This set of Prestressed Concrete Structures Multiple Choice Questions & Answers (MCQs) focuses on “Investigations”.
1. In the anchorage zone or the end block of a post tensioned prestressed concrete element, the state of stress distribution is considered as ____________
Explanation: In the anchorage zone or the end block of a post tensioned prestressed concrete element, the state of stress distribution is complex and three dimensional in nature, in most post tensioned members the prestressing wires are introduced in cable holes or ducts, preformed in the members, and then stressed and anchored at the end faces.
2. The stress distribution at a distance far away from the loaded face is computed from ____________
a) Simple bending theory
b) Complex bending theory
c) Axial bending theory
d) Parallel bending theory
Explanation: According to st.venant’s principle, the stress distribution at a distance far away from the loaded face (normally at a distance equal to or greater than the depth of the beam) can be computed from the simple bending theory.
3. The term anchorage zone or end block is termed as ____________
a) Zone between end and section
b) Zone between middle and section
c) Zone between edge and section
d) Zone between tension and section
Explanation: The zone between the end of the beam and the section where only longitudinal stress exists is generally referred to as anchorage zone or end block, as a result of this, large forces, concentrated over relatively small areas are applied on the end blocks, the highly discontinuous which are applied at the end while changing progressively to continuous linear distribution, develop transverse and shear stresses.
4. The transverse stresses developed in the anchorage zone are ____________
Explanation: The transverse stresses developed in the anchorages zone are tensile in nature over a large length and since concrete is weak in tension, adequate reinforcement should be provided to resist this tension.
5. Which knowledge is essential at the anchorage zone according to view of designer?
a) Transverse stresses
b) Distribution of stresses
c) Zone stresses
d) Anchorage stresses
Explanation: From the point of view of the designer, it is essential to have a good knowledge of the distribution of stresses in the anchorage zone, so that he can provide an adequate amount of steel, properly distributed to sustain the transverse tensile stresses.
6. The investigations studied the stress distribution in the anchorage zone stresses using ____________
a) Theoretical solutions
b) Linear equations
c) Pie diagrams
d) Charts and blocks
Explanation: A number of investigations have studied the stress distribution in the anchorage zone using empirical equations or theoretical equations or theoretical solutions based on two or three dimensional elasticity or experimental techniques.
7. Who among the one has done investigations on anchorage zone stress?
Explanation: The important investigations were those done by Magnel, Guyon, Iyengar, Zielinski, Rowe, Yettram, Robbins and Chandra sekhara, since the lines of force follow the same pattern with half the radius of curvature the length of the anchorage zone is halved, the transverse tension developed is also proportionately reduced, in similar way the greater the number of points of application of the prestressing force on the end block, the more uniform is the stress distribution.
8. The main aim of stress analysis in the anchorage zone is to obtain ____________
a) Zone tensile stress
b) Transverse tensile stress
c) Longitudinal tensile stress
d) Jack tensile stress
Explanation: The main aim of stress analysis in the anchorage zone is to obtain the transverse tensile stress distribution in the end block from which the total transverse bursting tension could be computed, the effect of transverse tensile stresses is to develop a zone of bursting tension in a direction perpendicular to the anchorage forces.
9. During anchorage of the end faces results in application of ____________
a) Small forces
b) Neutral forces
c) Large forces
d) Tensile forces
Explanation: In most post tensioned members, the prestressing wires are introduced in cable holes or ducts, performed in the members and then stressed and anchorage at end faces and as a result of this, large forces, concentrated over relatively small areas, are applied on end blocks.
10. The discontinuous forces applied at the end while changing progressively to develop ____________
a) Transverse and shear
b) Principle and shear
c) Bursting and shear
d) Longitudinal and shear
Explanation: The highly discontinuous forces which are applied at the end, while changing progressively to continuous linear distribution, develop transverse and shear stresses, the ratio of transverse tensile stresses to the average compressive stress gradually decreases with the increase in the ratio of the depth of anchor plate to that of the end block.
Sanfoundry Global Education & Learning Series – Prestressed Concrete Structures.
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