1. Introduction & Rivet Connection in detail .pptx

This PPT is about the joint in steel structure

1. | STEEL VS CONCRETE

+A significant difference between
steel and concrete constructions
is that the designer has more
control over the shape of
reinforced cement concrete
elements

«For Building Steel Structure,
designer is compelled to use
standard rolled sections

2. | Advantages and Disadvantages of Steel

«The main advantages of steel
structures are their smaller weight-to-
strength ratio, speed of erection and
dismantling, and its scrap value.

¢ Faster degradation of their strength in
the events of fire, requirement of
skilled, personnel and the accuracy
desired in fabrication are the major
drawbacks

3. I Steel Structures are divided into two principal groups:

+ Made mainly of

plates, sheets
STEEL + Exp: tanks, bins,

hit , of
STRUCTURES [patna

* These are assembly
of tension,
compression and
flexural members

+ Exp: truss frame,
rigid frames, girders
and columns, etc

4. 1 Some Examples of Steel Structures

Column

}

(a) Framed building

5. 1 Some Examples of Steel Structures

(b) Industria! building

6. 1 Some Examples of Steel Structures

. Knee bracket . Vertical stiffener
y : Sleeper \

be

” Floor beam
(c) Rail-road bridge

7. 1 Some Examples of Steel Structures

Tank
4

Circular
girder

¡— Bracing

(d) Overhead water tank

8. 1 Some Examples of Steel Structures

Cylindrical shaft
Breech opening
Flared portion
Clean-out door

(e) Self-supporting steel stack

9. ] Some “ie of Steel Structures

Tower leg

Bracing

(f) Transmission line tower

10. | Standards, Specifications and Codes

A standard contains a set of technical definitions,
specifications and guidelines for performance and
safety. It becomes code when adopted by
Governmental bodies.

1. IS Handbook No. | «Properties of Structural
Steel Rolled Sections

2. 1S:875-1987 Code of Practice for Design' Loads
for Building and Structures

3. IS: 800-2007 Code of Practice for use of
Structural Steel in General Building
Construction

11. BIS via BSB Edge

IS 800 : 2007
(Reaffirmed 2012)

ARA AR (Reaffimed 2017)
zara À aa Fai — ofa aña
CAT Gta )

Indian Standard

GENERAL CONSTRUCTION IN
STEEL — CODE OF PRACTICE

(Third Revision )

12. | ROLLED STEEL SECTIONS O.

* Rolling is a metal forming process in which metal is
passed through one or more pairs of rolls to
squeeze and reduce the thickness, to make the
thickness uniform, and/or to impart a desired
mechanical property. The concept is similar to the

rolling of dough. . A

Rolling is classified according to the temperature of
the metal rolled. If the temperature of the metal is
above its recrystallization temperature, then the
process is known as hot rolling. If the temperature
of the metal is below its recrystallization
temperature, the process is known as cold rolling.

13. | Rolled Structural Shapes and Dimensions

Flange t

(a) Rolled beams
and columns

Flange:

ty

al A
Web

kb]

(b) Rolled channels

14. | Rolled Structural Shapes and Dimensions

Leg Lt,
E,
peat

(c) Angles (unequal) (a) Tees

15. | Rolled Structural anaes and Dimensions
sa

k— 8— T — + la

IN
\

) ) d

|
| ds ? | \ )
5 | \ J)

| J} | | th lx SU |

——) Y SE) —

6 k— D—

‘Square hollow Rectangular hollow Circular bebo sections

sections (SHS) sections (RHS)

(e) Hollow sections (tubes)

A
°

16. | Rolled Structural Shapes and Dimensions

u

O O < 400 |
Square Circular |» 900 mm —

(f) Bars (g) Flats (h) Plates

17. 1. Pure iron (non alloy)
It is natural metal available directly in the Earth Ores
Silvery white in colour

It is very soft solid (such that it can be cut by knife) having high
ductility

It is not used in any structural element since it directly reacts with
oxygen and to form rust and reacts with moist air

It is available in Fe2+ and Fe3+ forms

2. Pig Iron:
* Basic Raw iron is called Pig iron (transported in the form of bricks)
* Itis also not used in any structural element since it is composed of
highest carbon content 5%)
* The pig iron can be converted into structural iron by removing
excess carbon content and by adding oxygen or chemicals in molten
stage

18. IRON

3. Cast Iron
+ It is the structural element (in specified shape from molten pig
iron having almost same properties of pig iron)
4. Wrought Iron
+ Lowest Carbon content (0.0-0.1%) of structural iron
+ It has high ductility, easily converted in specified shape
+ Largely used to make thin wires
5. Steel

+ Steel is an alloy of
(iron+carbon+chromium+copper+magnesium+nickel+silica)

+ The structural element used to resist any type of load

19. Carbon Content

Properies | Low carbon Medium carbon High carbon
ng Carbon ower than 025 weight Ta between 025 and 06 | In between 0.6 and 1.3
Pigtran(4-5%) Percent weight pect weight percent
> Cast Iron(2-4.5%) Tome Excellent ductility and Tow bardenablly. Hardest, strongest and
> Cast Steel (>2%) properties | toughness. ‘These steel grades canbe | Least ductile
> Carbon steel (less than 2%) Weldable and machinable | heat treated
> High carbon steel (0.6-1.4%) a rm o
2 ensite transformation
SM edium.car bonl0.25-0.0%) Some | Conman pods Tie Forhigieraragin such —] Un whee ra
>low carbon steel (less than 0.25%) | sppiicaions | Nuts, bolts shets et. asin machinery, hardness and wear
> Wrought Iron (less than 0.1%) ‘Automobiles and agric- resistance is required.
>Pure iron (0%) cultural parts (gears, Cutting tools, cable,
axels, connecting rods) Musical wires etc.
ete

Civil Engineering by Sandeep Jyani

20. INTRODUCTION

+ Steel is an alloy of Fe + Carbon

> MILD STEEL ( Carbon content — 0.23%)

> When carbon content is increased in steel then strength, hardness and
brittleness will increase but ductility will decrease.

> STAINLESS STEEL
> Alloy of iron and chromium
> Chromium is 18% and nickel is 8%
> Young’s modulus of steel ‘E’ is equal to 2x10° MPa or 200 GPa
1

>Ealuminium ~ Esteel

>E aluminium = 0.7x10° MPa or 70 GPa

Civil Engineering by Sandeep Jyani

a

21. INTRODUCTION

> Density of Steel

Psteet = 7850 kg/m?

LEN patumintum = LL = 2700 kg/m?

> Modulus of Rigidity (G)
> G=0.769 x 10° MPa
> Poisson’s Ratio (11)

lateral strain
TH ongitudinal strain

> u for mild steel = 0.286
> In Elastic range: 0.3
> In Plastic range: 0.5

Civil Engineering by Sandeep Jyani

22. INTRODUCTION

>Deflection/Increase in length

> 1
> (OL) mita steel = 3 (SL),

> Thermal coefficient
> steel = Bconcrete = 12 X 107$ °C-1
> au = 23 x 1076 °C-1
> Steel is ductile while concrete or rubber are brittle
> Note: Rubber is a very brittle material, there is very little plastic
deformation beyond elastic range

Civil Engineering by Sandeep Jyan

23. « IS 456: 2000
+ IS 800: 2007
+ 151343

+ 1510262
«15.383
«15875

Some Important Codes

RCC

Steel (2007-LSM, 1984-WSM)

Pre Stress Concrete

Design Mix

Fine and Coarse Aggregate

Design Load for buildings and structures

24. STANDARD STRUCTURAL STEEL SECTION

Bending stress Shear stress

In I-section, the web resists shear forces, while the flanges resist most of the bending
moment experienced by the beam

eering by Sandeep Jyani

25. STANDARD STRUCTURAL STEEL SECTION

; y-axis
i. ISLB 300 i

+ Indian standard light beam where overall
depth is 300mm.

* Maximum bending stress is resisted by flange
and maximum shear stress by web

+ Generally used in roof beam

ii. ISMB

* Indian Standard Medium flange beam generally
used in floor beams

* High moment of inertia about x-axis, so lateral
buckling occurs about y-axis

ISWB

+ Indian standard wide flange beam generally
used in column

+ High moment of inertia about y-axis, so they
have buckling strength about y axis

iv. ISJB
+ Indian standard junior beam
v. ISHB

+ Indian standard heavy beam

Civil Engineering by Sandeep Jyani 26

26. STANDARD STRUCTURAL STEEL SECTION

Equal Angle section
2. ANGLE SECTION

i. Equal angle section
+ ISA- 100x100x10
Where 10mm is the thickness of angle
section
100x100 both legs are same 100 10
ii. Unequal angle section

+ ISA - 150x100x10 100

Where 10mm is the thickness of angle
section
150x100 both legs are different Unequal Angle section
150
| 10

7100 ~

27. STANDARD STRUCTURAL STEEL SECTION

3. TSECTION
standard wide
flange T section

ii. ISST - Indian

standard long ISHT
legged T section

ISST

28. STANDARD STRUCTURAL STEEL SECTION

4. CHANNEL SECTION
+ They are used as Purlins or
columns(Purlin is a beam in a roof
truss which supports the roof
covering material)
i. ISJC- Indian Standard Junior
Channel Section
ii, ISLC - Indian Standard Light
Channel Section
iii. ISMC 300 - Indian Standard
Medium Channel Section where
300 is the overall depth of
channel section
iv. ISSC - Indian Standard Special
Channel Section

300mm

Civil Engineering by Sandeep Jyani

29. STANDARD STRUCTURAL STEEL SECTION

5. BOX SECTION - used in column

6. Flat SECTION —
* ISF — Indian Standard Flat Section
* Generally used in the design of lacing
and batten
* Eg. SOISFS
Here 50 is width of plate
And 8 is thickness of plate

BOX SECTION
Used in columns

¡eering by Sandeep Jyani

30. Uniaxial Tension Test

+ This test is of static type i.e. the load is
increased comparatively slowly from
zero to a certain value.

+ UTM or Tensile Testing Machine is used

r

Specimen with Circular Cross Section

Specimen with Rectangular Cross Section

Civil Engineering by Sandeep Jyani

31. Uniaxial Tension Test

(i) The ends of the specimen's are
secured in the grips of the testing
machine.

(ii) There is a unit for applying a load
to the specimen with a hydraulic or
mechanical drive.

(iii) There must be a some recording
device by which you should be able
to measure the final output in the
form of Load or stress.

ON

Specimen with Circular Cross Section

Civil Engineering by Sandeep Jyani

32. 1.

True Stress & Nominal Stress

Nominal stress - Strain OR Original Area
Conventional Stress - Strain diagrams:

Stresses are usually computed on the basis of the
original area of the specimen; such stresses are often
referred to as conventional or nominal stresses.

True stress — Strain Diagram:

Since when a material is subjected to a uniaxial load,

some contraction or expansion always takes place.

Thus, dividing the applied force by the Actual Area
corresponding actual area of the specimen at the

same instant gives the so called true stress.

33. Stress — Strain Curve for Mild Steel
Lower Yield Point
Upper Yield Point

Necking Region

Yield Plateau

Strain Hardening

Proportional Limit. '
Stress

Elastic

Plastic Region
Region

Strain €

34. Stress — Strain Curve for Mild Steel

+ OA is Proportionality limit

* OB is Elastic limit but OB is
Non linear

+ The slippage of the carbon
atom within a molecular
mass leads to drop down of
stress marginally from C to C’

+ Cis upper yield point

+ C’ is lower yield point (also
known as Yield Stress f,)

+ For exp Fe-250 =>
f,=250N/mm?

* C’Dis constant stress region

called Yield Plateau

Upper Yield Point

Elastic Limit.

P:

Lower Yield Point

Yield Plateau

roportional Limit.

Strain €

Neckihg Region

35. Stress — Strain Curve for Mild Steel
+ DE is Strain Hardening region, Rowen Mellieeine

material starts offering
resistance against deformation

* EF is Necking region where Elastic Li
drop down of stresses occur

Upper Yield Point
Necking Region
Yield Plateau

upto Failure point >
+ Necking region exists only in 2)

ductile material | BR XT f
+ In mild steel, ABC are closer to torse

each other, therefore it is O DAS

known as Linear Elastic Metal,
and Yield stress and elastic
stress is taken as 250N/mm?

* The Fracture or Failure in mild
steel depends upon
Percentage of carbon present
in a steel

Strain e

36. Stress — Strain Curve for Mild Steel
Lower Yield Point

+ The strain at yield stress is UBFerNJeIG Rein

about 0.00125 or 0.125% care =

+ CD represents plastic
Yielding i.e. it is the strain
which occurs after the
yield pointwithno = | UN ©*-----
increase in stress o

+ The strain at point Dis
about 0.015 or 1.5%

+ The strain in the range CD
lies between 10 to 15
times the strain at yield
point

Necking Region

Strain Hardening

Proportional Limit.
Stress

o Strain e

37. As per IS 800, for mild steel

Proportional Limit 190-220 N/mm?
Yield strength 230-250 N/mm?
Ultimate strength 410-530 N/mm?
Fracture Strength 250-300 N/mm?

Elongation of fracture 23-35%
Bearing Stress 0.75f,

38. PERMISSIBLE STRESS IN STEEL STRUCTURES

Yield stress fy

Factor of safety

+ It is the maximum load carried by the member without
deformation

+ In working stress method, it is assumed that members can
carry load up to elastic limit, hence members will be designed
such that they can resist less loads as compared to the
resistance of maximum capacity by proper factor of safety to
whole Permissible Stress

Permissible stress =

FOS = 1.67 for members subjected to AXIAL tension or compression
FOS = 1.50 for members subjected to bending
* Since in axial loading all fibers reach maximum stresses, but in

bending only extreme fibers will reach maximum stresses.
Hence FOS will be less for bending

Civil Engineering by Sandeep Jyani

39. Working Stress Method

+ In the field there are always worst combination of loads (DL, LL, EL,
WL, etc) hence members will be designed such that they can resist
more and more loads of actually we needed.

+ Ultimately size and cross section area of the member increases and
hence working/failure stress decreases

Load supplied to the members
Cross sectional area

« Working stress =

Or
Yield stress fy

« Working stress = Fr

Civil Engineering by Sandeep Jyani

40. Working Stress Method

+ Merits of WSM:
+ The members can not be failed in future having large life span
* The design is very simple

+ Demerits:
* Weight of the structure increases, hence it is uneconomical

Civil Engineering by Sandeep Jyani

41. Plastic state or Limit State Method

- The design of the members may touch the plastic range i.i FOS will be
desired for each loads by considering load combinations and strength
and servicibility requirements.

+ Hence it is called as Partial Factor of Safety
corresponding characteristic load
partial safety factor

* Design load =

42. PERMISSIBLE STRESS IN STEEL STRUCTURES

1. As per WSM

i. Maximum permissible AXIAL stress in compression is

given by
Ga = 0.60 fy
Used in the design of columns and struts.
Column is a compression member where bending moment exist
while in case of struts, also being a compression member, bending
moment is zero. Because strut is a component of roof trusses and
roof trusses are pin jointed connection having bending moment
equal to zero.
ii, Maximum permissible AXIAL stress in tension is given by
Ga = 0.60 fy
It is used in design of tension members

+ FOS = 1.67 for members subjected to AXIAL tension or compression

+ FOS = 1.50 for members subjected to bending

Civil Engineering by Sandeep Jyani

43. PERMISSIBLE STRESS IN STEEL STRUCTURES
1. As per WSM

iii. Maximum permissible bending stress in compression is given
+ Used in design of flexural (bending) member that is beam, built up beam, plate

girder etc.
Op = 0.66 fy

iv. Maximum permissible bending stress in tension is given
+ Used in the design of beams
O), = 0.66 fy

v. Maximum permissible average shear stress is given by
Tv avg = 0.40fy “ster mn
vi. Maximum permissible Maximum shear stress is given bj ee shear stress
Ty max = 0.45fy

+ FOS = 1.67 for members subjected to AXIAL tension or compression ene

+ FOS = 1.50 for members subjected to bending

Civil Engineering by Sandeep Jyani

44. PERMISSIBLE STRESS IN STEEL STRUCTURES

1. As per WSM

vi. Maximum permissible bending stress in column base is given by
ao=0.75 fy

Increase of permissible stress

+ When wind and earthquake load are considered, the permissible stresses in
steel structure are increased by 33.33%.

+ When wind and earthquake load are considered, the permissible stresses in
connections (rivet and weld) are increased by 25%.

Civil Engineering by Sandeep Jyan

45. PERMISSIBLE DEFLECTION IN STEEL
STRUCTURES

+ As per WSM, Maximum permissible horizontal and vertical deflection
is given by
_ span

~ 325

+ As per LSM, Maximum permissible horizontal and vertical deflection
is given by
a) If supported elements are not susceptible to cracking
span

~ 300
b) If supported elements o apuble to cracking

360

46. PERMISSIBLE DEFLECTION IN GANTRY GIRDER

Gantry girders are laterally unsupported beams to carry. heavy loads from place to place at the
construction sites

For manually operator crane, the maximum permissible deflection
is
_ span
~ 500
For electrically operator crane, the maximum permissible deflection
for a capacity upto 50T or 500kN
_ span
~ 750

. For electrically operator crane, the maximum permissible deflection
for a capacity more than 50T or SOOkN
span

5= 7000

47. FACTOR OF SAFETY FOR DIFFERENT STRESSES

yield stress =f

Factor of Safety = memes |

1. For axial stress, F.O.S. = De. 1.67
0.60f

2. For bending stress, F.O.S. = e 1:50
0.66f

3. For shear stress, F.O.S. = = - = 2.50
0.40f

+ FOS = 1.67 for members subjected to AXIAL tension or compression
+ FOS = 1.50 for members subjected to bendin,

ieering by Sandeep Jyanl

48. IMPORTANT
TERMS Pe

PITCH — It is the distance between
two consecutive/continuous rivets
measured parallel to the

direction of force. It is denoted by

END DISTANCE — It is the distance
etween centre of rivet and
edge/end of the plate element,
measured parallel to the
direction of force. —

GAUGE DISTANCE - It is the
distance between two continuous
rivets measured perpendicular to
the force of direction.

EDGE DISTANCE - It is the distance
between centre of rivet and
edge/end of the plate element,
measured perpendicular to the
force of direction.

¡0 ©

distance end
distance

49. Bearing Stresses: The Bearing Stress is nothing but compressive
stresses developed at the surfaces of two different materials

Or “Compressive force divided by characteristic area perpendicular to

TE

Shearing Stresses:

Two forces, equal and opposite in nature,
when act tangential to the resisting section,
as a result of which the body shear off across
the section is known as Shear Stress.

50. TYPE OF JOINTS

1. LAP JOINT:

+ It is the least efficient joint
as the lines of action of two
forces are not same.

+ In lap joints, the rivets are
subjected to single shear
and bearing.

* These forces form couple
and additional bending
stresses are developed in
the rivets

51. 10.5.1.2 Lap joint
In the case of lap joints, the minimum lap should not
‘be less than four times the thickness of the thinner part

. Single end fillet
should be used only when lapped parts are restrained
from openings. When end of an element is connected
only by parallel longitudinal fillet welds, the length of
the weld along either edge should not be less than the
transverse spacing between longitudinal welds.

52. TYPE OF JOINTS
2. BUTT JOINT

+ SINGLE COVER BUTT JOINT:

> The line of action of two forces is same therefore eccentricity is
eliminated completely which existed in Lap Joint hence this joint
is more efficient in carrying the force as compared to lap joint.

> But the connection is not symmetrical
+ The rivets are subjected to single shear and bearing.
+ teover 2 tmain (50 that the joint does not fail)

COVER PLATE

MAIN PLATE
Pp

53. TYPE OF JOINTS

2. BUTT JOINT

+ DOUBLE COVER BUTT JOINT:

> It is the most efficient joint because the line of action of two
forces is same and connection is symmetrical w.r.t applied
load.

+ The rivets are subjected to double shear and bearing.
+ Sum of thickness of cover plate > t,

‘main

COVER PLATE

MAIN PLATE

54. CONNECTIONS

+ In steel structure, various types of elements are connected together
using various types of connections like:
1. Riveted connections
2. Bolted connections
3. Welded connections

55. Strength of Plate

Section 1-1 — Tearing strength of plate
Section 2-2 > Bearing strength of plate
Section 3-3 > Shear strength of plate

56. Failure of Rivetted Joint

Failure of Rivets

1. Shearing Failure of Rivets
+ In a shearing failure, Rivet gets cut into two or more pieces

2. Bearing failure of Rivet

+ In a bearing failure, rivet cross section changes from circular
to elliptical

57. Failure of Rivetted Joint
Failure of Plates
1. Shearing Failure of Plate lie h

+ In this failure, cracks are developed eae ie + to
the applied forces direction

2. Splitting failure of Plate

. Splitting failure occur due to diagonal tención
in the plate at the rivet level

3. Bearing Failure of the plate
* This plate is pushed forward by the rivet. E

type of failure occurs generally due to 1 o
insufficient end distance 1

4. Tearing/Tension Failure of the plate

* The cracks are developed perpendicular to the p
direction of applied force

58. un. Failure of Plate

i. Shear, bearing and splitting failure of
plate are due to insufficient end
distance.

ii. By providing the proper end distance,
these three failure can be prevented.

iii. In the design of riveted joint which
should consider the remaining three
failure only, i.e., Shear and Bearing
paler of rivets and Tearing failure of
plate.

iv. Inthe design of riveted joint, we have to
ensure that, shear strength and bearing
strength of rivets is more than the
tearing strength of plate because rivet
QE is more dangerous than the plate

ailure.

distance end
distance

59. Strength of Revited Joint

» Plate

«| Shearing
* Bearing
« Splitting

+ Tearing

+ Rivet

+ Shearing
+ Bearing

Insufficient End Distance

60. CONNECTIONS

. RIVETED CONNECTIONS:

+ In the Riveted connection, rivets are inserted in the hole
made to join the two members together and hammering is
done to make head on other side.

* Rivets are made of mild steel. The riveting can be hot
riveting (or) cold riveting.
+ Cold riveting is not adopted for dia > 10 mm.

+ In cold riveting there is no gripping action but strength is
better due to cold working.

61. CONNECTIONS

. RIVETED CONNECTIONS:

+ When hot rivet is used, it becomes plastic, it expands
and fill the rivet hole completely in the process of
forming a head at the other end. On cooling, the rivet
shrinks in the length and diameter due to shortening
of rivet shank length.

The connected part becomes lighter consequently
resulting in tension of unpredictable amount in a
shank length and some compression in plates that are
connected

Due to reduction of diameter of shank on cooling, this
small amount of space available on cooling is
provided for temperature variation of unpredictable
amount

62. CONNECTIONS

1. RIVETED CONNECTIONS:

+ In hot riveting, rivets are heated to 550-1000°C and
hammering is done on other side to make head.
According to the type of hammering we have

i. Power driven rivets
ii. Hand driven rivets

* Power driven rivets have better quality control and hence have a
higher permissible stress.

+ Riveting can be done in the factory (or) in the field and
accordingly in these hop riveting & field riveting thus we have;

i. Power shop rivets

ii. Power driven field rivets

Hand driven field rivets

Note: For shop rivet

For field rivet O)
o

63. Power shop rivets
Power driven field rivets
Hand driven field rivets

CONNECTIONS

PDS 100 100 300
PDF 90 90 270
HDF 80 80 250

64. CONNECTIONS

. RIVETED CONNECTIONS:
* The nominal dia of rivet is said to be shank
0.70 {

dia under cold condition, and gross dia of
rivet is taken as dia of hole.

+» The strength of a rivet is based on its gross
diameter under the assumption that rivet
fills the hole completely.

* For ease in connection dia of hole is taken
larger than nominal dia of rivet thus as per
IS: code:

+ For nominal dia < 25 mm

* Gross dia = nominal dia + 1.5 mm,
dia of hole=0+1.5

+ For nominal dia > 25 mm
+ Gross dia = nominal dia +2 mm,
dia of hole = 0 +2

160

head

= nominal dia
shank

65. dia of hole=0+2

66

66. CONNECTIONS

1. RIVETED CONNECTIONS:

+ Due to many demerits, riveted connection is not in
practice in modern steel instruction.
+ Design of Riveted connection is same as that of
bolted connection but with the following differences:
* The diameter of rivet to be used in the calculation is
dia of hole, whereas for Bolted connection it is the
nominal dia.
+ The design stresses are different (IS : 800 : 1984) the
permissible stress are reduced for bolts.

67. CONNECTIONS

1. RIVETED CONNECTIONS:
* Strength of riveted joint
* Itis taken as minimum of shear strength, bearing strength and tearing
strength.
+ FOR LAP JOINT:

1. FOR ENTIRE PLATE
a) SHEAR STRENGTH OF RIVETS P p
P,=nxgxd®s«Fs

Where n — total number of rivets at joint
F, -> permissible shear stress in rivets
F,= 100MPa (WSM)
F, = ultimate shear stress in rivet
so in 1SM= 35
d >> gross diameter of rivet (hole diameter)
Gross dia = nominal dia + 1.5 mm, for nominal dia < 25 mm L
Gross dia = nominal dia + 2 mm, for nominal dia > 25 mm

68. CONNECTIONS

1. RIVETED CONNECTIONS: 1

+ FOR LAP JOINT:
1. FOR ENTIRE LENGTH P P
b) BEARING STRENGTH OF ALL RIVETS
P¿=nx (txd)xFy
Where n -> total number of rivets at joint
t — thickness of thinner main plate
F, > permissible shear stress in rivets (300MPa in WSM)
d > gross diameter of rivet (hole diameter) .
Gross dia = nominal dia + 1.5 mm, for nominal dia < 25 mm
Gross dia = nominal dia + 2 mm, for nominal dia > 25 mm
c) TEARING STRENGTH OF PLATE
P, = (B—n,d)txF;
Where n, — total number of rivets at critical section 1-1
+ thickness of thinner main plate ae
B > width of plate 1
F, > permissible tensile stress (Axial = 0.6fy = 0.6250 = 150MPa)
d >> gross diameter of rivet (hole diameter)
nominal dia + 1.5 mm, for nominal dia s 25 mm
la +2 mm, for nominal >25mm

nominal

69. CONNECTIONS

1. RIVETED CONNECTIONS:
+ LAP JOINT:
2. FORGAUGE LENGTH/PITCH LENGTH 8
a) SHEAR STRENGTH OF RIVETS
Pa=nx TAF,

Where n — total number of rivets at joint in crossed gauge
length

F, >> permissible shear stress in rivets

imate shear stress in rivet so in
Fu
Me 35x13
d > gross diameter of rivet (hole diameter)
Gross dia = nominal dia + 1.5 mm, for nominal dia < 25 mm
Gross dia = nominal dia + 2 mm, for nominal dia > 25 mm

70. CONNECTIONS

1 SECOND PLATE
1. RIVETED CONNECTIONS:

+ LAP JOINT: Pp EEN

2. FOR GAUGE LENGTH/PITCH LENGTH HA
b) BEARING STRENGTH OF RIVETS
Pg = a X (txd)xF, A —

Where n — total number of rivets at joint in crossed gauge length
t > thickness of thinner main plate
F, > permissible bearing stress in rivets (300MPa in
d > gross diameter of rivet (hole diameter)

c) TEARING STRENGTH OF PLATE
Pa = (9 - d)txF;
Where g -> gauge length
t > thickness of thinner main plate

F, > permissible tensile stress in plate(Axial = 0.6fy = 17°
0.6x250 = 150MPa)

When pitch distance is given then
P, = (P—3d)txFt

71. CONNECTIONS

MAIN PLATE
P

1. RIVETED CONNECTIONS:
+ DOUBLE COVER BUTT JOINT:
1. FOR ENTIRE WIDTH OF PLATE
+ SHEAR uae” OF RIVETS
Pu = 2un, x pdx,
Where n —> total number of rivets at joint
F, > permissible shear stress in rivets
F,= 100MPa (WSM) 1
d > gross diameter of rivet (hole diameter)

I
—v— ° Piss] |

72. CONNECTIONS

MAIN PLATE
1. RIVETED CONNECTIONS: P P
+ DOUBLE COVER BUTT JOINT:
1. FOR ENTIRE WIDTH OF PLATE

+ BEARING STRENGTH OF RIVETS
P, = nx (txd)xFp
Where n — total number of rivets at joint

t > min of (thickness of thinner main plate,
sum of cover plate thickness)

F, > permissible bearing stress in rivets i

d > gross diameter of rivet (hole diameter) 133] To]
La P

73. CONNECTIONS

MAIN PLATE
F

1. RIVETED CONNECTIONS:
+ DOUBLE COVER BUTT JOINT:

1. FOR ENTIRE WIDTH OF PLATE

+ TEARING STRENGTH OF PLATES

P, = (B—n,d)txF,
Where n, — total number of rivets at critical section 1-1

t > min of (thickness of thinner main plate,
sum of cover plate thickness)

B > width of plate
F, >> permissible strength of plate in tearing y,
d > gross diameter of rivet (hole diameter)

74. CONNECTIONS

1. RIVETED CONNECTIONS:
+ DOUBLE COVER BUTT JOINT:
2. FOR GAUGE LENGTH r
a) SHEAR STRENGTHOE RIVETS
Pa = 2x9, 1

Where n — total number of rivets at joint in crossed gauge
length (here 2)

F, -> permissible shear stress in rivets

itimate shear stress in rivet so in
Fu
Me a
d > gross diameter of rivet (hole diameter)

75. CONNECTIONS
1

[|
1. RIVETED CONNECTIONS: Lee]
+ DOUBLE COVER BUTT JOINT: P | | Pp
2. FOR GAUGE LENGTH/PITCH LENGTH ré ol
b) BEARING STRENGTH OF RIVETS 1
Pp = M x (txd)xF, 1
Where n > total number of rivets at joint in crossed gauge length
t > min (thickness of thinner main plate, sum of cover plate thickness)
F, > permissible bearing stress in rivets (300MPa in WSM)
d > gross diameter of rivet (hole diameter)

c) TEARING STRENGTH OF PLATE
Pu = (g-md)txFe
Where g >> gauge length
t > thickness of thinner main plate
F >> permissible strength of plate in tearing
n > total number of rivets at in critical section 1-1 in crossed gauge length (here 1)

76. a A ss Total force at a joint
+ Number of Rivets required at a jomi E rarcaarajona
Rivet Value
F
nes
Ry

+ Efficiency of joint
least value ofP, , Py , Pt

7 Strength of Solid main plate

100

P, = shearing strength of joint
Py = bearing strength of joint
P, = tearing stresngth of plate

77. « Efficiency for entire plate
* We have to ensure that P, is less because rivet failure is more dangerous
+ For Entire PLATE:

least value of P; , Py , Pt

NS oT eT To X 100
Strength of Solid main plate

_ (Bnd) xt xF

x 100
BxtxF;

>n
_ (B=nd)
=
For Gauge Length:
(G-d)xtxF

= = x 100
gxtxF

»n

x 100

a
EP x 100

78. Arrangement of Rivets

Rivets in a riveted joint are arranged in two forms, namely,
1. Chain riveting, 2. Diamond riveting.

79. + In chain riveting the rivets are P
arranged as shown

1-1, 2-2 and 3-3 shows sections on

either side of the joint

+ Section 1-1 is the critical section for
Main plate

+ Section 3-3 is the critical section for 1 2 3 3 2 1
Cover plate

+ Critical Section for main plate will

be outer most section — 2210015
+ Critical Section for cover plate will e e CH eee

be inner most section t— 0 e o: eee >
+ Strength for main plate oo e: ..o
+ Pı-ı=(B-3d)xtxF, aS aa

+ P2.2= (B—3d) Xt X F,+3Ry
+ P3_3 = (B—3d) xt x F, +6Ry

80. + In Diamond pattern of riveting,
section 1-1, section 2-2 and so on
has to be checked for main plate in
carrying a required load, but for
cover plate the last section is
checked for carrying a required load

+ Strength for main plate
"Py ¡=(B-d)xtxF,
*P22=(B-2d)xtxF,+R,
+ P3_3 = (B—3d) xtxF,+3R,
+ Strength for cover plate
* P3_3 = (B-3d) xtxF,
* Py_, = (B—2d) Xt x F,+3R,

:

E

81. + In Triangular Square Pattern of
Riveting, section 1-1 and the
section 2-2 is checked for main
plate in carrying a required load

+ And for cover plate, 4-4 (main | ———

plate) or first section for cover
plate is supposed to be checked
for cover plate , also section 3-3
and 2-2 is also checked for safety
+ Strength for main plate
«Pi =(B-d)xtxF,
*P2=(B-2d)xtxF,+R,
* P3_3 = (B—2d) Xt x F,+3R,
° Py_4 =(B-d)xtxF,+5R,

Ny
y
A

|

be

82. SPECIFICATIONS AS PER IS 800 - 1984

+ MINIMUM END AND EDGE DISTANCE
* This recommendation is provided to prevent three types of
failure in plates:
i. Splitting failure of plate
ii. Shearing failure of plate
iii. Bearing failure of plate
+ Edge distance and end distance(minimum)
* =1.5 xgross dia of rivet (machine cut element)
* The above provision is valid for the end distance and edge
distance is done by machine cut element.

83. SPECIFICATIONS AS PER IS 800 - 1984

* MINIMUM END AND EDGE DISTANCE
+ Edge distance and end distance(minimum)
+ =1.7 xgross dia of rivet (hand driven elements)
+ The above provision is valid for the end distance and
edge distance is done by hand driven elements.
+ But for analysis and design purpose, we adopt edge
distance and end distance(minimum)
+ =2.0xgross dia of rivet.

84. SPECIFICATIONS AS PER IS 800 - 1984
+ PITCH

+ Minimum pitch of rivet is 2.5 x nominal dia of rivet.
+ Maximum pitch of rivet or weld
+ IN COMPRESSION
* The maximum pitch provision is provided to ensure the
prevention of buckling between the connections
* Maximum pitch = min(12t or 200mm) where t is thickness for
thinner plate
+ IN TENSION
* The maximum pitch provision is provided to ensure the
prevention of separation of plates between the connections

* Maximum pitch = min(16t or 200mm) where t is thickness for
thinner plate

85. SPECIFICATIONS AS PER IS 800 - 1984

+ NOTE:

+ If the rivets are staggered (not in the same line)and of the
gauge distance smaller than 75mm, then above
recommended values in compression and tension zone for
maximum pitch are increased by 50%, i.e.,

+ For compression —

+ Maximum pitch = 18t or 300mm (minimum of the two)
+ For tension —

* Maximum pitch = 24t or 300mm (minimum of the two)

86. SPECIFICATIONS AS PER IS 800 - 1984

* Gauge length (g) should not be more than 100 +
At or 200 mm

+ Maximum Edge distance should not exceed 12TE

Wheree = [22
fy

+ When the member are exposed to corrosion, then
maximum edge distance should not be greater than
40 + 4t

87. TACK RIVETS

They are the rivets used to make the structural
component asa single unit.

They don’t carry any load because we consider
tack rivets not as a structural unit i.e., provided at ————T
the location of gussete plate.

The maximum pitch provided in the case of tack

ctions are placed back to

1
1
Li
!
1
T
O ©
TACK RIVETS

The above recommendations are valid for both

angle and channel section.

When two plates are attached to a [Eussete plate

back to back, then the maximum pitch is taken as
+ 32tor 300mm (whichever is minimum)

filler’ Lis

88. TACK RIVETS

+ Maximum pitch = 32t or 300mm
(When plates are not exposed to

[4

weather) 1 i

+ Maximum pitch = 16t or 200mm |

(When plates are exposed to weather) o. Oo El ®

STRUCTURAL RIVETS TACK RIVETS

+ For two members placed back to a 1

back, the maximum pitch of 1 !

. A T

tacking rivets + 1000mm 4 u

gussete plate filler'plate

A

SS

89. Unwin’s formula

« It is used when diameter of rivet is not known
9 = 6.04VE
Where t is thickness of thinner plate in mm
@= nominal dia of rivet in mm

90. NOTE:

1.
2.

For field rivet, the permissible stress is reduced by 10%.

The permissible stress in rivet under wind load condition as per
15800 can be increased by 25%.

The permissible stress in rivet under wind and earthquake load
condition as per IS800 can be increased by 25%.

When thickness of cover plate is not given, then the thickness of

5
cover plate should not be + = tmain(thinner)

91. ASSUMPTIONS IN DESIGN OF RIVETED JOINT

1.

The applied axial load is assumed to be shared by allthe
rivets equally.

. The tensile stress(0.6f,,), shear stress(0.4f,) and bearing

stress at their respective centres are assumed to be uniform.

. The effect of bending stress is neglected.

4. Grip length is the sum of thickness of two plates

1. Grip length I, + 54 (LSM)
2. Grip length I, + 86 (WSM)

Section 1-1 — Tearing strength of plate
Section 2-2 -> Bearing strength of plate
Section 3-3 -> Shear strength of plate

92. ASSUMPTIONS IN DESIGN OF RIVETED JOINT

5. The friction force b/w the plates is neglected.
6. (g — d)tF,<nR, (MOST IMPORTANT CONSIDERATION)

Where n is the number of rivets in shaded region 1

EL

93. Note

Single Rivetted Joint Means one line of rivets (in that line multiple
rivets can be there)

Double Rivetted Joint means two lines of Rivets are there (and each
line has multiple rivets)

94. Eccentric Riveted Connection

When the CG of the Group does not lie in the line of action of load,
then the connection is called as Eccentric Connection.

Flange of I section

95

95. Eccentric Riveted Connection

+ The effect of Eccentric load at the CG
of rivet group will be direct load at P
and Twisting moment T (T = Pe)

* Due to Direct load P, Shear stress is
developed in the rivets and due to
twisting moment, Twisting shear
stress is developed in rivet

+ Due to direct load P, bracket will bend
so bending stresses are developed in
the bracket

Flange of I section

96

96. Analysis of Eccentric Connection

Step 1: Shear Force (F,) in Rivet due to
Direct load P

F,= x À;
t 54 A;
If dia of rivets are same, then the cross
section area would also be the same,
there fore direct shear load is

FE = A;

x
nxA;

Flange of I section

F P
>F=-
Un

97

97. Analysis of Eccentric Connection

Step 2: Shear Force (F;) in Rivet due to
Twisting Moment T

TXT

FE; = a P= Pe
DE
(valid when dia of rivets are same)

Where 7; is the radial distance of each rivet
from centre of Rivet Group

Flange of I section

98

98. Analysis of Eccentric Connection

Step 3: Resultant Shear Force in the
Rivet (F3)

Fe [re + F2 + 2F,F,cos0

Flange of I section

99

99. Analysis of Eccentric Connection

Note:

+ If Resultant Shear Force is greater than
the Rivet Value R, , then the Rivet will
fail, so for the Rivet to be safe, Fk < R,

+ The direction of F is perpendicular to
the line joining CG of rivet group and the
centre of Rivet under consideration

+ Whatever moment P produces about CG

of the Rivet Group, F should also
produce the same moment about the CG

of the rivet group Flange of I section

+ The Critically Stressed Rivet is the one
for which r is maximum @ is minimum.

100

100. Que. Find the force in Extreme Rivet

300mm
Flange of I section

101