Slip Loss and Relaxation of Steel

Q.

What is capillary action in soldering?

Q. The percentage loss of prestress due to anchorage slip of 3 mm in a concrete beam of length 30 m which is post-tensioned by a tendon with an initial stress of $1200N/m{m}^2$ and modulus of elasticity equal to $2.1\times {10}^{5}N/m{m}^2,$ is

1. 0.0175
2. 0.175
3. 1.75
4. 17.5

Q. In case of Magnet-Blaton system of prestressing, each sandwich can generally anchor

1. 6 wires
2. 8 wires
3. 10 wires
4. 16 wires

Q. the magnitude of loss of prestress due to relaxation of steel is in the range of

1. zero to 1%
2. 2 to 8%
3. 8 to 12%
4. 12 to 14%

Q. Spalling stresses are produced in post-tensioned pre-stressed concrete members at

1. locations of maximum bending moment only
2. locations of maximum shear zone
3. anchorage zone
4. bond-developing zone

Q. In case of prestressed concrete members, the bursting stresses develops at

1. Bond zone
2. Maximum bending moment zone
3. Maximum shear stress zone
4. Anchorage zone

Q. At the time of initial tensioning, the maximum tensile stress immediately behind the anchorage should not exceed which one of the following?

1. 0.50 $\times$ultimate tensile stress
2. 0.60 $\times$ultimate tensile stress
3. 0.70 $\times$ultimate tensile stress
4. 0.80 $\times$ultimate tensile stress

Q. The loss due to relaxation of stress in steel in PSC member depends on

1. Applied stress level
2. Temperature
3. Type of steel

1. 1 and 2 only
2. 2 and 3 only
3. 1, 2 and 3
4. 1 and 3 only

Q. 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 $E_s=200GPa,$ the loss prestress due to anchorage slip is

1. 16%
2. 12%
3. 10%
4. 1.6%

Q. Spalling stresses are produced in post-tensioned pre-stressed concrete members because of

1. bursting force
2. highly concentrated tendon force
3. inadequate anchor block
4. maximum shear zone

Q. The percentage loss of pre-stress due to anchorage slip of 3 mm in a concrete beam of length 30 m, which is post-tensioned by a tendon with an initial stress of 1200 N/mm${}^2$ and modulus of elasticity equal to 2.1 x 10${}^5$N/mm${}^2$ is

1. 0.0175
2. 0.175
3. 1.75
4. 17.5

Q. Match List -I (Post - tensioning system) with List - II (Type of anchorage) and select the correct answer using the codes given below the lists:

List- I
A. Freyssient
B. Gifford-Udall
C. Lee-McCall
D. Magnel Blaton

List- II
1. Flat steel wedges in sandwich plates
2. High strength nuts
3. Split conical wedges
4. Conical serrated concrete wedges
Codes:
A B C D

1. $2143$
2. $4321$
3. $2341$
4. $4123$