Which prestressed concrete fabrication method involves tensioning tendons both before casting and after curing?

Which prestressed concrete fabrication method involves tensioning tendons both before casting and after curing?

• A. Pre-tensioned
• B. Post-tensioned
• C. Combination
• D. Bonded

Answer: (C)

This item tests how prestressing methods can combine different tensioning phases within one concrete element. In prestressed concrete, tendons can be tensioned before casting (pre-tensioning) or after the concrete has cured (post-tensioning). Pre-tensioning uses the force in the tendons early, then releasing transfers compression to the member. Post-tensioning strand is placed in ducts and tensioned after curing, anchoring at the ends to produce compression in the member. Some fabrication approaches mix both techniques in the same element, tensioning some tendons before casting and others after curing—this is known as combination prestressing. That’s why the best choice is the one indicating both timing methods. The other options describe single-phase methods (tensioning only before casting or only after curing) or bonded post-tensioning, which doesn’t inherently require tensioning both times, so they don’t fit the scenario described.

This item tests how prestressing methods can combine different tensioning phases within one concrete element. In prestressed concrete, tendons can be tensioned before casting (pre-tensioning) or after the concrete has cured (post-tensioning). Pre-tensioning uses the force in the tendons early, then releasing transfers compression to the member. Post-tensioning strand is placed in ducts and tensioned after curing, anchoring at the ends to produce compression in the member. Some fabrication approaches mix both techniques in the same element, tensioning some tendons before casting and others after curing—this is known as combination prestressing. That’s why the best choice is the one indicating both timing methods.

The other options describe single-phase methods (tensioning only before casting or only after curing) or bonded post-tensioning, which doesn’t inherently require tensioning both times, so they don’t fit the scenario described.