Transcript Seismic Bridge Design in Oregon

Highway Mobility After a CSZ Event & Mitigation
OSU CSZ Workshop
Bruce Johnson- July 18, 2012
ODOT Seismic Mitigation Efforts
1990 – Design for seismic loads considering
Cascadia Subduction Zone
1994/1997 – Assessment of vulnerability of
existing bridges
1997 – Begin including “life-safety” retrofit of
bridges in repair contracts
1997 – Lifeline routes identified
2007 – Network analysis of seismic vulnerability
2012 – Update to lifeline routes
2012 – Prepare Seismic Options Report
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Seismic Bridge Design in Oregon
adopt FHWA 2009 LRFD Seismic Design Guide Specs
adopt USGS 2002 seismic hazard maps
seismic hazard maps and adoption of FHWA ‘83 seismic design specs.
seismic force up to 12%g
seismic force up to 6%g
Seismic loads typ.
not considered
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Southern Cascadia Subduction Zone (CSZ)
Events have a 260-year frequency
HISTORY OF SEISMIC RISK IN OREGON
Seismic Strain (Risk)
Last Known Subduction Event:
January, 1700
Past Subduction
Zone Earthquakes
0
Frequency
1000
When will
the strain
release next?
1700
300 to 500 years
Time
2000
 Scientist’s most recent
estimates found 41
earthquakes over 8.0
magnitude
 Last event January 26,
1700
 There is a high
probability of a major
event within the next 50
years on the south
Oregon Coast.
Goldfinger, et al, OSU
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Earthquake Simulation Tool
Model of Oregon Highways
Scope of study:
 State owned
bridges
 Hwy. network:
Western Oregon,
Klamath Falls,
and the Columbia
River Gorge
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Estimating Damage and Mobility Impacts
for Likely Earthquakes
REDARS Seismic Simulation Computer Program
Six earthquake scenarios were used to estimate seismic
losses. Two are shown as examples:
Cascadia Subduction Zone: 9.0 magnitude earthquake
Estimated damage: $1.08 billion
Plus Significant Economic losses
Crustal: Portland Metro 7.0 magnitude earthquake
Estimated damage: $1.58 billion
Plus Significant Economic losses
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Cascadia Subduction Zone Earthquake
(Magnitude 9.0)
6
64
106
164
complete collapses
extensive
major
slight
Estimates Loss:
 $1,080 million for bridge repair and
replacement
 Significant Economic losses (travel time
related losses)
Damage States
Route
Slight
Moderate
Extensive
Complete
I-5 (MWC)
4
1
0
0
I-5 (MLL)
16
3
1
0
I-5 (DJJ)
27
0
0
0
I-84
13
1
0
0
US-101
7
14
36
5
US-26
7
5
0
0
I-205
8
2
0
0
I-405
7
0
0
0
US-30
4
2
2
0
US-20
5
3
5
0
OR-38
3
2
1
0
OR-42
4
13
13
1
Others
59
60
6
0
164
106
64
6
Total
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Seismic Risks
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A large damaging earthquake is likely to
occur in the next 50 years
Widespread major damage is expected with
loss of life, loss of utilities, and loss of
mobility in western Oregon
Secondary losses will be significant due to
lack of mobility by highways, waterways,
ports, and airports for fixed wing aircraft
Major economic distress will occur due to
relocation of businesses due to loss of
mobility and services
Solutions:
1. Retrofit existing bridges
2. Replace aging bridges
3. Prepare for recovery from damage and loss of mobility
Retrofit:
Phase 1 for “life safety” connects superstructure to the
substructure.
Phase 2 for “serviceability” strengthens the substructure
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Retrofitting Critical Bridges
to Reduce Major Mobility Risks
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Seismic Retrofit Methods
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Retrofitting Progress
First 16 Years Since Vulnerability was Identified
Years
Actions
1994/1997
CH2M Hill prioritization includes all state and local
bridges. Priority state bridges
1155
1994-2010
• Phase 1 retrofit added to repair projects
In the OTIA III program
• Replacements with seismic design
In the OTIA III program
Total number of bridges addressed
Future
Bridges still need retrofitting (219 years)
887
Delay due to OTIA III payback for 20 years.
72
6
40
150
268
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More Rational Prioritization
Potential route retrofit selection strategy
based on “cost vs. benefit”
 Estimate retrofit cost of considered routes
 Estimate benefit by altering bridge fragility and
reexamining impact on system
 Consider revised lifeline routes in prioritization
 Consider landslide and unstable slopes in
prioritization
 Refine retrofitting cost estimates
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Oregon Lifeline Routes Study
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Ch2M Hill
July 2011 Start
Focus on State Routes
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•
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Status:
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•
•
•
Response (life safety)
Recovery and rebuilding
Vulnerability assessments drafted
Prioritization algorithm drafted
Route selection early draft
June 2012 Final Report
Oregon Lifeline Routes Study
Tier 1 North South Routes:
• I-5
• I-405 to I-205
• I-205 to OR 58
• OR 58 to CA Border
• US 197/97
• US 197 from I-84 to US 97
• US 97 from US 197 to CA Border
• US 101
• Tillamook to Newport
• Florence to Coos Bay
Oregon Lifeline Routes Study
Tier 1 East-West Route (East):
• I-84 / I-205
• I-5 to US 197
• US 26
• I-84 to US 97
• OR 58
• I-5 to US 97
Tier 2 East-West Route (West):
• US 30
• US 101 to I-405
• OR 18/US99W
• I-5 to US 101
• OR 38
• I-5 to US 101
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•
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Protect citizens and businesses from
shaking and tsunami
Ensure rapid economic recovery
The Plan and recommendations to be
delivered to the Oregon Legislative
Assembly by February 28, 2013.
Seismic Options
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•
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Retrofit is a proven method to preserve bridges,
slopes, and landslides on the highway system
Retrofit is viable if done incrementally and
strategically on the highest priority routes
Significant reduction in secondary loss of life
and long term economic losses can be achieved
Route selection is critical to success and will
require widespread consensus
Tier 1 Route Map
•Phase 1 – $320M
•Phase 2 - $395M
Tier 1 Routes – Retrofit Cost
Tier 2 & 3 Route Map
•Tier 2 – $515M
•Tier 3 - $250M
Tier 2 Retrofit Cost
Tier 3 Retrofit Cost
Goal of Seismic Options:
Establish Priorities for
Achieving High Priority
Resiliency Within
Limited Retrofit Funding
ODOT Bridge Engineering and
Geo-Environmental Sections and
Planning Division
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Seismic Vulnerability of Oregon State
Bridges – Recommendations
Action that needs broad support and additional
funding to accomplish:
Develop a long-term strategy for mitigation of seismic
vulnerability and risk for entire highway system including
bridges, landslides, local roads, and critical facility access to
support a dedicated seismic retrofitting program for critical
transportation features.
House Resolution 3 – Resilient Oregon Plan due Feb 28, 2013
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•
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Protect citizens and businesses from
shaking and tsunami
Ensure rapid economic recovery
House Resolution 3
Directs (OSSPAC) to “lead and coordinate
preparation of an Oregon Resilience Plan that .
. . makes recommendations on policy direction
to protect lives and keep commerce flowing
during and after a Cascadia (megathrust)
earthquake and tsunami.”
The Plan and recommendations to be delivered to
the Oregon Legislative Assembly by February
28, 2013.
HR3 Resilience Definition
Protect Citizens from physical life-threatening
harm (from Earthquake and Tsunami)
Community recover rapidly with less
vulnerability through mitigation and predisaster planning
Cascadia Earthquake is M9.0 with average
500 years return.
HR 3 Resilience Definition
To Achieve Rapid Recovery, Require
Government Continuity, Resilient Physical
Infrastructure, Business Continuity
Resilient Physical Infrastructure is the
foundation
Resilience Planning Objective
Look at 50-year time window
Develop a comprehensive plan so that state is
resilient by 2062
Utilize concepts and ideas by SF Planning
+Urban Research Association and from
Resilient Washington Initative
Performance Goals for the
“Expected” Earthquake
Phase
Time Frame
Condition of the built environment
I
1 to 7 days
Initial response and staging for
reconstruction
II
7 to 60 days
Workforce housing restored –
ongoing social needs met
III
2 to 36 months Long term reconstruction
Lifelines and workforce are the key elements
Transparent Performance Measures
for Lifelines
Category
Performance Standard
Category I
Resume 100% service within 4 hours
Category II
Resume 90% service within 72 hours
95% within 30 days
100% within 4 months
Category III
Resume 90% service within 72 hours
95% within 30 days
100% within 3 years
Oregon Resilience Planning
Organizational Structure
OSSPAC
18 members appointed by Governor
Six representatives of government (Bldg Codes, DOGAMI, DLCD, OEM,
ODOT, DOE)
Six representatives of public interest (Legislature, Red Cross etc.)
Six representatives of industry and stakeholders (Struct., Banking, local
govern., multi-family, Bldg Owner, Utilities)
The mission of OSSPAC is to increase or improve:
1) earthquake awareness, education and preparedness;
2) earthquake risk information;
3) the earthquake safety of buildings and lifelines;
4) geoscience and technical information; and
5) emergency pre-disaster planning, response and
recovery efforts
http://www.oregon.gov/OMD/OEM/osspac/osspac.shtml
OSSPAC Steering Committee
Kent Yu (Chair, Public member/Structural)
Jay Wilson (vice Chair, Public member/local government)
Althea Rizzo (OEM, State Earthquake/Tsunami Manager)
Ian Madin (DOGAMI)
Stan Watters (Public member/Utilities)
Eight Workgroups
Magnitude 9.0 Earthquake/Tsunami Scenario
Critical/Essential Buildings
Energy
Telecommunications
Transportation
Tsunami Risk Mitigation
Water and Waste Water Systems
Business Continuity
Transportation Group
Led by Bruce Johnson (ODOT)
The Transportation Task Group will address the systems listed below:
Bridges (owned by ODOT, Counties or Cities)
Airports and Seaports
Railroads
Mass Transit (Trimet)
Columbia River
Work Plan
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April - Determine Resiliency Goals
May – Identify Vulnerabilities
August – Develop Mitigation/Strengthening
costs
September – Assess Mitigation Plan/Goals
October – Prioritize Investment Plan
November – Establish 50-year Funding
Plan to achieve resiliency and submit to
Steering Committee
Continuing Research Activities
Research is needed on the following
topics:
 Impacts of a large seismic event on the Oregon
transportation network for use in prioritization
 Evaluate bridges based on Oregon bridge types
 Evaluate and update vulnerability for typical
Oregon type bridge columns
 Cost/Benefit Analysis of Retrofitting
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Goal of Seismic Efforts:
Establish Priorities for
Limited Resiliency
And Retrofit $$
Bruce Johnson, State Bridge Engineer
ODOT Bridge Engineering Section
REDARS Research conducted by:
Peter Dusicka, Assistant Professor
Portland State University
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METRO Bridges
Bridge Name
I-5 Boone Bridge
I-5 Marquam
I-5 Interstate
I-5 Oregon Slough
I-205 Abernethey
I-205 Glen Jackson
I-205 South Channel
US30 Bypass St. Johns
I-405 Fremont
I-405 Fremont approach
US26 Ross Island
Sellwood, Hawthorne
Steel, Broadway
Morrison, Burnside
I
Expected Performance Notes
Slight Damage
Retrofitted Ph 1
Moderate
Retrofitted Ph 1
Collapse
Poor details, counterweight
Moderate
Poor girder connections
Moderate
Poor column confinement
Slight to moderate
Slight
Extensive
Poor column details
Moderate
Poor column details
Collapse
Poor column details
Collapse
Poor column details
Collapse
Collapse
Extensive