During the earthquakes at Northridge, Mexico City, and most recently, Christchurch New Zealand, many concrete buildings constructed prior to the 1976 Los Angeles City Building Code provisions, or similar era codes in other countries, performed poorly and collapsed, causing loss of human life, personal injury, and property damage. The poor performance of these older concrete buildings is due to deficiencies in the lateral force-resisting system that render the building incapable of sustaining gravity loads when the building is subjected to an earthquake.
Buildings that are within the scope of this ordinance and require retrofitting are concrete buildings with a roof and/or floor supported by a concrete wall or concrete column, submitted for plan check before January 13, 1977.