Finding the payoff in reducing risks

Northwest Hydropower AssociationFebruary 2013

Bill Christman, PEEngineering Services managerChelan County PUDWenatchee, WA

Earthquake

Cyprus Street Viaduct – Loma Prieta earthquake

Lack of anti-burst wrapping

Lack of connection between upper and lower vertical elements

Hurricane

Flooding in New York from Hurricane Sandy

Buildings in known flood zone – mapped before the storm

Dam failure

Sayano-Shushenskaya Hydro-electric Dam, Russia - 2009

Missing head cover bolts(known)

41 of 49 bolts recovered had fatigue cracks

10 years of increasingmachine vibration

Stadium collapse

University of Washington - 1987

Sequencing oversight in demolition – “tiny” wires removed too soon

Bridge collapse

Tacoma Narrows Bridge - 1940

Budget problems

Known weaknesses

Bridge collapse

I-35W Bridge in Minneapolis, Minn. - 2007

Shop drawing gusset plate omission

New load w/o verifyingdemand/capacity ratio

Bridge collapse

Lacey V. Murrow Floating Bridgeacross Lake Washington – 1960, above, and today, right.

Manhole coversleft open

Big storm causes internal flooding

Sound practice

Rocky Reach Dam, Columbia River, WA

Post-Folsom spill gate risk reduction:

Monitoring and good response to spill gate bearing wear

Sound practice

Rock Island Dam, Columbia River, WA

Monitoring and response to increased uplift

(Decrease in foundation drainage)

Space NeedleSeattle, Wash.

1961 – designed & built to withstand:• 200 mph winds• Magnitude 9.1 earthquake

Center of gravity is 5 feet above ground level

Sound practice

The higher the risk, the higher the cost

No ownershipin the results

No link to culture and institutional knowledge