## Prestressed Concrete Structures MCQ Set 1

1. The stresses developed in the prestressed structures are computed using:

a) Simple bending equations

b) Stress strain theory

c) Strain analysis

d) Stress curves

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2. Once the insitu concrete hardens, we assume the section to be:

a) Dilithic

b) Monolithic

c) Transverse

d) Longitudinal

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3. If the precast unit is propped during the placing of insitu concrete, the stresses due to self weight are computed using:

a) Section modulus

b) Eccentricity

c) Tension

d) Principle stress

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4. In most composite constructions which involve prestressed units and insitu cast concrete the latter is of:

a) High strength concrete

b) Medium strength concrete

c) Colored concrete

d) Reinforced concrete

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5. For computing the live load stresses, the effect of different moduli between the cast in situ and precast unit is considerable by:

a) Eccentricity

b) Modular ratio

c) Tensile stresses

d) Deflections

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6. In modulus of elasticity of insitu concrete of grade M20 will be about:

a) 25kn/mm^{2}

b) 30kn/mm^{2}

c) 35kn/mm^{2}

d) 40kn/mm^{2}

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^{2}, while the modulus of concrete in precast prestressed units could vary from 28 to 36kn/mm

^{2}for concrete grades of M30 toM60.

7. The modular ratio of precast prestressed unit is:

a) 2.0 to 1.6

b) 1.1 to 1.5

c) 2.4 to 1.4

d) 2.2 to 1.7

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^{2}is used in conjunction with precast units made of normal weight aggregates.

8. A precast pretensioned beam of rectangular section has a breadth of 100mm and depth of 200mm and the beam with an effective span of 5mm is prestressed by tendon with their centroidal coinciding with the bottom kern and the initial force in the tendons is 150kn. Find prestressing force?

a) 20n/mm^{2}

b) 34n/mm^{2}

c) 15n/mm^{2}

d) 12n/mm^{2}

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^{2}, p = 150kn = 150×10

^{3}Stresses due to prestressing force = (2P/A) = (2x150x10

^{3}/20000) = 15n/mm

^{2}.

9. Calculate stresses due to slab weight in precast sections given moment due to slab weight is 1200nm of section modulus 667×10^{3}?

a) 1.8n/mm^{2}

b) 1.5n/mm^{2}

c) 2.5n/mm^{2}

d) 2.3n/mm^{2}

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^{3}, moment due to slab weight is 1200nm Stresses due to slab weight in the precast sections = (1200000/667×10

^{3}) = 1.8n/mm

^{2}.

10. Calculate the stress of pretensioned beams assuming as propped during the casting of the slab if Z_{t} is 225×10, Z_{b} is 128x104mm^{3} and moment due to self weight is 1200nmm?

a) 12.3 and 4.5

b) 0.53 and 0.94

c) 0.23 and 0.45

d) 1.23 and 0.67

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_{t}= 225×10, Z

_{b}= 128×10

^{4}mm

^{3}, moment due to self weight =1200nmm Stresses due to this moment in the composite section: At top = (1200000/225×10

^{4}) = 0.53n/mm

^{2}(compression), At bottom = (1200000/128×10

^{4}) = 0.94n/mm

^{2}(tension).

## Prestressed Concrete Structures MCQ Set 2

1. Based on experimental investigations, the members of truss are analyzed on assumption that the joints are:

a) Rollers

b) SSB

c) UDL

d) Hinged

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2. Which action of joint does not affect the forces developed in the members?

a) Plasticity

b) Rigidity

c) Flexural

d) Ductile

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3. The trusses are analyzed for dead, wind and:

a) Wave loads

b) Fire actions

c) Snow loads

d) Tensile loads

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4. When loads are applied to the chords the bending moment developed are determined by assuming chord as a:

a) SSB

b) Continuous

c) Point

d) UDL

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5. Trusses must be analyzed for forces developed during:

a) Fabrication and erection

b) Twisting and lining

c) Grouting

d) Shortcrete

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6. One of the functions involved in construction management is:

a) House owners

b) Tax planners

c) Land

d) Area of site

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7. Which methods are widely used in project works?

a) PERT

b) CRT

c) TRC

d) WRE

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8. The grade of concrete used for construction of prestressed concrete structures is:

a) Heavy mix concrete

b) Design mix concrete

c) Partially mix concrete

d) Fully mix concrete

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9. The cement content limit which is not permitted unless special consideration has been considered in design:

a) 300

b) 400

c) 375

d) 475

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10. The aim of workability is to use the lower percentage of:

a) Coarse aggregates

b) Fine aggregates

c) Gravel

d) Sandstone

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## Prestressed Concrete Structures MCQ Set 3

1. The Zielinski and Rowe conducted experiments on concrete prismatic specimens using the technique?

a) Surface stress

b) Surface strain

c) Surface tension

d) Surface edge

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2. The parameters considered for concrete prisms are:

a) Midspans

b) Blocks

c) Cross sectional area

d) End block

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3. The distribution of transverse stress and ultimate load of the end block is not effected by:

a) Anchorage material

b) Curing concrete

c) Tendons applied

d) Jacking provided

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4. The Zielinski and Rowe developed empirical relations for computation of:

a) Maximum transverse tensile stress

b) Minimum transverse tensile stress

c) Zero

d) Constant

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5. The equation for maximum tensile stress, f_{max} is given as:

a) f_{c}(0.98-0.825(y_{po}/y_{o})

b) f_{c}(0.98-0.825(y_{po}/y_{o})

c) f_{c}(0.98-0.825(y_{po}/y_{o})

d) f_{c}(0.98-0.825(y_{po}/y_{o})

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_{vmax}= f

_{c}(0.98-0.825(y

_{po}/y

_{o}) which is valid for y

_{po}/y

_{o}= 0.3 to 0.7 bursting tension, F

_{bst}= pk(0.48-0.4(y

_{po}/y

_{o}), (y

_{po}/y

_{o}) = ratio of sides of loaded area to bearing area of the prism, f

_{v}= transverse tensile stress, f

_{c}= average compressive stress in the prism, p

_{k}= applied compressive force on the end block.

6. The creating bursting tension is given by:

a) F_{bst}(3-(f_{v}/f_{v,max})^{2})

b) F_{bst}(3-(f_{v}/f_{v,max})^{2})

c) F_{bst}(3-(f_{v}/f_{v,max})^{2})

d) F_{bst}(3-(f_{v}/f_{v,max})^{2})

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_{bst}, corred = F

_{bst}(3-(f

_{v}/f

_{v,max})

^{2}), ft = permissible tensile strength of concrete. To resist bursting tension, the reinforcement should be arranged between 0.2y

_{0}and 2y

_{0}providing the maximum intensity of stress.

7. Estimate the position and magnitude of the maximum transverse tensile stress and bursting tension for the end block with a concentric anchor force of 100kn using Rowe’s method?

a) 26.5n/mm^{2}

b) 26.5n/mm^{2}

c) 26.5n/mm^{2}

d) 26.5n/mm^{2}

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_{k}= 100kn, 2y

_{po}= 50mm, 2y

_{po}= 100mm, y

_{po}/y

_{o}=0.5, f

_{c}= (100×10

^{3}/100×100) = 10n/mm

^{2}, f

_{v(max)}= f

_{c}(0.98-0.825(y

_{po}/y

_{0})) = 10(0.98-0.825(0.5)) = 5.68n/mm

^{2}.

8. The end block and a prestressed beam, 200mm wide and 300mm deep, has two Freyssinet anchorages (100mm diameter) with their centre at 75mm from the top and bottom of the beam. The force transmitted by each anchorage being 200kn, estimate the maximum tensile and bursting tension?

a) 100kn

b) 50kn

c) 150kn

d) 200kn

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_{po}= (π/4×100

^{2}) = 89mm, side of the surrounding prism 2y

_{o}= 150mm, y

_{po}/y

_{o}= 0.593, average compressive stress f

_{c}= (200×103/150×150) = 8.9n/mm2, Tensile stress f

_{v(max)}= 8.9(0.98-0.825(0.593)) = 4.45n/mm

^{2}, Transverse tension F

_{bst}= 200×10

^{3}(0.48-0.4(0.593)) = 50000n = 50kn.

9. In case of large bridge girders with massive end block, for computation of bursting tension end block is divided into:

a) Axially

b) Rectangular

c) Symmetrically

d) Rounded

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10. The design strength assumed to act to sustain bursting tension is:

a) 0.56f_{y}

b) 0.49f_{y}

c) 0.87f_{y}

d) 0.12f_{y}

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_{y}and the stress however is limited to value corresponding to a strain of 0.1% when the concrete cover is less than 50mm.

## Prestressed Concrete Structures MCQ Set 4

1. The limit state design philosophy recognizes the need to provide:

a) Safe structures

b) Designed structures

c) Stressed structures

d) Curved structures

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2. The limit state design proposals have been evolved from the provisions of various:

a) Structures

b) Codes

c) Plan

d) Foundations

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3. A successful design should not only satisfy requirements but also ensure:

a) Serviceability

b) Total cost

c) Critical period

d) Planning

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4. The primary object of structural design is to obtain:

a) Structural plan

b) Structural solution

c) Structural design

d) Structural lane

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5. The permissible or working stress method of design, by Morsh is also referred as:

a) Limit theory

b) State theory

c) Elastic theory

d) Stress theory

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6. The inadequacy of the working load design in predicting ultimate loads of structure was recognized after:

a) Second world war

b) Cold war

c) Red war

d) First world war

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7. The structure designed by ultimate load method, although having a desirable margin of safety may not be safe at:

a) Serviceable

b) Durable

c) Ductile

d) Tension

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8. The ultimate load design concepts extended to the design of continuous beams and frames is referred as:

a) Working stress design

b) Permissible stress design

c) Limit state design

d) Collapse state design

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9. The philosophy of limit states is adopted and elaborated by:

a) European concrete committee(CEB)

b) European concrete committee(CEB)

c) European concrete committee(CEB)

d) European concrete committee(CEB)

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10. The new philosophy of design termed the limit state approach was incorporated in which country code:

a) Europe

b) Russia

c) Canada

d) India

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## Prestressed Concrete Structures MCQ Set 5

1. The analysis of stresses developed in prestressed concrete structural elements is based on how many assumptions?

a) 5

b) 4

c) 3

d) 2

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2. The tensile stresses when do not exceed the limit of modulus then change in loading of member results in:

a) Change of bending moment

b) Change of stress

c) Change in shear

d) Change in rupture

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3. Which conditions are negligible at the stage of visible cracking on concrete?

a) Bending conditions

b) Joint conditions

c) Zone conditions

d) Loading conditions

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4. The stresses due to prestressing are referred as:

a) Combined stresses

b) Bending stresses

c) Anchoring stresses

d) Tensioning stresses

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5. Which of the following notations are used for evaluating the relationship for combined stresses?

a) P, E, M, A, I

b) P, σ, M, g, I

c) P, W, M, π, L

d) P, θ, M, Z, L

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6. The uniform prestress in a concrete member subjected to concentric prestressing is:

a) P/e

b) P/s

c) P/t

d) P/a

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7. In case of eccentric prestressing force the support force F_{sup} is:

a) F_{sup} = p/a(1+ey_{b/i}^{2})

b) F_{sup} = p/a(1+ey_{b/i}^{2})

c) F_{sup} = p/a

d) F_{sup} = p/a-e_{b}

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_{inf}= (p/a+p

_{e}/z

_{b}) = p/a(1+ey

_{b}/i

^{2}), F

_{sup}= (p/a-p

_{e}/z

_{b}) = p/a(1-y

_{b}t/i

^{2}).

8. The diagram indicating the direct stress of the beam is:

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9. The diagram indicating the bending stress of the cross section the beam is:

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10. The cross section of beam is combination of:

a) Direct stresses and Bending stresses

b) Principal stresses and Shear stresses

c) Anchorage and Tension stresses

d) Flexural and Rigidity stresses