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Re: Jib crane impact factor

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Daryl, thank you for the information. I saw the impact loads in ASCE 7, but wasn't sure where my crane fit in. I have a question when using LRFD design with these factors. Is the factored live load Pu =

crane impact load factor * crane capacity

or 1.6 * crane impact load factor * crane capacity?

I have been using the latter formula, but with an impact factor 0f 2.0.

On 7/3/2013 10:40 AM, h.d.richardson(--nospam--at) wrote:

I have two sources for you: ASCE-7; and the Canadian National Building Code. These are in partial agreement. Both specify 1.25 for cab or radio controlled cranes and 1.1 for pendent operated electric cranes. ASCE-7 specifies 1.0 for hand geared hand operated cranes; CNBC includes them with pendent operated cranes.

I have designed, checked out, or load rated several hundred cranes in my career. I would recommend that you be nothing but conservative with any crane rated for 10 ton or less as operators tend to overload these quite frequently and quite substantially.



----- Original Message ----- From: "Drew Morris" <dmorris(--nospam--at)>
To: <seaint-seaosc(--nospam--at)>
Sent: Wednesday, July 03, 2013 11:57 AM

Truncated 578 characters in the previous message to save energy.

*Drew Morris, PE*| /Project Engineer/
BBFM Engineers, Inc. <>
510 L Street, Suite 200 | Anchorage, Alaska 99501
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