Bolted connection

1. Bolted Connection

2. Advantages of Bolted Connections
• Noiseless and quick fabrication
• No special equipment/process needed for installation
• Fast progress of work
• The connection supports loads as soon as the bolts are tightened
• HSFG bolts do not allow any slip between the elements connected
• Due to the clamping action, load is transmitted by friction only and the
bolts are not subjected to shear and bearing
• Due to the smaller number of bolts, the gusset plate sizes are reduced.
• Deformation is minimized
• No heating is required
• Alterations

3. Disadvantages of Bolted Connections
• Bolted connection have lesser strength in axial tension as the net
area at the root of the thread is less.
• Under vibratory loads the strength is reduced if the connections get
loosened.
• Unfinished bolts have lesser strength because of non uniform
diameter.
• Architectural look.

4. Classification of bolted connection
• On the basis of resultant force transferred
• On the basis of type of force experienced by
bolts
• On the basis forced transfer mechanism by
bolts

5. • On the basis of resultant force transferred
– Concentric connections
– Eccentric connections

7. On the basis of type of force experienced by
bolts
• Lap Joint
• Butt Joint
• Bolts in pure tension
• Bolts with tension and shear
Shear Force

8. Lap Joint

9. Butt Joint

10. On the basis forced transfer mechanism by bolts
• Bearing type
• Friction type

11. Types of bolts
• Bearing Type of bolts
– Unfinished bolts
– Finished bolts
• High strength Friction grip bolts

12. Unfinished bolts
Finished bolts
• High strength Friction grip bolts

13. Failure of Bolted connections
• Failure of bolts due to Shear, bearing and
tension
• Failure of connection plates due to bearing,
tearing or block shear failure

14. Failure of bolts due to Shear, bearing and tension
• Shear failure of bolts

15. • Bearing failure of bolts

16. • Tension failure of bolts

17. • Bearing failure of Plates

18. Block Shear Failure

19. TERMINOLOGY USED IN BOLTED CONNECTIONS

20. • Pitch (P): Pitch is center to center spacing of bolts in a row,
measured along direction of load.
• Gauge Distance (g): It is the distance between the two consecutive
bolts of adjacent rows and is measured at right angles to the
direction of load.
• End Distance (𝑒1): It is the distance in the direction of the from the
center of bolt hole to the end of the plate
• Edge Distance (𝑒2): It is the distance of bolt hole from the
adjacent edge of the plate.

21. • Pitch distance (P):
– Minimum pitch = 2.5X nominal dia. of bolt
– Maximum Pitch
1) Tension member = P ≯ 16 t or 200 mm whichever is less
t= thickness of thinner plate
2) Compression member = P ≯ 12 t or 200 mm whichever is less
3) Tacking bolts = 32t or 300 whichever is less
16t or 200 when exposed to weather
Tension member = P ≯1000mm
Compression member = P ≯ 600mm

22. • Gauge Distance (g) = The distance between the centers
of any two consecutive fasteners in a line adjacent and
parallel to an edge of an outside plate ≯ 100 mm plus 4t
or 200 mm, whichever is less, in compression and
tension members.
t = is the thickness of the thinner outside plate.

23. • Edge Distance (𝑒1)and End Distance (𝑒2)
– Minimum edge and end distance ≮ 1.7 x Hole Dia
(for hand flame cut edges)
– Minimum edge and end distance ≮ 1.5 x Hole Dia
(Rolled steel sections)
– Maximum edge distance and end distance
e≯ 12.t.Ԑ
Where Ԑ=
250
𝑓𝑦

24. Diameter of Bolt Hole (𝑑0)

25. Grade and properties of bolts

26. Strengths of bolted
connections
Design
strength of
bolts
Shear
strength of
bolts
Bearing
strength
of bolts
Tension
strength
of bolts (If any)
Design
strength of
Plates
Tensile
strength of
plate

27. • Number of bolt required (N) =
𝑓𝑜𝑟𝑐𝑒 𝑖𝑛 𝑚𝑒𝑚𝑏𝑒𝑟
𝑏𝑜𝑙𝑡 𝑣𝑎𝑙𝑢𝑒
• Bolt value is minimum of strength of bolt in Shear
, Bearing and Tension
• Efficiency of bolted joint (ƞ)=
𝑠𝑡𝑟𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑗𝑜𝑖𝑛𝑡
𝑠𝑡𝑟𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑚𝑒𝑚𝑏𝑒