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RANGANTHAN POLYTECHNIC
COLLEGE
Viraliyur (Po) , Thondamuthur (Via) , Coimbatore – 641109
DEPARTMENT OF CIVIL ENGINEERING
21041- THEORY OF STRUCTURES
ONE MARKS QUESTIONS
IV semester
PREPARED BY
S.SATHIYAMOORTHY
HOD/Civil
UNIT-1
1. Define propped cantilever.
A beam which has the support condition like one end rigidly
fixed other end simply supported is called propped cantilever.
2. Define flexural rigidity.
The product of young‘s modulus (E) of the material of beam and
moment of inertia (I) of the cross section of the beam is called the
flexural rigidity of the beam.
3. Give the three equilibrium equations.
£V= 0
£H = 0
£M= 0
4. What is a rigid propped?
For a prop there is no change in length of prop due to the force
in it.
5. What is a sinking propped?
A prop which destroys only a part of the deflection produced by
the load at the point of the prop.
6. What is Elastic propped?
The elastic prop destroy the deflection due to the load and at the
same time it is subject to a change in length due to the reaction in
the prop because the prop material is elastic.
7. Define slope of beam.
The rotation of any section of beam due to bending is called
slope of the beam
8. Define deflection of beam.
The transverse displacement of neutral fiber from its original
position at a section is called deflection
9. Define Elastic curve.
The configuration of the neutral fibre of the beam after bending
takes place is called Elastic curve.
10. Give the differential equation of flexure.
EL d2y/dx2 =M
11. Define Mohr’s Theorem – I.
The change in angle of slope between the tangents at any two
points
(A&B) on the elastic curve is equal to the area of bending moment
diagram in between these two points divided by flexural rigidity
(EI).
OAB= Area of BMD
EI
OAB= aAB
EI
Where OABis in radian
12. Define Flexural rigidity.
The product of Young’s modulus (E) and moment of inertia (I) is
known as flexural rigidity. Its unit is Nmm2.
Flexural rigidity= E * I.
13. Define Stiffness of beam.
The ratio between the maximum deflection of a beam to its
length is known as stiffness of a beam.
14. Define Strength of beam.
The greatest moment resisting capacity of a beam is known as
strength of a beam
M/I = F/Y is known as strength equation
15. Define Stiffness of a beam.
The ratio between the maximum deflection of a beam to is
length is known as stiffness of a beam.
16. Define statically determinate structure.
A structure is completely analyzed by using the three static
equilibrium equations alone is known as statically determinate
structure
Example:
Cantilever beam
Simply supported beam
Overhanging beam
Three hinged arch
Perfect frame
17. Define statically indeterminate structure.
A structure cannot be analyzed completely by using the three
static equilibrium equations alone is known as statically
indeterminate structure. Here some additional equations are
required to determine the reaction components
Example:
Propped cantilever
Fixed beam
Continuous beam
Redundant frame
18. Writedifferentmethods of analyzing statically indeterminate
structures.
The different methods of analyzing statically indeterminate
structures are
Slope deflection method
Theorem of three moment method
Moment distribution method
Column analogy method
Strain energy method
Kani’s method
Influence line method
19. Define Elastic curve.
The edge view of the deflected neutral surface of a beamis
known as elastic curve.
20. Define Flexural rigidity.
The product of young modulus (E) and moment of inertia (I) is
known as flexural rigidity. It is unit Nmm2
Flexural rigidity = EI –Nmm2
21. What is the degree of indeterminancy for a propped
cantilever?
Degree of indeterminancy (or)Redundancy = Number of
reaction components -number of static equations(or)Number of
unknown forces– number of known forces
d = r-S
r= Total number of reactions (Unknowns) = 3
S = Static (available) equilibrium equations =2
d = r – S = 3 – 2 = 1
Degree of indeterminancy for a propped cantilever = 1
22. Whatare different support conditions?
Simply supported beam
Cantilever beam
Fixed beam
Continuous beam
Propped cantilever beam
23. Write Mohr’s theorem – II.
The tangentialdeviation of any point (B) on the elastic curve
from a tangent any other point (A) on the elastic curve
perpendicular to the original axis of the beam is equal to the
moment of area of bending moment diagram in between these two
points divided by flexural rigidity (EI)
dBA= Area of BMD x xB
EI
dBA=aAB x xB
Unit-II
1. What is a fixed beam?
When the two ends of a beam are fixed damped or built- in
such that the slopes of the elastic curve at the two ends are zero
it is called as a fixed beam.
2. Give the maximum deflection at mid span for a fixed beam
with Udl throughout.
∫max = wL4
384EI
3. State Eddy’s theorem.
Eddy’s theorem states that the bending moment at any
point on the arch axis is proportional to the vertical distance
between the arch axis and the line of thrust.
4. Give the type of arches based on hinges.
Single hinged arches
Two hinged arches
Three hinged arches
Fixed arches
5. Give the equation for Radius in circular Arch.
R2 = x2 +[R- (h – y)]2= x2 + (r+y-h)2
6. What is meant by fixed beam?
A beam rigidly fixed at its two end supports such that the
slope at the two ends are zero is called fixed beam.
7. Differentiate between free BMD and fixed BMD.
Free BMD:
The beam is assumed as simply supported
The BM diagram is drawn based on the external load
applied
Since the beam is defected download the BM is a sagging
(+ve) bending moment
Slope is maximum at supports
Deflection is maximum
Fixed BMD:
The ends of the beam is fixed
The BM diagram is drawn only with respect to the fixed
end moment MA and MB
Since the beam is deflection upwards the BM is hogging (-
ve) bending Moment
Slope is zero at fixed ends
Deflection is minimum
8. What is Theoretical arch?
In the arch shown in the figure the line ABCDE
corresponds to links polygon (or) theoretical arch. A link
polygon which is in the state of compression is called the line of
thurst (or) linear arch (or) the theoretical arch .these will not be
any BM and shear force.
9. What is Actual arch?
The changing load position in the case of moving loads
will change the shape of the theoretical arch to suit the different
load positions. Hence in practice the arches are constructed in
smooth geometrical shapes like circular parabolic elliptical etc.
10. State Eddy’s theorem.
Eddy’s theorem states that the bending moment at any
section of an arch is equal to the vertical ordinate between the
theoretical arch and the center line of actual arch.
11. What are different types of arch?
According to materials used for construction
Metal arch
Masonry arch
Brick masonry arch
Stone masonry arch
R.C.C arch
According to geometric configuration
Circular / segmental arch
Parabolic arch
Elliptical arch
According to support and hinges
Three hinged arch
Two hinged arch
Single hinged arch
Fixed arch
12. Compare simply supported beam and fixed beam with
reference to maximum deflection.
Simply supported beam:
Slope is maximum at supports
Slope is zero at mid span
Deflection is maximum at mid span
Deflection is zero at supports
Fixed beam:
Slope is zeroat supports
Slope is also zero at mid span
Deflection is maximum at mid span
Deflection is zero at supports
13. What are the advantages of fixed beam over simply
supported beam?
Advantages:
Deflection is less
Slopes at the two ends is zero
Stiffer, stronger and stabler
Cross section of the beam is smaller, hence economical
Unit-III
1. What is carry over moment?
Carry over moment is defined as a moment induced at the
fixed end of a beam by the action of a moment applied at the
other ends. Which is hinged.
2. Define beam stiffness?
A second concept needed for the moment distribution
method is beam stiffness
3. Define distribution factor?
When several member meet at a joint and a moment is
applied at that joint to produce rotation without translation of the
members the moment is distributed among all the member
meeting at the joint proportionate to their stiffness
4. Define point of contraflexure?
The point at which where the bending moment changes its
sign from positive to negative or vice versa is called point of
contraflexure.
5. What is a rigid frame?
A rigid frame is a structure consisting of horizontal and
vertical members
6. What is a portrat frames?
Portrat frame is said to be symmetrical when symmetry
exists with respect to geometry loading and ends condition.
7. When does a beam is said to be continuous over an
intermediate supports?
Indeterminate beams
8. What is continuous beam?
A beam supported on one or more intermediate support is
called continuous beam
9. What are the indeterminate structures? Give examples.
A structure can be not be analysed completed by using the
three static equilibrium equations alone is known as statically
indeterminate structure.
Example:
Propped cantilever
Fixed beam
Continuous beam
Redundant frame
10. State the general methods of analysis of indeterminate
structures.
The different methods of analysing statically indeterminate
structures are: a) Slope deflection method
b) Theorem of three moment methods
c) Moment distribution methods
d) Column analogy methods
e) Strain energy methods
f) Kani’s methods
g) Influence line methods
11. Define Stiffness.
The moment required to rotate an end of a prismatic beam
through unit slope without translation is known as stiffness it is
also called as absolutestiffness (or) flexural stiffness
It is denoted by ‘K’
12. Define Relative stiffness.
The ratio of stiffness of various member meeting at a
structural joint is known as relative stiffness
13. Define Distribution factor.
Distribution factor for a member at a joint is the ratio of
stiffness of a member to the sum of stiffness of all member
meeting at that joint.
14. Define Distribution moment
The moment shared by a member at a joint in the
proportion of its stiffness or in relation to its distribution factor to
restore equilibrium of the joint in a direction opposite to the
applied moment is known as distribution moment.
15. Define Carry over moment.
The moment produced at the far ends of a prismatic beam
by the rotation of near end due to an applied moment is known
as carry over moment.
16. Define Carryover factor.
The ratio of carry over moment at the far end to the
applied moment at the near ends is known as carry over factor.
17. Define Portal frame
A frame consisting of beams resting on columns with rigid
joint is known as portal frame.
18. Define Symmetrical portal frame
A frame is symmetrical when symmetry exists with respect
to geometry loading and end conditions is known as
symmetrical portal frame .
UNIT-IV
1. Define a column.
A compression member lateral dimensions are small as
compared to its length is called a strut.A strut may be horizontal
inclined or vertical
A vertical strut is generally known as a column
2. Define short column.
A compression member whose unsupported length does
not exceed 10 times its least lateral dimension is generally
classified as a short column
3. Define critical load of the column.
The axial load which is just sufficient to keep the column in
equilibrium in a slightly deflected configuration is called the
critical load of the column.
4. Give the Euler’s Formula for long column.
If a long slender column of constant cross section is hinged
at both ends and is subjected to axial compression the critical
load P that will cause buckling is given by
P=∏2EI
L2
5. Define the slenderness ratio of the column.
It is limiting value is the stress at proportional limit.The
ratio (l/γ) is called the slenderness ratio of the column.
6. Define the working load.
Euler’s formula and Rankie’s formula give critical loads.
It is necessary to divide the critical loads by a suitable factor of
safety usually 2 to 3 in oder to obtain practical allowable
working loads
7. State the Rankine formula for critical loads of column.
Rankine formula is also known as Rankine Gordon Formula and
is given by
1/P = 1/PC + 1/PE
Where, P = Critical load
PC= Crusing load
PE= Euler’s critical load
8. Define buckling loads of a column?
The axial loads which is just sufficient to keep the column
in equilibrium in a slightly deflection configuration is called
critical loads of the column critical loads is also called as
buckling load.
9. What is axially loaded column?
The term centrally loaded and concentrically6 loaded are
also used for axially loaded column
UNIT-V
1. Define angle of repose of soil.
It is the maximum slope at which the soil particles will rest due
to their internal friction if left supported for a sufficient length of
time. This angle is measured in degrees and is denoted by ’Ø’.
2. What is plastic equilibrium of soil mechanics?
If the soil mass which is in elastic equilibrium is allowed to
expand or contract laterally rapture surface will from within the
mass and soil mass reaches a state of failure when this state of
failure exist in a soil mass it is said to be in a state of
equilibrium.
3. What are the failures of dams?
Failures of dams due to
Tension at the base section
Crushing of masonry at the base
Sliding along the base
Overturning about heel
4. What is retaining wall?
A wall constructed with masonry or concrete to retain
earth on one side of it is called retaining wall
5. Define Gravity dams.
The lateral water pressure resisted by only the self-weight
of dam is known as gravity dam.
Then following forces are acting on the gravity dam
Lateral water pressure
Self-weight of dam
Combined bending and direct stresses