04 Magenes

2015
2nd Intern. SPONSE Workshop
May 13, 2015, Pavia, Italy
Seismic Design of Buildings with Masonry
Infills: Possible Approaches Considering the
Structural and Nonstructural Performance
Guido Magenes & Paolo Morandi
Department of Civil Engineering and Architecture
University of Pavia, Italy
European Centre for Training and Research in
Earthquake Engineering, Pavia, Italy
2015
Overview
1. INTRODUCTION
2 . S TAT E O F T H E A R T & C U R R E N T D E S I G N A P P R O A C H E S
3. TRADITIONAL SOLUTION FOR INFILL CONSTRUCTION
F R A M E W O R K O F T H E E X P E R I M E N TA L / N U M E R I C A L
STUDY
i i . I N F I L L M O D E L C A L I B R AT I O N V S . E X P E R I M E N T S
i i i . C O R R E L AT I O N O F R E S P O N S E B A R E V S . I N F I L L E D
i v . O U T - O F - P L A N E V E R I F I C AT I O N
v . V E R I F I C AT I O N O F L O C A L E F F E C T S
vi. PROPOSED DESIGN PROCEDURE
4 . I N N O VAT I V E S O L U T I O N A N D “ I N S Y S M E ” P R O J E C T
i.
F I R S T E X P E R I M E N TA L R E S U LT S O N I N N O VAT I V E
SOLUTION
5. FINAL REMARKS
i.
MASONRY INFILLS - OVERVIEW
2015
Motivation
Damage to “non-structural” masonry infills and veneers
Significant source of economic losses and possible risk to human life
Emilia 2012
L’Aquila 2009
MASONRY INFILLS - INTRODUCTION
2015
Motivation
Damage to structural elements induced by global or local
interaction with masonry infills
L’Aquila 2009
Examples of known problems of local interaction:
Captive column
Günay & Mosalam [2010]
Short column &
concentrated strut action
Ricci et al. [2011]
Infills adjacent along partial
height of the column
MASONRY INFILLS - INTRODUCTION
Concentrated strut action
Ricci et al. [2004]
Infills adjacent along full
height of the column
2015
Motivation
Increasing use, in the Italian construction practice as well as
other European countries, of thicker masonry units for infills and
partition walls, coming from the increase in thermal
performance requirements. This may amplify the frame-infill
interaction problems
MASONRY INFILLS - INTRODUCTION
2015
Are masonry infills and partitions “structural” or
“non structural”?
Although in principle “non-loadbearing”, their mechanical
interaction with the “structure” is often non negligible (especially in
the case of frame or frame-equivalent structures).
Structural role (negligible or not) depends on how the masonry
walls are built (e.g. in contact or disconnected from frame).
Current seismic codes address the problem in different ways.
MASONRY INFILLS - INTRODUCTION
2015
How to account for masonry infills in design?
Crucial decision:
a) model explicitly the presence of infills in the structural model
(e.g. through the introduction of equivalent strut elements, or
other modelling options)
or
b) consider their influence in an approximate way by evaluating
the structural response from a “bare frame” analysis , correcting
then the results and the force/displacement demands to
account for global and/or local interactions.
MASONRY INFILLS - INTRODUCTION
2015
Option a): explicit modelling of infills
Implications:
attribution of a structural role to elements that are originally not
dedicated to such function, with consequences regarding
• the definition of the material structural properties
• control/inspection issues,
• more complex modelling,
• safety/performance checks,
to the extent that the higher overall complexity of the design would
most likely lead to the abandonment of the use of masonry for
building enclosures and partitions.
MASONRY INFILLS - INTRODUCTION
2015
Option b): allow “bare frame” analysis
Implications:
easier solution, but admissible only if
• the stiffness and strength of the masonry walls does not
completely override the structural behaviour of the bare
structure,
and
• rational/reliable ways are available to use/modify the bare
frame analysis results for the prediction of global and local
interactions, and consequently verify the performance design
objectives for structural elements and for the masonry elements.
MASONRY INFILLS - INTRODUCTION
2015
Options discussed in this presentation
•
•
ADHERENT SOLUTION
Unreinforced masonry (traditional construction approach)
Lightly reinforced masonry (improvement techniques)
• Verifications and damage control according to current code provisions
Sufficient? Complete? Clearly defined?
• Existing drift limits at Damage Limitation Limit State?
• Required drift limits at Ultimate Limit State?
•
•
UNCOUPLED SOLUTION (presence of gaps)
Technological problems (how to fill the gap for thermal and acoustic
insulation)
Verification of out-of-plane stability
Definition of reasonable gap sizes
•
INNOVATIVE SOLUTION
e.g. with sliding or deformable bed joints
•
MASONRY INFILLS - INTRODUCTION
Summary of Design Procedure - EC8
Bare frame design
Uncertainties related to material
properties
Complex numerical modeling
δDLS = 0.50 % - attached brittle
δDLS = 0.75 % - attached ductile
δDLS = 1.00 % - isolated or without
Verification of local
effects for structural
elements
Additional measures for non-structural masonry infills
Prevention of irregularities in plan and elevation
Measures against brittle failure, premature disintegration, out-of-plane failure
e.g.: application of light wire meshes, wall ties, concrete posts and belts
MASONRY INFILLS - CURRENT DESIGN CODES
Definition of Limit States – EC8 & NTC08
“[…] the structure as a whole, including structural and non-structural elements, and
equipment relevant to its function, must not be damaged or exposed to any significant
disruption of use.”
Damage Limitation Limit State
“The structure should be designed and constructed to withstand a seismic action [...]
without the occurrence of damage and the associated limitations of use, the costs of
which would be disproportionately high in comparison with the costs of the structure
itself. “
“An adequate degree of reliability against unacceptable damage shall be ensured by
satisfying the deformation limits [...]”
Ultimate Limit State
“The structure should be designed and constructed to withstand the design seismic
action[...] without global and local collapse, thus retaining its structural integrity and a
residual load bearing capacity after the seismic events.“
“It shall be verified that the behaviour of non-structural elements does not present risks to
persons and does not have a detrimental effect on the response of the structural
elements.”
Near Collapse Limit State
“[…] the structure may suffer serious damage and collapse of non-structural components
and installations as well as serious damage of structural components, but still retains a
margin of safety for vertical actions and a small margin of safety for collapse due to
horizontal actions.
How to quantify in design?
Italian National Code (NTC 08)
EC8 – Part 1
Operational Limit State
Experimental - Numerical Limit States
Definition of limit states for masonry infills
based on experimental evidence
• Interpretation of test results from quasistatic in-plane cyclic tests on bare and
infilled 1-storey 1-bay RC frame specimens
• Calibration of a numerical model
• Simple equivalent diagonal strut infill model
commonly defined by
» Axial stress-strain hysteretic rule
(cyclic)
+ corresponding envelope (monotonic)
» Strength and stiffness properties
(equivalent strut width)
• Global displacement behaviour vs. possible local
effects
• Evaluation of properties characterising strut
response
Recent tests carried out at UNIPV and EUCENTRE (2013)
Unreinforced masonry “robust” infill
(Morandi et al., 2014; Hak et al., 2014)
In-plane cyclic tests
Out-of-plane
cyclic tests
Morandi, P., Hak S., Magenes, G., (2014) “In-plane Experimental Response of Strong Masonry Infills”, Proc. of the 9th
International Masonry Conference 2014, 7-9 July 2014, Guimarães, Portugal.
Hak, S., Morandi, P., Magenes, G., (2014) “Out-of-plane experimental response of strong masonry infills”, Proc. of the
Second European Conference on Earthquake Engineering and seismology, 25-29 August 2014, Istanbul, Turkey.
Recent tests carried out at UNIPV and EUCENTRE (2013)
In-plane tests
In-plane test, bare frame, drift: 3.5% (TNT)
In-plane test, infilled frame, drift: 2.5% (TA2_IP)
In-plane test, infilled frame with opening, drift: 1.0% (TA4_IP)
Recent tests carried out at UNIPV and EUCENTRE (2013)
Out-of-plane tests - 1
a)
c)
e)
b)
d)
f)
Infill with no opening (i.e. two-way
bending)
Force-displacement response:
(a) TA3 (1.0% IP drift)
(b) TA1 (1.5% IP drift)
(c) TA2 (2.5% IP drift)
(d) Comparison of TA1, TA2 and TA3
Infill with opening (1.0% IP drift)
Force-displacement response:
(e) TA4 – left panel
(g) TA4 – right panel
Recent tests carried out at UNIPV and EUCENTRE (2013)
Out-of-plane tests – 2
a)
b)
One-way (vertical) bending – no
previous in-plane damage
(a) F-D response TA5
(b) Deflected shape TA5
(c) Progression of damage TA5
c)
Review of tests carried out at UNIPV (1999)
Unreinforced and lightly reinforced masonry “weak” infill
• Existing experimental results - Calvi & Bolognini (1999, 2001)
Unreinforced infill (UR)
Lightly reinforced infill
Rebars in the bed joints (RB)
Mesh in the plaster (MP)
Calvi, G.M., Bolognini D. [1999] Seismic response of R.C. frames infilled with weakly reinforced hollow masonry
panels, Research Report, University of Pavia, Department of Structural Mechanics, Pavia, Italy.
Calvi, G.M., Bolognini D. [2001] Seismic response of RC frames infilled with weakly reinforced masonry panels,
Journal of Earthquake Engineering, Vol. 5, No. 2, pp. 153-185.
Performance Levels for a Single Infill
• Increasing levels of infill damage in function of inter-storey drift,
Life safety
consideration of experimental damage propagation
Damage Limitation
A–B
0.30 < δ ≤ 0.50
Ultimate
B–C
0.50 < δ ≤ 1.75
δ ≤ 0.20
0.20 < δ ≤ 0.35
0.35 < δ ≤ 1.00
δ ≤ 0.20
0.20 < δ ≤ 0.30
0.30 < δ ≤ 1.00
Damage
Operational
O–A
δ ≤ 0.30
Damage
without opening
with opening
Drift [%]
Damage
Drift [%]
without
opening
SLENDER INFILL
STRONG INFILL
Limit State
Reference
Drift [%]
M A S O N R Y I N F I L L M O D E L C A L I B R AT I O N
Limit States for Infilled RC Structures
Limit State
(system)
(Operational
Damage Limitation
Ultimate
Requirement
None of the infills has
reached Point A.
None of the infills has
reached Point B.
None of the infills has
reached Point C.
Some infills are damaged,
but can be easily and
economically repaired.
A significant number of infills
are severely damaged and
reparability is economically
questionable, lives are not
threatened.
Infills are considered
undamaged.
Description
B εB = εm'
fB
fA
A
2
3
ε A = εm'
Axial stress
fC
O
εC = εu
C
Limit
State
Limit
State
(panel)
Operational
Operational
Damage
Damage
Limitation
Limitation
Ultimate
Ultimate
Reference
Point A
Point B
Point C
Referenc
e
Strain
Ewθ
Strain
Drift
ε A εB
Axial strain
εC
Drift
Symbol
M A S O N R Y I N F I L L M O D E L C A L I B R AT I O N
Point A
ε ≤εA
ε ≤εA
δ ≤δA
δ ≤δA
Point B
ε A < ε ≤ εB
ε A < ε ≤ εB
δ A < δ ≤ δB
δ A < δ ≤ δB
Point C
ε B < ε ≤ εC
ε B < ε ≤ εC
δ B < δ ≤ δC
δ B < δ ≤ δC
Failure
Beyond C
ε > εC
δ > δC
Representative Masonry Infill Typologies
Slender masonry infill
Weaker (T1)
Strong
“Robust”
Medium (T2)
Decanini et al. [1993]
Compression
at the centre
Compression
at the corners
Shear sliding
Diagonal tension
Strain properties – from calibration on experimental results
MASONRY INFILLS -NUMERICAL STUDY – FRAMEWORK
Numerical Model
Concentrated plasticity approach
for RC elements
•
Structural analysis program RUAUMOKO
•
One-component Giberson frame
element
•
Modified TAKEDA hysteresis rule
Equivalent diagonal strut model
for masonry infills
•
Hysteretic rule, Crisafulli [1997]
•
Diagonal strut width bw, Decanini et al. [1993]
•
Relative
bw K1
=
+ K2
dw parameter
λh
stiffness
[1969]
λ =4
MASONRY INFILLS -NUMERICAL STUDY – FRAMEWORK
E wθ t w sin 2θ
4Ec I c hw
λ, Stafford Smith
Typical Building Configurations
• Systematic numerical study on buildings satisfying EC8 & NTC08
• Parametric analyses on planar frame configurations
» Building height: 3, 6 and 9 storeys
» Ductility class: medium and high
» Reference peak ground acceleration: 0.05g, 0.15g, 0.15g, 0.25g and 0.35g on
soil class B
• Parametric analyses on spatial frame and wall-frame dual system configurations
» Building height: 6 storeys
» Ductility class: medium and high
» Reference peak ground acceleration: 0.25g and 0.35g on soil class B
• Different infill typologies and percentages of infill (constant along building
height)
4 bare
12 infilled
30 bare
228 infilled
MASONRY INFILLS -NUMERICAL STUDY – FRAMEWORK
4 bare
12 infilled
Nonlinear Time-History Analyses
• Seismic input [REXEL, 2010]
ULS TR = 475 years
DLS TR = 50 years
10 natural records compatible
with site specific design spectra
according to NTC08, scaled to
each level of seismicity
Storey displacements
Inter-storey drifts
Infill damage (strut axial strain)
Assessment of limit states
Storey
Response evaluation
Displacement [m]
For each case study
• DLS OK? ULS OK?
For each record (percentage of
frames satisfying requirements)
For average response
M A S O N R Y I N F I L L S - N U M E R I C A L S T U D Y – R E S U LT S
ULS 0.25g DCH T1
ULS 0.35g DCH T1
Drift [%]
Implications for Design Drift Limitation
• Drift limit applicable to bare
frame in order to control
related infilled frame drift
• Safe-sided drift limit
• DLS: δDLS,0 = δm’
• ULS: δULS,0 = δu
• too conservative?
• Correlation of bare and infilled
frame drifts
Bare Frame
Infilled Frame
Drift
δ [%]
DLS δDLS
ULS δULS
DLS δm’
ULS δu
T1, T2
≤ 0.50
-
≤ 0.30
≤ 1.00
S /with O
≤ 0.50
-
≤ 0.35
≤ 1.00
S /without O
≤ 0.50
-
≤ 0.50
≤ 1.75
?
Introduction of refined inter-storey drift limits in function of specific design
parameters at both limit states
design PGA, storey height, ductility class - structural stiffness
infill typology and percentage of infill
Definition of simplified infill density-stiffness coefficient Cj for each storey j
M A S O N R Y I N F I L L S - N U M E R I C A L S T U D Y – R E S U LT S
Comparison of bare and infilled
frame average drift demands per
storey for increasing PGAs
Prediction:
δj, Cj
δw,j
Infilled Frame Drift
δw,j
Prediction of Infilled Frame Drifts
T1
Bare Frame Drift
δj
General expression
δw , j
 δm , j’ δ j
, δ j ≤ δm , j’ + δC , j C j

= δm , j’ + δC , j C j
 δ −δ C , δ > δ ’ + δ C
j
m, j
C, j
j
 j C, j j
Infilled Frame Drift δw,j
Unreinforced infill
2
3
δC , j = δm , j’
Bare Frame Drift
δj
M A S O N R Y I N F I L L S - C O R R E L AT I O N B A R E V S . I N F I L L E D F R A M E
T1
Comparison of bare and infilled
frame average drift demands per
storey for increasing PGAs
Prediction:
δj, Cj
δw,j
Infilled Frame Drift
δw,j
Prediction of Infilled Frame Drifts
δ '
m
Unreinforced
infill
 δm , j’ δ j
, δ j ≤ δm , j’ + δC , j C j

= δm , j’ + δC , j C j
 δ −δ C , δ > δ ’ + δ C
j
m, j
C, j
j
 j C, j j
Ewθ
2
δC , j = δm , j’
O
3
Infilled Frame Drift δw,j
Infill force
δw , j
T1
Bare Frame Drift
δj
General expression
fB
T1
ULS drift
DLS drift
Infill drift
Bare Frame Drift
δj
M A S O N R Y I N F I L L S - C O R R E L AT I O N B A R E V S . I N F I L L E D F R A M E
Simplified vs. refined drift demand prediction
Simplified vs. refined drift demand prediction
Refined (average) vs simplified drift demands, 3-storey 2-d frame (F): a j = 2, DLS; b j = 2,
ULS
Refined (average) vs simplified drift demands, 9-storey 2-d frame (F): a j = 4, DLS; b j = 4, ULS
Refined (average) vs simplified drift demands, 6-storey 3-d frame & wall-frame (T3): a j = 2,
DLS & ULS; b j = 4, DLS & ULS
Out-of-Plane Resistance and Demand
• Resistance
• No code recommendations (EC8)
• Arching action mechanism
(EC6, non-seismic actions, undamaged infill)
• Vertical plaster reinforcement
(from existing experimental results)
ARCHING STRENGTH CAPACITY
2
wR,χ
2
t 
t 
F
= 0.72  w  fd + 7.2  w  As fy ≤ wa = a
hw Lw
 hw 
 hw 
PLASTER REINFORCEMENT
• Demand (EC8)
• Out-of-plane resistance verification
for non-structural elements
Equivalent static horizontal seismic
force
Fa =
S aWa γ a
qa
Sa =

ag S  3(1 + z w /H )
−
0.5


g  1 + (1 − Ta /T1 )2

M A S O N R Y I N F I L L S - O U T - O F - P L A N E V E R I F I C AT I O N
Out-of-Plane Strength Reduction
Strength Reduction
βa,j
Strength Reduction
βa,j
Degradation of out-of-plane resistance with increasing in-plane drifts
Simplified strength reduction coefficient (in function of limit state drifts δDLS,0 and
δULS,0
)
Strong without opening
Slender
Strong with opening
ARCHING
wR,χ,β
2
2

 REDUCTION
 tw 
 tw 
= 0.72  fd + 7.2   As fy βa, j


 hw 
 hw 


PLASTER REINFORCEMENT
O U T - O F - P L A N E V E R I F I C AT I O N
Measures to Prevent Local Effects
• Local damage to vertical structural elements
L’Aquila 2009
• Concentrated column shear demands
Short column &
concentrated strut action
Captive column
Günay & Mosalam [2010]
Ricci et al. [2011]
Infills adjacent along partial
height of the column
• Code requirements (EC8)
Conceptual design
Capacity design
VC , Ed,cl = γ Rd
Concentrated strut action
2 MC ,Rd
lcl
Critical regions
Ricci et al. [2004]
Infills adjacent along full
height of the column
Verification – minimum of
• Capacity design force
VC ,Ed, M = γ Rd
2MC ,Rd
CONTACT LENGTH
lc
• Horizontal strut force
VC,Ed,w = Fw,hor = fv0twLw
SLIDING SHEAR STRENGTH
V E R I F I C AT I O N O F L O C A L E F F E C T S
Column Shear Demands
External columns of 2D case study frame structures
Vw,C = Fw,hor,act − VC
Average effective shear demands from activated strut force
Strut force activation
aw =
Fw ,hor ,act
Fw ,hor
Variation of shear demands
Design parameters (PGA, ductility class)
Building configuration, type of infill, position
6-storey
DCH
Storey
Unreinforced masonry
T1, T2, T3
Strut Force Activation [%]
Shear demand in function of in-plane drift
Infilled Frame Drift [%]
V E R I F I C AT I O N O F L O C A L E F F E C T S
6-storey
DCH
Strut Force Activation
aw [%]
Column Shear Demands
External columns of 2D case study frame structures
Vw,C = Fw,hor,act − VC
Average effective shear demands from activated strut force
Strut force activation
aw =
Fw ,hor ,act
Fw ,hor
Variation of shear demands
Design parameters (PGA, ductility class)
Building configuration, type of infill, position
aw, j
δ w, j ≤ δ DLS,0 / 3
2.1δ w, j / δ DLS,0 ,


0.375 δ w, j / δ DLS,0 + 0.575, δ m ' / 3 < δ w, j ≤ δ DLS,0
=
δ m ' < δ w, j ≤ 2δ DLS,0
 0.05 δ w, j / δ DLS,0 + 0.9,

1.0,
δ w, j > 2δ DLS,0

Unreinforced masonry
T1, T2, T3
Strut Force Activation [%]
Shear demand in function of in-plane drift
Infilled Frame Drift [%]
V E R I F I C AT I O N O F L O C A L E F F E C T S
Design shear forces (EC8)
VC ,Ed,l = min(VC ,Ed,w ,VC ,Ed, M )
GOVERNING
VC ,Ed,w,a = aw, j Fw,hor
Summary of Proposed Design Procedure
δDLS,0
Bare Frame Drift
δj
PROPOSED DESIGN PROCEDURE
δDLS,0
Infilled Frame Drift
δw,j
Strut Force Activation
aw,j [%]
δULS,0
LOCAL EFFECTS
OUT-OF-PLANE
Strength Reduction
βa,j
Infilled Frame Drift
δw,j
DRIFT PREDICTION
INFILLED FRAME
δDLS,0
δDLS,0/3
Infilled Frame Drift
δw,j
2δDLS,0
Simplified design tools
PROPOSED DESIGN PROCEDURE
Uncoupling the infill from the frame
HORIZONTAL GAP
VERTICAL
GAP
Gaps between masonry infill and r.c.
frame (e.g., with mortar joints)
Aiming to allow in-plane relative
displacement but guarantee out-ofplane stability
Adequate material to fill the gaps
?
Positive aspects (in theory):
Limitation of in-plane infill damage at DLS and ULS (?) (if
gap well designed)
No detrimental local effects due to frame-infill interaction
Ok design procedure as bare frame
Advantages if infills are located irregularly in
plan/elevation
Critical aspects:
Suitable connection “sliding-joint” between
infill and frame.
Adequate material in the joints between
frame and infill (thermal, acoustic, fire
insulation).
Out-of-plane flexural strength of masonry
must be guaranteed (reinforcement?)
SIZE OF GAP!!!! (for collapse prevention)
Innovative solution: infill with “sliding bedjoints”
First proposals:
Mohammadi et al., 2011
M.Preti, E.Giuriani,
L.Migliorati (2012-2014)
Advantages:
Control of in-plane infill damage at DLS and ULS, possibly working also at collapse prevention (CO)
No detrimental local effects due to frame-infill interaction
Ok to design as bare frame (negligible local interaction effects)
Advantages if infills are located irregularly in plan/elevation
Enhancement of the overall energy dissipation capacity without a significant increase of stiffness and
strength
No need of large vertical “gaps”, and no risk of sudden stiffening and “pounding” between frame and
infill once gap closes
I N N O V AT I V E S O L U T I O N S
Innovative solution: infill with “sliding joints”
Ongoing “INSYSME” European FP7 Project (2013-2016)
MASONRY
HORIZONTAL
“SLIDING JOINTS”
Beam-infill
Horizontal “gap”
Column-infill
connections
and
Vert. interface
Advantages:
Critical aspects:
Control of in-plane infill damage at DLS and ULS
No detrimental local effects due to frame-infill interaction
Ok design procedure as bare frame
Advantages if infills are located irregularly in plan/elevation
Enhancement of the overall energy dissipation capacity without a
significant increase of stiffness and strength
No need of large vertical “gaps”
No risk of “pounding” between frame and infill
Column-infill connections and vertical
interface
“Sliding bed-joints”
Out-of-plane flexural strength of masonry
Adequate material in the “gap” between
beam and infill (thermal, acoustic, fire
insulation).
“Complexity” in construction above all in
the case of infill with openings.
I N N O V AT I V E S O L U T I O N S
Innovative solution: infill with “sliding joints”
5) BEAM-INFILL
HORIZONTAL “GAP”
1) SHEAR KEY
2) INTERFACE
3) MASONRY
I N N O V AT I V E S O L U T I O N S
4) HORIZONTAL
“SLIDING JOINTS”
Innovative solution: infill with “sliding joints”
“INSYSME” European FP7 Project (2013-2016)
Testing of sub-structures: two infilled frames
FIRST INFILLED FRAME:
1 In-plane cyclic test of an infill wall without opening (low and high velocity) +
1 Out-of-plane test dynamic test (on shaking table)
SECOND INFILLED FRAME:
1 In-plane cyclic test of an infill wall with opening +
1 Out-of-plane static test
Shaking table testing of model buildings
1 MODEL BUILDING:
• 2 storeys, 3D frame
• Infill walls with opening + infill walls without opening
• Innovative partitions + “traditional” partitions
I N N O V AT I V E S O L U T I O N S
In-Plane Low-Velocity Cyclic Test
Target level
In-Plane Test - Low Velocity Protocol
Drift [%]
3
2.5
2
1.5
1
0.5
0
-0.5
-1
-1.5
-2
-2.5
-3
1D
2D
3D
4D
5D
6D
7D
8D
9D
10D
11D
12D
13D
14D
15D
16D
17D
18D
Drift
[%]
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.50
0.60
0.80
1.00
1.25
1.50
1.75
2.00
2.50
3.00
Displacement
[mm]
1.56
3.13
4.69
6.25
7.81
9.38
10.94
12.50
15.63
18.75
25.00
31.25
39.06
46.88
54.69
62.50
78.13
93.75
In-Plane High-Velocity Cyclic Test
In-Plane Test - High Velocity Protocol
2.5
2.50
2
1.5
2.00
1.50
0.5
Drift (%)
Drift [%]
1
1.00
0
-0.5
-1
0.50
-1.5
-2
0.00
0.30
0.60
0.90
1.20
Frequencies [Hz]
1.50
-2.5
0
I N N O V AT I V E S O L U T I O N S - E X P E R I M E N T S
2000
4000
6000
8000
10000
12000
14000
In-Plane Low-Velocity Cyclic Test - RESULTS
Quadro fessurativo
6D – 0.30%
In-Plane Low-Velocity Cyclic Test - RESULTS
Quadro fessurativo
10D – 0.60%
In-Plane Low-Velocity Cyclic Test - RESULTS
Quadro fessurativo
13D – 1.25%
In-Plane Low-Velocity Cyclic Test - RESULTS
Quadro fessurativo
16D – 2.00%
In-Plane Low-Velocity Cyclic Test - RESULTS
Quadro fessurativo
18D – 3.00%
In-Plane High-Velocity Cyclic Test
In-Plane Low-Velocity Cyclic Test - RESULTS
3% In-Plane Drift
In-Plane Low-Velocity Cyclic Test - RESULTS
500
-3
-2
Drift [% ]
0
-1
1
2
3
400
300
200
Force [kN]
100
0
-100
-200
-300
-400
-500
-100
-80
-60
-40
-20
0
Displacement [mm]
I N N O V AT I V E S O L U T I O N S - E X P E R I M E N T S
20
40
60
80
100
In-Plane Low-Velocity Cyclic Test - RESULTS
-3
600
-2
Drift [% ]
0
-1
Frame w.
adherent infill
1
2
3
Frame w.
innovative infill
400
Bare frame
Force [kN]
200
0
-200
Bare Frame
Innovative Infill
Innovative Infill Contribution
Traditional Infill
Traditional Infill Contribution
-400
-600
-100
-80
-60
-40
-20
0
20
Displacement [mm]
Thickness:
• Innovative infill: 25 cm + 2+2 cm of plaster
• Traditional adherent infill: 35 cm
40
60
80
100
In-Plane Low-Velocity Cyclic Test - RESULTS
-3
600
-2
Drift [% ]
0
-1
1
2
3
Adherent infill
contribution
400
Force [kN]
200
0
Innovative infill
contribution
-200
Bare Frame
Innovative Infill
Innovative Infill Contribution
Traditional Infill
Traditional Infill Contribution
-400
-600
-100
-80
-60
-40
-20
0
20
Displacement [mm]
Thickness:
• Innovative infill: 25 cm + 2+2 cm of plaster
• Traditional adherent infill: 35 cm
40
60
80
100
Observations from in-plane test
• Plastinc hinge frame mechanism could develop as designed from a
«bare frame» analysis
• Significant reduction of local frame-to-infill interaction at higher
damage levels
• Damage easily repairable at damage control limit states (and also at
life safety performance level)
• Added energy dissipaton from sliding mechanism
CONCLUSIONS
Out-of-Plane Dynamic Test: to be performed
Conclusions
• A possible design approach for infilled RC structures with traditional
masonry infills has been described, based on experimental and
numerical results.
– Introdution of refined drift limits in function of density-stiffness
–
–
Infill strength, deformation capacity and layout
Structural stiffness properties
– Evaluation of predicted drifts for infilled structural configuration
– Out-of-plane verification accounting for expected in-plane damage
– Verification of local effects in function of expected strut force activation
• The seismic performance of an infill innovative solution is being
carried out through an experimental campaign.
• The first results experimental results are very encouraging
regarding the effectiveness of the proposed solution.
CONCLUSIONS
Acknowledgements
The research described in this presentation was and still is being
developed by the authors in collaboration with several former and
present graduate students:
Dr. Sanja Hak, formerly doctoral student at the ROSE school,
currently post-doc researcher at University of Zagreb, Croatia
Mr. Riccardo Milanesi currently doctoral student at the UME school
Mr. Milad Oliaee currently doctoral student at the UME school
Their contribution, hard work and original thoughts are gratefully
acknowledged.
Funding from the Italian Brick Producers Association , from the DPCRELUIS framework project and from the European Commission (FP7
project «INSYSME») is also acknowledged.
ACKNOWLEDGEMENTS
2015
2nd Intern. SPONSE Workshop
May 13, 2015, Pavia, Italy
Thank you for your attention
Guido Magenes & Paolo Morandi
Department of Civil Engineering and Architecture
University of Pavia, Italy
European Centre for Training and Research in
Earthquake Engineering, Pavia, Italy