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A precast pretensioned beam of rectangular section has a breadth of 100mm and depth of 200mm and the beam with an effective span of 5mm is prestressed by tendon with their centroidal coinciding with the bottom kern and the initial force in the tendons is 150kn. Find prestressing force?

A precast pretensioned beam of rectangular section has a breadth of 100mm and depth of 200mm and the beam with an effective span of 5mm is prestressed by tendon with their centroidal coinciding with the bottom kern and the initial force in the tendons is 150kn. Find prestressing force? Correct Answer 15n/mm2

A = (100×200) = 20000mm2, p = 150kn = 150×103 Stresses due to prestressing force = (2P/A) = (2x150x103/20000) = 15n/mm2.

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