3. Life Safety Through the Eyes of an SE
GET PEOPLE
OUT THE
DOOR ALIVE
Seismic Retrofit
4. Life Safety Through the Eyes of an SE
The purpose of this code is to establish
the minimum requirements to
safeguard the public health, safety and
general welfare…
(IBC 2006, 101.3)
Seismic Retrofit
5. Life Safety Through the Eyes of an SE
Structural Code generally
does not consider:
Building economics
Business interruption losses
Sustainability
Seismic Retrofit
6. Building State After a Major Earthquake
Northridge Earthquake
Magnitude 6.7
Estimated Economic
Loss $49.3 billion
PEER (2000)
Seismic Retrofit
7. Building State After a Major Earthquake:
Northridge
SDEDC (1994)
Seismic Retrofit
9. Performance Based Seismic Design:
Basics
Next generation seismic
design methodology
Originally developed by
FEMA for existing buildings
Applicable for new design
Considers each element’s
energy dissipation capacity
Seismic Retrofit
10. Performance Based Seismic Design:
Pairing
Target Building
Performance Levels
Operational Performance
Performance Level (1-B)
Performance Level (5-E)
Life Safety Performance
Immediate Occupancy
Collapse Prevention
Level (3-C)
Level (1-A)
Once every 100 years a b c d
Once every 250 years e f g h
Hazard Level
Earthquake
Once every 500 years i j k l
Once every 2500 years m n o p
Seismic Retrofit
11. Performance Based Seismic Design:
Levels & Acceleration
Performance levels Acceleration Options
Operational Typical
Immediate Occupancy 50%/50 (1/100 year)
Life Safety (IBC) 20%/50 (1/250 year)
Collapse Prevention 10%/50 (1/500 year)
2/3 of 2%/50 (IBC)
2%/50 (1/2500 year)
Any probability between
those listed above
Seismic Retrofit
15. Common Weaknesses: Concrete
Ductility is big issue:
Continuous beam
reinforcing
Hoop spacing
Lap splices
Under-reinforced (primary)
Seismic Retrofit
