Part D – Fill in the blanks: Loss of prestress due to anchorage slip is an (a)   loss.

Part D – Fill in the blanks: Friction loss occurs in (a)   tensioned concrete members only.

Part D – Fill in the blanks: In one-end jacking, minimum prestress occurs at (a)   .

Part D – Fill in the blanks: Relaxation loss in steel tendons is a (a)   dependent loss.

A concrete beam is post-tensioned with a tendon having initial stress of $$1200\ \text{N}/\text{mm}^2$$ . Anchorage slip = $$3\ \text{mm}$$ . Length of beam = $$30\ \text{m}$$ . Modulus of elasticity of steel = $$2\times10^5\ \text{N}/\text{mm}^2$$ . Calculate the percentage loss of prestress due to anchorage slip.

(a)  

A prestressed concrete beam is pre-tensioned with an initial force of $$150\ \text{kN}$$ . Final prestressing force after all losses is $$141\ \text{kN}$$ . Determine the percentage loss of prestress.

(a)  

A rectangular prestressed concrete beam has prestressing force $$=400\ \text{kN}$$ , section $$=200\ \text{mm}\times400\ \text{mm}$$ , and eccentricity $$=100\ \text{mm}$$ . Find the maximum compressive stress in concrete.

(a)