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Prestressing strands

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the grade of strands shall be G270 with a yield strength of 1650 MPA and ultimate strength of 1860 MPA. Strands shall be protected against corrosion. It shall be cold drawn, stress relieved, low relaxation, uncoated, seven wires and high tensile strength.



Properties

1.Tensile strength: strand shall be tested at the laboratory to verify the tensile strength. 




2.Modulus of elasticity: the relation between stress and strain remain linear up to 90% of ultimate strength. We can notice this from the figure below. The value for modulus of elasticity for strands is given by AASTO 5.4.2 for strands equal to 197000 MPA, for bars equal 207000 MPA. 








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