Vulnerability Studies and Transportation Resilience Planning for a Cascadia Event

Pacific Northwest Waterway’s Association - October 10, 2018 Bruce Johnson, Oregon DOT State Bridge Engineer Forces of Nature – Crustal Earthquakes in OR

Scotts Mills, March 25, 1993

Klamath Falls, September 20, 1993 Seismic Event Sources

► Crustal: 15-20 earthquakes each year with less than 3.0 magnitude. Potential for 5.0 to 6.0 magnitude. •Example: 1993 Scotts Mills and Klamath Falls - 5.6 to 6.0 magnitude.

► Intraplate: Deep earthquake within a Tectonic plate with up to 6.0 or 7.0 magnitude. •Example: 2009 Grants Pass - 4.1 magnitude

► Interplate or Subduction Zone: At eastern edge of the Juan de Fuca Plate, 8.0 to 9.0 magnitude. •Example: 1700 Oregon Coast - 8.3 magnitude. 3 Cascadia Subduction Earthquake Magnitude 9.0 Paradigm Shift Can we learn from other similar events or do we have to learn the hard way? Cascadia Subduction Earthquake . Strong Ground Shaking (M9 w/ 2 - 4 min shaking) . Tsunami within 15 to 25 minutes Cascadia Subduction Zone Earthquakes

Recurrence

Mw Mw Mw Mw ~9 8.5-8.8 8.5-8.3 7.6-8.4 500 430 yrs 320 yrs 240 yrs yrs

(Modified from Goldfinger et al. (in press) by adding magnitude estimates and some labels) What actually happens during a large earthquake? Synchronous turbidity currents are triggered within a few minutes of each other along the length of the margin

ASCE, 2012 Chris Goldfinger, OSU he Rogue Apron site is a typical margin site, fed by the Rogue Canyon with heads near the shelf dge. ASCE, 2012 Turbidite In Cascadia, onshore and offshore paleoseismology Paleoseismology: have revealed a long history of great earthquakes. Extending the earthquake record We set out in 1999 to prove the turbidite story wrong, and failed. Cascadia Core Sites: Cascadia Turbidite 1999 = gray Paleoseismology based on event correlation along 2002 = yellow strike. 2009 = green 1) Aerial extent Selected older 2) Synchroneity, and existing cores = 3) Sedimentology. white

Stratigraphic correlation, tests of synchronous triggering, and 14C ages have led to a credible (we think) record of 43 events of variable size and strike length during the Holocene.

ASCE, 2012

Northern Margin For the northern margin, probabilities are relatively low, many intervals longer than 360 years are in the paleoseismic record. The failure analysis suggests at 360 years, 25% of repeat times will have been exceeded. Conditional probability in 50 years is 12% (7-15%).

Southern Margin

For the southern margin, 70-93% of repeat times will have been exceeded. Conditional probability in 50 years is 37% (32-42%).

ASCE, 2012 Damage in the tsunami zone will be nearly complete.

PHOTO CREDIT: US PHOTO US CREDIT: NAVY M9 Tohoku earthquake & tsunami Modeled M9 tsunami at Rockaway Beach Severe ground movement in Western Oregon will cause widespread damage to lifelines and infrastructure. The Oregon Resilience Plan 50-year Comprehensive Plan

Save Lives

Protect our Economy

Preserve our Communities

169 Expert Volunteers

$ Millions in donation of professional services

 One-year Schedule Oregon Resilience Study - Four Study Zones The Oregon Resilience Plan

Required by the legislature, Transportation is supported by critical Governor

Comprehensive plan, developing a strategic approach Transportation Group

. Led by ODOT Bridge Section . The Transportation Task Group addressed these systems: Bridges (owned by ODOT, Counties or Cities) Airports and Seaports Railroads Mass Transit (Trimet) Columbia River Ports

Transportation Component – Broad Participation

• Ports: Portland, Astoria, Coos Bay • Federal Agency: USCG (Astoria) • Universities: OSU, PSU • Consultants: Ch2M Hill, HDR, KPFF, Quincy, OBEC • Local Governments: AOC, LOC, Western Cities and Counties • State Agencies: Transportation, Aviation, Forestry Concepts

Retrofit increases Strategic planning resiliency if is critical to success and will done require widespread incrementally & consensus strategically Secondary loss of life and long term economic losses can be significantly reduced Bridge Span Collapse Bridge Bent Failure The solution

RETROFIT Methods/Phases

For serviceability For life safety to to keep the bridge prevent collapse functional New & Retrofit Highway Bridge Seismic Design Criteria

“Life Safety” (no collapse) connects beams to the columns.

“Serviceability ” strengthens the substructure for use within 72 hours after an event. (Immediate occupancy, building code)

Hazard Level - Recurrence Interval for Highway Bridges

National Code (AASHTO) - Design for Life Safety (no collapse) at a 1000-year recurrence interval using USGS 2002 Hazard Maps.

Oregon Code – Design for “no collapse” at a 1000-year recurrence interval using 2014 USGS Hazard Maps and “Serviceability” Design for usability within 72 hours after a CSZ 2014 (USGS) Scenario event. (2-level design criteria)

Phase 1 & 2 Retrofit (no collapse)

Phase 1 Retrofit The goal of seismic retrofit is “life safety”

under the design earthquake Phase 1 & 2 Retrofit Cost 2 Retrofit & 1 Phase Phase 1 Retrofit 1 Cost Phase Retrofit Landslide Railroads 2012 Operational Airports After EQ-Tsunami – Valley Columbia River Ports & Dredged Nav. Channel Columbia River Ports Port of Portland Facilities Coastal Ports Damage to lifelines and interdependency will slow restoration of services and rebuilding of the economy. Key Finding – Liquid Fuel Dependency

• Liquid Fuel vulnerability is a key issue for transportation

ODOT Resiliency Planning

1. Assess Vulnerability of Assets • Bridges and landslides (rockfall) damage states 2. Estimate cost of mitigation (retrofit) 3. Establish priority of Lifelines (ETR’s for rescue, recovery) 4. Estimate impact to rescue efforts and economy 5. Prioritize plan for mitigation, considering condition of assets 6. Establish Investment options 7. Develop triage approach for reduced level of mobility 8. Coordinate investment plan statewide with other modes/sectors

FOCUS ON HIGHWAY BRIDGES Cascadia Subduction Zone Earthquake (Magnitude 9.0)

Estimates Loss: 6 complete collapses . $1,080 million for bridge repair and extensive 64 replacement 106 major Damage States . Significant Economic losses (travel time Route 164 slight related losses) 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

Total 164 106 64 6 I-5 BooneSlight Bridge IModerate-5 Marquam Bridge I-205Moderate Abernathy Bridge USExtensive 30 Bypass St. Johns Bridge I-405Moderate Fremont Bridge USCollapse 26 Ross Island Bridge Columbia River bridges USCollapse 30 Longview-Rainier Bridge ICollapse-5 Interstate Bridge Slight to

I-205Moderate Glenn Jackson Bridge Retrofitting progress First 16 years since vulnerability was identified

Years Actions

1994/1997 Prioritized total bridge needs 1155

1985-2012 Phase 1 retrofit added to projects 355 (STIP & OTIA III program) bridges addressed

Bridges still needing retrofitting Future 800 (Over 200 years at current funding) 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 Available on the ODOT Bridge Engineering Section website at:

http://egov.oregon.gov /ODOT/HWY/BRIDGE/

November 2009 • Identify strategic lifeline routes • Minimize long term economic

damage

• Estimate Cost to address overall bridge condition -Oregon Highway Seismic Options Report

Route selection

Survivability • Emergency responders • Critical care facilities

Life Support • Critical care facilities • Life support resources • Evacuation routes

Economic Recovery • Critical freight corridors • Mobility into and out of the region • Routes between large metro areas

Total Seismic PLUS Program Cost

Program Total Bridge Cost Landslides/Rockfalls Cost Total Seismic PLUS Phases Program Costs 1 $738 Million $197 Million $935 Million 2 $632 Million $272 Million $904 Million 3 $612 Million $483 Million $1,095 Million 4 $640 Million $126 Million $766 Million 5 $1,432 Million $0 $1,432 Million Total $4.1 Billion $1.0 Billion $5.1 Billion Major Seismic Event: Isolated Areas

Total economic loss: $350 B Isolated Zones: Full Seismic Program

Reduce economic loss by: $84 B Cost = $5.1 Billion Economic Loss Avoided = $84 Billion Take Home Learnings… Next Steps

Engage local Bridge communities condition – Bridge funding for Triage include seismic Approach

58 ODOT Seismic Expenditures In HB2017

Example: $500 million/yr from HB2017 State funds: $250 million Seismic: $61 million/yr (bridges, unstable slopes and facilities) • Goal is to complete Phase 1 in 25 years • Study Triage Approach using lower cost alternative local routes for Phases 2-5 • Earmarked funding for Southern Oregon Triage and Center Street Bridge in Salem ODOT Resiliency Planning

Thank you!

Bruce Johnson, State Bridge Engineer ODOT Bridge Engineering Section

Seismic Retrofit Methods

Older overpasses are Footings are New columns have vulnerable at their joints enlarged and continuous and columns, they need pilings driven ¾” steel to be retrofitted deep into spirals on to help them ground for 3” centers stand up to structures support a quake. built in vertical soft soil. rods.

Older concrete Old columns have columns are vertical rods and ½” Cable fitted with a steel hoops on 12” supports steel casing. centers. During a keep road quake the columns beds from A thin layer of collapse concrete grout separating at under joints and hold fills in gaps. lateral motion. bridge decks to columns.