GATE 2023 Design of concrete Structures Rank Booster Quiz 41

A simply supported rectangular concrete beam of span 10 m has to be prestressed with a force of 2500 kN. The tendon is of parabolic profile having zero eccentricity at the supports. The beam has to carry an external uniformly distributed load of intensity 40 kN/m. Neglecting the self weight of the beam, the maximum dip of the tendon at the mid-span to balance the external load should be

The loss of stress in steel due to elastic shortening or deformation is

Consider the statements for a pre tensioned beam

1) There is no loss due to anchorage slip and shrinkage of concrete.

2) There will be no loss if all wires are simultaneously tensioned.

A post tension beam section drawn below consists of three cables of 100 mm² area. Initial prestressing in cable is 600 N/mm². If tensioning is done successively one by one, the loss of prestress in second cable will be {m = 6}.

A pre tensioned concrete beam 100 mm wide and 300 mm deep, initial force of 150 kN at an eccentricity of 50 mm, moment of inertia is 225 × 10⁶ mm⁴, initial stress in steel is 400 N/mm² modular ratio is 8, estimate the percentage loss due to elastic shortening.

A 6 m long simply-supported beam is prestressed as shown in the figure.

The beam carries a uniformly distributed load 6 kN/m over its entire span. If the effective flexural rigididty and the effective prestressing force is 200 kN, the net increase in length of the prestressing cable (in mm, up to two decimal places) is ___________