Subject: Structural Analysis-I (SA-I)/ TOS/ Structural Mechanics
1.
If load is acting on the longitudinal axis of column, it is called .
a)
Horizontal load
b)
Axial load
c)
Eccentric load
d) Vertical load
Ans: b
Explanation:- if load is acting on the longitudinal axis of column, it
is called as axial load. And if load is acting at an eccentricity from the
axial axis of column then its is called as eccentric load.
2.
If load is acting away from the longitudinal axis of column, it is called .
a)
Horizontal load
b) Axial load
c) Eccentric load
d) Vertical load
Ans: c
Explanation:- if load is acting on the longitudinal axis of column,
it is called as axial load. And if load is acting at an eccentricity from the
axial axis of column then its is called as eccentric load.
3. The
horizontal distance between the longitudinal axis of column and the line of
action of load is called .
a)
Eccentricity
b)
Axial distance
c)
Vertical distance
d)
None of these
Ans: a
4.
In the column,
axial load produces
a)
Both direct and
bending stress
b)
Bending stress
c)
Direct stress
d)
None of these
Ans: c
Explanation:- in column axial load produce only direct stresses
(P/A) at the base. Whereas eccentric load produce both direct and bending
stresses at the base.
5.
In the column,
eccentric load produces
a)
Both direct and
bending stress
b)
Bending stress
c)
Direct stress
d)
None of these
Ans: a
Explanation:- in column axial load produce only direct stresses (P/A) at the base. Whereas eccentric load produce both direct and bending stresses at the base.
6.
Maximum stress (σmax) =
a)
Direct stress (σ0)
x Bending stress (σb)
b)
Direct stress (σ0)
- Bending stress (σb)
c)
Direct stress (σ0)
+ Bending stress (σb)
d)
Direct stress (σ0)
/ Bending stress (σb)
Ans: c
7.
Minimum stress (σmin) =
a)
Direct stress (σ0)
x Bending stress (σb)
b)
Direct stress (σ0)
- Bending stress (σb)
c)
Direct stress (σ0)
+ Bending stress (σb)
d)
Direct stress (σ0)
/ Bending stress (σb)
Ans: b
8.
For rectangular section,
Maximum stress (σmax) =
a) P/A
(1+6e/b)
b) P/A(6e/b)
c) P/A(1/6e)
d) P/A
(1-6e/b)
Ans: a
9.
For rectangular section,
Minimum stress (σmin) =
a) P/A
(1+6e/b)
b) P/A(6e/b)
c) P/A(1/6e)
d) P/A
(1-6e/b)
Ans: d
10.
The
maximum distance of load from the centre of column, such that if load acts
within this distance there is no tension in the column. This maximum distance is called .
a)
Axial distance
b)
Vertical distance
c)
Limit of Eccentricity
d)
Eccentricity
Ans: c
11.
When load is
acting within e limit, σmin will be .
a)
Tensile
b)
Compressive
c)
Zero
d)
None of these
Ans: b
12.
When load is acting at the point of e limit, σmin will be _ .
a)
Tensile
b)
Compressive
c)
Zero
d)
None of these
Ans: c
13.
When load is
acting beyond e limit, σmin
will be .
a)
Tensile
b)
Compressive
c)
Zero
d)
None of these
Ans: a
14.
For no tension in column
a)
Load must act within elimit
b)
σ0 > σb
c)
e ≤ b/6
d)
Any one of the above
Ans: d
15.
The
centrally located portion of a section within the load line falls so as to
produce only compressive stress is called as .
a)
Core of section
b)
Limit of eccentricity
c)
Middle third rule
d)
None of the above
Ans: a
16.
Limit of eccentricity for solid circular
section is given by
a) D/8
b) D/6
c) D/5
d) None
of these
Ans: a
17.
Limit
of eccentricity for rectangular section is given by
a)
d/6 or b/6
b)
d/4 or b/4
c)
d/8 or b/6
d)
d/6 0r b/8
Ans: a
18.
For
no tension condition in the base of a short column of hollow circular cross
section, the limit of eccentricity is
a)
(D2
+ d2) /8d
b)
(D2
+ d2) /6d
c)
(D2
+ d2) /8D
d)
(D2
+ d2) /6D
Ans: c
19.
Calculate core of
section for circular column of diameter 400mm.
a)
60mm
b)
75mm
c)
55mm
d)
50mm
Ans: d
Explanation:- core of the section is the central portion of
radius D/8. i.e 400/8=50 mm
20.
Calculate
core of section for rectangular section of size 250mm x 500mm.
a)
41.66mm
and 83.33mm
b)
52.66mm and 81.33mm
c)
31.66 mm and 73.33mm
d)
55.66mm and 85.66mm
Ans: a
Explanation:- core of the section for rectangle is the central parallelogram
portion of having edge distance at D/6 or B/6 from mid point or cg of section.
i.e 250/6 or 500/6=41.66mm or 83.33mm
21.
For
rectangular chimney coefficient of wind resistance is
a)
1.5
b)
2
c)
1
d)
0.5
Ans: c
22.
For
circular chimney coefficient of wind resistance is
a) 0.87
b) 0.57
c) 0.47
d) 0.67
Ans: d
23.
For solid circular
chimney of diameter D section modulus is given
by
a)
πD3/32
b)
πD3/16
c)
πD3/8
d)
πD3/12
Ans: a
24.
For
hollow circular chimney of external diameter D and internal diameter d section
modulus is given by
a)
Π(D4-d4)/16D
b)
Π(D4-d4)/12D
c)
Π(D4-d4)/32D
d)
Π(D4-d4)/22D
Ans: c
25.
For
hollow square section having B x B as external dimension and b x b as internal
dimension section modulus is given by
a)
(B4-b4)/6B
b)
(B4-b4)/6b
c)
(B4+b4)/6B
d)
(B4+b4)/6b
Ans: a
26.
In
rectangular chimney if wind pressure acts on projected area of width b then
section modulus is given by
a)
bd2/8
b)
bd2/6
c)
bd2/4
d)
bd2/3
Ans: b
27.
In
rectangular chimney if wind pressure acts on projected area of thickness d then
section modulus is given by
a)
db2/8
b)
db2/4
c)
db2/3
d)
db2/6
Ans: d
28.
A
rectangular column is 200mm wide and 100mm thick. It is carries a load of 180KN
at an eccentricity of 100mm in the plane bisecting thickness. Find direct stress.
a)
9N/mm2
b)
8N/mm2
c)
7N/mm2
d)
6N/mm2
Ans: a
Explanation:- direct stress = P/A
=
180x1000/(200x100) = 9 N/mm2
29.
A
rectangular column is 200mm wide and 100mm thick. It is carries a load of 180KN
at an eccentricity of 100mm in the plane bisecting thickness. Find bending stress.
a) 25.99N/mm2
b) 26.99N/mm2
c) 27.99N/mm2
d) 22.99N/mm2
Ans: b
Explanation:- bending stress = M/z
= (180x1000x100)/(100x2002/6) = 27 N/mm2
30.
A
hollow circular steel column having external and internal diameter 500mm and
300mm respectively carries an eccentric load of 200kN acting at eccentricity of
60mm. find direct stress.
a) 1.69N/mm2
b) 2.79N/mm2
c) 1.59N/mm2
d) 2.29N/mm2
Ans: c
31.
A
hollow circular steel column having external and internal diameter 500mm and
300mm respectively carries an eccentric load of 200kN acting at eccentricity of
60mm. find bending stress.
a) 1.12N/mm2
b) 2.12N/mm2
c) 1.59N/mm2
d) 2.29N/mm2
Ans: a
32.
A
masonary wall 10m high, 3m wide and 1.5m thick is subjected to a wind pressure
of 1200N/m2 Find direct stress. If unit weight of masonary is 20kN/m3.
a)
250kN/m2
b)
200kN/m2
c)
225kN/m2
d)
175kN/m2
Ans: b
33.
A
masonary wall 10m high, 3m wide and 1.5m thick is subjected to a wind pressure
of 1200N/m2 Find bending stress. If unit weight of masonary is 20kN/m3.
a)
50kN/m2
b)
45kN/m2
c)
35kN/m2
d)
40kN/m2
Ans: d
34.
A
square chimney 3m x 3m outside and 0.375m thick is 20m high. A wind pressure
intensity 1.2kN/m2 is acting on it. If specific weight of chimney is
18kN/m3 Find direct stress at the base of chimney.
a)
260kN/m2
b)
360kN/m2
c)
350kN/m2
d)
460kN/m2
Ans: b
35.
A
square chimney 3m x 3m outside and 0.375m thick is 20m high. A wind pressure
intensity 1.2kN/m2 is acting on it. If specific weight of chimney is
18kN/m3 Find bending stress at the base of chimney.
a) 233.77kN/m2
b) 333.77kN/m2
c) 350.77kN/m2
d) 460.77kN/m2
Ans: a
36. The
ratio of the length and diameter of a simply supported uniform circular beam
which experiences maximum bending stress equal to tensile stress due to same
load at its mid span, is
a) 1/8
b) 1/4
c) 1/2
d) 1/3
Answer: c
Explanation: Bending Stress = M/Z, Tensile stress =
P/A
FROM
QUESTION, Bending stress = Tensile stress
i.e. M/Z = P/A
M = PL/4, Z = (π * D3)/32
, A = (π*D2)/4
after putting these values
L/D = ½
37. Simply supported rolled steel joist 8 m
long carries a uniformly distributed load over it span so that the maximum
bending stress is 75 N/mm². If the slope at the ends is 0.005 radian and the
value of E = 0.2 × 106 N/mm², the depth of the joist, is
a) 200 mm
b)
250 mm
c)
300 mm
d) 400 mm
Answer: d
Explanation: Slope = wl^3/24EI.
0.05 = wl^3/24EI.
I = wl^3/24000.
We know that, F/Y = M/I
here F = 75N/mm2., Y =
d/2. & L = 8000mm.
by substituting values an solving we will get,
d = 400 mm
38.
The ratio of the length and depth of a simply supported rectangular beam
which experiences maximum bending stress equal to tensile stress, due to same
load at its mid span, is
a) 1/2
b) 2/3
c) 1/4
d) 1/3
Answer: b
Explanation:-Bending Stress=M(max)/Z =(PL/4)/(I/y)
=(PL/4)/[(bd^3/12)/(d/2)]
=(PL/4)/[bd^2/6]
=3PL/2bd^2
Now,
Tensile Stress=P/A =P/bd.
Since,
according to question,
Bending Stress=Tensile Stress
PL/2bd^2=P/bd.
L/d=2/3
39. The ratio of the
area of cross-section of a circular section to the area of its core, is
a) 4
b) 8
c) 12
d) 16
Answer: d
Explanation:-Area or
column = π x D2/4
Radius of core, r = D/8
Area of core = π x r2 = π x (D2)/64
Ratio , (π x D2/4 ) / (π x (D2)/64) = 64/4 =16
40. The assumption in
the theory of bending of beams is:
a) Material is homogeneous
b) Material is isotropic
c) Young’s modulus is same in tension as well as
in compression
d) All the above
Answer: d
41. A dam means
a) Water retaining structure
b) Soil retaining structure
c) Cross Draining work
d) Water treatment structure
Ans: a
42. Tension occurs in a dam section at
a) Heel
b) Toe
c) At centre of base
d) Top edge
Ans: a
43. Formula for
eccentricity
a) e = z - b/2
b) e = z + b/2
c) b/2 - z
d) b/2 + z
Ans: a
44. According to middle third
rule ‘e’ should be less than
a) b/2
b) b/6
c) z/6
d) z/2
Ans: b
45. If ‘e’ > b/6
------------ occurs at
heel
a) tension
b) compression
c) bending
d) shear
Ans: a
46. The most commonly used
section for a dam is
a) Rectangular
section
b) Triangular
section
c) Trapezoidal
section
d) Any section
Ans: c
47. The minimum base width for
a rectangular section is
a) H/ ÖS
b) H/ S2
c) H/S
d) H2/S
Ans: a
48. In masonry dam total
horizontal thrust is 120MN and total vertical force is 300MN.If the coefficient
friction at base is 0.8 factor of safety against sliding is -------
a) 1.0
b) 1.5
c) 2.0
d) 2.5
Ans: c
49. The structure constructed for retaining the earth at
their back is called
a) Retaining wall
b) Dam
c) Intake
d) Retaining well
Ans: a
50. Due to
active earth pressure the retaining wall may slide -------------
a)
Away from back fill
b) To wards back fill
Ans: a
51. Due to
passive earth pressure the retaining wall may slide -------------
a)
Away from back fill
b) Towards back fill
Ans: b
52. What are the various forces acting on the retaining wall.
(a) Earth pressure
(b) Wt.of retaining wall
(c) None of the above
(d) Both (a) and (b)
Ans: d
53. If the resultant passes within the base
of the retaining wall , there is no
(a) Tension
(b) Compression
(c) Sliding
(d) Over turning
Ans: c
54. For check against sliding
(a) µw = p
(b) µw > p
(c) µw < p
(d) µw = 0
Ans: b
55. If Z and I are the section
modulus and moment of inertia of the section, the shear force F and bending
moment M at a section are related by
(a) F=M/y xI
(b) F=M/Z
(c) F=dM/dx
(d) F=∫M dx
Ans: c
56. The section modulus of a
rectangular section is proportional to
(a) area of the section
(b) square of the area of the section
(c) product of the area and depth
(d) product of the area and width
Ans: a
57. Stress may be expressed in
Newtons
(a) per millimetre square (N/mm2)
(b) per centimetre square (N/cm2)
(c) per metre square (N/m2)
(d) All of the above
Ans: d
58. The centre of gravity of a
trapezoidal dam section whose top width is a, bottom width is b and the
vertical side is a, from its vertical face is
(a) (a2+ab+b2)/3(a+b)
(b) (b2+bc+c2)/3(b+c)
(c) (a2+ab+c2)/3(a+c)
(d) none of these
Ans: a
59. A rectangular bar of width b and
height h is being used as a cantilever. The loading is in a plane parallel to
the side b. The section modulus is
(a) bh3/12
(b) bh2/6
(c) b2h/6
(d) none of these
Ans: c
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