Question-What are three key types of reinforcement used in pre stressing?

Answer-(i)Spalling reinforcement -

Spalling stresses are established behind loaded area of anchor blocks and this causes breaking away of surface concrete. These stresses are induced by strain incongruity with Poisson's effects, by the shape of stress trajectories.

(ii)Equilibrium reinforcement -
Equilibrium reinforcement is necessary where there are several anchorages in which pre stressing loads are useful sequentially.

(iii)Bursting Reinforcement -
Tensile stresses are induced through pre stressing operation and maximum bursting stress occurs where stress trajectories are concave towards a line of action of load. Reinforcement is required to oppose these lateral tensile forces.