Briefing on the Chile Earthquake of February 27, 2010 - Scott A. Ashford Professor and Head School of Civil and Construction Engineering Oregon ...
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Briefing on the Chile Earthquake of February 27, 2010 Scott A. Ashford Professor and Head School of Civil and Construction Engineering Oregon State University
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December 20, 2010
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Talca (AP Photo)
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Concepcion (AP Photo)
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Santiago (AP PHOTO/Carlos Espinoza)
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Pelluhue (AP Photo)
Pacific “Ring of Fire” 9 December 20, 2010 ORWARN
Comparison of Haiti Chile
and Chile earthquakes
• Haiti was:
• Magnitude 7.0
• Shallow Strike-Slip under
urban area
• Vulnerable infrastructure Haiti
• Chile was:
• Magnitude 8.8
• Subduction Zone EQ
covering huge area
• Over 500 more powerful
• Last 6 times as long
• Less vulnerable infrastructure
10 Finite fault models by Gavin Hayes, USGS
December 20, 2010
National Earthquake Information Center
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Ruta 5
200 mi
Bridge Team Members
Valparaíso
Mark Yashinsky, Team Leader
Santiago
•Caltrans
Nazca Plate
Rodrigo Oviedo
•Universidad Catolica de Chile
Scott Ashford
•Oregon State University Talca
Luis Fargier-Gabaldon
•Universidad de los Andes, Merida.
Matias Hube
•Universidad Catolica de Chile
Traveled over 2000
South km
America from Santiago
Plate
to Temuco and back over 5 days
Temuco
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December 20, 2010
ORWARN Ruta 5Temporary shoring shear key of the beam
Vertical axis
Rotation or
twisting of
the deck
Lateral
displacement
De c k
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AbutmentSeismic bars
Failed shear Undamaged
key shear key
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December 20, 2010
ORWARNTubul Bridge
Eight span simply supported
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steel girders on pier walls.
December 20, 2010
Collapsed attributed to
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unseating of beams17 December 20, 2010 ORWARN
Summary of Observations on Bridges
Structures with less continuity generally suffered more damage or
collapse
• Diaphragms, larger shear keys, continuous spans, wide seats
seemed to improve the seismic performance of the observed
structures.
Localized damage suggests the importance of local site effects
(soil/topography or directivity).
Significant liquefaction and lateral spreading was observed in
Concepcion and along coast which adversely impacted the
performance of bridges.
Widespread fill settlement was easily repairs, but adversely
affected traffic.
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December 20, 2010
ORWARNHow did buildings perform?
Considering only buildings between 1985 to 2009
• Buildings that collapsed: 4 (app.)
• Buildings to be demolished: 50 (estimate)
• Number of buildings 3 + story: 9,974
• Number of buildings 9 + story 1,939
• Failures 3 + story buildings: 0.5%
• Failures 9 + story buildings: 2.8%
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ORWARN21 December 20, 2010 Santiago ORWARN
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Santiago23 December 20, 2010 Santiago ORWARN
Summary: Majority of engineered buildings performed well Structural damage to attributed to •Earthquake demands above code levels •Slender walls with high axial stress •Absence of confinement reinforcement •In some cases, vertical irregularities •(Unconfined lap splices in walls) 24 December 20, 2010 ORWARN
Nonstructural components
Similarly to U.S. practice, code
requirements for design and anchoring
nonstructural components are not
always enforced
With few exceptions, practice for
seismic anchoring of nonstructural
components considerably lags practice
for structural components.
The state of practice for seismic
anchoring of nonstructural components
appears to be in worse situation than
common practices in the western U.S.
Many observed failures of anchors,
hangers, and bracings similar to those
currently used in the U.S.
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December 20, 2010
ORWARNOverall performance of
Public Health Hospital System according to
Ministry of Health Website
Total in shaken region: 100
17 to be completely rebuilt
8 with major damage
54 requiring minor repair
21 apparently undamaged
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March 30, 201027 December 20, 2010 ORWARN
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Key findings identified issues known to affect patient safety or functionality • Communications • The need for evacuations • Elevators • Loss of power • Loss of water • Water damage • Loss of bulk oxygen tanks • General disruption from ceiling and wall damage • Disruption to fragile areas • Paper medical records, pharmacies, and laboratories • Damage to medical equipment 29 December 20, 2010 ORWARN
Tsunami • Major tsunami for 500km of Chilean coastline • Maximum inundation 11m • Maximum run-up 30m • Loss of life limited thanks to local awareness and good signing • Most tsunami-related deaths from tourists 30 December 20, 2010 ORWARN
1500 homes destroyed in Dichato from tsunami; only 17 residents killed 31 December 20, 2010 ORWARN
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Summary of other Lifeline Performance
• Electric Power
• Immediate blackout to 90% of Chile’s population
• Transmission capability to provide power within 24 hours
• Distribution system service restored with two weeks
• Telecommunication
• Both landlines and wireless service serverely affected
• Most cell sites ran out of battery power within 3 hours of quakes,
eliminating communications with repair crews and hospitals
• Most services restored within seven days
• Water and Wastewater severely impacted along coast
• Personnel shortages avoided by supplying food/water
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ORWARNOverall, Chile performed pretty well • “Only” 500 people were killed • Over 200 bridges damaged, 50 collapsed • Over 80,000 dwelling units destroyed • Over 50 mid-rise buildings severely damaged, 4 collapsed • Black-out affected 90% of population • Most telecommunication systems shut-down within hours of earthquake due to loss of power • Problems with water, sewer, ports, and other lifelines • Interdependence of lifelines was major factor 35 December 20, 2010 ORWARN
Vancouver
Ruta 5
200 mi
North America Plate
I-5 Valparaíso
Cascadia Subduction Zone
Santiago
Seattle Nazca Plate
Washington
Juan de Fuca Plate
Talca
Portland
Salem
Corvallis
Oregon
South America Plate
Pacific
Plate Temuco
Medford
Ruta 5
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Gorda
December 20, 2010Plate
ORWARN Redding
200 mi
I-5What are the implications for Oregon?
• 2010 Chile Earthquake • Future CSZ Earthquake
• Peru-Chile Subduction Zone • Cascadia Subduction Zone
• Magnitude 8.8 • Magnitude 9.0
• Shaking and Tsunami • Shaking and Tsunami
• Modern Building Codes • Modern Building Codes
• $30B damages • Damages estimated at $30B*
• About 500 dead • Estimated up to 5000 dead*
• 7 EQ M=8.0+ in past 100 yrs • No M=7.0 is past 100 years
• Last M=8.0 in 1995 • Last M=9.0 in 1700
• Occur about every 15 yrs • Occur about every 300 yrs
*Source: DOGAMI 2010
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December 20, 2010
ORWARNThree major earthquakes in 2010: Haiti, Chile, Darfield • 7.1M Darfield Earthquake occurred on Sept. 4, 2010. • Christchurch, New Zealand, with population of 400,000. • Region of high seismic hazard. • Effort to increase resilience of lifelines started in 1990’s, focusing on interdependence and critical infrastructure • The Kiwi’s did very well • No deaths • But several miles of water and sewer mains were damaged. • One years worth of repairs in 6 days • After two weeks, still 40% of sewage dumping into river 38 December 20, 2010 ORWARN
Examples from Japan and New Zealand 39 December 20, 2010 ORWARN
What have we learned?
What can we do?
1. The 2010 Chile Earthquake was Oregon’s earthquake.
We are due for a magnitude 8.5 to 9.0 earthquake along the
Cascadia Subduction Zone.
2. We are less prepared.
Chile is “fortunate” to have so many earthquakes.
There is not a structure in Oregon that felt the last big earthquake.
3. We must start improving our lifeline resilience.
A resilient utility network is critical for Oregon to “bounce back.”
OSU is working with ODOT and other lifelines to improve resilience.
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December 20, 2010
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