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Monday, 02 June 2014 15:29cat

Thousands of Los Angeles buildings may need to be seismically retrofitted after PEER report

Written by  TheStructuralEngineer.info

A decade after the identification of potentially vulnerable concrete school buildings across the state of California, a new report published by UC Berkeley based Pacific Earthquake Engineering Research Center (PEER) brings attention back to the older concrete LA buildings. The list contains 1,454 buildings, including schools, offices, theaters, churches and many residential buildings. 

 The scientific team's scope of work was to identify structures that may not be adequately reinforced to sustain a strong shake and spot those buildings that they considered were worth of a closer seismic evaluation. According to UC Berkeley Prof. Moehle, "Some of these buildings are perfectly safe in their current condition, some of them may already have been retrofitted, but there will be some within this inventory of buildings that are likely to be judged as vulnerable". 

The list contains 1,454 concrete buildings, among which 214 are schools, 200 commercial units, more than 100 residential buildings, dozens of hospitals as well as many LA landmarks such as the Capitol Records Tower, the TCL Chinese Theatre and the CBS Studios. According to NBC4 I-Team, digging in the report, maximum occupancy of the buildings is nearly half a million people. 

And although hospitals have state-imposed deadlines for retrofitting or even replacing earthquake susceptible structures, retrofitting of schools was urged but not required after the initial report ordered by the California legislature with Assembly Bill 300 in 1999. Among the potentially earthquake vulnerable schools, at least seven concrete structures are believed to be at risk of collapse after an earthquake, according to Los Angeles Unified School District manager of maintenance and operations Roger Finstad. He also reported that there are plans underway to retrofit or replace the particular structures, just like 30 other school buildings that were retrofitted or replaced following the AB300 study. He also acknowledged the need to cross check the PEER list to come up with the exact number of school structures that need to be re-evaluated. 

The release of the PEER inventory made a major impact, and initially contained the approximate coordinates of the identified structures. Exact street addresses were provided to the Los Angeles Department of Building and Safety but became public after many requests under California's Public Records Act. This made many individual owners and companies to cross-check their records finding discrepancies, especially in the case of hospitals.

Sources: NBCLANBCLA-2

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