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