17.03.2008

New York crane update

Reports from New York say that the tower crane collapse this weekend in which the death toll has now climbed to seven, was caused by the dropping of the new anchor collar being installed at the 18th floor level. The tower had just been climbed to a total height of around 60 metres.

The heavy steel collar weighs as much as five tonnes and was dropped when its nylon web slings appear to have given way causing it to crash into an anchor on the ninth floor ripping it free from its ties into the building. The two loose collars then plummeted into the bottom collar located on the third floor level. This held but a supporting brace was broken.
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The two upper collars piled up against the lowest collar and tie

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This photo sent in by a reader is purported to be a close up of the three collars showing the frayed web slings as far as we can determine it is genuine.

The crane's 40 tonne counterweight was positioned towards the street, effectively pulling the tower away from the building and onto the apartment block across 51st street. The tower broke at the point of impact sending the top of the tower, superstructure and jib into another building across 50th street.

Seven bodies have now been recovered, six of them construction workers and one woman visiting the town for today’s St Patrick’s days celebrations.

The first four construction workers, which inlcude the crane driver have been identified as: Wayne Bleidner, 51; Brad Cohen, 54; Anthony Mazza, 39; and Aaron Stephens, 45. The three people found Monday have not yet been identified.
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Several mobile cranes were brought in from Bay Crane today to remove the fallen tower

Cranes arrived to day to remove the leaning tower from 51st street while recovery work continued in 50th street.

Vertikal Comment

This is a dreadful accident and one of the worst for a long time, it demonstrates how a simple failing can lead via a chain of events to catastrophe.

If the slings or chain blocks holding the new tie in collar had been oversized with a back up maybe it owuld not have occured?

If the cranes counterweight had been positioned over the building would it have simply pulled the tower into the building rather than across the street?

Should there have been a device on the tower to prevent the collars from sliding 30 to 40 metres down the tower?

Hopefully we can at the very least learn something from this dreadful accident rather than simply looking to place blame.