[Corus] SHS Jointing - Flowdrill and Hollo-bolt

8/2/2019 [Corus] SHS Jointing - Flowdrill and Hollo-bolt

1/13

Corus Tubes library publication

The contents of this publication are current, when republishedit will be in the new Corus housestyle.


2/13

SHS Jointing

Flowdrill &

Hollo-Bolt


3/13

Flo

wdrill&

Hollo-B

olt Flowdrill &

Hollo-BoltJointing

for Hollow Sections

Flowdrill and Hollo-Bolt give a choice of two

methods to produce bolted joints in

Hollow Sections. Both systems offer the

following benefits:

q They produce bolted joints of structuralcapacity in Hot Finished Rectangular HollowSections (HFRHS).

q They minimise the change in the fabricationprocess by using connection details whichare standard in the construction industry.

q They reduce fabrication by removing theneed to weld plates or other fittings onto theoutside surface of the RHS.

q They simplify erection by using fully threadedbolts -an increasing practice in theconstruction industry.

q They maintain aesthetics by producing aflush face on the RHS after fabrication.

Design GuidanceThe design guidance produced in thispublication is for Flowdrill and Hollo-Boltsystems with grade 8.8 bolts in conjunction withTubes and Pipes hot finished structural hollowsections. The design guidance, for joints insimple construction, result from Tubes & Pipesinitial research work undertaken in connectionwith CIDECT (Ref. 1). The guidancecomplements the information published by theBCSA/SCI and is presented in a form

compatible with their publication Joints inSimple Construction (Ref. 2).

Further test work is being undertaken toestablish design guidance for semi-rigidjoints.

Procedural checks are given for bearing, shearand local bolt pull out of the RHS wall and forthe combined effect of the column axial loadand the structural integrity tensile load ofBS 5950 : Part 1.

The combined check for the column axial loadand the structural integrity tensile load

recognises that the flexibility of the RHS facecaused by the tensile load can, in the presenceof the column axial load, reduce the overall jointcapacity.


4/13

Flowdrill Hollo

-B

oltFabrication and

ConstructionGeneral detailing recommendations for beam

column connections, given in this

publication, are in accordance with the

BCSA/SCI publication -Joints in Simple

Construction (Ref. 2).Both Flowdrill and Hollo-Bolt use fully threaded

bolts which allows standardisation of bolt

lengths throughout the construction. Where

beams are connected to adjacent faces of an

RHS column a check must be made with the

chosen bolt length to ensure that assembly is

possible (see Fig. 3 and 6) and the bolts do

not touch.

Both Flowdrill and Hollo-Bolt are suitable for use

with the two standard grades of Tubes & Pipes

SHS to BS EN10210-1 of S275J2H and

S355J2H (formerly BS4360 Gr43D and 50Drespectively).

At present, application of the Flowdrill process

is limited to RHS thicknesses up to and

including 12.5mm. For thicknesses of 16mm

and over, conventional drill and tap methods are

recommended, although due to the RHS

material strength being lower than that of the

grade 8.8 bolts, pull out strengths may be below

the bolt tension capacity.

Reference

1. Comit International pour leDveloppment et ltude de laConstruction Tubulaire

UK Member

British Steel plcTubes & Pipes

PO Box 101

Corby

Northants NN17 5UA

2. Joints in Simple Construction

Volume 1 : Design methods

Volume 2 : Practical applications

Published jointly by:

BCSA SCI4 Whitehall Court Silwood Park

Westminster Ascot

London Berks SL5 7QN

SW1A 2ES


5/13

Flow

dril

lThe ToolsThe initial hole is made by a Flowdrill tool

consisting of a tungsten carbide bit held in a

Flowdrill Morsetaper collet adaptor (Fig. 1). The

tool can be used in a conventional drilling

machine or CNC machine as found in

fabricators works, provided it has adequate

horsepower and spindle speed.

1st stageThe tungsten carbide bit is brought into contact

with the RHS wall where it generates sufficient

heat to soften the steel. The bit is then

advanced through the wall and in so doing the

metal is redistributed (or flows) to form an

internal bush. As well as drilling the initial hole,

the tool is fitted with the means of removing any

surplus material which may arise on the outside

of the RHS section. The cycle time for

Flowdrilling is similar to that for conventional

drilling. However, if done on CNC machines the

feed rate can be slow at the beginning, rapidly

increasing as the material softens to improve

efficiency.

2nd stageThe 2nd and final stage is to tap the Flowdrill

bush. This is done by roll threading the bush

with a Coldform Flowtap. The complete cycle is

shown in Figure 2.

TheProcess

Flowdrill data :

The Flowdrill system was developed by Flowdrill BV in Holland, and is available in the UK from

their agent - Robert Speck Ltd,. Little Ridge, Whittlebury Road, Silverstone, Northants NN12 8UD.

Tel: 01327 857307 Contact Mr Mike Carpenter.

Flowdrill Flowdrilling is basically a thermal drillingprocess which makes a hole through thewall of a structural hollow section without

the removal of metal normally associated

with a drilling process. The formed hole is

then threaded by the use of a roll thread

forming tool, leaving a threaded hole which

will accept a standard fully threaded bolt.

Tool holder

Collet

Flowdrill bit

Fig. 1

Fig. 2

1st Stage 2nd Stage


6/13

Drilling machine parameters :

Table 1 gives a guide to required machine

parameters for producing Flowdrill holes for

M12 to M24 bolts:

Note: The Flowdrill process is not suitable for

hand held or magnetic clamp type drilling

equipment when used in the sizes shown.

Flowdrill detailing requirements.

See Fig. 3 and Table 3.

Note:

q Flowdrilled joints used at

locations exposed to the

weather should not be

considered as water tight.

q Flowdrilling is not suitable

for use with pre-galvanised

materials.

Drill length: The recommended length ofFlowdrill bits varies with the thread size andthickness of material as given in Table 2.

Drill care: Flowdrills are made from tungstencarbide. They are extremely hard but cannotwithstand shock loads. After drilling each hole,FD KS paste should be applied to the Flowdrill

whilst it is still hot, so minimising oxidation andpreventing build up on the surface.

Flat surface: the raised rim on the outer surfaceof the RHS material caused during Flowdrillingshould be removed using Flowdrills with cuttingedges provided on the collar. One rotation of thecutter is all that is required to remove the rim.

Table 1

Table 2

Table 3 (See Fig. 3 for nomenclature)

Thread size

Flowdrill size

M/c spindle

speed rpm

M/c feed rate

Motor power

KW Min

Tapping speed

rpm

M12

10.9

1000-1500

2

250

M16

14.8

700-1100

2.5

200

M20

18.7

600-1000

3.5

150

M24

22.5

500-800

5

100

0.1/0.15mm (0.004/0.006 inches) per rev

Flowdrill Length

Thread SizeMax materialthickness

(mm)

3

5

6

8

10

12

16

M12

Short

Long

Long

Long

-

-

-

M16

Short

Short

Long

Long

Long

-

-

M20

Short

Short

Short

Long

Long

Long

-

M24

Short

Short

Short

Long

Long

Long

-

Dimensions

(mm)

A1

B1

C1

D1

E1 Minimum

Min Bolt Centres

M12

7

13

18

30

M16

10

17

20

40

M20

12

22

26

50

M24

15

25

29

60

Thread size/Bolt diameter

Varies with overall bolt length (Lb) specified

C1/2 + tc (for connection made to a single face or opposite faces)

B1/2 + A1 + D1 + tc (for connection made to adlacent faces)

E1

tp

tc

Lb

E1

B1

A1

D1

C1

Min bolt centres

Width

Fig. 3


7/13

Holl

o-Bolt

Hollo-Bolt

The pre-assembled unit (Fig. 4) is

inserted through normal tolerance holes

in both the attatchment plate and the

RHS. As the bolt is tightened the cone is

drawn into the body, spreading the legs,

and forming a secure fixing. Once

installed only the Hollo-Bolt head and

collar are visible (Fig. 5).

The Hollo-Bolt

HOLLO-BOLT is a pre-assembled

three part fitting consisting of body,

cone and bolt.

Further information on

Hollo-Bolt is available from

Lindapter International

A Division of Victaulic plc.,Lindsay House, Brackenbeck Road,

Bradford, West Yorkshire, Tel: 01274 521444

England, BD7 2NF Fax: 01274 521130

Hexagon Head

Location Flats

Body

Cone Knurling

Collar

Fixture

RHS

Cone

Legs

Central Bolt

Fig. 4

Fig. 5


8/13

Drilling requirements:

Hollo-Bolt uses a plain drilled

hole which can be made on

site or in the fabrication shop

using all normal drilling

equipment. The finished hole

should have a tolerance of

-0.2mm to +1.0mm from the

nominal given in the data table(Table 4).

Material Options

Standard product is manufactured from mild

steel and is electro-zinc plated with the addition

of JS500 1000 hour saltspray corrosion

protection. The central fastener is a grade

8.8 bolt.

For special applications, the Hollo-Bolt is

available manufactured from 316 stainless steel,

with a grade A4-80 central bolt. This will not be a

stocked item, and would be manufactured to

order.

Installation

The only tools required to fit Hollo-Bolt are two

spanners - an open ended spanner to hold the

collar and a torque wrench to tighten the central

bolt. Alternatively a power operated electrichand tool is in development.

Should the steelwork need to be adjusted,

the fixing can simply be removed and the

hole reused with another Hollo-Bolt.

Sealing Options

In certain applications, it may be necessary to

seal the Hollo-Bolt to prevent ingress of water or

other corrosive agents. For details of sealing

options available, please contact Lindapter.

Special Options (manufactured to order)q Stainless steel

q Button head setscrew q Socket head capscrew

q Countersunk setscrew/body q Special body lengths

Table 4 (See Fig. 6 for nomenclature)

Bolt

size

M8

M10

M12

M16

M20

Bolt

length

(V)

mm

45

49

53

57

80

Fixing

thickness

(W)

Min Max

mm

3 22

3 22

3 25

3 28

3 34

Bolt

centres

(X)

Min

mm

35

40

50

55

70

Internal

min. edge

distance

(Y)

mm

13

15

18

20

25

Edge

distance

(E1)

Min

mm

50-tp

55-tp

60-tp

65-tp

90-tp

Bolt

hole

dia.

(Dh)

mm

14

18

20

26

33

Across

flats

main

body

mm

19

24

30

36

46

Tightening

torque

Nm

21

40

78

190

300

E1

tp

tc

V

YX

W

Width

Fig. 6

Fig. 7


9/13

Simple connections between Universal

beams and RHS columns can be made

using double angle web cleats or

flexible end plates.

The following procedural checks are

compatible with the BCSA/SCI rules for

Joints in Simple Construction (Ref. 2).

Double Angle Cleats Flexible End Plates

Notes

q The cleats or end plates are generally positioned as close to the top flangeof the beam as possible to provide adequate positional restraint and a plate

length of at least 0.6D is usually adopted to give adequate torsional restraint

(BS 5950: Part 1, Table 9).

q Bolt gauge g: 90mm g 140mm, but g 0.3 x RHS face width B.

q Although it may be possible to satisfy the design requirements with tp< 8mm,

it is not recommended in practice because of the likelihood of weld

distortion during fabrication and damage during transportation.

q The plate thickness and gauge limitations apply equally to partial depth and

to full depth end plates.

If necessary, to comply with structural integrity requirements for a 75 kN tie force,

the connection must have at least 2 no. M20, Grade 8.8 bolts in tension with

/ 140mm, t 8mm and g 140mm.

Design ofJoints inSimple

Construction

Face of column Face of column

ID ID

g g

Length of cleat

I 0.6D

Length of plate

I 0.6D

Cleat thickness, tptp= 8mm or 10mm

Plate thickness, tptp= 8mm or 10mm

Flowdrill hole diameter, DhDh = d+2mm for d 24mmDh = d+3mm for d > 24mmFor Hollo-Bolt Dh see Table 4.

Bolt diameter, d Bolt diameter, d

End projection t1, approx 10mm


10/13

Basic Requirement

For Shear

Local shear and bearing capacity of theRHS column wall and bolts.

Q Pv_2

Pv = local shear capacity of

RHS column wall

= smaller of 0.6pycAv and

0.5 UscAvnetAv = [g/2 + (n -1) p = et] tc

with [et 5 d]

Avnet = Av - n d tcn = number of rows of bolts

p = bolt pitch

d = nominal bolt diameter (or

hole diameter in RHS

columns for Hollo-Bolt)

g = bolt gauge width

tc = RHS column wall

thickness

pyc = design strength of RHS

colunm wall (S275 = 275

N/mm2 : S355 =

355 N/mm2)

Usc = ultimate tensile strength

of RHS column wall

For bearing

Q Pbsc_2

Pbsc = bearing capacity of the RHS

column wall per bolt = d tc pbscpbsc = bearing strength of the RHS

column wall (S275 =

460 N/mm2 : S355 = 550 N/mm2)

Bolt Check (Table 5)

The single shear capacity for Flowdrill and

Hollo-Bolt can be taken as follows:-

Flowdrill

Bolt diameter

-

-

M12

M16

M20

M24

kN

-

-

31.6

58.9

91.9

132

Bolt diameter

M8

M10

M12

M16

M20

-

kN

12

25

38

75

100

-

Flowdrill

tc

p

p

p

g

Q/2 Q/2

Q

et

n rowsof bolts

Critical sections


11/13

Structural integrity-local bolt pull-out

of RHS colmn wall.

Note: This check is only needed if it is

necessary to comply with structural

integrity requirements.

Basic Requirement

Tie force Local bolts pull-out

resistances

Local bolt pull-out resistances

= 2 n Pp(si)

The local bolt pull-out design resistance

in kN of a grade 8.8 bolt in a flowdrilled

hole or a Hollo-Bolt should be taken from

the following tables which are based on

test results:

Note:

1. The tension capacity of Grade 8.8 bolts for

normal design and for structural integrity

design is shown in the shaded areas.

2. The pull-out resistances for structural

integrity Pp(si) are less than those for normaldesign because the design method

presented here for structural integrity leads

to thinner cleats or end plates than for

normal design methods, based on BS 5950:

Part 1, and, as a result, will lead to higher

prying forces. This has been taken into

account in the quoted resistances.

Flowdrill normal design strength (Pp(n)kN

RHS column wall thickness tc mm

Grade S275 (Grade 43) Grade S355 (Grade 50)

Bolt

diameter

mm

M16

M20

M24

6.3

60

85

101

8

95

122

10

70

97

134

12.5

110

159

5

59

102

103

6.3

130

70

110

8-12.5

159

5

46

70

80

Flowdrill structural integrity design strength (Pp(si)kN

RHS column wall thickness tc mm

Grade S275 (Grade 43) Grade S355 (Grade 50)

Bolt

diameter

mm

M16

M20

M24

6.3

40

56

67

8

63

81

10

46

65

89

12.5

73

106

5

39

68

68

6.3

86

46

73

8-12.5

106

5

30

46

53

Hollo-Bolt design strengths

Bolt

diameter

mm

M8

M10

M12

M16

M20

Normal design

strength (Pp(n))

kN

16

26

38

70

110

Structural integrity

design strength (Pp(si))

kN

10

17

25

46

73

Table 6

Table 7

Table 8

n rows ofbolts (criticalbolts arethose inthe column)

Tie force


12/13

Basic Requirement

Tie force Tying capacity of RHS column

wall

Tying capacity of RHS column wall8 mu

= (1+ 1.5 (1 - 1)0.5 (1 - 1)0.5)(1 - 1)

Mu = moment capacity of RHS

column wall per unit lengthpyctc

2

=4

pyc = design strength of the RHS column

(S275 = 275 N/mm2 : S355 = 355 N/mm2)

tc = thickness of RHS column wall

n1 = (n - 1)p - d

2

(B - 3tc)

g1 =

(B - 3tc)

d1 =

(B - 3tc)

B = overall width of RHS columnwall to which the connection is

made.

d = bolt diameter (or hole diameter

in RHS column for Hollo-Bolt)

g = bolt gauge width

n = number of rows of bolts

p = bolt pitch

Structural integrity - tie forcecapacity of RHS column wall in the

presence of axial compression in the

column.

Note: This check is only needed if it is

necessary to comply with structural

integrity requirements.

tc

1.5 tc

Tie force

(applied at

bolt positions)

Bolt holes

deducted

Yield lines

B

p

g

(n-1)p


13/13

British SteelTubes & Pipes

PO Box 101, Weldon Road,Corby, Northants, NN17 5UA

Tel: 01536 402121Fax: 01536 404111

TD3

84.1

2E.9

5

Documents

[Corus] SHS Jointing - Flowdrill and Hollo-bolt