experimental investigation of the behaviour of pinned … · experimental investigation of the...

Experimental investigation of the behaviour

of pinned beam–to–column connections to

pure shear monotonic and cyclic excitation

SAFECASTPERFORMANCE OF INNOVATIVE MECHANICAL CONNECTIONS IN

PRECAST BUILDING STRUCTURES UNDER SEISMIC CONDITIONS

SERIES Workshop 2 September 2010, Ohrid

pure shear monotonic and cyclic excitation

I. N. Psycharis, H. P. Mouzakis, G. D. Kremmyda

Laboratory for Earthquake Engineering

National Technical University, Athens, Greece

The SAFECAST project

PERFORMANCE OF INNOVATIVE MECHANICAL CONNECTIONS PERFORMANCE OF INNOVATIVE MECHANICAL CONNECTIONS

IN PRECAST BUILDING STRUCTURES UNDER SEISMIC IN PRECAST BUILDING STRUCTURES UNDER SEISMIC

CONDITIONSCONDITIONS

• Research for the benefit of SME’s

• Grant agreement number: 218417

• Project Coordinator: Dr Antonella Colombo – ASSOBETON

SERIES Workshop 2 September 2010, Ohrid

• Project Coordinator: Dr Antonella Colombo – ASSOBETON

Consortium

• 5 National Associations of precast concrete producers:� ASSOBETON, Italy

� ANDECE, Spain

� ANIPB, Portugal

� SEVIPS, Greece

� TPCA, Turkey

The SAFECAST project

• 7 Research Institutions (RTD providers):

� Joint Research Centre – Elsa Laboratory, Italy

� Politecnico di Milano, Italy

� National Technical University of Athens, Greece

� Istanbul Technical University, Turkey

� Laboratorio Nacional de Engenharia Civil. Portugal

� University of Ljubljana, Slovenia

SERIES Workshop 2 September 2010, Ohrid

� University of Ljubljana, Slovenia

� Labor, Italy

• 4 SME’s

� DLC, Italy

� PRELOSAR, Spain

� LUGEA, Italy

� HALFEN, Germany

The SAFECAST project

• The project aims to the experimental investigation and

numerical validation of the dynamic behavior of joints and

connections in precast structures towards a correct seismic

design.

• The research activity is directly relevant to the interests of the

precast construction industry, thus it is directed to the precast

SERIES Workshop 2 September 2010, Ohrid

precast construction industry, thus it is directed to the precast

systems commonly used in the participating countries.

• The research is focused on dry connections, consisting of

mechanical devices, which is the most common type in

modern precast buildings, especially industrial buildings, in

southern Europe and elsewhere.

The SAFECAST project

Five types of connections are considered:

1. Between adjacent floor or roof elements

2. Between floor or roof panels and supporting beams

3. Between columns and

SERIES Workshop 2 September 2010, Ohrid

3. Between columns and beams

4. Between segments of columns or between columns and foundations

5. Between cladding panels and structural elements

Pinned beam−to−column connections

35 15 60 15 35

50 60 50

Plan view

1 1

2 dowels O20 bolted

Cast insitu concreteCast insitu concrete

Precast beamPrecast beam

60

Precast column

Cast insitu concrete Cast insitu concrete

2 dowels O20 bolted

SERIES Workshop 2 September 2010, Ohrid

60

60

4O12Protruding bars from the beam

Precast beam Precast beam

Cast insitu concrete Cast insitu concrete

1 dowel O20 bolted1 dowel O20 bolted

4O12Protruding bars from the column

4O12Protruding bars from the beam

4O12Protruding bars from the column

Section 1-1

Pure shear tests at NTUA

SERIES Workshop 2 September 2010, Ohrid

Experimental setup for pure shear tests

RE

AC

TIO

N W

ALL

SPECIAL APPARATUS

FOR UNIAXIAL

APPLICATION OF FORCE

TEST

SERIES Workshop 2 September 2010, Ohrid

JACK

RE

AC

TIO

N W

ALL

TEST

SPECIMEN

FASTENING MECHANISM

Experimental setup for pure shear tests

SERIES Workshop 2 September 2010, Ohrid

Reinforcement of specimens

Concrete: C30/37

Steel: S500

SERIES Workshop 2 September 2010, Ohrid

Reinforcement of specimens

SERIES Workshop 2 September 2010, Ohrid

column beam

Test program

dowels d Excitation

2 Ø25 0.10

Push

Pull

Cyclic × 2

1 Ø25 0.10

Push

Pull

Cyclic × 2

2 Ø16 0.10

Push

Pull

d

SERIES Workshop 2 September 2010, Ohrid

2 Ø16 0.10 Pull

Cyclic × 2

1 Ø32 0.20

Push

Pull

Cyclic

2 Ø25 0.15Pull

Cyclic

2 Ø25 0.20Pull

Cyclic

2 Ø25 0.10+anch. plate Cyclic

Green: done

Blue: ongoing

Monotonic PUSH - PULL: 2 ∅25, d = 10 cm

SERIES Workshop 2 September 2010, Ohrid

Monotonic PUSH - PULL: 2 ∅25, d = 10 cm

SERIES Workshop 2 September 2010, Ohrid

Monotonic PUSH - PULL: 2 ∅25 vs 1 ∅25

SERIES Workshop 2 September 2010, Ohrid

Comparison with analytical expressions

2 dowels 2 dowels ∅∅25, d = 10 cm: 25, d = 10 cm: FFmaxmax(push) (push) ≈≈ 470 470 kNkN, , FFmaxmax(pull) (pull) ≈≈ 230 230 kNkN

• Shear failure of dowel

⇒ FvR = 2×123.25 = 246.50 kN

• Compression of concrete

⇒ Vud,b = 2×58.11 = 116.22 kN

sydvR

3

1AfF ⋅=

ydcdsbud,

651ffA

γ

.V ⋅⋅⋅=

SERIES Workshop 2 September 2010, Ohrid

• Concrete cone splitting

� Push: ⇒ Vud,c = 2×241.41 = 482.82 kN

� Pull: ⇒ Vud,c = 2×85.34 = 170.68 kN

• Tassios (1985) and Greek Precast Code

⇒ Du,d = 2×99.50 = 199.00 kN

ydcdsm

bud,γ

23

p

51

b

bcdb

ccud,

11 /

/

cd

lfd

γ

.V

⋅⋅=

ysck

2du, ffΦδD ⋅⋅⋅=

Observed damage: monotonic PUSH

SERIES Workshop 2 September 2010, Ohrid

Spalling of cover

concrete at columnCracks around dowelSpalling of cover

concrete at beam

Observed damage: monotonic PULL

Spalling of cover

concrete at beamDIRECTION OF

MOTION

AT SMALL

DISPLACEMENT

SERIES Workshop 2 September 2010, Ohrid

concrete at beamMOTION

Observed damage: monotonic PULL

Destruction of the

dowel duct and the

grouting at beam

AT LARGE

DISPLACEMENT

SERIES Workshop 2 September 2010, Ohrid

grouting at beam

Spalling of

concrete at column

Observed damage: monotonic PULL

Dowels are

restrained by

lower hook.

SERIES Workshop 2 September 2010, Ohrid

lower hook.

Observed damage

SERIES Workshop 2 September 2010, Ohrid

Cyclic tests: Loading protocol

Velocity = 0.2 mm/s

0

20

40

60

en

t (m

m)

1 dy

2 dy

3 dy

4 dy

6 dy

8 dy

SERIES Workshop 2 September 2010, Ohrid

0 2000 4000 6000 8000 10000

Time (sec)

0

-60

-40

-20

Dis

pla

ce

m

Cyclic tests: 2 ∅25, d = 10 cm

SERIES Workshop 2 September 2010, Ohrid

Cyclic tests: 2 ∅25, d = 10 cm

SERIES Workshop 2 September 2010, Ohrid

Cyclic tests: 2 ∅25, d = 10 cm

SERIES Workshop 2 September 2010, Ohrid

Cyclic tests: 2 ∅25 vs 1 ∅25

SERIES Workshop 2 September 2010, Ohrid

Future tests: Bending & Shear

Aims and Restrictions

� Formation of plastic hinge at bottom of column, in order to check q-factor and ductility. However, this reduces the forces that are developed at the

SERIES Workshop 2 September 2010, Ohrid

developed at the joint.

� Development of large displacements and rotations at joint, in order to check its behavior.

� Restrain forces and overturning moments within the shaking table capacity.

SHAKE TABLE

Bending & Shear: Experimental setup

SERIES Workshop 2 September 2010, Ohrid

Bending & Shear: Experimental setup

SERIES Workshop 2 September 2010, Ohrid

SAFECAST

PERFORMANCE OF INNOVATIVE MECHANICAL CONNECTIONS IN PRECAST BUILDING

STRUCTURES UNDER SEISMIC CONDITIONS

SERIES Workshop 2 September 2010, Ohrid

Grant agreement number: 218417

Project Coordinator: Dr Antonella Colombo – ASSOBETON

www.safecastproject.eu