Building Codes

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Building Codes
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Building codes collapse prevention
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The Uniform Building Code

• Building Seismic Safety Council (FEMA), 1996
• Evolution of earthquake hazard maps
• UBC-Level 4, area of highest risk

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Areas of High Population/Seismic Risk
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Seismic zones and Faults
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Seismic zones and population
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Damage Mapped by Damaged Buildings
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Structural problems

• Earth material
• Soft story
• HOG
• Cripple wall
• House off foundation
• Chimneys
• Water heaters
• URM

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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

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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?

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Uniform Building Code

• 1973- requires bracing of cripple walls
• 1991- stronger bracing for cripple walls

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Cripple wall retrofit
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Uniform Building Code

• 1935- Foundation bolting

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Bolting Methods
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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

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Uniform Building Code

• 1991-Bracing of water heaters

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Uniform Building Code

• 1935- reinforcement of masonry foundations
• 1986- Unreinforced Masonry retrofit law
• 1993- how retrofitting is done

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Building Code Objective
Full Operational
Operational
Life safe
Near Collapse




M6.5
M7.0
Basic objective
Essential/hazardous objective
M7.5
Safety-critical objective
M8.0