Prestressed concrete is a process for resolving concrete's natural weakness in tension.
Prestressing tendons (normally made of high tensile steel cable or rods) are employed to arrange a clamping load that forms a compressive stress to equalize the tensile stress occurs because of a bending load.
(i) Spalling reinforcement
Spalling stresses are developed in the areas behind the loaded faces of anchor blocks and it leads to departing of surface concrete. These stresses are produced with strain inconsistency with Poisson’s effects or with the shape of stress trajectories. The spalling stresses are arranged because of the strain compatibility with regard to the effect of Poisson’s ratio. For prestressing concrete bride, the stress in the reinforcement (0.87fy) should have been retained to manage cracking whereas the bars should have been set as closer to the end face as possible and fixed over the concrete edge.
(ii) Equilibrium reinforcement
Equilibrium reinforcement is essential when there exist various anchorages wherein prestressing loads are employed successively. It is found in building construction & bridge.
(iii) Bursting Reinforcement
Tensile stresses are caused throughout pre-stressing operation and the highest bursting stress happens where the stress trajectories are concave against the line of action of the load. The objective of Reinforcement is to withstand these lateral tensile forces.
Article Source : http://www.engineeringcivil.com
Prestressing tendons (normally made of high tensile steel cable or rods) are employed to arrange a clamping load that forms a compressive stress to equalize the tensile stress occurs because of a bending load.
(i) Spalling reinforcement
Spalling stresses are developed in the areas behind the loaded faces of anchor blocks and it leads to departing of surface concrete. These stresses are produced with strain inconsistency with Poisson’s effects or with the shape of stress trajectories. The spalling stresses are arranged because of the strain compatibility with regard to the effect of Poisson’s ratio. For prestressing concrete bride, the stress in the reinforcement (0.87fy) should have been retained to manage cracking whereas the bars should have been set as closer to the end face as possible and fixed over the concrete edge.
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| Image Source : http://www.brainkart.com |
(ii) Equilibrium reinforcement
Equilibrium reinforcement is essential when there exist various anchorages wherein prestressing loads are employed successively. It is found in building construction & bridge.
(iii) Bursting Reinforcement
Tensile stresses are caused throughout pre-stressing operation and the highest bursting stress happens where the stress trajectories are concave against the line of action of the load. The objective of Reinforcement is to withstand these lateral tensile forces.
Article Source : http://www.engineeringcivil.com
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