This set of Strength of Materials Multiple Choice Questions on “Rectangular Dam Analysis”.
1. 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
Answer: c
Clarification: Self weight of masonry = W = Area of cross-section × 1× Specific weight of masonry.
= (10×4)×1×20 = 800 kN.
2. 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
Answer: c
Clarification: 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. 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
Answer: a
Clarification: Resultant force (R) = (P2 + W2)1/2 = 5002 + 8002.
= (5002 + 8002)1/2
= 943.39 ~ 943.4 kN.
4. When the reservoir is empty tension occurs at ___________
a) Toe
b) Heel
c) Top width
d) Bottom width
Answer: a
Clarification: 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. 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
Clarification: Mix proportion for M15 grade concrete is 1:2:4.
| Grade of concrete | Mix proportionate |
| M10 | 1:3:6 |
| M15 | 1:2:4 |
| M20 | 1:1.5:3 |
6. Laterite is an example of ___________ rock.
a) Siliceous
b) Argillaceous
c) Calcareous
d) Metamorphic
Answer: b
Clarification: The Rocks having (Gneiss) aluminium or clay as the main component, such rocks are known as argillaceous rocks. Example: Slate, Laterite.
7. ________ is crystalline and compact in structure.
a) Marbles
b) Granite
c) Kadapa slabs
d) Shahabad stones
Answer: a
Clarification: 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. 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
Answer: c
Clarification: 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. Formation of white patches on the surface on the bricks is ____________
a) Tempering
b) Porosity
c) Shrinkage
d) Efflorescence
Answer: d
Clarification: 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. Kiln burning involves 90% of first class bricks.
a) True
b) False
