07 manus 12 bolted joints 09

Wardenier RHS Joints - Oslo Course 2009

Bolted Joints between Hollow Sections

Prof.dr.ir. Jaap Wardenier

Em. Delft University of Technology


Types of Bolted JointsTypes of Bolted Joints

1. Joints with Bolts in Shear

2. Joints with Bolts in Tension

Bolted hollow section joints can typically be classified

into two groups, depending on how the bolts are loaded:


Splice Joints with Bolts in ShearSplice Joints with Bolts in Shear

Interior/Exterior Splice Plates for large RHS


Splice Joints with Bolts in ShearSplice Joints with Bolts in Shear

Gussets with External Splice Bars permits sealing with cap plates


Diagonal Bracings in a Braced-Frame

Slotted plates welded into the ends of a RHS diagonal bracing


Slotted Gusset Plates into Truss Members

Slotted plate into a CHS member, with the gusset plate tapered for aesthetic appeal


Some bolted Joints


Bolted Joints with Bolts in Shear


Bolted Joints for Truss Supports


Double Channel

Beams

Bolted to Plates

on

RHS Column

Faces


Bolted Joints with Bolts in Shear


Bolted Gusset-Plate Joints to RHS

Limitation:

Member widths must be closely matched.

Potential Problem:

Welding contraction tends to pull the gussets inwards. The gussets may need to be spread slightly by jacking after welding.


Bolted Gusset-Plate to RHS Joints

Design needs to consider potential failure modes:

1. Shear failure of bolts

2. Bolt bearing: On the hollow section and on the gusset plate

3. Yielding or buckling of the gusset plate, using the Whitmore

criterion

4. Tear Out of the gusset plate (tension only) – All possible failure paths

5. Tear Out of the hollow section (Member tension load only)

– Examine all possible failure paths



3. Yielding or buckling of the gusset plate, using the Whitmore

criterion

If load is compression; buckling

capacity is based on a column of

width (g + 1.15 ∑ p), depth of tp ,

a length equal to the minimum of

L1, L2 and L3 and an effective

length factor of 0.65.


Bolted fin plate Joint


Fin plate (or shear tap) Joints

y,c0

0

f

E114.0

t

d≤

y,c0

0

f

E4.1

t

b≤

Avoid

too much

distortion

of the

column face:A

Section A-A

A


Fin plate Joint

Check for:

a.beam web failure

b.bolt shear failure

c.bolt bearing failure

d.plate failure

e.weld failure

f. column punching shear failure

g.column face plastification

(only for horizontal loads)

b, e and f should not be governing!

A

Section A-A

A


Fin plate Joint

Avoid:

b. bolt shear failure → stronger than other criteria

e. weld failure → 2a.fs,weld > tp.(0.58 fp,y)

f. column punching shear failure

→ 2 tc.(0.58 fc,y) > tp.(0.58 fp,y )

b, e and f should not be governing!

A

Section A-A

A


Fin plate Joint

d. Plate failure

65

65

65 65

70

70

70

(a) (b)

Tensile Rupture

ShearRupture

ShearRupture

A

Section A-A

A


Other Plate and T stub Joints

D

Section D-D

DE

Section E-E

E B

Section B-B

B


Bolted Joints to diaphragm plates


Bracing Joints (see welded plate to RHS connections)

∆

θ

hp

bp

hc

tc

bc

h 'p

w

Np

β = b / bp c

β' = (b + 2w) / (b - t )p c c

b ' = b - tc c c


Bolted Joints


PRYING FORCES develop when flange-plates lever against each other.

⇒ Prying forces increase the load in the bolts

⇒ Early failure of the connection

Joints with Bolts in Tension

N N

B =N

2B =

N

2

Q Q

B =N

2+ Q B =

N

2+ Q


Bolted Flange-Plate to RHS Joints

With bolts along 2 sides of the hollow section

Connection behaviour is

representative of

2-dimensional prying

models


Bolted Joints

Yield lines at distance

b’=b-d/2+ti


Bolted End Joints at 4 sides

If no prying:

1u

m

12pyp bB

1ptf

4

1⋅=

γ⋅⋅⋅⋅

Modified AISC:

Yield lines along

outer sides RHS

Use p or p’ (minimum)

bb11


Single sided bolted Joint


Wall Thickening


Single sided bolting

1.1. LindapterLindapter HolloBoltHolloBolt

2.2. Huck UltraHuck Ultra--twisttwist

3.3. FlowdrillFlowdrill

4.4. OthersOthers

1.


2. Huck

Ultra-Twist


Column Joints Using Huck Ultratwist FastenersColumn Joints Using Huck Ultratwist Fasteners

Column splice

Beam-to-column end-plate

connection


One-Sided Bolting using FlowdrillOne-Sided Bolting using Flowdrill

- The Flowdrill extrudes a precision hole in the hollow section, with 80% of the molten displaced material flowing down and 20% up.

- This forms a boss of 3 times the hollow section thickness, which can then be threaded with a Flowtap.

- Conventional bolts can then be screwed into the holes from one side.

- Less tolerance for field bolting relative to conventional bolt holes.

www.flowdrill.nl


Flow drill blind bolted joints

Up to 12.5 mm


Other Methods: Welded Threaded Studs


Other Methods: Welded Nuts


Design Recommendations


Design Recommendations

Simulate as standard RHS-RHS T-joint, with outer bolt

centres as the RHS bracing corners, with a reduction for

the bolt holes


Example: Cast steel node for space frames

This one not produced anymore


Nails in Shear

Powder–activated fasteners, or "nails", can be used as structural

connectors for mating circular hollow sections

Ideal for poles – especially in remote locations


Joint design is based on classic failure modes

for bolted joints:

1. Shear failure

of fasteners

2. Fastener bearing

on the base metal3. Net section fracture of

the tube cross section


The end of the

lectures on

Bolted Joints

Do not stiffen

in this wrong way!!!

Do not stiffen

in this wrong way!!!



4. Tear Out of the gusset plate (tension only) – All possible failure paths

Gusset Tear to

Edge of Plate


4. Tear Out of the brace – All possible failure paths

Bolt

Pattern

Tear out

07 manus 12 bolted joints 09

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