Connections are critical structural elements that join members in steel structures. Common connection types include bolted, welded, and bolted-welded combinations. Connections are classified based on the connecting medium, type of forces transmitted, and elements joined. Riveted connections were previously common but have been replaced by bolted connections which are faster and cheaper to install. Welded connections provide rigidity but require careful design to avoid cracking. Modern connections often combine bolting and welding for strength and economy. Shear and moment connections behave differently in transmitting forces between members like beams and columns. Proper connection design is important for structural integrity and safety.

1. CONNECTIONS IN
STEEL STRUCTURES

2.  Connections are structural elements used for joining
different members of a structural steel frame work.
 Steel Structure is an assemblage of different
member such as “BEAMS,COLUMNS” which are
connected to one other, usually at member ends
fastners,so that it shows a single composite unit.

4.  Bolts
 Weld

5.  Connecting Plates
 Connecting Angles

6.  On the Basis of Connecting Medium.
 According to the type of internal forces.
 According to the type of structural Elements
 According to the type of members joining

7.  Riveted Connections
 Bolted Connections

8.  Welded Connections
 Bolted-Welded Connections

9.  Used for very long time.
 Made up of:
Round Ductile steel bar called shank.
A head at one end
The length of the rivet should sufficient to form the
second head.
 Design - very similar to bearing type of
bolted connection.

10.  Heating of the rivet
 Inserting it to an oversize hole pressure to the head.
 Squeezing the plain End by Pneumatic driver Round
head.
 On Cooling Reduces in
Length–Clamping Force

12.  The introduction of high strength structural bolts.
 The labour costs associated with large riveting
crews
 The cost involved in careful inspection and removal
of poorly installed rivets.
 The high level of noise associated with driving
rivets.

13.  Fastened Together primarily by Bolts.
 Bolts may be loaded in:
Tension
Shear
Both Tension & Shear
 Threads of bolts under shear force:
Excluded - Increased strength
Included - Decreased stregth.

14.  Bearing type bolts
 High strength friction grip bolts (HSFG)

15.  The most common type is bearing bolts in clearance
holes, often referred to as
1. Black Bolts
 Ordinary, unfinished, rough, or common bolts.
 Least Expensive
 Primarily - Light structures under static load such as
small trusses, purlins etc

16. 2. Turned Bolts
 Similar to unfinished bolts.
 Shanks - Hexagonal Rods
 Primarily - Light structures under static load such as
small trusses, purlins etc
 Expensive – Limited use – Structures with no
Slippage Connections

17. 3. Ribbed Bolts
• Round head similar to Rivets.
• Raised ribs parallel to the shank.
• Actual Diameter - slightly Larger than the hole
• Tightly fit into the hole.
• Popular - Economical in Material &
Installation

18.  Uses when bearing type bolts slips under shear
 High strength bolts (8G or 10K grade) Pre-tensioned
against the plates to be bolted together so that
contact pressure developed between the plates being
joined
 Prevents relative slip when extra shear is applied
 Higher Shear Resistance.

19. Advantages
1. The bolting operation is very silent
2. Bolting is a cold process hence there is no risk of fire
3. Bolting operation is more quicker than riveting.
4. Less man power is required in making the connections.
Disadvantages
1. If subjected to vibratory loads, results in reduction in
strength get loosened.
2. Unfinished bolts have lesser strength because of non
uniform diameter

20.  whose components are joined together
primarily by welds.
Welding Notations were developed by
American Welding Society (AWS).

21. • Groove ( More reliable than others)
 Fillet (Mostly used, Weaker than groove and
others)
 Plug (expensive – poor transmission of tensile
forces)
 Slot (expensive - poor transmission of tensile
forces)
 Plug and Slot welds – stitch different parts of
members together.

22.  Horizontal
 Vertical
 Overhead
 Flat

23.  Economical – Cost of materials and labors.
 Efficiency is 100% as compared to rivets (75- 90%)
 Fabrication of Complex Structures – Easy – like
Circular Steel pipes.
 Provides Rigid Joints – Modern Practice is of Rigid
Joints.

24.  No provision for expansion or contraction therefore
greater chances of cracking.
 Uneven heating and cooling - member may distort -
may result in additional stresses.
 Inspection is difficult and more costlier than rivets

25.  Most connections are Shop Welded and Field Bolted
types.
 More Cost Effective
 Better Strength &
Ductility characteristics –Fully welded.

26.  Shear (semi rigid, simple) connections
 Moment (rigid) connections

27.  Allows the beam end to rotate without a significant
restraint.
 Transfers shear out of beam
 Most Common Types:
Double clip
Shear End Plate
Fin Plate

28.  Designed to resist both Moment and Shear.
 Often referred - rigid or fully restrained connections
• Provide full continuity between the connected
members
• Designed to carry the full factored moments.
 Principal Reason - buildings has to resist the
effect of lateral forces such as wind and
earthquake.

29. Bolted splice Moment Connection
Field Bolted Moment Connection

30.  Single plate angle Connections
 Double web angle connections
 Top and seated angle connections
 Seated beam connections

31. Two Step Process
 A plate is welded to secondary section (beam)
 An Angle is welded to Primary Section (column or
Beam)
 single shear plate welded to secondary
beam and bolted to Primary beam or column.

32.  Two angles welded or shop bolted to the web
of a secondary beam.
 After erection the angles are bolted or site
welded to the primary member (beam or
column).

33.  Generally used in case of moment connections.
 Two angles are provided at top and bottom of
the beam to resist moment.
 Generally used for lesser moments where
heavy loads are not acting

34.  Generally used in case of shear connections.
 A seating angle - at bottom of secondary
beam - shop welded to the primary member.
 Seating angle resists vertical shear coming
from the beam.

35.  Beam to beam connections
 Column to column connections
(column splices)
 Beam to Column Connections
 Column Base Plate Connections

36. Two Types
 Primary Beam to Secondary Beam Connection
 Beam Splice

37.  Connects column to column.
 Column splice comes under this category.
 Used to connect column sections of different
sizes.
 Splices - designed for both moment
and shear unless intended to
utilize the splices as internal
hinges.

38.  Connects Beam to column.
 Very Common
 A wide range of different types are used
Fin Plates
End Plates
Web or Flange Cleats
Hunched Connections

39.  Beams are normally attached using two or
more bolts through the web.
End plate connections
 single plate welded to the end of the beams
 Bolted to the column flange or web - two or bolts
pair.
Fin plate connections
 Single Plate welded to the Column.
 Beams are normally attached using two or more
bolts through the web.

41.  Steel plates placed at the bottom of Columns.
 Function - to transmit column loads to the
concrete pedestal.
 The design of a column base plate:
determining the size of the plate.
determining the thickness of the plate

42.  A layer of grout should be placed between
the base plate and its support for the purpose
of leveling.
 Anchor bolts should be
provided to stabilize the
column during erection
or to prevent uplift.

44.  R Usually cost of fabrication and erection
constitute as high as 50% of the total cost of
steel structures, per tones of material used

45. BY
NAVEEN ANKUR SWARNAKAR
&
AJEET SHARMA