28.08.2007
Boom failure causes havoc
Yesterday evening a contractor noticed that a lattice boom section on one of the large Manitowoc crawler cranes it was using had been overloaded to the point that a number of chords in the base section had cracked or buckled.
The crane, which was working on the new Royal Bank of Scotland building in Stamford Connecticut, was fully rigged with boom and luffing jib at the time, it is one of four on the site
The contractor, Turner Construction initially said that the section was overloaded during erection. However an independent inspection agency checked the crane on Friday and Saturday, and the further inspection on all the cranes was conducted on Monday morning by a state inspector, all failed to spot any problem.
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A boom lift is used to check out the boom
Police initially evacuated around 400-people from the surrounding area in downtown Stamford fearing that the boom might collapse at any moment. The contractor put around 60 of them in a local hotel overnight.
A team was called in to repair the section sufficiently to allow it to be lowered while another crane was also brought in as a replacement.
Vertikal Comment
Cranes of this size often have strengthened boom sections after the butt, specifically to cope with the high stresses generated during erection, as well as to help support the full load of the boom and jib above.
In a number of accidents or incidents this year regular boom sections appear to have been inserted in this location rather than the heavy duty reinforced one, however this does now seem to be case here.
If the initial damage was caused by the erection, it is a shame the operator and riggers did not spot it at the time, when it would have been very easy to have lowered the boom and replaced the section. Bringing down such a big rig from the fully elevated position is a highly precarious job.
However given that the fault is at the base, it is far more likely that the boom was over-derricked in which case the operator is extremely lucky that the whole thing did not come crashing down.
Thankfully the contractor spotted the damage and took action before it was too late.
pdbabe
I am sorry this is total misinformation this was operator error I was there the crane boom was on the ground for reconfiguration of the boom and the operator was booming it back up and continued to hold the override button forcing the boom against the stops and twisting the base. Turner contracting spread this lie to save their butts. I would swear to this in a court of law.