7/25/2019 Assignment 03 Dpsc

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How do you estimate the loss of pre-stress due to

i)Relaxation of steel ii) Shrinkage iii) Elastic deformation iv) creep of concrete

A rectangular concrete beam 180 mm wide and 400 mm deep is simply supported over a span of 8 m a

reinforced 3 wires of 8 mm diameter. The wires are located at a constant eccentricity of 80 mm and are subje

to an initial stress of 1200 N/mm2. Calculate the percentage loss of stress in the wires if the wires if the beam

Pre tensioned ii) Post tensioned. Take Es = 210 kN/mm2, modular ratio = 6, slip at anchorage = 0.8 mm, frictio

efficient = 0.002/m, relaxation of steel stress = 6%. Adopt creep and shrinkage co-efficient as per IS: 1343

specifications.