RCC_APPSC CE Quiz-5

Prestressing losses in post tensioned and pre tensioned beams are respectively

What will be the maximum possible uniformly distributed load (inclusive of self-weight) over the entire span of a simply supported beam of span ‘L’ such that the deflection at midspan at service condition is Zero ? The cross-section is rectangular. The prestressing forces ‘P’ is applied with uniform eccentricity ‘e’ Assume no losses.

In post-tensioned elements, the zone within which the applied prestressing force on steel is fully dissipated into concrete and made to act as a distributed force is known as_________.

When the tendons are placed at an eccentricity of e, the extreme fibre stresses in beam are:

Find the maximum compressive stress in the concrete of a rectangular beam (100mm x 200mm) prestressed with a force of 200kN at an eccentricity of 50mm.

An ordinary mild steel bar with Young’s modulus 200 GPa is prestressed to working stress of 200 MPa. The effective stress left in steel is ________  if the permanent negative strain due to shrinkage and creep is 0.0008.

Loss of prestress due to anchorage slip occurs:

A post tensioned concrete beam of size 150 mm x 300 mm is prestressed by three cables each with a cross sectional area of 40 mm². An initial stress of 1300 MPa is applied. The loss of stress due to elastic shortening in the beam when simultaneous tensioning and anchoring of all three cables are done will be:

In case of curved ducts, the loss of prestress depends upon the redius of curvature (R) of the duct and the coefficient of friction () between duct surface and the tendon. The tension at any point of the cable distance ‘x’ from the end is given by____________.

A 4.8 m long post-tensioned prestressed concrete beam is prestressed by a parabolic cable with eccentricity of 15 mm above C.G. at both supports and 45 mm below C .G. at the midspan. The beam is tensioned from one end. In the estimation of maximum loss due to friction, what should be the cumulative angle turned by the parabolic profile?