MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 27 Mcqs, each offering curated multiple-choice questions to sharpen your Prestressed Concrete Structures knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In prestressed concrete members steel is under |
| A. | Compression |
| B. | Bending |
| C. | Tension |
| D. | Torsion |
| Answer» D. Torsion | |
| 2. |
During tensioning of prestressing tendons the breakage of wires in any one prestressed concrete member shall not exceed |
| A. | 2.5% |
| B. | 7.5% |
| C. | 10% |
| D. | 12.5% |
| Answer» B. 7.5% | |
| 3. |
A rectangular concrete beam of 250 mm wide and 600 mm deep is pre-stressed by means of four 10 mm diameter high tensile bars located at 200 mm from the soffit of the beam. If the effective stress in the wires is 500 N/mm2. What is maximum bending moment that can be applied to the section WITHOUT causing tension at soffit of the beam? |
| A. | 24.5 kNm |
| B. | 26.5 kNm |
| C. | 31.5 kNm |
| D. | 38.5 kNm |
| Answer» D. 38.5 kNm | |
| 4. |
Precast concrete tiles with marble chips on the surface are known as: |
| A. | mosaic tiles |
| B. | lime tiles |
| C. | granite tiles |
| D. | marble tiles |
| Answer» B. lime tiles | |
| 5. |
Long span concrete bridges are usually constructed as a |
| A. | Prestressed slab |
| B. | Reinforced concrete beam and slab type |
| C. | Composite, prestressed beam type |
| D. | Prestressed box-girder type |
| Answer» E. | |
| 6. |
For pre-stressed structural elements, high strength concrete is used primarily because |
| A. | Both shrinkage and creep are more |
| B. | Shrinkage is less but creep is more |
| C. | Modulus of elasticity and creep values are higher |
| D. | High modulus of elasticity and creep values are lower |
| Answer» E. | |
| 7. |
For a prestressed beam, if all the tendons of are tensioned simultaneously in a smooth duct having zero coefficient of friction then which of the following statement comes true regarding loss recorded in prestress while post tensioning? |
| A. | The loss due to elastic shortening may or may not be zero but due to friction it is always zero. |
| B. | The loss due to elastic shortening and friction is always zero |
| C. | The loss due to elastic shortening is zero but due to friction it may or may not be zero. |
| D. | None of the two mentioned loss would be zero. |
| Answer» D. None of the two mentioned loss would be zero. | |
| 8. |
Consider the following statements:Correct estimation of loss of prestress is required for assessing1. The serviceability behaviour of a PSC beam.2. The ultimate shear resistance of PSC beam.3. The ultimate moment of resistance of PSC beam.Which of the above statements is/are correct? |
| A. | 1, 2 and 3 |
| B. | 3 only |
| C. | 2 only |
| D. | 1 only |
| Answer» B. 3 only | |
| 9. |
On the areas immediately behind external anchorage, the permissible unit bearing stress on the concrete, after accounting for losses due to relaxation of steel, elastic shortening, and seating of anchorages, shall not exceed ______. |
| A. | 048 fci \(\sqrt{\frac{A_{bearing}}{A_{punching}}}\)or 0.8 fck Whichever is smaller |
| B. | 0.48 f ci \(\sqrt {\frac{{{A_{bearing}}}}{{{A_{punching}}}}} \) or 0.40 fckWhichever is smaller |
| C. | 0.48 f ci \(\sqrt {\frac{{{A_{bearing}}}}{{{A_{punching}}}}} \) or 0.76 fck Whichever is smaller |
| D. | 0.48 fci \(\sqrt {\frac{{{A_{bearing}}}}{{{A_{punching}}}}} \) or 0.78 fck Whichever is smaller |
| Answer» B. 0.48 f ci \(\sqrt {\frac{{{A_{bearing}}}}{{{A_{punching}}}}} \) or 0.40 fckWhichever is smaller | |
| 10. |
IS : 1343 – 1980 limits the minimum characteristic strength of pre-stressed concrete for post-tensioned work and pretension work is |
| A. | 25 MPa, 30 MPa respectively |
| B. | 25 MPa, 35 MPa respectively |
| C. | 30 MPa, 35 MPAa respectively |
| D. | 30 MPa, 40 MPa respectively |
| Answer» E. | |
| 11. |
A simply supported beam of span 24 m is to be designed to carry a central concentrated load of 200 kN. If 40 cm is the dip of the cable at the loading point from the neutral axis, the effective prestress is |
| A. | 300 kN |
| B. | 3000 kN |
| C. | 200 kN |
| D. | 2000 kN |
| Answer» C. 200 kN | |
| 12. |
A simply supported post-tensioned prestressed concrete beam of span L is prestressed by a straight tendon at a uniform eccentricity ‘e’ below the centroidal axis. If the magnitude of prestressing force is ‘P’ and flexural rigidity of beam is ‘EI’, the maximum central deflection of the beam is |
| A. | \(\frac{{Pe{L^2}}}{{8\;EI}}\) (Upwards) |
| B. | \(\frac{{Pe{L^2}}}{{16\;EI}}\) (Downwards) |
| C. | \(\frac{{Pe{L^2}}}{{16\;EI}}\) (Upwards) |
| D. | \(\frac{{Pe{L^2}}}{{8\;EI}}\) (Downwards) |
| Answer» B. \(\frac{{Pe{L^2}}}{{16\;EI}}\) (Downwards) | |
| 13. |
If the loading on a simply supported pre-stressed concrete beam is uniformly distributed, the centroid of the pre-stressing tendon should be as |
| A. | A straight profile along the lower edge of the kern |
| B. | a parabolic profile with convexity downward |
| C. | A straight profile along the centroid axis |
| D. | A circular profile with convexity upward |
| Answer» C. A straight profile along the centroid axis | |
| 14. |
Normally prestressing wires are arranged in |
| A. | upper part of the beam |
| B. | lower part of the beam |
| C. | centre |
| D. | Anywhere |
| Answer» C. centre | |
| 15. |
As per IS 1343 – 1980, the minimum 28 days compressive strength for pre-tensioned member is: |
| A. | 50 N/mm2 |
| B. | 30 N/mm2 |
| C. | 25 N/mm2 |
| D. | 40 N/mm2 |
| Answer» E. | |
| 16. |
In PSC, concrete of high strength is used because |
| A. | It results in smaller cross-section |
| B. | Bearing stresses are generated in anchorage zones |
| C. | Shrinkage cracks are reduced |
| D. | All of the above |
| Answer» E. | |
| 17. |
In a post-tension pre-stressed concrete beam, the end block zone is in between the end of the beam and the section where |
| A. | The shear stresses are maximum |
| B. | Only shear stresses exist |
| C. | No lateral stresses exist |
| D. | Only longitudinal stresses exist |
| Answer» E. | |
| 18. |
In a pre-stressed concrete beam section shown in the figure, the net loss is 10% and the final pressurising force applied at X is 750 kN. The initial fiber stresses (in N/mm2) at the top and bottom of the beam were |
| A. | 4.166 and 20.833 |
| B. | -4.166 and -20.833 |
| C. | 4.166 and -20.833 |
| D. | -4.166 and 20.833 |
| Answer» E. | |
| 19. |
In case of prestressed concrete element, which statement is not correct? |
| A. | Concrete remains uncracked and it protects steel from corrosion |
| B. | It can be used more effectively in liquid retaining structures. |
| C. | The stiffness of structure is less due to uncracked condition of concrete. |
| D. | Shear resisting capacity is increased due to pre-compression. |
| Answer» D. Shear resisting capacity is increased due to pre-compression. | |
| 20. |
A simply supported prestressed concrete beam is of 25 m span. The initial stress is 1000 Mpa. The slip in the jack during tensioning has been 2 mm. If Es = 200 GPa, the loss of prestress due ot anchorage slip is |
| A. | 16% |
| B. | 12% |
| C. | 10% |
| D. | 1.6% |
| Answer» E. | |
| 21. |
In a pre-stressed concrete beam, the ratio of applied pre-stressing force (P) to the concrete capacity of the section in compression is known as ______. |
| A. | Moment ratio (R) |
| B. | Eccentricity (ϵ) |
| C. | Reinforcement Ratio (m) |
| D. | Efficiency factor (ρ) |
| Answer» E. | |
| 22. |
Consider the following statements;1) In a reinforced concrete member subjected to flexure, the externally applied moment is resisted by an internal couple formed by steel and concrete and their magnitudes vary with the applied moment, while the lever arm of the internal couple remains constant2) In a prestressed concrete. Member, the external moment is resisted by an internal couple, but it is the lever arm that changes with the loading conditions and the stress in steel remain practically constantWhich of the above statements is/are correct? |
| A. | 1 only |
| B. | 2 only |
| C. | Both 1 and 2 |
| D. | Neither 1 nor 2 |
| Answer» D. Neither 1 nor 2 | |
| 23. |
As per IS 1343:1980, members having no tensile stress permitted under working conditions are known as: |
| A. | limited pre-stressed members |
| B. | partially pre-stressed members |
| C. | half pre-stressed members |
| D. | fully pre-stressed members |
| E. | initially pre-stressed members |
| Answer» E. initially pre-stressed members | |
| 24. |
In a composite construction |
| A. | Interface slipping is prevented by using shear connector |
| B. | Differential shrinkage is overcome by using the same grade of concrete for both the components. |
| C. | Precast member is always designed to carry the weight of in-situ concrete without props. |
| D. | The in-situ concrete cannot be pre-stressed. |
| Answer» B. Differential shrinkage is overcome by using the same grade of concrete for both the components. | |
| 25. |
A post-tensioned beam of span 25 m is prestressed with 20 numbers of 40 mm diameter cables, each stressed to 1500 MPa with eccentricity e = 0 at supports and e = 500 mm at mid span, varying parabollically. If the shear force as the support section due to externally applied load is 4500 kN what is the nearest magnitude of the shear force resisted by the stirrups? |
| A. | 3060 kN |
| B. | 4540 kN |
| C. | 250 kN |
| D. | 1480 kN |
| Answer» E. | |
| 26. |
Losses in prestress in pretensioned beams are more than the losses in post tensioned beams due to the |
| A. | effect of elastic shortening |
| B. | frictional force through bonding |
| C. | excess shrinkage |
| D. | anchorage slip |
| Answer» B. frictional force through bonding | |
| 27. |
In a pre-stressed member, it is advisable to use |
| A. | low-strength concrete |
| B. | high-strength concrete |
| C. | high-strength concrete and high-tension steel |
| D. | high-strength concrete and low-tension steel |
| Answer» D. high-strength concrete and low-tension steel | |