Upload
phungtu
View
219
Download
4
Embed Size (px)
Citation preview
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 1 Scawthorn
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Repair and Reconstruction - Critical Issues
Charles Scawthorn, S.E., D.EngProfessor, Kyoto University
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 2 Scawthorn
Critical Issues
• Who• What• Where – siting issues• When• Why• How to rebuild - maps, materials, codes
• Who• What• Where • When• Why• How
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 3 Scawthorn
Siting Issues
• Faulting• Landslide• Liquefaction Undamaged Buildings next to fault, M7.4
Turkey, 1999
Faults not the biggest issueFaults not the biggest issue
Adapazari, heavily damaged by Liquefaction, M7.4 Turkey 1999
Landslide / Liquefaction – limits sites for rebuilding adds time and cost
Landslide / Liquefaction – limits sites for rebuilding adds time and cost
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 4 Scawthorn
Reconstruction?URM / PreCast Collapse
Photos: K. Miyamoto
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 5 Scawthorn
Seismicity of China 2300 BC present, M>5
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 6 Scawthorn
China Seismicity Record, by Era and Magnitude
75% recorded since 1900M > 7
75% recorded since 1900M > 7
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 7 Scawthorn
PGA, 10% probability of exceedance in 50 years (Units are in g)
2001 National Seismic Zoning map of China
Substantial uncertainty in zoning map
Wenchuan zoning needs to be increased (a lot)
Substantial uncertainty in zoning map
Wenchuan zoning needs to be increased (a lot)
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 8 Scawthorn
Earthquake “Performance”Chinese Building Code philosophylike US, Japanese European codes:
1. Minor earthquake: no damage2. Design level earthquake: damage but no loss of life3. Strongest earthquake expected at the site without
total collapse, but potentially with extreme damage
Codes protect life, not damageDamage accepted in the design, to dissipate energy
With Vision 2000, codes shifting to Performance Basis
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 9 Scawthorn
China Building Code – Earthquake Design
<1957 Soviet code, but not much used1974 TJ11-74
1978 Revised (Tangshan earthquake) TJ11-78.
1989 Seismic Design Code for Buildings. GBJ- 11-89
1991 Tall Bldgs: Regulation on the Design and Construction of Tall Reinforced Concrete Buildings JGJ-3-91
2001 National Standards of the People's Republic of China, Code for Seismic Design of Buildings (GB50011-2001)
2008 Current code? Zonation? Compliance?
(Shuping 1993)
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 10 Scawthorn
Engineered Building Reconstruction
PreCast combined with URM
NON-Ductile Reinforced Concrete
Photos: K. Miyamoto
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 11 Scawthorn
NON-ductile
DUCTILE
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 12 Scawthorn
Engineered Building Reconstruction
Assuming modern standards are to be met, many damaged buildings are going to be uneconomical to repair.
Photo: XIAO
YanNon-Ductile detailing, 2008 Wenchuan Earthquake
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 13 Scawthorn
SchoolsCalifornia
• 1933 Earthquake Field Actschools special design review
• last 75 years, no school collapse or loss of life.
• State-wide review in 2000 14% vulnerable:
Assumed OK
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 14 Scawthorn
Seismic Rehabilitation Costs
Seismic Rehabilitation cost approximately $620,000 / building (C¥ 780,000 / building based on PPP ratio)
Seismic Rehabilitation cost approximately $620,000 / building (C¥ 780,000 / building based on PPP ratio)
Retrofitted schoolNiigata, Japan
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 15 Scawthorn
Non-Engineered Buildings
Earth or stone rubble walls, Earth roof
Brick (or stone) wallsRCC roof
Brick walls, Tin roofRCC Frame, Tin Roof
Figs. © C. Scawtorn, 2004
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 16 Scawthorn
Earth or stone rubble walls, Earth roof
Brick (or stone) wallsRCC roof
Brick walls, Tin roofRCC FrameFigs. © C. Scawtorn, 2004
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 17 Scawthorn
Confined MasonryTechnology
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 18 Scawthorn
Non-engineered BuildingsNon-engineered buildings will be built back the same unless:
• Owners are educated
• Builders and Craftsman are trained
• Achieve Code complianceby institutions for Code enforcement
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 19 Scawthorn
Non-engineered Buildings – Improving Quality
World Bank sponsored project
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 20 Scawthorn
All ChinaDue to underzoning… parts of China … many high riskbuildings / infrastructure.
Need: Major program to:
• New seismic zonation
• Identify hazardous buildings
• Long-term retrofitting program
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 21 Scawthorn
SummaryIF we’re not to rebuild the next disaster – that is, if we seek to meet modern standards, then:
• Siting in the steep terrain areas is going to be a major, time consuming problem, requiring detailed geotechnical investigations
• Repair: many damaged buildings will be found to be uneconomical to reconstruct –the losses will be higher than currently estimated.
• Reconstruction:
• Engineered structures – will be rebuilt at a significantly higher standard than what they replaced. This will add 5-30% to cost
• Document engineering and scientific lessons to be learned
• Non-engineered structures, especially rural housing, will need special education, training and advisory programs (such as in Pakistan)
• Longer-Term: a National Earthquake (Natural Hazards!) Mitigation Programneeds to be developed, to address Earthquake, Flood, Typhoon…
Government of China & the World Bank GroupEarthquake Recovery and Reconstruction: International Experience and Best Practice
June 12, 2008, Beijing
Seismic Resistant Reconstruction – Critical Issues 22 Scawthorn
Thank you
Charles Scawthorn