1. 1989 Loma Prieta Earthquake Mitigation and Reconstruction

2. The earthquake hit San Francisco on October 17, 1989, at 5:04 local time
A magnitude of 7.0 on the Richter scale or a 6.9 on the moment magnitude scale
Occurred during the 3rd game of the world series
The quake killed 63 people

3. Fatalities and Damage
The fatalities were low because of the World Series -traffic was very light
Nimitz Freeway double-deck portion of the freeway collapsed
The support columns of the upper-deck failed
It crushed the cars on the lower level

4. Oakland Bay Bridge
The Oakland Bay Bridge was built in seismic engineering was less advanced
The western span of the bridge collapsed during the shaking
It was repaired and upgraded a month later:
Diagonal Box Beams: reduces lateral movement
High-Strength Concrete Supports
New nuts and bolts

5. Sept 2009 Replacement Bridge still under construction ->
The eastern span of the bridge is currently being replaced
-has yet to be completed
We know much more about the structural integrity of bridges
The new span will be more earthquake resistant

6. Mitigation The Earthquake could have been devastating
Originally the death toll was projected to be at least 300
The stadium had been reinforced shortly before the earthquake happened
This prevented thousands of injuries and deaths

7. Restoring Running Water
250 water main breaks in the Marina alone
Hundreds of water department staff worked
The staff worked 24 hours a day repairing water mains
Water service restored after a few days
Service renewals continued for months

8. Planning for the next one..
Emergency drinking plan – special fire hydrants set up around the city to provide drinking water to citizens
67 hydrants marked with blue water drop
Every resident is to be prepared for 72 hours after a major disaster
If one pump station fails another station will kick in

9. NERT program (Neighbourhood Emergency Response Team)
-Fire department trained dozens of citizens in every neighborhood to be able to help others during an earthquake
2002 – rebuilt water system to withstand major earthquake
Built new pipeline to use during emergency

10. Liquefaction Marina area had many homes and buildings damaged
Built on a mixture of sand, dirt, rubble and contained high amounts of groundwater
Waves are much more severe in these areas

11. Liquefaction and building damage can be mitigated through:
1. Seismic retrofitting (reinforcing old buildings)
2. Base Isolation (springs absorb the waves of earthquake)
3. Supplementary dampers (similar to shock absorbers in cars)
4. Addition of structural support (adding frames and supports)
5. Exterior reinforcement (reinforcing the building on the outside)

12. Reinforcing Buildings
Loma Prieta showed many of the structural flaws of buildings and homes
-Buildings codes were not being enforced strictly enough
The California Earthquake Authority
-Developing plan to encourage people to reinforce their homes by providing rebates
-Provide more training to contractors, engineers, and inspectors

13. Important Lessons learned
Most damage was to older buildings
Hazardous buildings should be strengthened or removed
Old homes should be attached to their foundations
-crippled walls should be braced
Building codes and permits need to be followed

14. References http://wsspc.org/Newsletters/2009/eNews_091509.pdf
ge=222
f_the_San_Francisco_%E2%80%93_Oakland_Bay_Brid ge