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