Building Codes
Building codes: collapse prevention
The Uniform Building Code
• Building Seismic Safety Council (FEMA), 1996• Evolution of earthquake hazard maps• UBC-Level 4, area of highest risk
Areas of High Population/Seismic Risk
Seismic zones and Faults
Seismic zones and population
Damage Mapped by Damaged Buildings
Structural problems
• Earth material
• Soft story
• HOG
• Cripple wall
• House off foundation
• Chimneys
• Water heaters
• URM
Uniform Building Codes
• 1927- First UBC required, fire safety
• updated every 3 years• recognition of new
weaknesses in designs• recognition how earth
materials influence seismic waves
Soft Story Collapse
• Parking garage is a soft story
• Scenes like this were familiar near the epicenter
• Where have you seen this type of structure?
Uniform Building Code
• 1973- requires bracing of cripple walls
• 1991- stronger bracing for cripple walls
Cripple wall retrofit
Uniform Building Code
• 1935- Foundation bolting
Bolting Methods
Chimneys
• Built before 1970• Not properly
reinforced• Tear down chimney• 2007 building code
– Specific types of brick and mortar
– Extensive anchoring with specific requirements of attachment
• 1991-Bracing of water heaters
Uniform Building Code
• 1935- reinforcement of masonry foundations
• 1986- Unreinforced Masonry retrofit law
• 1993- how retrofitting is done
Uniform Building Code
Full Operational Operational Life safe Near Collapse
Safety-critical objective
Essential/hazardous objective
Basic objective
M6.5
M7.0
M8.0
M7.5
Building Code Objective
Top Related