AIR Updates Analysis of Damages from Chile Earthquake

According to catastrophe risk modeling firm AIR Worldwide, a more complete picture of damages is beginning to emerge in the hardest-hit regions of Bio Bio and Maule, four days after the devastating Mw8.8 earthquake struck off of Chile’s central coast. AIR noted that “with a fuller understanding of the scope of destruction, officials have reported that as much as 80 percent to 90 percent of some towns in the epicentral region have been destroyed in the quake.”

Dr. Guillermo Franco, senior research engineer at AIR Worldwide, noted that “according to the data we have collected during the past few years, in Chile today, masonry (reinforced, confined, or unreinforced) is the predominant construction type, accounting for roughly 60 percent of residential buildings and more than 40 percent of commercial buildings.

“Wood frame is fairly common for residential construction as well, accounting for about 20 percent of the residential building stock. Concrete, which is typically used for mid- to high-rise apartment buildings, accounts for approximately 15 percent of residential structures. About one third of commercial buildings use reinforced concrete, while steel construction accounts for about 15 percent. Industrial buildings are typically erected using steel or light metal.”

He added that Chile’s “strong building code specifies the earthquake loads that need to be resisted. The detailing of connections is generally based on the American Concrete Institute standard (ACI-318 Spanish version), and it is up to the construction engineer of record to abide by it. While the building code applies nationally, construction practices can vary significantly from company to company and from region to region.”

According to AIR’s analysis, “damage to infrastructure, including ports, will extend significantly the interruption of business operations of Chile’s lucrative wine and salmon industries. Up to one fifth of Chile’s copper-mining capacity was halted after the quake, but has since resumed.

“Chile’s capital of Santiago, 325 km (200 miles) from the epicenter, has fared much better. Thousands of modern mid-rise and high-rise buildings in the capital withstood the earthquake without structural damage, thanks to a strict building code. On the other hand, there are several instances of mid-rise apartment buildings that, while still standing, have suffered structural damage sufficiently severe to require their demolition.”

AIR said it is continuing to “analyze the available information on this event and will be sending a post-disaster survey team to affected areas.”

Source: AIR Worldwide – www.air-worldwide.com