OSHA Reports on Irma's Toppled FL Cranes
A recent report by the U.S. Department of Labor’s Occupational Safety and Health Administration has found that the three cranes that collapsed last year after Hurricane Irma tore through Miami did so because of wind turbulence, a factor that the cranes were not designed for.
The three hammerhead tower cranes, Sk-315 models, were the only cranes out of more than 20 that failed during the storm.
The first boom snapped around 10:30 a.m. on Sept. 10, 2017, and was soon joined by two more, after the storm had rolled through the Miami area.
The week prior, officials warned residents who live near cranes that Irma’s winds could prove dangerous. Residents were told to evacuate because of the danger the large cranes posed.
The deputy director of the building department for the City of Miami said in a statement that he would not advise staying next to a site that had a construction crane, noting that though the many of the cranes are certified to withstand a hurricane, that only goes so far.
The OSHA report suggests that though the cranes that fell were designed for maximum wind speeds of 95 mph, they were not necessarily designed for the wind turbulence. The report says that it was the lateral and upward wind loads that caused the jibs to separate from the equipment’s turntables and collapse.
One of the cranes was manufactured by Terex Peiner GmbH and the other two by Noell Service and Maschinenetechnick GmbH; the agency recommends that the manufacturers re-evaluate the jib-to-turntable connection design to prevent detachment during turbulent winds. It also recommends adding jib pendants to the SK-315 to provide more stability.
President of third-party inspection firm Crane Safety & Inspections Greg Teslia told the Engineering News-Record that everyone did everything right with the information they had; it just wasn’t enough for Irma’s winds.
“There’s really nothing that the contractors could have done to prevent this from happening besides dismantling the whole crane, which would’ve been impossible in the time they had,” he said. “These cranes aren’t made out of armor, and wind is their enemy.”
Now, several lawsuits are winding their way through the courts. L&R Structural Corp., the subcontractor of the Vice apartment complex and the site of the first crane breakage, is suing Maxim Crane Works, which rented out all three of the cranes. Related Group, a developer at both of the other two sites, is suing Maxim as well as Terex.