SEMI FINALS

Question 1

Most of the codes provide for the loss of stress due to relaxation of steel as a percentage of initial stress in steel.

Answer 1

Loss due to relaxation of stress in steel

Question 2

Values varying from 0 to 90MPa for stress in wires varying from ____ to ___

Answer 2

0.5fpu to 0.8fpu

Question 3

Characteristic strength of prestressing tendon

Answer 3

fpu

Question 4

Is the loss of stress in steel under nearly constant strain at constant temperature

Answer 4

Relaxation

Question 5

Depends upon the tendon form of alignment, which generally follows a curved profile along the length of the beam

Answer 5

Loss due to curvature effect

Question 6

Depends upon the local deviations in the alignment of the cable

Answer 6

Loss of stress due to wobble effect

Question 7

Is the result of accidental or unavoidable misalignment, since duck or sheaths cannot be perfectly located to follow a predetermined profile throughout the length of beam

Answer 7

Wobble or wave effect

Question 8

The prestressing force at the jacking end

Answer 8

Po

Question 9

Coefficient of friction between the cable and duct.

Answer 9

μ

Question 10

Friction coefficient for wave effect

Answer 10

k

Question 11

The IS Code recommend for the value of k per 100m for normal condition

Answer 11

0.15

Question 12

The IS Code recommend for the value of k per 100m for thin walled ducts where heavy vibrations are encountered and in alter adverse conditions

Answer 12

1.5

Question 13

In prestress, the combined effect of prestressing force and external load can be resolved into a

Answer 13

single force

Question 14

The locus of the points of application of this force in any structure is termed as

Answer 14

Pressure Line

Question 15

The load in pressure line is such that stress at the top fiber of support and bottom fiber of central span is

Answer 15

Zero

Question 16

Refers to the evaluation of permissible prestress, stresses under service load, ultimate strength, and entire load, similar to axial load

Answer 16

Analysis of members under flexure

Question 17

Based on allowable stresses at transfer

Answer 17

Permissible prestress

Question 18

These are compared with allowable stresses under service conditions

Answer 18

Stresses under service loads

Question 19

This is compared with the demand under factored loads

Answer 19

Ultimate Strength

Question 20

The entire load versus ____ behavior

Answer 20

deformation

Question 21

Assumption
Concrete is a ______ material

Answer 21

homogeneous elastic material

Question 22

Assumption
Within the range of working stress, both concrete and stell behave elastically withstanding the small amount of creep, which occurs in both the materials under the

Answer 22

sustained loading

Question 23

Assumption
A plane section before bending is assumed to remain plane even after bending, which implies a ______ across the depth of the member

Answer 23

linear strain distribution

Question 24

Assumption
Prestress concrete is one in which there have been introduced internal stresses of such _______ that stresses resulting from given external loading is counter balanced to desired degree

Answer 24

magnitude and distribution

Question 25

Assumption Plane sections remain plane until failure, known as

Answer 25

Bernoulli's hypothesis

Question 26

Assumption Perfect bond between concrete and prestressing steel for

Answer 26

bonded tendons

Question 27

3 Principle of Mechanics

Answer 27

1. Equilibrium of internal forces with external loads 2. Compatibility of the strains in concrete 3. Constitutive relationship

Question 28

The compression in concrete (C) is ____ to the tension (T) in tendon.

Answer 28

equal

Question 29

The couple of CT are equal to the moment due to ______

Answer 29

external loads

Question 30

_______ of the strains in concrete and in steel for bonded tendons

Answer 30

Compatibility

Question 31

The formulation involves the first assumption of plane remaining plane after

Answer 31

bending

Question 32

For unbonded tendons, the compatibility is in terms of

Answer 32

deformation

Question 33

______ relationships relating the stresses and the strains in the materials

Answer 33

Constitutive

Question 34

Variation of internal forces in reinforced concrete

Answer 34

C₂ > C₁ Z₂ ≈ Z₁

Question 35

Variation of internal forces in prestressed concrete

Answer 35

C₂ ≈ C₁ Z₂ > Z₁

Question 36

Compression and tension at transfer due to self weight symbol

Answer 36

C₁ T₁

Question 37

Compression and tension under service load symbol

Answer 37

C₂ T₂

Question 38

Self weight symbol

Answer 38

W₁

Question 39

Service load symbol

Answer 39

W₂

Question 40

Lever arm at transfer symbol

Answer 40

Z₁

Question 41

Lever arm under service load symbol

Answer 41

Z₂