Question

1. what are prestressed concrete structures?
2. what are pretensioned and posttensioned concrete structures?

Answer 1

1. Prestress concrete is a type of construction technique in which the tension reinforcement provided in concrete in the form of cables are prestressed, which means subjected to a tension force due to which compressive stress is developed in the reinforcement region (Tension zone) when force is removed but cables are restrained by the surrounding concrete. This helps in reducing tensile stresses in section after the application of loads.

2. Pretensioned concrete (Tension in cable before concreting) is a type of prestressed concrete in which the reinforcing cables are stressed before concrete is placed and prestressing force is removed after the concrete is set.

Post tensioned concrete (Tension in cable after concreting) is a type of prestressed concrete in which concrete member is cast first by making a provision (duct) to insert reinforcing cable. The cables are inserted in the ducts and grouting is done in remaining space. The force is removed by providing anchorage at the ends.