Yesterday, a number of beams fell from a crane about 40 stories at the World Trade Center site's Tower 4, hitting a truck. Only one person suffered minor injuries in the incident that one ironworker said "sounded like a bomb."
It turns out that the crane's cable snapped—another ironworker said, "The cable looked like a snake coming down. Then all hell broke loose"— and the objects that fell were "three 62-foot-long steel beams weighing an estimated 38,000 pounds." And they fell onto the truck that had brought them to the site—the driver was still in the truck's cab, but he wasn't injured. Here's raw video from the scene—also, here's a dizzying picture taken from WTC 1, looking at Tower 4:
Via a reader
The site's contractor, Tishman Construction, says it is investigating the incident. According to the Post, "Investigators were checking at least two possible causes for the disaster. One was a hydraulic failure on the crane... A failure in the hydraulic system could have caused the cable to suddenly unspool from the winches that control it. As the cable and its load suddenly dropped, an emergency braking system would kick in. If the brakes are applied too abruptly, they can cause the cable to snap, said sources. Another possibility was that as the crane was raised over the last few days, an engineer miscalculated the amount of play the cable would need. A cable can snap if it has too much or too little slack, said sources."
In 2007, a sling holding seven tons of steel fell 25 stories onto a trailer at the Goldman Sachs building site, injuring architect Robert Woo who was inside. Woo has been trying to regain mobility with help of a robotic exoskeleton.
