How would Portland-area bridges fare in a magnitude 8 or 9 Cascadia Subduction Zone earthquake?

Based on various government reports, here’s a summary:

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Broadway Bridge: Collapse

Bridge could fall from its supports. Piers and columns could fail.

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Burnside Bridge: Extensive Damage

Bridge could fall from supports. Piers and columns could fail.

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Fremont Bridge: Moderate Damage

Fairly resistant due to design style. Approaches could collapse.

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Glenn Jackson Bridge: Moderate Damage

Built very close to current code. Designed for seismic activity.

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Hawthorne Bridge: Collapse

Deck surface could slide off pier. Counterweights create risk.

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Interstate Bridges: Collapse

Counterweights make this bridge vulnerable. Approaches could fail due to liquefaction.

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Marquam Bridge: Moderate Damage

Cables and restraints help tether deck to columns. Liquefaction could put approaches at risk.

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Morrison Bridge: Extensive Damage

Could have column failure. Approaches are at risk.

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Ross Island Bridge: Collapse

Highly vulnerable to shaking. Won’t flex, likely to crumble.

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Sauvie Island Bridge: Minor Damage

Constructed in 2008 under modern seismic design requirements.

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Sellwood Bridge: Minor Damage

Built to high standards for seismic resiliency.

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St. Johns Bridge: Extensive Damage

Approaches are very vulnerable to major damage or collapse.

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Steel Bridge: Collapse

Counterweights and design put this bridge at great risk.

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Tilikum Crossing: Minor Damage

Built to high standards for seismic resiliency.