On Tuesday, July 19th, a crane, with its boom extended 25 stories high, buckled and collapsed onto the active Tappan Zee Bridge in New York. Thankfully and amazingly, no one was killed and only a couple people sustained minor injuries, but traffic on the bridge was stopped for hours. All but one lane was re-opened on the bridge within 8 hours of the collapse. After the collapse, work began to try to determine the cause of the accident.
Three different investigations are currently underway, led by the New York State Police, the State Labor Department, and OSHA. The fallen crane’s black box has been recovered in hopes of revealing any information that could be useful, just like in airplanes. In cranes, the black box records valuable data, including weight distribution and boom angles. Interviews have also been conducted with the operator of the crane.
At the time of the collapse, the crane, a Manitowoc lattice-boom crawler crane (according to the New York Times), was positioned on top of the new and adjacent bridge under construction. Working in tandem with an operator of a remote-controlled vibrating hammer, the crane operator was tasked with driving steel piles, some as large as 300 feet long and 6 feet in diameter, into the Hudson River bed below, when something went wrong.
The New York Times spoke with Jeff J. Loughlin, a representative of the International Union of Operating Engineers Local 137, and he remains confident that this collapsed was not caused due to operator error. Wind has also been ruled out as a cause, as it was very calm that day. Laughlin theorized that the collapse could have been caused by the pile finding a soft spot in the river bed, causing the hammer to drop rapidly. But, that’s only a theory, for now.
The most sobering thought of this accident was that the pile driving procedure was extremely routine at this point of the project. Around 1,000 piles have been driven into the river bed already, but this is the first time a crane has gone down. It’s a strong reminder that no matter how routine we think our work is, it’s still construction work and it’s still very dangerous.
Full story: Investigations Into Tappan Zee Crane Collapse Ask How a Routine Job Went Awry | New York Times