Recent Advances on the Increase of Resilience and Sustainability of School Infrastructure
,
1
Seismic Retrofitting Program of School Buildings in Taiwan
DirectorNational Center for Research on Earthquake Engineering
ProfessorNational Taiwan University
Shyh-Jiann Hwang
February 24, 2021
• Established at National Taiwan University in 1990• Mission:
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x Pre-quake preparation – Disaster preventionx Emergency response – Disaster reductionx Post-quake recovery – Disaster relief
Introduction of NCREE
Outlines
• Introduction• Evaluation and Retrofitting
Technologies• School Retrofitting Program• Residential Building Program• Conclusion
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Vulnerability of School Buildings
5
Taiwan 1999 Chi-Chi EQ
Mexico 1985 Mexico City EQ
Collapse of school buildings
0 1 2 3 4 5 6 7RF Drift Ratio(%)
0
500
1000
1500
2000
2500
3000
3500
Base
She
ar (k
N)
P.T. Retrofit Specimen Benchmark Specimen
1444
2985 at Roof Drift Ratio 0.98%
at Roof Drift Ratio 0.86%
Effectiveness of PT-Rod RetrofittingIn-situ school testing, Tainan, Taiwan (2007)
Simple Survey (2009-2011)
Field investigation: • 3,721 public schools25,843 buildings
• 228 college students4,426 days per person
School building included:• Buildings constructed before 1999
• Buildings occupied by students or teachers
fA6
CAWA
Total Floor Area above 1st Floor
1st Floor Capacity
Seismic Index:fg
WWCCAwaAA
DemandCapacity
6WWuu�
fA6Demand
Capacity CA WA
Preliminary Evaluation
11
Nonlinear Static AnalysisCapacity Spectrum
AnalysisPushover Analysis
Performance-Target Ground Acceleration Ap
Ap
13
Modeling of Vertical Members
14
V
ΔΔs
Vmn
ΔaΔe,mn
V
ΔΔn Δa
Vn
Vcr
Δcr
ShearPlastic Hinge
Flexural Plastic Hinge
Well known
In dispute
Shear critical column: low f’c, less transverse reinforcement
Static Test
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Research on Seismic Capacity of Members
Shaking Table TestStatic Test
Columns WallColumn
-10 -5 0 5 10-800
-400
0
400
800
3DL
側力強度
(kN)
層間位移角(%)
實驗值分析值
Collapse Behavior of RC Column
1001
fAN
401
f401"4
1003
H cg
u
cn
tc
�c
X�U�
Elwood & Moehle (Spectra 2005; ACI 2005)
� �
¸¸¹
·¨¨©
§
T�T
T�
tandfAsNtan
tan1100
4H
cytstu
2
n
sΔ
aΔ
'
uV
0
V
u'sΔ aΔ
v
Nu
Flexural Shear
Shaking Table Tests for Column Collapse Behavior
18Yavari et al. (2010)
sΔ
bV
y'
V
'0
yV
n' aΔ蘇瑞翔等人(2007)
吳俊霖等人(2009)
Experimental Verification of Shear Strength
19
test nV V
)(MPafcc
AVG = 1.20COV = 0.10
1.180.18
1.240.08
1.270.22
33 29 11 86 60
1.150.14
RC
'Displacement
V
'
V
Short Column Shear Wall Typical Column
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'
V
'
Shea
r St
reng
th
Displacement
V
Wall with Opening
Backbone Curves for Shear Critical Members
Softened Strut-and-Tie Model
Hua-Lien (2005) Yun-Lin (2005)
Tao-Yuan (2006) Tainan (2007)
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-4 -2 0 2 4Story Drift (%)
-1500
-1000
-500
0
500
1000
1500
Base
She
ar (k
N)
In-Situ Tests of School Buildings –Verification of Pushover Analysis
RC Wing Wall (2005) Composite Column (2006)
Steel Jacketing (2007)RC Jacketing (2007)
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In-Situ Tests of School Buildings –Verification of Retrofitting Methods
� Basic Methodology from ATC-13
Structural Properties
Plan, Dimensions, Section details,
Material strength, Soil condition
Seismic Magnitude
Damaged Conditions
Site PGA,Longitudinal PGA for individual building
Damage records,Definition of "damage"
Chi-Chi Earthquake Damage Database of School Buildings in Taiwan
NCREE-07-023Tu et al.
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Verification of Acceptance Criteria (35 Buildings)
0
0.5
1
1.5
2
Safe
Unsafe
CapacityDemand
Collapse Heavy Medium Small Slight
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CDR=
Strategy for School Upgrading in Taiwan
Census
Evaluation
Design and
Construction
Dat
abas
eco
llect
ed b
y in
tern
et
Field Investigation
PreliminaryEvaluation
Detail Evaluation
Peer Review
Retrofit Design
RetrofitConstruction
Rebuild
Maintenance
Maintenance
Peer Review
Inspection
Safe
Unsafe
Safe
Unsafe
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Unification of Process
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• Complex Parties: governmental official, school teacher, engineer, constructor,student, parent
• Tight Schedule: annual budget, short construction period
• Unification Document: operation specification,contract document, design manual
Budget Control - Service Payment
New Construction
SeismicRetrofitting
Design Payment = Rate u Construction Fee
Design Payment = Rate u Floor Area
Innovation forQuality
Payment perQuantity
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Budget Control - Economic Methods
RC Column Jacketing RC Wing Wall RC Shear Wall
Isolated Device DamperSeismic Devices with Patents Ö Prohibited
Traditional Retrofitting Method Ö Encouraged
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Quality Control - Review and Inspection• Peer Review for Design
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School Staff
Constructor
Engineer
School Staff
Engineer
3 Reviewers
Budget Saving
32%100%
68%
• Inspection for Construction
Quality Control - Workshops• Workshops for Engineers, School Administrators,
Educational Officials
• Case Study
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Website and Database
https://school.ncree.org.tw
Database
• Data Collecting• News Announcement• Download Service• Exchange of Information
• Process monitoring• Decision making
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Epicenter
Junior High S.No retrofitting30km from epicenter
Vocational S.Retrofitted31km from epicenter
Kaohsiung Jia-Xian EQML = 6.4, March 4, 2010Retrofitting Effectiveness
Wing Wall
RC Wall 38
Cost of School Retrofitting in Taiwan
2
2
Retrofitting fee NT$ 2,250 /mActual Cost: = = Rebuilt fee NT$ 22,000 /m
10%
10%
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Census
Evaluation
Retrofitting
Under processing
Design
Data deadline: 2020.03.31
School Buildings Upgrading Projects
x Project span from 2009 to 2022x Upgrading rate by construction up to 37%
Build
ing
No.
27,241
17,780
10,353
1,328
8,710
0
5000
10000
15000
20000
25000
30000
Census Evaluation Design Retrofitting
Earthquake Damages of Buildings with Soft and Weak First Story
11‐story Hotel2018 Hualien EQ
14‐story Condominium2016 Meinong EQ
12‐story Condominium2018 Hualien EQ
Characteristics of Damaged Buildings
• Older RC building
• Soft and weak first story
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Source : DEGENKOLB RECONNAISANCE TEAM2016 MEINONG TAIWAN EARTHQUAKE DEBRIEF
Interim Seismic Retrofit
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Building with soft first story
Removal of seismic deficiency
Prevent Building Collapse Immediately during Earthquake
City Building type Process Method
Tainan7-story
Condominium + 1F market
Open bidding Addition of external frames
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Interim Retrofitting Case – External Frames
Features of Project• Field investigation• Advanced evaluation method• Screen and prioritization• Unified procedure• Budget and quality control• Website and database
NCREE
LocalGovernments
CentralGovernment
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Technology
Administration
Compulsory
Monitoring
Acknowledgementz Ministry of Education (MOE)z Ministry of Science and Technology (MOST)z National Applied Research Laboratories
(NARLabs)z Schools of Cheng Junior High, Kou-Hu
Elementary, Ruei-Pu Elementary and Guan-Miao Elementary
z County Governments of Hualien, Yunlin, Taoyuan and Tainan
z Universities of NTU, NTUST, NYUST, NCKU, NKFUST, NCTU, etc.
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