EXPERIMENTS OF END PLATE JOINTS IN AMBIENT AND FIRE ... 2011/Presentations/Day1/Perttola_12102011.pdf · METNET, Aarhus 2011 1 EXPERIMENTS OF END PLATE JOINTS IN AMBIENT AND FIRE

Faculty of Built Environment, Department of Structural Engineering

Research Centre of Metal Structures, Seinäjoki, Hämeenlinna

METNET, Aarhus 2011 1

EXPERIMENTS OF END PLATE JOINTS IN AMBIENT AND

FIRE CONDITIONS UNDER BIAXIAL BENDING

RESEARCH TEAM: Hilkka Ronni, Henri Perttola, Markku Heinisuo, Keijo Fränti

PRESENTATION: Keijo Fränti

Tampere University of Technology

Research Centre of Metal Structures,

Frami, Kampusranta 9 C, FI-60320 Seinäjoki, Finland




FOUR TEST DESCRIBED …

▪ Two pairs of tests (four tests) on splice joints for (RHS) tubes are described.

All the joints were under biaxial bending.

▪ In a pair, two similar joints were tested: one in room temperature and

another one at elevated temperature (in furniture under ISO 834 standard fire).

▪ These four tests belong to the larger test series (of 29 tests) through which the

applicability of the component method for three dimensional (3D) analysis

is studied.

▪ The preliminary results of the ongoing research on the 3D component method

are presented in the case of the described tests.



500

20

500

CFRHS 250x150x10

20

tpn = 10 / 20 /

verticalsupport

35

plate 20 x 295 x 280

Holes D22

v

Mid section

35

CFRHS 250x150x10

TE1, TE3

End sections

end plate tp x 290 x 390

295

a8

F

end plate + loading shelf

28

01

0

20

10

10

30

230

30

30

30

330

70

70

390

290

8 8

8

4

DET A

A


JOINT TESTS: SPECIMEN

BOLTS + WASHERS + NUTS M20-10.9

END PLATE JOINT (FLANGED SPLICE)

Steel S355

TUBE: CFRHS 250x150x10 - S355

500

20

500

CFRHS 250x150x10

20

tpn = 10 / 20 /

verticalsupport

35

plate 20 x 295 x 280

Holes D22

v

Mid section

35

CFRHS 250x150x10

TE1, TE3

End sections

end plate tp x 290 x 390

295

a8

F

end plate + loading shelf

28

01

0

20

10

10

30

230

30

30

30

330

70

70

390

290

8 8

8

4

DET A

A

Test pairs

tpn (nominal)

[mm]

tp (measured)

[mm]

ReH

[MN/m2 ]

Rm

[MN/m2]

A5

%

TE1 and TE1* 10 11.0 429 582 24

TE3 and TE3* 20 20.3 380 564 26

* = SPECIMEN IN FIRE TEST

Similar joints in room temperature and in fire tests, dimensions and properties of end plates:




SPECIMEN

HINGE

BALL JOINT

HYDRAULIC JACK

BEARING

ROLLER

SHELF (welded to the specimen)

LOAD CELL

TESTING ARRANGEMENTS (T=20 °C), BIAXIAL BENDING:

35 °

35 °

F

TRANSVERSE MOVEMENT IS ALLOWED AT MID SPAN!




▪ PROCEDURE: LOAD IS INCREASED (IN RATE 0.1kN/s) UP TO FAILURE

DIMENSIONS OF THE SPECIMEN (=TUBES

AND THEIR SPLICE) ARE SELECTED IN

SUCH A WAY THAT THE DEFORMATIONS

WERE CONCENTRATED ON THE JOINT!

MR = PL/4

θ = 2(v - vb,el ) /L

TEST RESULTS (T = 20 °C), BIAXIAL BENDING:

▪ MAIN INTEREST IS IN THE ROTATIONAL BEHAVIOUR OF THE JOINT

Moment-rotation

0

20

40

60

80

100

0 20 40 60 80 100 120 140 160

Q [mrad]

M [

kNm

]

TE3, t=20mm

TE1, t=10mm




FAILURE MODES, T = 20 °C

TE1: THIN ENDPLATE (t = 11.0 mm): TE3: THICK END PLATE (t = 20.3 mm):

VISBLE NECKING IN

THE LOWEST BOLT !

EC3: MODE I (COMPLETE YIELDING

OF THE FLANGE) OK!! EC3: MODE II (BOLT FAILURE WITH

YIELDING OF THE FLANGE) OK!!

LOWEST BOLT




K1, K2, K3 and K4

Chain

Threaded round barThreaded round bar

Transducer S1 Transducer S2

K2K2

K2

K1

K3

K4K4

Chain

Square hollow sections (SHS):

Hydraulic JackHydraulic Jack

Tachymeters

K2K2

K3

K3

K2

K1

Furnace

Tested specimen

TESTING ARRANGEMENT, FIRE TESTS:

510

CFRHS 250x150x12.5

4M20 (10.9)

CFRHS 250x150x12.5

11 or 20

20

FF

Rigid Support

510

LOAD WAS MAINTAINED WHILE THE

SPECIMEN WAS HEATED

(TRANSIENT TEST)!

NOTE: Tests in room temperature and in fire

were both three point (biaxial) bending tests!

gas burner




1 2

34

11

12

13

14

5 7

6

8

910

0

100

200

300

400

500

600

700

800

900

0 5 10 15 20 25 30 35 40

Tem

pera

ture

[°C

]

Time [min]

TE1*

Furnace

ISO834

Thermocouple average 1-4, in the middle of the side

Thermocouple average 5-10, in the corners

Thermocouple average 11-14, in the bolts

A/V=50

A/V=100

TEST TE1: STANDARD FIRE IN FURNACE TEMPERATURES OF FLANGES AND BOLTS

13 min: 20 min: 26 min:

TEST IS OVER (few minutes after failure) TE1*: SUSTAINED LOAD LEVEL M = 0.16*Mu, T = 20°C

FAILURE WHEN T = Tcr = 800 ° C




0

100

200

300

400

500

600

700

800

900

0 5 10 15 20 25 30 35 40

Tem

pera

ture

[˚C

]

Time [min]

TE3*

Furnace

ISO834

Thermocouple average 1-4, in the middle of the side

Thermocouple average 5-10, in the corners

Thermocouple average 11-14, in the bolts

A/V=50

A/V=100

FIRE TEST TE3*

SUSTAINED LOAD LEVEL: M = 0.16*Mu, T=20°C

Tkr = 655 °C




FAILURE MODES IN FIRE TESTS

M = 0.23*Mu, T=20°C M = 0.16*Mu, T=20°C

FAILURE MODE: EXCESSIVE DEFORMATIONS

= FLANGÈ YIELDING + BOLT EXTENSION

FAILURE MODE: FAILURE OF THREADS IN

THE LOWEST BOLT OF THE JOINT

(completely different failure mode than in

test TE3 arranged in room temperature)

Tcr, average = 800 °C Tcr , average= 655 °C

TE1: THIN ENDPLATE (t = 11 mm) TE3: THICK ENDPLATE (t = 20,3 mm)




0

10

20

30

40

50

60

70

80

0 100 200 300 400 500 600 700 800 900

Mo

men

t [k

Nm

]

Temperature [°C]

Moment resistance versus temperature, TE1*

TE1*, fire test

Componentmethod (method 2)

TE1, room temperature test

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800 900

Mo

men

t [k

Nm

]

Temperature [°C]

Moment resistance versus temperature, TE3*

Componentmethod (red. factor for carbon steel)

Componentmethod (red. factor for bolts)

TE3*, fire test

TE3, room temperature test

COMPONENT METHOD, FIRE TESTS (SIMPLIFIED RESULTS)

ON SAFE SIDE BOTH AT ROOM

TEMPERATURES AND IN FIRE

NOTE: Excessive deformation of the end

plate in the decisive role in both cases!

ON SAFE SIDE AT LOW TEMPERATURES

(reductions according to carbon steel)

ON SAFE SIDE AT HIGH TEMPERATURES

(redaction according to bolts) !

NOTE1: Different failure modes for the

joint in ambient and fire conditions .

NOTE2: In fire, the behaviour of the bolt

is in the decisive role!




SUMMARY

MORE 3D JOINT TESTS ARE NEEDED IN FUTURE!

1) No tests on the bolted end plate steel joints in biaxial bending were found in

literature … the tests described were ”pilot tests” in their character!

NOTE1: Some weak axis bending tests has been arranged in ambient conditions

NOTE2: In general, there is lack of joint tests in fire (quite new research area!)

3) Remarks concerning the ongoing research on 3D component method:

▪ The preliminary results on the applicability of the 3D component method are

quite encouraging for the joints under biaxial bending in ambient conditions.

▪ ”Joints in fire” is more challenging case than ”joints in room temperature”!

2) Observations based on four tests were described :

▪ The failure modes of two similar joints may be different in room temperatutre and in fire!




THAT’S IT, THANK YOU!

SPECIMEN UPSIDE DOWN ON LABORATORY FLOOR AFTER ROOM TEMPERATURE TEST TE3, Pmax ~ 400 kN (Mmax ~ 100kN)

FEM SIMULATION BY ABAQUS:

Documents

EXPERIMENTS OF END PLATE JOINTS IN AMBIENT AND FIRE ... 2011/Presentations/Day1/Perttola_12102011.pdf · METNET, Aarhus 2011 1 EXPERIMENTS OF END PLATE JOINTS IN AMBIENT AND FIRE