c t t c large-scale testing and analysis of m f...

LARGE-SCALE TESTING AND ANALYSIS OF CONCRETE-ENCASED STEEL COUPLING BEAMS

Charles Pankow Foundation

Principal Investigators: John Wallace, UC Los Angeles, & Ron Klemencic, MKA Student Investigator: Christopher Motter, UC Los Angeles

Structural / Earthquake Engineering Research Lab, UC Los Angeles

Test Objectives:

•Evaluate embedment

equations at large-scale

•Create realistic wall

strains at connection,

i.e. cyclic wall tension –

compression

•Primary test variable:

embedment length

FlatM

CT

CT

Vbeam

n.a.

FlatM

C T

C T

Vbeam

n.a.

Specimen Details:

εc = 0.003n.a.

2

'

0 0

2 c cc cf f

'0.85c cf f

β1x

x

Vn

ale

strain

Coupling Beam:

Shear Wall:

Testing Protocol:

Damage Photos:

Test Results:

•Beam 1 (32” embedment, light wall loading)

•Minimal strength degradation at large rotation

•Beam 2 (24” embedment, moderate wall loading)

•Greater strength degradation, pinching

•Reduced capacity in negative direction

likely due to tension across connection

•Overall excellent performance for both beams

Conclusions:

Test Set-Up:

Embedment Model Marcakis & Mitchell (1980),

Mattock & Gaafar (1982)

Cyclic wall tension-compression

across the connection

Embedment Detail:

Acknowledgements: •Robert Tener, Charles Pankow

Foundation

•Ron Klemencic, John Hooper,

Dave Fields (MKA)

•Steve Keowen, Alberto Salamanca,

Harold Kasper, Bob Nigbor (UCLA)

•PEER

Construction Pictures:

Cross-Section Embedment Detail Computer Rendering

(courtesy: MKA) Shear Wall Reinforcement

Steel Section

‚ 20 3 4"

11'

8'

200

kip

actu

ato

r

STRONG

FLOOR

2'-6"

4'-9"

1'-6"

8'

7'-3"

2'-8" 2'

2'-9"

1'-6"

2'-8" 2'

2'

400

kip

actu

ato

r

400

kip

actu

ato

r

15'

5'-6"

5'

STEEL

SECTION 1' 1' 1' 1' 1' 1' 1' 1'

24'

22'

CONCRETE

TOP BEAM

SHEAR WALL

STEEL SECTION STEEL SECTION

FO

OT

ING

300 k act.

BEAM #1BEAM #2

•Beam 1, 32” embedment

•Wall moment ~0.4My

just above connection

•Beam 2, 24” embedment

•Wall moment ~0.7My

just above connection

Beam 1 after 3% rotation Beam 2 after 3% rotation

Beam 1 after 6% rotation Beam 2 after 6% rotation