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