InfrastructureHurricanes will test Florida buildings, built under new, post-Wilma building codes

In 2005 Hurricane Wilma was responsible for five deaths and millions of dollars worth of damage in Florida. Seven years later, those parts of the state where Wilma wreaked its havoc have been rebuilt, including the buildings that make up the Miami skyline, featuring high-rise office buildings and expensive condominiums. Residents know it has been some time since a hurricane that significant has hit the Miami area.

“We have been lulled to sleep as a community. When we do get the next Cat[egory] 5 or anything above a Cat 3 or 4, that will be the first test,’’ Dan Whiteman, president of Miami-based Coastal Construction Group told the Miami Herald. Whiteman predicts the new buildings, most of which were designed with wind-tunnel testing, should perform well in all but the most severe conditions. “I don’t think there are going to be any significant problems with the buildings built since 2005.’’

The Herald reports that when Wilma hit, most high rise buildings were under older codes which allowed weak glass, which aimed to protected against a low grade hurricane, not significant crosswinds or flying debris.

“After Wilma, everyone looked and wondered why all that glass fell over Biscayne [Boulevard] and Collins Avenue,’’ Whiteman told the Herald. “They found out a lot of roofs have gravel and a lot of roof debris became flying missiles.”

Lab research done at the Laboratory for Wind Engineering Research at the International Hurricane Research Center at Florida International University has helped Miami update its building codes. High rise buildings that “cross the comfort threshold’’ for people inside by swaying too much in high winds can be revamped to change the aerodynamics, especially at the corners, according to Arindam Gan Chowdhury, the director of the lab.

Even with the changes, many of the high-rise building stand very close to each. Buildings which use sub-standard materials or which were built under older codes could still have an effect on buildings which equipped to handle high winds and rain, but not flying debris from older structures.

“One that has gone through wind-tunnel testing is not likely to be hurt,’’ said FIU professor Paul Irwin. “But if it’s hit by flying debris off another building, that’s different.’

The Herald notesthat today, most buildings in the skyline area follow codes that were set after hurricane Andrew in 1992, and have been updated several times since. Buildings are now required to install impact-resistant glass up to 30-feet above ground to protect against flying debris, and backup generators are required to provide power for elevators and emergency lighting in case power goes out.

After Wilma, some owners fought for and won the right to rebuild their old properties to the same specifications as they were before the hurricane. Charles Danger, Miami-Dade County’s building chief, knows that the improvements will help, but is still confused as to why some building owners refuse to update their properties.

“Basically some of these buildings were put back the same way and they are going to fail the same way. Some owners didn’t do anything different. They followed the old code because they were allowed to,’’ Danger told the Herald. “Some used the old material, but attached it better. Others put it according to the new code. If we ever get hit, we’ll see who was smart and who wasn’t.

“We’re better off now than we were before, but I’m still concerned about buildings that were revamped not to meet the new code.”