Engineering Questions with Answers - Multiple Choice Questions

# Strength of Materials MCQs Rectangular Dam Analysis

1 - Question

Calculate the self-weight of the masonry of the rectangle dam of 10 m height and 4 m wide. Consider specific weight of masonry as 20kN/m3.
a) 600 kN
b) 500 kN
c) 800 kN
d) 1000 kN

Explanation: Self weight of masonry = W = Area of cross-section × 1× Specific weight of masonry.
= (10×4)×1×20 = 800 kN.

2 - Question

Water-cement ratio varies normally from ______________ to __________
a) 0.42 – 0.45
b) 0.45 – 0.48
c) 0.42 – 0.48
d) 0.45 – 0.5

Explanation: The ratio to which the required amount of water is added to weight of cement to obtain desired consistency and workability of concrete mix is known as water cement ratio. It varies from 0.42 to 0.48.

3 - Question

Calculate the resultant force of dam with given self weight 800kN and water pressure be 500kN.
a) 943.4 kN
b) 956.7 kN
c) 948.6 kN
d) 939.1 KN

Explanation: Resultant force (R) = (P2 + W2)1/2 = 5002 + 8002.
= (5002 + 8002)1/2
= 943.39 ~ 943.4 kN.

4 - Question

When the reservoir is empty tension occurs at ___________
a) Toe
b) Heel
c) Top width
d) Bottom width

Explanation: For no tension to develop in the damn section in any condition, the eccentricity should be less than b/6. When the reservoir is empty, tension occurs at toe and compression occurs at heel.

5 - Question

What is the mix proportion for M15 grade concrete?
a) 1:1:2
b) 1:2:4
c) 1:3:6
d) 1:4:8

Explanation: Mix proportion for M15 grade concrete is 1:2:4.
M10 1:3:6
M15 1:2:4
M20 1:1.5:3

6 - Question

Laterite is an example of ___________ rock.
a) Siliceous
b) Argillaceous
c) Calcareous
d) Metamorphic

Explanation: The Rocks having (Gneiss) aluminium or clay as the main component, such rocks are known as argillaceous rocks. Example: Slate, Laterite.

7 - Question

________ is crystalline and compact in structure.
a) Marbles
b) Granite

Explanation: Marble is a metamorphic rock and is made from limestone, this is a very costly stone. It is less durable. It is crystalline and compact in structure. So it can take a fine polish. It is not very hard.

8 - Question

As per IS, the standard dimensions for a brick is _______ (in cm).
a) 19×8×8
b) 19×9×8
c) 19×9×9
d) 19×8×9

Explanation: The shape of a brick should be uniform with rectangular surface and its size should be standard with 19×9×9 cm. They should have a uniform red colour and it should be well burnt.

9 - Question

Formation of white patches on the surface on the bricks is ____________
a) Tempering
b) Porosity
c) Shrinkage
d) Efflorescence

Explanation: A good brick should not contain excess alkaline soils when the bricks are exposed to the atmosphere. It should not absorb moisture. If it attracts moisture then dampness occurs and results in the formation of white patches. Hence the brick begins decaying.

10 - Question

Kiln burning involves 90% of first class bricks.
a) True
b) False

Explanation: Kiln burning is a permanent structure. There is complete control on fire. It produces a large scale of manufactured bricks, it takes only 24 hours in burning the bricks and 12 days for cooling. It produces 90% of burnt bricks.

11 - Question

______ bricks can withstand up to a temperature of 1800°C.
a) Refractory
b) Fly ash
c) Clay
d) Cement

Explanation: The bricks made from refractory clay are called refractory bricks. The weight of these bricks is 2 kN/m3. The standard size is 230× 65× 113 mm. These bricks can withstand up to the temperature of 1800°C.

12 - Question

According to IS, the minimum expansion joint in construction should be ________
a) 18mm to 30 mm
b) 15mm to 24mm
c) 18mm to 25mm
d) 22mm to 30mm

Explanation: According to Indian standards 456- 2000, it is desirable to provide 18 mm to 25 mm thick expansion joints after every 30 to 45 m construction of length.

13 - Question

The edges formed by the intersection of plane surfaces of a brick are known as _________
a) Arises
b) Stretcher
d) Frog

Explanation: In any bond, the edges formed by the intersection of plane surfaces of a brick are termed as arises. These are straight and sharp in case of good bricks or brick tiles.

14 - Question

The depression made in the face of brick during its manufacture is _________
a) Brick tile
b) Bat
c) Frog
d) Quoin closer

Explanation: The depression provided on any face of the brick during its manufacture can be termed as frog. A hand moulded bricks has one frog. A pressed brick has two frogs.

15 - Question

Calculate the eccentricity of a rectangular dam of width 4 m. Take the distance between the water face and point where resultant cuts the base as 5.25 m.
a) 2.25m
b) 3.25m
c) 4.35m
d) 5.35m

Explanation: Eccentricity = e = Z – b/ 2
Where Z = 5.25 m & b = 4m ; Now, e = Z- b/2
e = 5.25 – 4/2
= 3.25m.

16 - Question

### Strength of Materials MCQs Trapezoidal Dam as Vertical Side Phase

Calculate the horizontal water pressure acting on a dam. The total depth of water be 13m. Take specific weight of water be 10kN/m3.
a) 765 kN
b) 845 kN
c) 965 kN
d) 1175 kN

Explanation: Horizontal water pressure(P) = w×h2/ 2.
Where w = 10 kN/m3. h= 13m.
P = 10×132/ 2 = 845kN.

17 - Question

Calculate the self-weight of a rectangular dam of 22m high and 8m wide. It contains water upto a height of 20m. Consider the specific weight of masonry be 25 kN/m3.
a) 3560 kN
b) 5432 kN
c) 4400 kN
d) 5680 kN

Explanation: Consider 1m length of the dam. The total depth of dam is 22 metres.
Self weight of masonry (W)= (22×8)×1×25
= 4400kN.

18 - Question

The pressure intensity of water at free surface is ________
a) Zero
b) Maximum
c) Minimum
d) Uniform

Explanation: The pressure intensity of water at a free surface is always zero and increase linearly to a maximum at the base and is equal to “ wh”.

19 - Question

Self weight of dam acts in ___________ direction.
a) Vertical
b) Horizontal
c) Inclined
d) Parallel

Explanation: Self weight of the Dam at vertically downwards passing through centre of gravity of the damn section and Total horizontal water pressure acts horizontally at heel of the dam.

20 - Question

The maximum compressive stresses developed at the base of the dam should not exceed permissible ___________ stresses for masonry.
a) Tensile
b) Crippling
c) Compressive
d) Shear

Explanation: To avoid the failure of crushing, the maximum compressive stress developed at the base of the dam should not exceed the permissible compressive stress for masonry with which the dam is constructed.

21 - Question

For no _______ to develop in the dam section the resultant should always lie within the middle third.
a) Compression
b) Tension
c) Shear
d) Buckling

Explanation: For no tension to develop in the dam section at any condition, the eccentricity developed with the resultant should be always less than b/6. The resultant must always lie within the middle third.

22 - Question

Calculate the self weight of trapezoidal dam with top width 5m and bottom width 8m. The height of dam is 15 m. Consider specific weight of masonry be 25kN/m3.
a) 3456.5 kN
b) 2768.5 kN
c) 2437.5 kN
d) 3450 kN

Explanation: Consider 1m of length, area of trapezoidal dam be (a+b)/2 ×H
The self weight of trapezoidal dam (W) = (a+b)/2 × H × 1 × 25
W = 2437.5 kN.

23 - Question

The material(earth) retained by the retaining wall is called as __________
a) Surcharge
b) Turf
c) Foliate
d) Back fill

Explanation: The material retained by the retaining wall is called back fill. The top surface of the back fills maybe him the horizontal or inclined.

24 - Question

The inclination of surcharge to the horizontal is called ____________
a) Surcharge elevation
b) Surcharge angle
c) Surcharge factor
d) Surcharge depression

Explanation: The back fill lying above a horizontal plane at an elevation of the top of wall is known as a surcharge and its inclination to the horizontal is called surcharge angle.

25 - Question

Which of the following is practical pressure?
a) Active earth pressure
b) Passive earth pressure
c) Soil moisture tension
d) Horizontal water pressure

Explanation: The pressure exerted by back fill on retaining wall is called an active earth pressure. This is the minimum earth pressure exerted by the soil. This is also known as practical pressure.

26 - Question

The angle of internal friction for water is __________
a) 180°
b) 100°
c) 0°
d) 270°

Explanation: Angle of internal friction is defined as the maximum slope at which the particles of soil will come in rest due to their internal friction. It is also called an angle of repose for water it is 0°.

27 - Question

Which of the following is theoretical pressure?
a) Active earth pressure
b) Passive earth pressure
c) Soil Tension
d) Horizontal water pressure

Explanation: The pressure exerted by the retaining wall on the retained earth is called passive earth pressure. This is a maximum earth pressure due to maximum shear stress on the retaining wall. This is also known as theoretical pressure.

28 - Question

Which of the following is an example for plasticizer?
a) Ca
b) Mg
c) Zn
d) Hg

Explanation: The combination of both inorganic and organic materials which will help to reduce the water content for getting higher workability are known as plasticizers. Examples are calcium, sodium, salts of hydrocarbons etc.

29 - Question

_______ curing is adopted for columns and walls.
a) Moist curing
b) Membrane curing
c) Ponding
d) Descending stage

Explanation: In this curing, the exposed surface of the concrete is kept in a damp and moist condition for a long time, the vertical members like columns and walls can be adopted for this type of curing.

30 - Question

Prestressed concrete is an example of _____________
a) Malleability
b) Ductility
c) Fatigue
d) Plasticity

Explanation: Fatigue is the property of a material by which the material with stands to repeating, reversing or varying upcoming loads. The best example of fatigue is concrete and prestressed concrete.

31 - Question

### Strength of Materials MCQs Trapezoidal Dam as Inclined Side Phase

Calculate the eccentricity of a trapezoidal dam with a distance between the centre of gravity and point where the resultant cuts the base is 5m. The bottom width of the dam is 3m.
a) 2.5m
b) 3.5m
c) 4.5m
d) 5m

Explanation: The eccentricity (e) = Z – b/2.
Z= distance between the centre of gravity and point where the resultant cuts the base is 5m.
= 5-3/2 = 1.5m.

32 - Question

Which of the following is not a failure of retaining wall?
a) Structural slide
b) Shear sliding
c) Crushing
d) Slope pitching

Explanation: Crushing Failure is related to dams. The retaining walls are the structures constructed to store earth on one side especially in case of hill or ghat roads.

33 - Question

________ pressure which occurs commonly in dams.
a) Passive earth pressure
b) Active earth pressure
c) Soil moisture tension
d) Wind pressure

Explanation: Active earth pressure is exerted by backfill on retaining walls. It is also called as practical pressure. It occurs commonly in dams.

34 - Question

_________ failures contribute 40% to earthen dams.
a) Seepage
b) Structural
c) Hydraulic
d) Natural

Explanation: On the basis of various investigation reports and case studies, hydraulic failures contribute about 40% of failures to earthen dams. The rest of the failures is shared by seepage failures and structural failures.

35 - Question

Which of the following filters are also known as chimney drains?
a) Horizontal filter
b) Inclined filter
c) Rock toe
d) Toe drain

Explanation: The filters which are laid across the outer slope of the impervious core are called as inclined filters. They are also known as Chimney drains. They are provided mainly to collect the seepage emerging out of the core.

36 - Question

Zoned earthen dams are also known as ______
a) Heterogeneous dams
b) Core wall dams
c) Homogeneous dams
d) Hydraulic dam

Explanation: The dams are constructed on shallow pervious foundations in this dam section about outer zones are made fairly pervious material and the inner most zoning called “hearting” is done was fairly impervious material. It is also known as heterogeneous dam.

37 - Question

___________ dams are built with key trenches.
a) Heterogeneous earth dam
b) Homogeneous earth dam
c) Earth Dam with Core wall
d) Rolled fill dam

Explanation: The outer zones of this dam are made of pervious material as in zoned dam. In this case, it is essentially build cut-off wall (cut-off trench) built quite deep preferably upto impervious rock layer in the foundation.

38 - Question

Line of seepage is also known as __________
b) Phreatic line
d) Hydraulic seepage line

Explanation: The line within the dam section below which there are positive hydrostatic pressures in a dam and above the line the hydrostatic pressures are negative. It gives a divide line between dry and saturated soils.

39 - Question

____________ represents the top stream line.
a) Phreatic line
d) Hydraulic seepage line

Explanation: Phreatic line is also called a line of seepage or saturation line. The phreatic line represents the top streamline and hence helps us in drawing the flow net.

40 - Question

The hydrostatic pressures on phreatic line are equal to____
a) Zero
b) Maximum
c) Minimum
d) Constant

Explanation: The hydrostatic pressure on phreatic line is equal to atmospheric pressure and hence equal to zero, the flow through the body of the dam below the phreatic line reduces the effective weight of the soil and thus reduces the shear strength of the soil.

41 - Question

Expand MWL?
a) Minimum water level
b) Maximum water level
c) Meagre water level
d) Most wind level

Explanation: The water level that is attained during floods is called the maximum water level. The dams and spillway sections are designed to withstand water pressure at this level.

42 - Question

______ is the difference of Level between full reservoir level and top of the dam.
a) Net free board
b) Gross free board
c) Design free board
d) Over free board

Explanation: In dams, in order to prevent the overtopping during peak floods, a sufficient margin is provided between the full reservoir level and top of the dam. This is known as gross free board.

43 - Question

By keeping the phreatic line within the downstream toe, the ___________ can be avoided.
a) Piping
b) Gullying
c) Sloughing
d) Over topping

Explanation: If the filter at downstream side toe is choked then also the downstream too becomes saturated. In such circumstances, some erosion occurs in downstream to this causes sloughing. To avoid this phreatic line must be within the downstream toe.

44 - Question

Springs(closely coiled) are examples of _____________
a) stiffness
b) hardness
c) toughness
d) creep

Explanation: The property of a material or substance which offers resistance to bending action and measures the load required to be applied is called stiffness. It is denoted by s or k. Springs are the best examples of stiffness.

45 - Question

Perennial canals are also known as ________
a) Inundation canal
b) Productive canal
c) Feeder canal
d) Permanent canal