SSC-JUNIOR ENGINEER (Civil & Structural) Online Exam 2019 (Part-III)

Total Questions: 50

11. A simply supported beam of overall depth 150 mm has neutral axis at 50 mm from extreme top fibre. Permissible flexural stresses in extreme compression and extreme tension fibre are restricted to 15 MPa and 25 MPa respectively. If the load on the beam is increased gradually, then :

Correct Answer: D. failure of section will be due to stresses in extreme bottom fibre reaching to maximum permissible tensile stresses
Solution:A simply supported beam overall depth 150 mm has neutral axis at 50 mm from extreme top fibre. Permissible flexural stresses in extreme compression and extreme tension fibre are restricted to 15 MPa and 25 MPa respectively. If the load on the beam is increased gradually, then failure of section will be due to stresses in extreme bottom fibre reaching to maximum permissible tensile stresses.

12. Reinforcement provided in a rectangular RCC beam of effective depth 500 mm is such that actual depth of neutral axis is at 300 mm from extreme compression fibre. Fe 415 steel is used and provided on tension face only. It is a :

Correct Answer: C. over reinforced section
Solution:Reinforcement provided in a rectangular RCC beam of effective depth 500 mm is such that actual depth of neutral axis is at 300 mm from extreme compression fibre. Fe 415 steel is used and provided on tension face only. It is a balanced section.

13. Froude's number is a ratio of :

Correct Answer: B. inertial forces to gravity forces
Solution:In open channel hydraulics, the Froude number is a very important non-dimensional parameter.
The Froude Number is a dimensionless parameter measuring the ratio of "the inertia force on a element of fluid to the weight of the fluid element"-the inertial force divided by gravitational force.

The Froude Number is relevant in fluid dynamic problems where the weight (gravitational force) of the fluid is an important force.

14. In 1 : 36 model of a spilway, the velocity is 2 m/s. What is the corresponding velocity in the prototype?

Correct Answer: C. 12 m/s
Solution:

15. A planimeter measures the area of figure. traversed clockwise with anchor point inside and tracking with M = 100 cm², additive constant C = 20, initial reading 3.436, final reading 8.945, The zero mark of the dial passed the index once in the reverse direction. The area measured was :

Correct Answer: D. 1550.9 cm²
Solution:No explanation given in the book

16. A retaining wall with vertical back retains a mass of cohersion-less soil, surface of which is level with top of the wall. Active lateral earth pressure coefficient (in terms of 'Φ') i.e., angle of internal friction of backfill is given by :

Correct Answer: A.
Solution:The lateral pressure acting against smooth wall AB is due to the mass of soil ABC above failure line AC which makes an angle of 45°+ Φ/2 with the horizontal. The lateral pressure distribution on wall AB of height H increases in simple proportion to depth. The pressure acts normal to the wall AB (see fig. below).

Pₐ acts at a height H/3 above the base of the wall.

17. or 4.6 type bolt conforming to IS 1367, respective ultimate tensile strength and yield strength will be :

Correct Answer: B. 400 MPa and 240 MPa
Solution:No explanation given in the book

18. Which of the following is a reason for negative error in chaining?

Correct Answer: D. Rise in temperature
Solution:Variation in Temperature. (Cumulative, + or -). When a chain or tape is used at temperature different from that at which it was calibrated, its length changes. Due to the rise in the The measured distance is thus less and the error temperature, the length of the chain increases. becomes negative. Due to the fall in temperature, the length decreases. The measured distance is thus more and the error becomes negative. In either cases the error is cumulative.

19. What must be the height of a cylindrical sample for split tensile strength test of stone, if the diameter is 50 mm?

Correct Answer: A. 100 mm
Solution:The cylindrical specimen shall have diameter not less than four times the maximum size of the coarse aggregate and not less than 150 mm. The length of the specimens shall not be less than the diameter and not more than twice the diameter.

For diameter d = 50mm Height of the cylinder = 2 × d = 2 × 50 = 100mm

20. The percentage of fly ash used in high volume fly ash concrete is :

Correct Answer: D. 50 - 60%
Solution:Fly Ash: Finely divided residue resulting from the combustion of the powdered coal and transported by the flue gases and collected by the electrostatic precipitator.

High volume fly ash concrete is a concrete where a replacement of 50 to 60 percentage of cement is made with the usage of fly ash.