Deck 3: Prestressed Concrete Tanks and Structural Members

Question 1

When a sliding joint is made what is interposed at the junction of wall and base?

A)rubber
B)timber
C)plastic
D)soil

Answer 1

rubber

Question 2

In the fixed base joint the junction is between the tank wall and______________          

A)slab
B)footing
C)beams
D)columns

Answer 2

footing

Question 3

Calculate circumferential prestress of a cylindrical prestressed concrete water tank given that the thickness is 12mm, loss ratio is 0.75, the maximum stress under working pressure is 1n/mm²(Nd value is 720)?

A)9.4n/mm²
B)5.6n/mm²
C)11.2n/mm²
D)15.2n/mm²

Answer 3

9.4n/mm²

Question 4

wires of 8mm diameter stressed to 1200n/mm² are to be used for vertical prestressing?

A)15
B)12
C)8
D)4

Question 5

Calculate the spacing of 5mm wires having a loss ratio of 0.075, compressive stress is 10.75n/mm², 5mm diameter wires stress is 1000n/mm², 12 wires of 8mm diameter are stressed to 1200n/mm²(Nd = 840n/mm²)?

A)15.4mm
B)11.6mm
C)12.4mm
D)18.5mm

Question 6

Calculate the maximum vertical moment due to prestress if given self weight moment is 16.5kn/m, thickness is 0.115m and loss ratio is 0.0075?

A)15.4
B)21.5
C)25.4
D)2.6

Question 7

Find vertical prestressing force if characteristic strength is 8.2, wires are stressed at 1000n/mm², diameter is 150mm?

A)1500kn
B)1230kn
C)4567kn
D)8967kn

Question 8

Prestressed concrete tanks have been widely used for the storage of______________          

A)gas
B)air
C)fluids
D)water

Question 9

The metal linear concept in prestressed tanks has proved to be success in case of

A)air tanks
B)water tanks
C)fluid tanks
D)vapour tanks

Question 10

Calculate minimum wall thickness given a cylindrical prestressed water tank of internal diameter 30m over a depth of 7.5m and the permissible compressive stress at transfer is 13n/mm² and the maximum compressive stress under working pressure is 1n/mm² and the loss ratio is 0.75?

A)43.8
B)82.3
C)64.5
D)90.4

Question 11

Calculate vertical prestressing force if wires of 5mm diameter with an initial stress of 1000n/mm² are available for circumferential winding and Freyssinet cables made up of 12 wires of 8mm diameter stressed to 1200n/mm² are to be used for vertical prestressing?

A)15
B)12
C)8
D)4

Question 12

What is beam?

A)structural member subjected to transverse loads
B)structural member subjected to axial loads only
C)structural member subjected to seismic loads only
D)structural member subjected to transverse loads only

Question 13

Structural members subjected to bending and large axial compressive loads are known as

A)strut
B)purlin
C)beam-column
D)lintel

Question 14

Members used to carry wall loads over wall openings are called

A)purlin
B)rafter
C)girder
D)lintels

Question 15

Load transfer by a beam is primarily by

A)bending only
B)shear only
C)bending and shear
D)neither bending nor shear

Question 16

What are spandrels?

A)exterior beams at floor level of buildings
B)interior beams at floor level of buildings
C)exterior columns
D)interior columns

Question 17

Members used in bridges parallel to traffic are called

A)spandrel
B)stringers
C)purlin
D)joist

Question 18

Which of the following statement is correct?

A)beams are termed as fixed beams when end condition do not carry end moments
B)beams are termed as simply supported beams when ends are rigidly connected to other members
C)beams are termed as fixed beams when ends are rigidly connected to other members
D)beams are termed as continuous beams when they do not extend across more than two support

Question 19

Complex stresses may occur when

A)loads are inclined to principal axes
B)loads are along principal axes
C)symmetrical section are used
D)small values of shear and bending moment occur at section

Question 20

Simple bending takes place if

A)loading passes above shear centre for single symmetric open section
B)loading passes below shear centre for single symmetric open section
C)loading plane coincides with one of the principal planes of doubly symmetric section
D)loading plane do not coincide with one of the principal planes of doubly symmetric section

Question 21

Which of the following buckling does not occur in beam?

A)lateral buckling of whole beam
B)local buckling of web
C)local buckling of flanges
D)longitudinal buckling of web

Question 22

A foundation rests on______________          

A)base of the foundation
B)foundation soil
C)subgrade
D)foundation soil and subgrade

Question 23

For initial estimate for a beam design, the width is assumed?

A)1/10th of span
B)1/30th of span
C)1/15th of span
D)1/5th of span