T-Stub ConnectionComponent Tests

James A Swanson and Roberto T Leon

School of Civil and Environmental Engineering

Georgia Institute of Technology

Atlanta, Ga.

http://www.ce.gatech.edu/~sac/

SAC Subtask 7.03

Tests on Bolted ConnectionsSAC Subtask 7.03

Tests on Bolted Connections• Synthesis of existing data• Testing:

– Individual T-stubs and angles– Full-scale exterior-type connections

• Interpretation• Design Recommendations• Further testing

• Synthesis of existing data• Testing:

– Individual T-stubs and angles– Full-scale exterior-type connections

• Interpretation• Design Recommendations• Further testing

ApproachApproach

• Identify and quantify individual failure modes

• Assess influence of monotonic vs. cyclic loading

• Develop simplified models

• Calibrate with advanced FEM

• Provide design aids (?)

• Identify and quantify individual failure modes

• Assess influence of monotonic vs. cyclic loading

• Develop simplified models

• Calibrate with advanced FEM

• Provide design aids (?)

View of the Test SetupView of the Test Setup

size of T-section or clip angle

size and number of bolts:

beam flange thickness

type of bolt

VariablesVariables

Test SetupTest Setup

Typical Tension Failure (little prying action)Typical Tension Failure (little prying action)

Prying DeformationsPrying Deformations

Typical Tension Bolt FailuresTypical Tension Bolt Failures

Bolt Hole Elongation Prior to FailureBolt Hole Elongation Prior to Failure

Net Section FailureNet Section Failure

Block Shear Failure

InstrumentationInstrumentation

A - relative slip

B - stem uplift

C - bolt uplift

D - stem elongation

E - overall elongation

G - instrumented bolt

A - relative slip

B - stem uplift

C - bolt uplift

D - stem elongation

E - overall elongation

G - instrumented bolt

EEDD

CC

GG

BB AA

Connection Spring Model

T-Stub Spring Model

1

2

3 45

6

4) Shear Bolts

5) Bearing Deformation

6) Connection Slip

1) Tension Bolts

2) Tee Flange

3) Tee Stem

TA-01 P/Including Post Fracture Data

Deformation (in)

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Lo

ad (

kip

)

-500

-400

-300

-200

-100

0

100

200

300

400

500

Deformation (mm)-10 -5 0 5 10 15 20 25 30 35 40

Lo

ad (

kN)

-2000

-1500

-1000

-500

0

500

1000

1500

2000

Group 3 - P/

Deformation (in)

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Lo

ad (

kip

)

0

100

200

300

400

500

Deformation (mm)

-2 0 2 4 6 8 10 12 14 16 18 20 22 24

Lo

ad (

kN)

0

500

1000

1500

2000

TA-01TA-02TA-03TA-04

Group 3 - P/Uplift

Deformation (in)

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Lo

ad (

kip

)

0

100

200

300

400

500

TA-01TA-02TA-03TA-04

Deformation (mm)

-2 0 2 4 6 8 10 12 14 16 18 20 22 24

0

500

1000

1500

2000

Lo

ad (

kN)

TA-05 vs TA-07 P/

Deformation (in)

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Lo

ad (

kip

)

0

100

200

300

400

500

TA-05TA-07

Deformation (mm)

0 4 8 12 16 20 24 28 32 36 40

0

500

1000

1500

2000

Lo

ad (

kN)

Group 1 Test Results

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

3" 4" 5" 6" 7" 8"

Tension Bolt Gage (in)

Ult

ima

te L

oa

d (

kip

)

Actual Estimate Design

TA-03 P/Bolt Force #3

Total Applied Load (kip)

-500 -400 -300 -200 -100 0 100 200 300 400 500

Bo

lt F

orc

e (k

ip)

0

10

20

30

40

50

60

70

80

90

100

Total Applied Load (kN)

-2000 -1500 -1000 -500 0 500 1000 1500 2000

Bo

lt F

orc

e (k

N)

0

50

100

150

200

250

300

350

400

SAC Test FS-03SAC Test FS-03

W21x44 beam

W14 x 145 column

T same as TD-01

7/8 in. A490 bolts

W21x44 beam

W14 x 145 column

T same as TD-01

7/8 in. A490 bolts

SAC FS-03: Initial view of top flangeSAC FS-03: Initial view of top flange

SAC FS-03: Initial yielding in T and beamSAC FS-03: Initial yielding in T and beam

SAC FS-03: Initial crack between last line of boltsSAC FS-03: Initial crack between last line of bolts

SAC FS-03: Final failureSAC FS-03: Final failure

Conclusions• The spring model should work well in predicting

stiffness characteristics.

• Net section fracture and block shear (after

extensive yielding) are the most desirable failure

modes because of their ductility.

• Component testing can provide a more

economical means of testing than conventional

full scale testing.

AcknowledgementsThe work presented here is funded by the Federal

Emergency Management Association (FEMA)

through a grant to SAC

• Structural Engineers Association of California (SEAOC)

• Applied Technology Council (ATC)

• California Universities for Research in Earthquake Engineering

(CUREe)