Quiz: Civil Engineering

Exam: GATE

Topic: MISCELLANEOUS

Each question carries 1 mark

Negative marking: 1/3 mark

Time: 15 Minutes

Q1. The recommended partial factor of safety fer steel as per IS 456: 2000 is:

(a) 1.5

(b) 1.15

(c) 1.00

(d) 0.87

Q2. The minimum grade of concrete to be used for the construction near sea coast as per Is 456: 2000 is:

(a) M15

(b) M20

(c) M25

(d) M30

Q3. The flexural strength of M25 concrete as per IS 456:2000 is?

(a) 3 MPa

(b) 3.5 MPa

(c) 4 MPa

(d) 4.5 MPa

Q4. If the characteristic strength is defined as that value follow which not more than 50% results are expected to fall, then what is the value of target mean strength (in MPa) to be considered in mix design of M30 concrete considering the standard deviation of 6 MPa?

(a) 24 MPa

(b) 30 MPa

(c) 31.58 MPa

(d) 21 MPa

Q5. An elastic isotropic body is in a hydrostatic state of stress as shown in the figure. For no change in the volume to occur, what should be the value of Poissonâ€™s ratio?

(a) 0

(b) 0.5

(c) 0.25

(d) 1

Q6. The major and minor principal stresses at a point are 130 MPa and -130 MPa respectively. The maximum shear stress at the point is?

(a) 130 MPa

(b) 260 MPa

(c) Zero

(d) 65 MPa

Q7. A simply supported steel beam of length 5 m sags due to its own weight. Assuming a uniform curvature of 0.002 m^(-1) along the span, the maximum deflection (mm) of the beam at mid-span is?

(a) 5.5 mm

(b) 6.25 mm

(c) 9 mm

(d) 12 mm

Q8. A solid circular shaft having diameter of 100 mm is made up of a material which can withstand maximum shear stress of 110 MPa, the maximum torque (in kNm) that the shaft can resist is **__**

(a) 21.58KNm

(b) 20.23KNm

(c) 16.76KNm

(d) 18.76KNm

Q9. The plastic modulus of a section is 5.4Ã—10^(-4) mÂ³. and the shape factor is 1.5 if the plastic moment capacity of the section is 180 kNm, what is the yield stress material?

(a) 250 MPa

(b) 333 MPa

(c) 415 MPa

(d) 350 MPa

Q10. The Bod removal efficiency (in percentage) during primary treatment under normal conditions is about

(a) 6.5%

(b) 85%

(c) 30%

(d) zero

Solutions

S1. Ans.(b)

Sol. AS per IS 456, the partial factor of safety for steel is taken as 1.15 and for concrete, its generally taken as 1.5.

S2. Ans.(d)

Sol. As per IS 456:2000, concrete in sea water or exposed directly along the sea coast shall be of minimum M20 grade in the case of PCC construction. In case of RCC construction, its should be at least M30.

S3. Ans.(b)

Sol. f_cr = 0.7 âˆš(f_ck )

= 0.7 âˆš25 = 3.5 N/mmÂ²

S4. Ans.(b)

Sol.

If f_ck is defined as the value bellow which not more than 50% of results are expected to fall, then f_m=f_ck so the target mean strength of concrete to be considered in the design mix = f_m=f_ck=30 MPa

S5. Ans.(b)

Sol. volumetric strain, âˆˆ_v = ((Î´x+Î´y+Î´z)/3) (1-2Î¼) = âˆ†V/V

If âˆ†V=0,1-2Î¼=0 as Î´x+Î´y+Î´x=0

â‡’ Î¼ = 1/2 = 0.5

S6. Ans.(a)

Sol. Ï„_max=(Ïƒ_P1- Ïƒ_P3)/2

= (130-(-130))/2= 130 MPa

S7. Ans.(b)

Sol.

From the property of circle,

(2R â€“ Î´) Î´ = l/2Ã—l/2

â‡’ Î´_max = l^2/8R

= 5^2/8Ã—0.002

= 6.25 Ã— 10^(-3) m

= 6.25 mm

S8. Ans.(a)

Sol. Ï„_max = 16T/(Ï€D^3 )

â‡’ Ï„ = (Ï€D^3)/16 Ï„_max

= Ï€(100^3 )/16Ã—110

= 21.5875 kNm

S9. Ans.(b)

Sol. M_P = fy. Z_P

â‡’ f_y = MP/Z_P

=(180Ã—10^6 N-mm)/(5.4Ã—10^(-4)Ã—10^9 mm^3 )

= 333.33 N/mmÂ²

S10. Ans.(c)

Sol. In primary treatment,

BOD removal efficiency = 30 â€“ 35%

Suspended solids removal efficiency = 60 -70%