Wind speed and cranes built to ASME B30.5

[Anthony LHT]

Greetings,
I would like to know from what American national, or if none' international standard is applied by American crane manufacturers when determining operational wind speeds that are in the manuals and LR charts. I have spent a few hours chasing my tail around the Internet on this and am back to where I started with the all too common phrase "as stated my the manufacturer".

Is there a American national standard adopted for crane design operation wind speeds? I have worked with EN13000 and AS1418 and they are very prescriptive about what wind speeds to use, how and where on the crane to apply the loadings, 3 second gust speeds, etc. but I cannot find anything in U.S. codes.

Any pointers in the right direction would be greatly appreciated.

Regards, LHT

 

[JStephen]

There is an ASCE 37 for loads on structures during construction that COULD be applied; whether that's what the manufacturers use, I don't know. I've not used it, but I think it's similar to ASCE 7, but with provisions for shorter exposure times.
One drawback on ASCE 7 is that it doesn't adequately address exposed structural members such as a crane boom, and ASCE 37 may have the same shortcomings.

 

[racookpe1978]

A lot of that "fall back to manufacturer limits" is intended not for "construction" of the crane (or the buildings or gear it is being to fabricate), nor for the added wind loads on the crane when it is being used outside in the weather, but for operational use. You simply CANNOT reasonably and safely operate a crane hook and exposed load in high winds - regardless of how much "strength" the crane boom and hook and wire rope and crane pivot pad and counterweights might be actually capable of handling.

However, if the max operating wind speed is (say) 20 mph at the top of the hook (that's way too high), then the crane designer will not use 45 mph for a wind load force when the crane boom is carrying its maximum rated gravity load. He will use a wind force of that 20 mph maximum (with a gust factor, etc.) But the rating authorities prefer to let the manufacturer set the rated conditions.

 

[Anthony LHT]

OK, Thank you both for replying. If it is left up to the manufacturer than that is all I need to know.

FYI it was never my intention to try and engineer my way out of sticking to the rated wind conditions of the crane. I have been a Lifting and Hoisting Engineer for the past 12 years, working with many American designed and manufactured cranes; just only in the offshore sector where API 2C and ABS rules apply. This is my first time working with land based mobile cranes and I like to know what I'm working with.

Cheers, LHT