Earthquake Retrofitting – L.A.’s Tough New Building Code

Both the Wilshire Grand Center in Los Angeles and the Salesforce Tower in downtown San Francisco are currently under construction in areas known for seismic activity.  As such, the skyscrapers will be built utilizing the most high-tech earthquake modeling and engineering techniques available.  For example in the case of the Salesforce Tower, the building design was put through a series of 22 computer simulation tremblors that were modeled on real earthquakes that took place in the Bay Area.  The design passed all of the tests including a simulation of the 1906 earthquake that was estimated to be in the 7.6 range. 

 

In early October, the L.A. city council passed the nation’s most comprehensive seismic regulations that will require approximately 15,000 buildings in the city to be retrofitted to better withstand extreme shaking from an earthquake.  The riskiest buildings targeted in the new ordinance were built before 1980.  They including brittle concrete buildings that are found along many of the major boulevards in L.A. and wood-frame apartment complexes built over carports. 

The council’s decision was influenced by a study that reported over 65 people lost their lives in structures such as these in the 1971 and 1994 earthquakes.   L.A.’s mayor, Eric Garcetti was quoted in the L.A. Times saying, “Today's actions will save lives.”  He added, “I'm not interested in making history or having the toughest laws. I'm interested in preserving our city's ability to survive and thrive after an earthquake.”  Under the new ordinance, wood-frame structures must be earthquake retrofitted in five years and the retrofitting on concrete structures will have to be done over the next 30 years.  

The Conco Companies are a leading supplier of concrete services for the Western U.S.  We got our start in the Bay Area in 1959 by offering clients the best value on a wide range of concrete services and products.  Since that time, we have taken a leading role as one of the top concrete contractors in the region. We have four regional offices serving California, Nevada, Washington, Oregon and Colorado.

Source: latimes.com/local/lanow/la-me-ln-earthquake-safety-retrofit-20141208-story.html