Q1: If A is the sectional area of a prestressed rectangular beam provided with a tendon prestressed by a force P through its centroidal longitudinal axis, the compressive stress in concrete, is

ANS:A -

The compressive stress in concrete of a prestressed rectangular beam provided with a tendon prestressed by a force P through its centroidal longitudinal axis can be calculated using the formula for stress: σ=P/A​ Where:

• σ = Compressive stress in the concrete (force per unit area).
• P = Prestressing force applied through the centroidal longitudinal axis of the beam.
• A = Sectional area of the concrete in the beam's cross-section.

This formula represents the distribution of compressive stress in the concrete due to the prestressing force P applied by the tendon. The stress is calculated by dividing the applied force P by the cross-sectional area A of the concrete. It's important to note that this formula assumes uniform stress distribution across the cross-section of the beam. In practice, factors such as the shape of the beam, tendon profile, and prestressing force distribution may affect the actual stress distribution in the concrete. Engineering standards and design codes provide guidelines for calculating and evaluating prestress-induced stresses in concrete members to ensure structural safety and performance.