Engineering Questions with Answers - Multiple Choice Questions

# Stress Distribution – Vertical Pressure – 2

1 - Question

For maximum vertical stress, the shear stress is _________ if the load is 30 kN and r=4m.
a) 0.4356 kN/m2
b) 0.1359 kN/m2
c) 0.1518 kN/m2
d) 0.3625 kN/m2

Explanation: Given,
r=4m
Q=30 kN
τrz=0.0725Qr2
τrz=0.07253042
∴ τrz=0.1359kN/m2.

2 - Question

What will be the intensity of shear stress at a depth of 4m and at a radial distance of 1m from concentrated load of 20 kN?
a) 0.4356 kN/m2
b) 0.244 kN/m2
c) 0.652 kN/m2
d) 0.128 kN/m2

Explanation: Given,
Z=4m
Q=20 kN
r=1
The Boussinesq’s shear stress τrz is given by,
τrz=3Qr2πz3[11+(rz)2]52
∴ τrz=32012π43[11+(14)2]52
∴ τrz=0.128 kN/m2.

3 - Question

If r/z ratio is 2 and load of 20 kN is acting at a point, then the vertical pressure at a depth 6m is ____________
a) 0.4356 kN/m2
b) 0.244 kN/m2
c) 0.1518 kN/m2
d) 4.72*10-3 kN/m2

If r/z ratio is 2 and load of 20 kN is acting at a point, then the vertical pressure at a depth 6m is ____________
a) 0.4356 kN/m2
b) 0.244 kN/m2
c) 0.1518 kN/m2
d) 4.72*10-3 kN/m2

4 - Question

The Boussinesq influence factor for r/z ratio equal to 1 is given by ____________
a) 0.3840
b) 0.5465
c) 0.0844
d) 0.2312

Explanation: Given,
r/z=1
The Boussinesq influence factor is given by,
KB=32π[11+(rz)2]52
KB=32π[11+12]52
KB=0.0844.

5 - Question

When the maximum vertical stress is 0.235 kN/m2 at a radial distance of 4m from the point load is __________ kN.
a) 42.34
b) 10.56
c) 20.76
d) 30.65

Explanation: Given,
z)max=0.235 kN/m2
r=4m
since the maximum vertical stress is
(σz)max=0.0888Qr2
∴ Q=(σz)maxr20.0888
∴ Q=0.235420.0888
Q=42.34 kN.

6 - Question

The Boussinesq’s vertical pressure σz under a uniformly loaded circular area is given by ________
a) σz=q[1[11+(az)2]32]
b) σz=q[1+[11+(az)2]32]
c) σz=q[11+(az)2]32
d) σz=q[1[11+(az)2]52]

Explanation: The Boussinesq’s vertical pressure σz under a uniformly loaded circular area is given by,
σz=q[1[11+(az)2]32]

where, q=load intensity per unit area
z= depth of point.

7 - Question

The Boussinesq influence factor for uniformly distributed circular area is given by ____________
a) KB=[1[11+(az)2]32]
b) KB=[1+[11+(az)2]32]
c) KB=[11+(az)2]32
d) KB=q[1[11+(az)2]52]

Explanation: The Boussinesq influence factor for uniformly distributed circular area is given by,
KB=[1[11+(az)2]32]
where the KB= Boussinesq influence factor which is a function of r/z ratio which is a dimensionless factor.

8 - Question

If θ is the apex angle which the line joining the apex makes with the outer edge of the loading of a circular area, then the Boussinesq’s vertical pressure σz under a uniformly loaded circular area is given by ______________
a) σz=q[1-sin3θ]
b) σz=q[1-cos3θ]
c) σz=q[1-tan3θ]
d) σz=q[1-cos2θ]

Explanation: The Boussinesq’s vertical pressure σ_z under a uniformly loaded circular area is given by,
σz=q[1[11+(az)2]32]. If θ is the apex angle which the line joining the apex makes with the outer edge of the loading of a circular area, then the term,
[11+(az)2]32=cos3θ
∴ σz=q[1-cos3θ].

9 - Question

The Boussinesq’s vertical pressure σz due to line load is given by ________
a) σz=5qπz1[1+xz2]2
b) σz=3qπz1[1+(xz)2]2
c) σz=2qπz1[1+(xz)2]2
d) σz=2qz1[1+xz2]2

Explanation: The Boussinesq’s vertical pressure σz due to line load is given by,
σz=2qπz1[1+(xz)2]2
Where q’=line load intensity per unit length
Z= depth of point.

10 - Question

The Boussinesq’s vertical pressure σz due to line load at a point situated vertically below the line load is given by ________
a) σz=2qπz
b) σz=3qπz
c) σz=2qπz1[1+(z)2]2
d) σz=2qz

Explanation: The Boussinesq’s vertical pressure σz due to line load is given by,
σz=2qπz1[1+(xz)2]2 at a point situated vertically below the line load implies x=0
∴ σz=2qπz1[1+(0z)2]2
∴ σz=2qπz.

11 - Question

If θ is the angle subtended by the edges of the strip load, then the Boussinesq’s vertical pressure σz due to strip load is given by ________
a) σz=qπ(θ+sinθ)
b) σz=qπ(θsinθ)
c) σz=qπ(sinθ)
d) σz=qπθ