7 Cas Perspect
-
Upload
riddhi-patel -
Category
Documents
-
view
217 -
download
0
Transcript of 7 Cas Perspect
-
8/11/2019 7 Cas Perspect
1/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -1-
Doctoral School: StructuresCIVIL-706 Advanced Earthquake Engineering
Retrofittingmethods
-
8/11/2019 7 Cas Perspect
2/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -2-
Content
Strategies
Weakening
Steel bracing
Reinforced concrete shear walls
Jacketing
Masonry reinforced by composites
-
8/11/2019 7 Cas Perspect
3/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -3-
Seismic retrofitting strategies
In the plane strength-ductility
-
8/11/2019 7 Cas Perspect
4/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -4-
Seismic retrofitting techniques
Passive Additional new lateral bracing system
! Reinforced concrete shear walls
! Steel bracing
Seismic improvement of elements (columns orshear walls) of the existing structure
! By jacketing (concrete, steel, composites )
! By composite strips
! By additional post-tensioning
Semi-active
Seismic isolation
Additional energy dissipation devices! By friction
! By liquid mass
-
8/11/2019 7 Cas Perspect
5/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -5-
Seismic retrofitting strategies
Illustration: initial situation
-
8/11/2019 7 Cas Perspect
6/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -6-
Seismic retrofitting strategies
1st
option: additional RC shear walls
Increase in strength
Increase of seismic forces anddecrease of deformations
-
8/11/2019 7 Cas Perspect
7/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -7-
Seismic retrofitting strategies
2nd
option: columns jacketing
Increase in ductility and strength
Increase of damping anddisplacements
-
8/11/2019 7 Cas Perspect
8/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -8-
Seismic retrofitting strategies
3rd
option: bracing + beam weakening
Increase in strength and ductility
Increase of seismic forces and damping
-
8/11/2019 7 Cas Perspect
9/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -9-
Seismic retrofitting strategies
4th
option: isolators + dampers
Decrease in strength, increase in ductility
Decrease of seismic forces and displacements of the structure,increase of damping
-
8/11/2019 7 Cas Perspect
10/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -10-
Reinforcement not always optimal
Mind the first intuition
Increase of seismic
demand(for constant ductility and
damping)
-
8/11/2019 7 Cas Perspect
11/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -11-
Reinforcement not always optimal
Example: tank in Valais
-
8/11/2019 7 Cas Perspect
12/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -12-
Reinforcement not always optimal
Tank: seismic isolation
-
8/11/2019 7 Cas Perspect
13/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -13-
Tank in VS
Decrease ofdemand:
- decrease of frequency- increase of damping
Displacements
-
8/11/2019 7 Cas Perspect
14/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -14-
Reinforcement not always optimal
Example: moment-resisting steel frame
-
8/11/2019 7 Cas Perspect
15/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -15-
Reinforcement not always optimal
Beam weakening(dog bone)
-
8/11/2019 7 Cas Perspect
16/92
-
8/11/2019 7 Cas Perspect
17/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -17-
Architectural challenge !!
-
8/11/2019 7 Cas Perspect
18/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -18-
Physic building at ETH Zurich
-
8/11/2019 7 Cas Perspect
19/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -19-
Reinforced concrete shear walls
Building in Fribourg
-
8/11/2019 7 Cas Perspect
20/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -20-
Reinforced concrete shear walls
Delicate intervention in the building
-
8/11/2019 7 Cas Perspect
21/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -21-
Police building in Sion
-
8/11/2019 7 Cas Perspect
22/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -22-
RC frame infilling
RC precast panels and post-tensioning
-
8/11/2019 7 Cas Perspect
23/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -23-
RC frame infilling
RC precast panels and post-tensioning
-
8/11/2019 7 Cas Perspect
24/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -24-
RC frame infilling
Static-cyclic tests
-
8/11/2019 7 Cas Perspect
25/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -25-
RC frame infilling: failure mode
-
8/11/2019 7 Cas Perspect
26/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -26-
Jacketing: deficient overlapping
-
8/11/2019 7 Cas Perspect
27/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -27-
Jacketing: RC bridge piles
-
8/11/2019 7 Cas Perspect
28/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -28-
Steel jacketing: RC bridge pile
Elliptic jacketing - rectangular pile
-
8/11/2019 7 Cas Perspect
29/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -29-
Jacketing: composites
Easy to apply, light, resistant, durable
-
8/11/2019 7 Cas Perspect
30/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -30-
Jacketing: composites
Failure of retrofitted RC column
Fragile failure of the jacket but
ductile behavior of the column
-
8/11/2019 7 Cas Perspect
31/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -31-
Unreinforced masonry very vulnerable
Failure modes
in-plane
Pay attention for out-of-plane
-
8/11/2019 7 Cas Perspect
32/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -32-
Unreinforced masonry buildings
Example in Yverdon
-
8/11/2019 7 Cas Perspect
33/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -33-
Prototype building tests
5 stories, 1:1, reinforced masonry
-
8/11/2019 7 Cas Perspect
34/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -34-
Masonry: conventional techniques
Reinforced plaster
Anchor 6mm
Welded mesh 4-6mm
@150 - 200 mm
Existing wall
Reinforced cement
coating
Welded mesh
4-6mm
250-400 mm
25-30 mm
250-400 mm
250-400 mm
25-30 mm
-
8/11/2019 7 Cas Perspect
35/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -35-
Masonry: conventional techniques
Shotcrete
-
8/11/2019 7 Cas Perspect
36/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -36-
Masonry: conventional techniques
Shotcrete: static-cyclic tests
-
8/11/2019 7 Cas Perspect
37/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -37-
Masonry: conventional techniques
Bracing and confinement (RC column)
14-16 mm
.c. tie-column
Existing masonry wall
Existing masonry wall
R.c. tie-column
14 -16 mm
240
1 1
Section 1-1
240
240
-
8/11/2019 7 Cas Perspect
38/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -38-
Masonry: conventional techniques
External or internal post-tensioning
-
8/11/2019 7 Cas Perspect
39/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -39-
Masonry: conventional techniques
Center-core
-
8/11/2019 7 Cas Perspect
40/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -40-
Composites: carbon fiber
-
8/11/2019 7 Cas Perspect
41/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -41-
Retrofitting: composites
On the twoinferior stories
-
8/11/2019 7 Cas Perspect
42/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -42-
Increase of ductility
Static-cyclic tests
-
8/11/2019 7 Cas Perspect
43/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -43-
Dynamic tests EPFL-ETHZ
-
8/11/2019 7 Cas Perspect
44/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -44-
Experimental results
-
8/11/2019 7 Cas Perspect
45/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -45-
Experimental results
-
8/11/2019 7 Cas Perspect
46/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -46-
Experimental results
-
8/11/2019 7 Cas Perspect
47/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -47-
Dynamic tests: test parameters
1. Aspect Ratio (0.7, 1.4)
2. Mortar Type
3. Material Type (glass, carbon, and aramid)
4. Fiber Product (fabric, grid, and plates)
5. Upgrading Configurations
Wall parameters
Strengthening materials
-
8/11/2019 7 Cas Perspect
48/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -48-
Experimental results
URM Long Specimen(L1-REFE)
32 kN
Upgraded Long Specimen(L1-WRAP-G-F)
65 kN
-
8/11/2019 7 Cas Perspect
49/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -49-
-20
Long URM(L1-REFE)
Long Upgraded(L1-WRAP-G-F)
Horizontal Displacement mm)
F
c
a
W
a
T
k
N
-80
-60
-40
20
40
60
-20 -15 -10 -5 5 10 15 20
0
0
Hysteresis curves: before and after
-
8/11/2019 7 Cas Perspect
50/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -50-
Sample Hysteretic Behavior
![mm]
-70
-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
70
-20 -15 -10 -5 0 5 10 15 20
F[kN]
L2-GRID-G-F
Test Run 19
UG1R 220%
-
8/11/2019 7 Cas Perspect
51/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -51-
Experimental results: lateral strength
0
0.5
1
1.5
2
2.5
3
3.5
HUpgraded/H
Reference
N=57 kN
L1-WRA
P-G-F
L2-GRID-G-F
L1-WRAP-G-X
!
=0.0
72%
!=0.068%
!
=0.0
28%
!
=0
.049%
S
1-LAMI-C-X
S1-WRAP-G-F
S2-WRAP-A-F
!=0.072% !=0.189%
"=?
-
8/11/2019 7 Cas Perspect
52/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -52-
Different FRP products and configurations
1. Long Walls
+Fabrics of
Glass FRP
+Grids of
Glass FRP
-
8/11/2019 7 Cas Perspect
53/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -53-
1. Long Walls (Cont.)
+Fabrics of Glass FRP
-Plates of Carbon FRP
Different FRP products and configurations
-
8/11/2019 7 Cas Perspect
54/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -54-
+Plates of
Carbon FRP
2. Short Walls
+Fabrics of
Glass FRP
Different FRP products and configurations
-
8/11/2019 7 Cas Perspect
55/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -55-
+Fabrics of
ARMID FRP
2. Short Walls (Cont.)
Different FRP products and configurations
-
8/11/2019 7 Cas Perspect
56/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -56-
L2-GRID-G-F L1-WRAP-G-FCompression FailureFRP Rupture
Failure Modes1.Masonry Compression &Tearing of the FRP
F il M d
-
8/11/2019 7 Cas Perspect
57/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -57-
Failure Modes2.Tearing of the FRP
-
8/11/2019 7 Cas Perspect
58/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -58-
Failure Modes3.Debonding and Anchorage Failure
-
8/11/2019 7 Cas Perspect
59/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -59-
Failure ModesNo Failure Was Reached
-
8/11/2019 7 Cas Perspect
60/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -60-
Anchorage Solutions1. Ductile Connection (Hamilton)
-
8/11/2019 7 Cas Perspect
61/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -61-
-
8/11/2019 7 Cas Perspect
62/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -62-
Masonry reinforced by composites
Master Bkir Omrovic, EPFL 2005
-
8/11/2019 7 Cas Perspect
63/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -63-
Masonry reinforced by composites
Without anchorage
-
8/11/2019 7 Cas Perspect
64/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -64-
Design
Shear
2FRPhFRPhFRP )E(!0.0104)E(!0.02050.0119# +$=Triantafillou 98:
F = Fm+ FFRP
FFRP= !hEFRP #eff
Fm= EC6
-
8/11/2019 7 Cas Perspect
65/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -65-
Design
Shear (part FFRPof composites)
Triantafillou andAntonopoulos
AC 125
-
8/11/2019 7 Cas Perspect
66/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -66-
Comparison with tests (ElGawady)
Shear
-
8/11/2019 7 Cas Perspect
67/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -67-
Design
Flexural strength (usual model)
-
8/11/2019 7 Cas Perspect
68/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -68-
Design
Flexural strength (usual model)
equilibrium:
neutral axis:
strength:
-
8/11/2019 7 Cas Perspect
69/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -69-
Comparison with tests (ElGawady)
Flexural strength
-
8/11/2019 7 Cas Perspect
70/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -70-
Model
Analytical (doctoral thesis ElGawady, 2004)
-
8/11/2019 7 Cas Perspect
71/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -71-
Masonry infill frames
Truss model (FEMA 356)
-
8/11/2019 7 Cas Perspect
72/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -72-
Masonry infill frames
Truss model (NZSEE 2002)
-
8/11/2019 7 Cas Perspect
73/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -73-
Masonry infill frames
Truss model (NZSEE 2002)
potential column shear
-
8/11/2019 7 Cas Perspect
74/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -74-
Masonry infill frames
Truss model (NZSEE 2002)
potential column shear
-
8/11/2019 7 Cas Perspect
75/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -75-
Masonry infill frames
Truss model (NZSEE 2002)
short column effect
-
8/11/2019 7 Cas Perspect
76/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -76-
Masonry infill frames
Truss model (FEMA 356)
opening considerations
NZSEE:
-
8/11/2019 7 Cas Perspect
77/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -77-
Lightly RC squat shear walls
Static-cyclic tests (doct. thesis Greifenhagen)
-
8/11/2019 7 Cas Perspect
78/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -78-
Lightly RC squat shear walls
Static-cyclic tests (doct. thesis Greifenhagen)
h ~ 0.003
v ~ 0.003
-
8/11/2019 7 Cas Perspect
79/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -79-
Lightly RC squat shear walls
Test program
-
8/11/2019 7 Cas Perspect
80/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -80-
Lightly RC squat shear walls
Specimen reinforcement
h=0.28%
v=0.31%
-
8/11/2019 7 Cas Perspect
81/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -81-
Lightly RC squat shear walls
Specimens after failure
M3
-
8/11/2019 7 Cas Perspect
82/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -82-
Lightly RC squat shear walls
Results (failure modes and crack pattern)
sliding shear slidingrebars failure rocking
concrete fail. crushingdiag. tension rebars fail.
wall M3 wall M4
wall M2wall M1
-
8/11/2019 7 Cas Perspect
83/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -83-
Lightly RC squat shear walls
Results (hysteretic curves)
-
8/11/2019 7 Cas Perspect
84/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -84-
Lightly RC squat shear walls
Diagonal tension failure: specimen M3
Ultim.
LS67
LS65
LS69Crack pattern M3
-
8/11/2019 7 Cas Perspect
85/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -85-
Lightly RC squat shear walls
Summary of test resultsShear capacity
Brittle shear failure is not observed.
Tests provide evidence for inherent shear strength of concrete.
Peak shear stress: 1.4 .. 1.9 N/mm^2
Dimensionless shear capacity:0.28 < c < 0.52
Deformation capacity Negative effect of lacking horizontal reinforcement not evidenced.
Flexural deformation dominates the plastic response.
Observed drifts: 0.90 .. 2.20%.
Low to moderate ductile behavior is observed (5.6 < %< 8.0).
Energy dissipation and stiffness
Dissipated energy nearly is equal to 70 % of introduced energy. Stiffness decreases by 80 % up to %= 1.0 and by 95% up to failure.
-
8/11/2019 7 Cas Perspect
86/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -86-
Example industrial building
Plane
-
8/11/2019 7 Cas Perspect
87/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -87-
Example industrial building
Cross-section
-
8/11/2019 7 Cas Perspect
88/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -88-
Example industrial building
Model
-
8/11/2019 7 Cas Perspect
89/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -89-
Example industrial building
Proposed
measure
-
8/11/2019 7 Cas Perspect
90/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -90-
Example bridge
Precast concrete bridge
-
8/11/2019 7 Cas Perspect
91/92
CIVIL-706 - retrofitting methods
EPFL-ENAC-SGC 2009 -91-
Example precast concrete bridge
Diag M- of interior piles
-
8/11/2019 7 Cas Perspect
92/92
Example precast concrete bridge
Transversal displacement-based evaluation
0
0.5
1
1.5
2
2.5
3
3.5
4
0 20 40 60 80 100
Sd [mm]
Sa[m/s
2]
2.0 Hz
0.50 Hz
0.75 Hz
1.0 Hz1.5 Hz
wr,d
wd