By: Kendall Jones on September 15th, 2017
Hurricane Irma Collapses Cranes, Reigniting Debate Over Safety
Last Sunday, three tower cranes collapsed in South Florida as Hurricane Irma pummeled the state with heavy winds and rain. The first crane came down in Miami about an hour after Irma made landfall 110 miles southwest on Cudjoe Key on Sunday morning.
The first crane to collapse was at the construction site for Vice, a luxury apartment complex on Biscayne Boulevard in Miami. The boom, or jib, snapped off and was dangling over the side of the building while the counterweights fell through the interior and pierced the building’s upper plate.
The second crane to come down was at the site of the Gran Paraiso, part of a condominium complex, a couple of miles north on N.E. 30th Terrace in the Edgewater neighborhood of Miami. The boom on that crane snapped and three counterweights fell to the street below and were embedded several inches into the pavement, while another counterweight fell into the interior of the building.
The third crane collapse occurred in Fort Lauderdale, about 25 miles north of Miami, at the Auberge Residence and Spa. Both the boom and the counterweights failed as a result of Irma’s winds.
At this time, the full extent of the damage caused by the cranes collapsing is unclear as crews were assessing the buildings and cranes this week and whether or not any other cranes in South Florida suffered damage. It is also unclear what, if any, other factors outside of Hurricane Irma caused the cranes to collapse. Federal OSHA will be investigating the collapses in the coming days and it will probably take months to complete.
On Sept. 5, the City of Miami issued a statement via Twitter that began, “Currently, there are 20 to 25 construction cranes in the City of Miami. These tower cranes are designed to sustain winds up to 145 miles per hour, not a Category 5 Hurricane.” At the time the city released that statement, Irma was a Category 5 hurricane with sustained winds of 185 mph. Miami was still in the potential forecast track of where Hurricane Irma could make landfall as a Category 5 storm.
It should be noted that the 145-mph threshold stated by the City of Miami is a tad misleading. The towers, or masts, of the cranes are probably designed to withstand winds of that speed, not the rest of the crane including the operator cabin, boom and counterweights.
Per OSHA regulations, Standard Number 1926.1433(c) states that “Tower cranes manufactured on or after November 8, 2010 must meet the prototype testing requirements in BS EN 14439:2006 (incorporated by reference, see § 1926.6).” The European standard BS EN 14439:2006 requires that cranes be made to withstand winds of 151 kph, roughly 93 mph. Without knowing the manufacturer and model of the cranes that collapsed, we have no way of knowing what wind speeds they were made to withstand.
For the types of tower cranes that collapsed, prepping and securing the cranes for a hurricane or high winds typically involves releasing the parking brake on the slew to allow the boom to swing freely and act like a weathervane in high winds. The slewing unit, or turntable, should also be lubricated to ensure that it can swivel freely and the hook block should be raised and pulled in close to the cabin. If cranes are expected to experience wind speeds greater than what they are built to withstand, they should be disassembled to prevent collapse.
The question now is what else, if anything, could have been done to prevent the cranes from collapsing and whether additional measures should be enacted to prevent this from happening when the next major hurricane strikes.
Some industry experts claim that taking down all the cranes in South Florida ahead of Irma would have been virtually impossible. Dismantling the cranes would have taken anywhere from five days to a couple of weeks and there weren’t enough companies certified to do the work. It would have required closing streets and bringing in additional mobile cranes, which could have hindered evacuation efforts. Others have argued that additional crews could have been brought in from out of state to at least get the booms and counterweights down before Irma struck.
There’s a compelling argument for both sides of the debate. Hurricanes are unpredictable and forecasting their exact path is difficult when the storm is any more than three days out. If all the cranes had been removed from South Florida and Irma had shot past the state into the Gulf of Mexico, then a lot of resources would have been wasted in the effort.
On the other hand, Irma could have taken a more easterly route as was previously forecast and made landfall as a major Category 5 hurricane, taking the eye wall over Miami and more cranes would have likely collapsed causing more damage to the area. As it stands now, all of the cranes in the area will need to be thoroughly inspected for damages before they can be put back into use and the cranes that collapsed will need to be taken down for repairs or be replaced.
Having stricter regulations on cranes in hurricane-prone areas is a topic that will be discussed and contemplated in the weeks ahead and it won’t be the first time. Back in 2008, Miami-Dade County implemented an ordinance regarding crane safety that, among other things, would have required tower cranes to withstand hurricane wind speeds exceeding 140 mph.
Several construction trade groups sued the county and had to enforcement of the ordinance overturned, arguing that the ordinance preempted OSHA regulations and that it was not a state approved regulation of occupational safety and health issues.
In 2012, subsection 11 was added to Florida Statute 489.113 stating:
“Any local act, law, ordinance, or regulation, including, but not limited to, a local building code or building permit requirement, of a county, municipality, or other political subdivision that pertains to hoisting equipment including power-operated cranes, derricks, hoists, elevators, and conveyors used in construction, demolition, or excavation work, that is not already preempted by the Occupational Safety and Health Administration under 29 C.F.R. parts 1910 and 1926, including, but not limited to, local worksite regulation regarding hurricane preparedness or public safety, is prohibited and is preempted to the state. This subsection does not apply to the regulation of elevators under chapter 399 or to airspace height restrictions in chapter 333.”
So, while it’s possible to change the laws in a state that are stricter than OSHA regulations, in Florida those changes would have to come at the state level. Per OSHA, their standards set minimum safety and health requirements and they encourage states to run their own approved programs and set stricter standards than those laid out in federal laws.
There’s also nothing construction companies or developers to take preemptive measures by either removing cranes ahead of storms or installing cranes engineered to withstand winds stronger than what OSHA requires.
About Kendall Jones
Kendall Jones is the Editor in Chief at ConstructConnect. He has been writing about the construction industry for years, covering a wide range of topics from safety and technology to industry news and operating insights.