Prestressed Basic Topics

Which of the following is a pre-tensioning system of prestressing?

• Freyssinet system

• Magnel-Blaton system

• Hoyer system

• Lee-McCall system

High tensile steel used in prestressed concrete has a yield strength generally greater than:

• 250 MPa

• 415 MPa

• 600 MPa

• 1000 MPa

Which of the following is an advantage of prestressed concrete?

• Increased section size

• Less deflection under service load

• Increased self-weight

• Low initial cost

In post-tensioning, prestress is applied:

• Before casting concrete

• During mixing of concrete

• After concrete has gained sufficient strength

• After curing is completed

Which system uses wedge action for anchoring tendons?

• Hoyer system

• Freyssinet system

• Gifford-Udall system

• Lee McCall system

Which of the following tendon profiles is most effective in reducing midspan deflection?

• Straight

• Concentric

• Parabolic

• Bent

Which one is NOT a type of prestressing?

• Linear prestressing

• Pre-tensioning

• Post-tensioning

• External prestressing

The line of thrust in a prestressed beam refers to:

• Bending stress line

• Neutral axis

• Resultant location of compressive forces

• Line of zero stress

Which of the following is a time-dependent loss of prestress in concrete?

• Elastic shortening

• Anchorage slip

• Friction loss

• Creep of concrete

Elastic shortening loss is more critical in:

• Post-tensioned members

• Pre-tensioned members

• Beams with low eccentricity

• Beams under ultimate load