Subject :- Design of Steel Structures / DOS-I(Steel)LSM / SE-I(Steel)
Unit-I :- Introduction to Steel structures
1. Steel is mainly an alloy of
a) Sulphur and Zinc
b) Zinc and tin
c) Iron and Carbon
d) Phosphorous and Tin
Answer:
c
2. Which of the following is a disadvantage of Steel as construction material?
a) High strength per
unit mass
b) High durability
d) Reusable
c) Fire and corrosion resistance
Answer:
d
Explanation: Steel has high strength per unit mass, highly
durable, and is reusable. But steel is poor in fire and corrosion resistance,
it needs to be protected.
3. Elastic Modulus of Steel is __________
a) 1.5 x 109 N/mm2
b) 2.0 x 105 N/mm2
c) 2.0 x 105 N/m2
d) 1.5 x 109 N/m2
Answer:
b
Explanation: Elastic modulus = Stress/Strain. As per IS
800-2007, elastic modulus of steel is 2.0 x 10⁵ N/mm².
4. Unit mass of Steel is ________
a) 7850 kg/m3
b) 785 kg/m3
c) 450 kg/m3
d) 450 kg/cm3
Answer:
a
b) 0.3
c) 1.0
d) 2.0
Answer:
b
Explanation: Poisson’s ratio = transverse strain/axial
strain. As per IS 800-2007, Poisson’s ratio of steel is 0.3 in elastic range
and it is 0.5 in plastic range.
6. Structural Steel normally has less carbon
content than _______
a) 0.6%
b) 1.0%
c) 3.0%
d) 5.0%
Answer:
a
Explanation: Structural Steel normally have a carbon
content less than 0.6%. Carbon content increases hardness, yield and tensile
strength of steel but it decreases ductility and toughness.
7. The permissible percentage of Sulphur and
Phosphorous content in steel is?
a) 1.0%, 3.0%
b) 3.0%, 1.0%
c) 0.1%, 0.12%
d) 1.0%, 1.0%
Answer:
c
Explanation: Sulphur content is generally between 0.02 –
0.1%. If more than 0.1%, it decreases strength and ductility of steel. If
Phosphorous is more than 0.12%, it reduces shock resistance, ductility and
strength of steel.
8. When Manganese is added to steel than, it…………..
a) decreases strength
and hardness of steel
b) improves corrosion resistance
c) decreases ductility
d) improves strength and hardness of steel
Answer:
d
Explanation: Manganese is added to improve strength and
hardness of steel . Based on Manganese content, steel are classified as Carbon
Manganese steel (Mn >1%) and Carbon Steel (Mn <1%). If its content
exceeds 1.5%, it increases the formation of martensite and hence decreases
ductility and toughness.
9. What is the effect of increased content of
Sulphur and Phosphorous in Steel ?
a) yields high
strength
b) affects weldability
c) increases resistance to corrosion
d) improves resistance to high temperature
Answer:
b
Explanation: When sulphur and phosphorous is used beyond
0.06%, it imparts brittleness and affects weldability and fatigue strength.
10. ……………. is added to steel to increase
resistance to corrosion?
a) Carbon
b) Manganese
c) Sulphur
d) Copper
Answer:
d
Explanation: Addition of small quantity of copper
increases resistance to corrosion. Even Chrome and Nickel are added to impart
corrosion resistance property to steel.
11. Which of the following properties are get affected
due to addition of carbon and manganese to steel?
(i) tensile strength and yield property (ii) Ductility (iii)
Welding (iv) Corrosion resistance
a) i and ii only
b) i, ii, iii
c) i and iii only
d) i and iv only
Answer:
b
Explanation: Increased quantity of carbon and manganese
imparts higher tensile strength and yield properties but lowers ductility which
is more difficult to weld.
12. Which property of steel will improve by adding Chrome and Nickel to Steel?
a) strength
b) ductility
c) weldablity
d) corrosion resistance and high temperature resistance
Answer:
d
Explanation: Steel is weak in fire and corrosion
resistance. So, to improve corrosion resistance and high temperature
resistance, chromium and nickel are added to steel.
13. Which of the following is the property of high
carbon steel?
a) high toughness
b) reduced ductility
c) high strength
d) reduced strength
Answer:
b
Explanation: High carbon steel contains high carbon
content. Hence it has reduced ductility, toughness and weldability.
14. For which type of work High carbon steel is
used?
a) structural
buildings
b) fire resistant buildings
c) for waterproofing
d) transmission lines and microwave towers
Answer:
d
Explanation: High carbon steel is used in transmission lines
and microwave towers where relatively light members are joint by bolting.
15. What is the permissible percentage of
micro-alloys in medium and high strength micro-alloyed steel?
a) 0.1%
b) 0.5%
c) 0.25%
d) 1.0%
Answer:
c
Explanation: Medium and High strength micro-alloyed steel
have low carbon content, but alloys such as niobium, vanadium, titanium or
boron are added to achieve high strength.
16. Fire resistant steels are also called as
____________
a) Thermomechanically
treated steel
b) Stainless steel
c) Weathering steel
d) High strength steel
Answer:
a
Explanation: Fire resistant steels are also called as
thermomechanically treated steel. They perform better than ordinary steel under
fire.
17. The minimum percentage of chromium and nickel
added to stainless steel is ………
a) 0.5%, 10.5%
b) 2%, 20%
c) 10.5%, 0.5%
d) 30%, 50%
Answer:
c
Explanation: Stainless steel are low carbon steels to
which a minimum of 10.5% chromium (maximum 20%) and 0.5% nickel is added.
18. Match the pair of Type of steel with its ultimate tensile
strength :
TYPE OF STEEL ULTIMATE
TENSILE CAPACITY
(A) Carbon Steel (i)
700-950 MPa
(B) High Strength
Carbon Steel (ii)
440-590 MPa
(C) Weathering Steel (iii)
410-440 MPa
(D) High Strength
quenched & tempered steel (iv)
480 MPa
(E) Medium and High
strength microalloyed steel (v)
480-550 MPa
a) A-iii, B-v, C-iv,
D-i, E-ii
b) A-i, B-ii, C-iii, D-iv, E-v
c) A-v, B-iv, C-iii, D-ii, E-i
d) A-ii, B-iii, C-v, D-i, E-iv
Answer:
a
a) low-carbon steel
b) low-alloy atmospheric corrosion-resistant steel
c) high strength quenched and tempered steel
d) fire resistant steel
Answer:
b
Explanation: Weathering steel are low-alloy atmospheric
corrosion-resistant steel. They are often left unpainted. They have an ultimate
tensile strength of 480 MPa.
20. Match the pair of Type of steel with its yield strength:
TYPE OF STEEL YIELD
STRENGTH
(A) Carbon Steel (i)
300-450 MPa
(B) High Strength
Carbon Steel (ii)
350 MPa
(C) Weathering Steel (iii)
350-400 MPa
(D) High Strength
quenched & tempered steel (iv)
230-300MPa
(E) Medium and High
strength microalloyed steel (v)
550-700 MPa
a) A-i, B-ii, C-iii,
D-iv, E-v
b) A-i, B-iii, C-v, D-iv, E-ii
c) A-iv, B-iii, C-ii, D-v, E-i
d) A-v, B-iv, C-iii, D-ii, E-i
Answer:
c
Explanation: Yield Strength is the stress that a material
can withstand without any permanent deformation i.e. the point of stress at
which any material starts to deform plastically. The yield strength of carbon
steel is 230-300MPa, 350-400 MPa for High Strength Carbon Steel, 350 MPa for Weathering
Steel, 550-700 MPa for High Strength quenched & tempered steel, 300-450 MPa
for Medium and High strength microalloyed steel.
21. Which of the following are correct criteria to be considered while designing?
a) Structure should be
adequately safe, should have adequate serviceability
b) Structure should be aesthetically pleasing but structurally unsafe
c) Structure should be cheap in cost even though it may be structurally unsafe
d) Structure should be structurally safe but less durable
Answer:
a
Explanation: Structure should be designed such that it
fulfils it intended purpose during its lifetime and be adequately safe in terms
of strength, stability and structural integrity and have adequate
serviceability. Structure should also be economically viable, aesthetically
pleasing and environment friendly.
22. What do you mean by serviceability?
a) It refers to
condition when structure is not usable
b) It refers to services offered in the structure
c) It means that the structure should perform satisfactorily under different
loads, without discomfort to user
d) It means that structure should be economically viable
Answer:
c
Explanation: Serviceability is related to utility of
structure. The structure should perform satisfactorily under service loads,
without discomfort to user due to excessive deflection, cracking, vibration,
etc. Other considerations of serviceability are durability, impermeability,
acoustic and thermal insulation etc.
23. Analysis is referred to determination of
_____________
a) determination of
axial forces, bending moment, shear force etc.
b) determination of cost of structure
c) determination of factor of safety
d) drafting architectural plans and drawings
Answer:
a
Explanation: Analysis refers to determination of axial
forces, bending moment, shear force, torsional moments etc. acting on different
members of structure due to applied loads and their combinations.
24. The structure is statically indeterminate
when________________
a) static equilibrium equations are sufficient for determining internal forces
and reactions on that structure
b) structure is economically viable
c) static equilibrium equations are insufficient for determining internal
forces and reactions on that structure
d) Structure is environment friendly
Answer:
c
Explanation: When the static equilibrium equations are
insufficient for determining internal forces and reactions on that structure,
the structure is said to be statically indeterminate. Analysis of these
structures is complex and cannot be analysed only by using laws of statics,
various analytical methods like slope deflection method, moment distribution
method, etc.
25. Which of the following is one of the methods
of analysis which is prescribed in the code for steel structures?
a) Hinge Analysis
b) Limit Analysis
c) Dynamic Analysis
d) Roller Analysis
Answer:
c
Explanation: Code suggests the use of any of the following
methods of analysis for steel structures : (i) elastic analysis, (ii) plastic
analysis, (iii) advanced analysis, (iv) dynamic analysis.
26. Which method is mainly adopted for design of
steel structures as per IS code 800-2007?
a) Limit State Method
b) Working Stress Method
c) Ultimate Load Method
d) Earthquake Load Method
Answer:
a
Explanation: Steel structures and their elements are
normally designed by limit state method. When limit state method cannot be
conveniently adopted, working stress method may be used.
27. Which IS code is used for general construction
of steel?
a) IS 800
b) IS 456
c) IS 875
d) IS 262
Answer:
a
Explanation: IS 800:2007 is the code of practice for
general construction in steel. It is issued by Bureau of Indian Standards.
28. Which of the following is correct relation
between permissible and yield stress?
a) Permissible Stress
= Yield Stress x Factor of Safety
b) Permissible Stress = Yield Stress / Factor of Safety
c) Yield Stress = Permissible Stress / Factor of Safety
d) Permissible Stress = Yield Stress – Factor of Safety
Answer:
b
Explanation: Permissible Stress = Yield Stress / Factor of
Safety. Permissible Stress is the amount of stress that will not cause failure.
It is a fraction of yield stress. It takes care of overload or other unknown
factors.
29. In Working Stress Method, which of the
following relation is correct?
a) Working Stress ≥
Permissible Stress
b) Working Stress ≤ Permissible Stress
c) Working Stress = Permissible Stress
d) Working Stress > Permissible Stress
Answer:
b
Explanation: In Working Stress Method, Working Stress should
be less than or equal to Permissible Stress. Each member is checked for number
of different combinations of loadings.
30. Arrange the following in ascending order
according to their factor of safety in working stress method :
(i) tension members,
(ii) long column, (iii) short column, (iv) connections
a) i < ii < iii
< iv
b) i < iv < ii < iii
c) i = iii < ii < iv
d) iv = i < iii < ii
Answer:
c
Explanation: In working stress method, the factor of
safety for the above are as follows : (i) for tension members = 1.67, (ii) for
long column = 1.92, (iii) for short columns = 1.67, (iv) for connections =
2.5-3.
31. Load Factor is ……………..?
a) ratio of working
load to ultimate load
b) product of working load and ultimate load
c) ratio of ultimate load to working load
d) product of working load and factor of safety
Answer:
c
Explanation: Load Factor = working load / ultimate load.
In ultimate load design, different types of loads and load combinations have
different load factors assigned.
32. Which of the following is not a main element
of framed structure?
a) Shear connector
b) Beam
c) Column
d) Lattice member
Answer:
a
Explanation: For framed structure, the main elements are
beam, column, beam-column, tie and lattice members.
33. Which of the following are subjected to both
axial loads and bending moments?
a) Column
b) Lattice member
c) Beam-Column
d) Beam
Answer:
c
Explanation: Beams are those elements which are subjected
to bending moments and shear force only. Columns are subjected to axial loads.
Beam-Column is subjected to axial load and bending moment. In special cases,
beams are subjected to torsional moments.
34. How much percentage increase of permissible
stress is allowed when dead load, live load and wind load are considered
together in WSM?
a) 50%
b) 40%
c) 60%
d) 33%
Answer:
d
Explanation: In working stress method, working stress ≤
permissible stress.
Stress due to dead load + live load ≤ permissible stress
Stress due to dead load + wind load ≤ permissible stress
Stress due to dead load + live load + wind load ≤ 1.33 permissible stress.
35. Limit State Method is based on _____________
a) calculations on
service load conditions alone
b) calculations at working loads and ultimate loads
c) calculations on ultimate load conditions alone
d) calculations on earthquake loads
Answer:
b
Explanation: Working stress method is based on
calculations on service load conditions alone. Ultimate Strength method is
based on calculations on ultimate load conditions alone. In Limit State method,
safety at ultimate loads and serviceability at working loads are considered.
36. Limit state is defined as…………..?
a) Acceptable limits
for safety and serviceability requirements after failure occurs
b) Acceptable limits for safety after failure occurs
c) Acceptable limits for safety and serviceability requirements before failure
occurs
d) Acceptable limits for serviceability after failure occurs
Answer:
c
Explanation: Acceptable limits for safety and
serviceability requirements before failure occurs is called limit state. In
Limit State design, structures are designed on the basis of safety against
failure and are checked for serviceability requirements.
37. Which of the following format of factor is
used in limit state method?
b) Partial safety
factor
a) Single safety factor
c) Load factor
d) Wind factor
Answer:
a
Explanation: Limit state method uses partial safety factor
format that helps to provide adequate safety at ultimate loads and adequate
serviceability at service loads, by considering all possible limit states.
38. Which of the following factors is included in
the limit state of strength?
a) Fire
b) Failure by excessive deformation
c) Corrosion
d) Repairable damage or crack due to fatigue
Answer:
b
Explanation: Limit state of strength are prescribed to
avoid collapse of structure which may endanger safety of life and property. It
includes (i) loss of equilibrium of whole or part of structure, (ii) loss of
stability of structure as a whole or part of structure, (iii) failure by
excessive deformation, (iv) fracture due to fatigue , (v) brittle fracture.
39. ……………….. factors are included in the limit
state of serviceability?
a) Brittle facture
b) Fracture due to fatigue
c) Failure by excessive deformation
d) Deformation and deflection adversely affecting appearance or effective use
of structure
Answer:
d
Explanation: Limit state of serviceability includes (i)
deformation and deflection adversely affecting appearance or effective use of
structure, (ii) vibrations in structure or any part of its compound limiting
its functional effectiveness, (iii) repairable repair or crack due to fatigue,
(iv) corrosion, (v) fire.
40. What is permanent action according to classification
of actions by IS code?
a) due to construction
and service stage loads
b) due to self weight
c) due to accidents
d) due to earthquake loads
Answer:
b
Explanation: Permanent actions are actions due to self
weight of structural and non structural components, fittings, ancillaries,
fixed equipments etc.
41. Which of the following relation is correct?
a) Design Load =
Characteristic Load
b) Design Load = Characteristic Load + Partial factor of safety
c) Design Load = Characteristic Load / Partial factor of safety
d) Design Load = Characteristic Load x Partial factor of safety
Answer:
d
Explanation: Design Load = Partial factor of safety x
Characteristic Load.
This partial safety factor accounts for possibility of unfavourable deviation
of load from characteristic value, inaccurate assessment of load, uncertainty
in assessment of effects of load and in assessment of limit state being
considered.
42. Which of the following is the correct relation
between design and ultimate strength?
a) Design Strength =
Ultimate strength + Partial factor of safety
b) Design Strength = Ultimate strength – Partial factor of safety
c) Design Strength = Ultimate strength x Partial factor of safety
d) Design Strength = Ultimate strength /Partial factor of safety
Answer:
d
Explanation: Design Strength = Ultimate strength /Partial
factor of safety.
This partial safety factor accounts for possibility of unfavourable deviation
of material strength from characteristic value, variation of member sizes,
reduction in member strength due to fabrication and tolerances and uncertainty
in calculation of strength of members.
43. Which of the following criteria is to be
satisfied in selection of member in limit state method?
a) Factored Load ≤
Factored Strength
b) Factored Load > Factored Strength
c) Factored Load ≥ Factored Strength
d) Sometimes Factored Load < Factored Strength (or) Factored Load >
Factored Strength
Answer:
a
Explanation: Limit Sate method is also known as load and
resistance factor design. Load factors are applied to service loads and then
theoretical strength of member is reduced by application of resistance factor.
The criteria is to be satisfied in selection of member in limit state method is
factored load ≤ factored strength.
44. The partial factor of safety for resistance
governed by yielding is;
a) 1.5
b) 2.0
c) 1.10
d) 1.25
Answer:
c
Explanation: Partial factor of safety for resistance
governed by yielding and resistance of member to buckling is 1.10. The loads
are multiplied or resistances are divided by this factor to get design values.
45. The partial factor of safety for resistance governed
by ultimate strength is;
a) 1.25
b) 1.10
c) 1.5
d) 2.0
Answer:
a
Explanation: Partial factor of safety for resistance
governed by ultimate strength is 1.25. Factors affecting ultimate strength are
stability, fatigue and plastic collapse. The loads are multiplied or
resistances are divided by this factor to get design values.
46. Which IS code is used for calculating
different loads on different structures?
a) IS 800
b) IS 456
c) IS 808
d) IS 875
Answer:
d
Explanation: IS 875-1987 (1 to 5 parts) is recommended by Bureau of
Indian Standards for calculating various types of loads on the structure. Part
1 is for dead loads, part 2 for imposed loads, part 3 for wind load, part 4 for
snow loads and part 5 for special loads and combinations.
47. ………………. load is to be considered on liquid
retaining structure.
a) hydrostatic load
b) wave and current load
c) earth pressure
d) dynamic load
Answer:
a
Explanation: Hydrostatic load is considered on liquid
retaining structures or hydraulic structures. Wave and current load is
considered in marine and offshore structure. Earth pressure is considered in
basements, retaining walls, column footings, etc. Dynamic load is due to
earthquake and wind.
48. The probability that a specific load will be
exceeded during life of structure depends on _______
a) wind
b) factor of safety
c) period of exposure
d) partial factor of safety
Answer:
c
Explanation: The probability that a specific load will be
exceeded during life of structure depends on period of exposure. It also
depends on magnitude of design load.
49. What is mean by characteristic load?
a) seismic load
b) load which will be exceeded by certain probability during life of structure
c) load which will not be exceeded by certain probability during life of
structure
d) pressure load
Answer:
c
Explanation: Characteristic load is the load which will
not be exceeded by certain assumed or pre-assumed probability during life of
structure. These loads are anticipated loads due to self weight, imposed load,
snow, wind load, etc.
50. …………. of the following is not included in
imposed load classification?
a) Residential load
b) Industrial load
c) Educational load
d) Earthquake load
Explanation: Imposed loads are gravity loads other than dead load and cover factors such as occupancy by people, stored material etc. It is classified into following groups : (i)residential, (ii)educational, (iii)institutional, (iv)assembly halls, (v)office and business buildings, (vi)mercantile buildings, (vii)industrial, (viii)storage buildings.
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