Download presentation
Presentation is loading. Please wait.
1
BFC 43003 Structural Steel and Timber Design
CHAPTER 2: CONNECTION BFC Structural Steel and Timber Design Assoc. Prof. Dr. DYeoh 2014
2
Course content Assoc. Prof. Dr. DYeoh 2014
3
Outline of lecture Example of connections Purpose of connection
Welded connection – general information Bolted connection – general information Design examples of bolted connection and welded connection Assoc. Prof. Dr. DYeoh 2014
4
Example of connections
Assoc. Prof. Dr. DYeoh 2014
5
Beam-column with end-plate bolted connection
Beam-column connected to column flange Beam-column connected to column web Assoc. Prof. Dr. DYeoh 2014
6
Beam-column and beam-beam bolted connection
Use of END PLATE Beam-column and beam-beam bolted connection Detailing to steel-concrete composite floor Assoc. Prof. Dr. DYeoh 2014
7
Use of END PLATE Assoc. Prof. Dr. DYeoh 2014
8
Assoc. Prof. Dr. DYeoh 2014
9
Beam-column with web cleat bolted connection
Assoc. Prof. Dr. DYeoh 2014
10
Beam-column with fin plate bolted connection
Assoc. Prof. Dr. DYeoh 2014
11
Beam-column with seating cleat bolted connection
Bolt in tension Beam loaded vertically Bolt in shear Assoc. Prof. Dr. DYeoh 2014
12
Assoc. Prof. Dr. DYeoh 2014
13
Assoc. Prof. Dr. DYeoh 2014
14
Beam-column with welded connection
Assoc. Prof. Dr. DYeoh 2014
15
Classification of connection
Assoc. Prof. Dr. DYeoh 2014
16
Force transmission – simple design
Splices Force transmission – simple design Moment connection – continuous design Moment and force connection - continuous design Assoc. Prof. Dr. DYeoh 2014
17
Simple method connection frame
Semi-rigid method connection frame Rigidly connected frame Assoc. Prof. Dr. DYeoh 2014
18
When is it a ROLLER connection? Or when is it a PINNED connection?
Or when is it a RIGID/FIXED connection? Assoc. Prof. Dr. DYeoh 2014
19
Can the connection resist (1), (2) and/or (3)?
Think of… TRANSLATION VERTICAL TRANSLATION HORIZONTAL ROTATION Can the connection resist (1), (2) and/or (3)? Assoc. Prof. Dr. DYeoh 2014
20
2. TRANSLATION HORIZONTAL 3. ROTATION
1. TRANSLATION VERTICAL 2. TRANSLATION HORIZONTAL 3. ROTATION Which can this connection resist? Is this a PINNED or RIGID connection? Assoc. Prof. Dr. DYeoh 2014
21
2. TRANSLATION HORIZONTAL 3. ROTATION
1. TRANSLATION VERTICAL 2. TRANSLATION HORIZONTAL 3. ROTATION Which can this connection resist? Is this a PINNED or RIGID connection? Assoc. Prof. Dr. DYeoh 2014
22
2. TRANSLATION HORIZONTAL 3. ROTATION
1. TRANSLATION VERTICAL 2. TRANSLATION HORIZONTAL 3. ROTATION Which can this connection resist? Is this a PINNED or RIGID connection? Assoc. Prof. Dr. DYeoh 2014
23
2. TRANSLATION HORIZONTAL 3. ROTATION
1. TRANSLATION VERTICAL 2. TRANSLATION HORIZONTAL 3. ROTATION Which can this connection resist? Which is a PINNED or RIGID connection? Assoc. Prof. Dr. DYeoh 2014
24
Bolted and welded end plate
Beam-column Rigid connection All welded Bolted and welded end plate Bolted and welded extended end plate, and stiffener Assoc. Prof. Dr. DYeoh 2014
25
Purpose of connection Assoc. Prof. Dr. DYeoh 2014
26
Connection is very important and is a weak link
To transfer forces between one member element to another and subsequently transmit to the foundation Connection is very important and is a weak link Failure can often happen at the connection Connection must be ductile Assoc. Prof. Dr. DYeoh 2014
27
Welded connection Assoc. Prof. Dr. DYeoh
Assoc. Prof. Dr. David Yeoh 2014 2014 27
28
Some features of welded connection:
Convenient for off-site fabrication Expensive on site Can be more aesthetic than bolts Convenient with hollow sections Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 28
29
Types of Weld Fillet Weld Butt Weld Leg Throat Leg
Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 29
30
Design of welds, Fw,Ed < Fw,Rd
Given in Clause 4.5 Design using simplified method is given in Clause and Directional method in Clause Design is based on assuming shear and normal forces in weld Simplified approach given as Throat thickness Design strength Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 30
31
Bolted connection – types of bolt
Assoc. Prof. Dr. DYeoh 2014
32
Two types Structural (black) bolts (NON PRE-LOADED)
High strength friction grip (HSFG) bolts (PRE-LOADED) this is not covered in this lecture Assoc. Prof. Dr. DYeoh 2014
33
Bolt Types – Structural (NON PRE-LOADED)
Shear loads are transmitted through bearing and cross sectional area of the bolt. Bearing Bearing Shear Assoc. Prof. Dr. DYeoh 2014
34
Bolt Types – Slip resistant (HSFG) (PRE-LOADED)
Large tension in bolt Shear loads are transmitted by friction between plies. Bolts are tightened to their proof load in order to develop high bearing forces between plies. Friction provides strength Bearing stresses Between plies Assoc. Prof. Dr. DYeoh 2014
35
Real Bolted Joint Behaviour
HSFG Force Slippage Non-linear as bolts yield Structural Initially linear response Higher stresses Deformation Initial clearance Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 35
36
Simplified Bolted Joint Behaviour
Force Failure assumed here Equal stresses Deformation Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 36
37
Bolt Descriptions M20 grade 8.8
Diameters given in millimetres prefixed by M Hole diameters normally 2-3mm bigger than the bolt Lengths given in millimetres Grade gives yield and ultimate strength in N/mm2 (see Table 3.1 EC3 Part 1-8) M20 grade 8.8 Diameter=20mm UTS=8*100=800N/mm2 MYS=8*8=640N/mm2 Assoc. Prof. Dr. DYeoh 2014
38
Bolt diameter – shank and thread
(tensile stress area) Bolt head Bolt dia Assoc. Prof. Dr. DYeoh 2014
39
Detailing requirement EC3 Part 1-8 Design of Joints Clause 3.5
Assoc. Prof. Dr. DYeoh 2014
40
Nominal standard hole clearance for Non Pre-loaded bolt
M12 and M14, provide 1 mm M16 and M24, provide 2 mm M27 and above, provide 3 mm Assoc. Prof. Dr. DYeoh 2014
41
Symbols for end and edge distance and spacing of fasteners
(Figure 3.1 of EC3-1-8) Minimum and maximum allowable distances (spacing, end and edge) are given in Table 3.3 of EC3-1-8 Assoc. Prof. Dr. DYeoh 2014
42
Failure modes and design checks in bolted connection EC3 Part 1-8 Design of Joints Clause 3.6 and Table 3.4 Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 42
43
Which bolt is most stressed?
THINK CRITICALLY Which bolt is most stressed? What kind of stress is the bolt resisting? Apart from the bolt, is the member (beam or column) under any stress? Assoc. Prof. Dr. DYeoh 2014
44
Failure modes Bolt shear Plate shear or tear-out Bolt bearing
Plate bearing Bolt tension failure Tension on net section Assoc. Prof. Dr. DYeoh 2014
45
Shear failure in bolt Double Shear Single Shear
Two failure planes One failure plane Single Shear Double Shear Theoretical failure load given by Area acting in shear (given in codes) Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 45
46
Shear resistance check inequality
0.6 Table 2.1 Assoc. Prof. Dr. DYeoh 2014
47
Bearing failure in plate
Bolt pulls through plate or element Bearing Theoretical failure load given by Empirical factor(s) (given in codes) Plate thickness Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 47
48
Bearing resistance check inequality
Table 3.4 Table 2.1 Assoc. Prof. Dr. DYeoh 2014
49
Tension failure in bolt
Connection force Reaction force Larger bolt force Failure load given by Flexible plates can increase Tensile forces due to “prying” k accounts for limited of ductility in tension Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 49
50
Tension resistance check inequality
Table 3.4 Table 2.1 Assoc. Prof. Dr. DYeoh 2014
51
Combined shear and tension resistance check inequality
Table 3.4 Assoc. Prof. Dr. DYeoh 2014
52
Block tearing - Plate Failure
Section failure End failure Block tearing is controlled by bolt separation limits. Design methods for tension members is given in Clause EC3 Part 1-8 Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 52
53
Block Shear Failure Assoc. Prof. Dr. DYeoh
Assoc. Prof. Dr. David Yeoh 2014 2014 53
54
Summary of design checks in bolt connections
Identify load paths within connection Check each link Failure prevented by Limitations on distance between bolts (Table 3.3) Limitations on edge distance (Table 3.3) Checks on Shear stresses in bolts (Table 3.4) Tensile stresses in bolts (Table 3.4) Combined stresses in bolts (Table 3.4) Check on capacity of plate and element (3.10) Check on shear capacity of plate Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 54
55
Design - Splice connection
Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 55
56
Given splice connection, double shear M20 Grade 4.6 bolt
Hole clearance +2mm Splice plate is grade S275 Verify detailing requirement and find strength of connection Assoc. Prof. Dr. DYeoh 2014
57
Check detailing requirement (Table 3.3)
22 = 26.4 mm 26.4 mm 22 = 48.4 mm Assoc. Prof. Dr. DYeoh 2014
58
Assoc. Prof. Dr. DYeoh 2014
59
Check shear resistance per bolt for two shear plane For 3 bolts, Fv,Rd = 282 kN
Assoc. Prof. Dr. DYeoh 2014
60
Check bearing resistance per bolt
From EN , fu of plate (Grade S275, t>3 mm) = 410 N/mm2 In direction of load transfer: For end bolts, For inner bolts, Assoc. Prof. Dr. DYeoh 2014
61
Perpendicular to the direction of load transfer
For edge bolts, k1 is the smaller of p2 is not applicable here as there is no inner bolt Assoc. Prof. Dr. DYeoh 2014
62
Bearing resistance 3 bolts
Bearing resistance of one shear plane per bolt (take the smallest plate thickness and the corresponding strength), Bearing resistance 3 bolts Assoc. Prof. Dr. DYeoh 2014
63
Shear resistance, Fv,Rd= 282 kN Bearing resistance, Fb,Rd= 477 kN
The strength of this splice connection is governed by shear, FRd= 282 kN Assoc. Prof. Dr. DYeoh 2014
64
Design – Beam-column connection with bracket (combined shear and tension)
Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 64
65
Assoc. Prof. Dr. DYeoh 2014
66
< Tension resistance, Ft,Rd (Table 3.4 EC3 Part 1-8)
Assoc. Prof. Dr. DYeoh 2014
67
Combined shear and tension (Table 3
Combined shear and tension (Table 3.4 EC3 Part 1-8) inequality is given as… Assoc. Prof. Dr. DYeoh 2014
68
Assoc. Prof. Dr. DYeoh 2014
69
Assoc. Prof. Dr. DYeoh 2014
70
y1 is the distance of the most stressed bolt from the bolt with zero stress
Assoc. Prof. Dr. DYeoh 2014
71
Assoc. Prof. Dr. DYeoh 2014
72
Assoc. Prof. Dr. DYeoh 2014
73
Assoc. Prof. Dr. DYeoh 2014
74
Design – Beam-column connection with bracket (combined shear and torsion)
Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 74
75
Assoc. Prof. Dr. DYeoh 2014
76
Assoc. Prof. Dr. DYeoh 2014
77
Assoc. Prof. Dr. DYeoh 2014
78
Assoc. Prof. Dr. DYeoh 2014
79
Assoc. Prof. Dr. DYeoh 2014
80
Assoc. Prof. Dr. DYeoh 2014
81
Assoc. Prof. Dr. DYeoh 2014
82
Assoc. Prof. Dr. DYeoh 2014
83
Assoc. Prof. Dr. DYeoh 2014
84
Assoc. Prof. Dr. DYeoh 2014
85
Assoc. Prof. Dr. DYeoh 2014
86
Assoc. Prof. Dr. DYeoh 2014
87
Assoc. Prof. Dr. DYeoh 2014
88
Assoc. Prof. Dr. DYeoh 2014
89
Assoc. Prof. Dr. DYeoh 2014
90
Assoc. Prof. Dr. DYeoh 2014
91
Design – Bracing connection (welding, bolt in tension, and block tearing)
Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 91
92
Worked Example of bracing connection design
Steel Construction Institute SCI Student Worked Example Pages 71 to 80 Assoc. Prof. Dr. DYeoh 2014
93
Explaining block tearing
Assoc. Prof. Dr. DYeoh 2014
94
Design – Beam-column connection with web cleat (vertical and horizontal shear, and block tearing)
Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 94
95
Aside Most distant spring most highly stressed when bar rotates
Springs Bar Rotation Most distant spring most highly stressed when bar rotates Similar to bolts in bolt group when beam rotates due to moments Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 95
96
Shear Stresses in Bolts
Shear in these bolts Column Beam Bolts must resist Shear due shear force Shear due to moment Centre of rotation needed for moment shear Pe Centre of rotation e P Assoc. Prof. Dr. David Yeoh 2014 Assoc. Prof. Dr. DYeoh 2014 96
97
Design for Shear Stresses
Total shear obtained from vector sum of shear forces Force due To eccentricity Vh Vv V Force due to load on beam+ eccentricity Total force In bolt Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 97
98
Tensile Stresses in Bolts
Column Tensile stresses in top bolt in column Beam r NA Pe e Tension and shear in this bolt Second moment of area of bolt group P Very similar to stress calculations in beams Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 98
99
Design – Column base plate connection
Assoc. Prof. Dr. DYeoh Assoc. Prof. Dr. David Yeoh 2014 2014 99
100
Determine minimum area required
Estimate the additional bearing width, c (Clause item 4) Calculate the thickness of base plate, tp Check capacity of plate in bending (using first principle concept) Check bolt tension capacity for uplift force Check bolt shear capacity for lateral force Check bolt combined shear and tension capacity for moment Assoc. Prof. Dr. DYeoh 2014
101
Worked Example of column base connection design
Steel Construction Institute SCI Student Worked Example Pages 89 to 90 Assoc. Prof. Dr. DYeoh 2014
102
x is the additional bearing width, c
Assoc. Prof. Dr. DYeoh 2014
103
Assoc. Prof. Dr. DYeoh 2014
104
Check bending capacity of base plate
Assoc. Prof. Dr. DYeoh 2014
105
Assoc. Prof. Dr. DYeoh 2014
106
End of Connection Assoc. Prof. Dr. DYeoh 2014
107
What have been covered? What have you learned? Assoc. Prof. Dr. DYeoh
2014
Similar presentations
