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Re: Re[2]: Crane Design; SE v. ME

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Most customers will balk at paying for such a detailed analysis, but I
applaud those who are so enlightened.  FWIW, for typical building cranes
(say up to 30T and 60ft span), I specify crane-to-building connections
and bracing  to comply with 1994 UBC, "at the roof level", and with I =
1.5.  This will give a static value of 0.9 "g".  Compare this to the CMAA
- specified values of 0.1 to 0.15 "g".

Russ Nester
rnester(--nospam--at)juno.com

On Wed, 10 Mar 99 11:49:15 EST "Robert Rogers"
<robert.rogers(--nospam--at)woolpert.com> writes:
>==SNIP=========================
>
>     From: rnester(--nospam--at)juno.com [mailto:rnester(--nospam--at)juno.com]
>     Sent: Wednesday, March 10, 1999 1:30 AM
>     To: seaint(--nospam--at)seaint.org
>     Subject: Re: Crane Design; SE v. ME
>
>     Drew ---
>
>     In general, cranes are cranes, not building structures.  The 
>manufacturer
>     certifies complience with Crane Manufacturers Association of 
>America
>     (CMAA), ANSI, and OSHA requirements, including installation (if 
>within
>     contract scope).  None of these codes and standards address 
>earthquake
>     loads and seismic design.
>
>===SNIP========================
>
>Although CMAA and ANSI standard do not address this issue, ASME has a 
>standard 
>that does (if I remember correctly). For bridge cranes that handle 
>hazardous 
>material (i.e. nuclear, toxic, etc.)ASME NOG-1 addresses seismic 
>loading and 
>bridge crane design.  However, this standard would have to be invoked 
>in the 
>contract documents and requires a very stringent treatment of the 
>structural 
>design of the crane.
>
>
>Short of this, if the crane runway is in the building I don't, 
>offhand, see how 
>you can get by without performing a response spectrum analysis of the 
>building 
>to obtain the accelerated response spectrum at the bridge crane level. 
> Once 
>this is known, a model can be setup with the crane and an analysis 
>performed.
>
>______________________________ Reply Separator 
>_________________________________
>Subject: RE: Crane Design; SE v. ME
>Author:  seaint(--nospam--at)seaint.org at Internet
>Date:    3/10/99 10:53 AM
>
>
>
>
>-----Original Message-----
>From: rnester(--nospam--at)juno.com [mailto:rnester(--nospam--at)juno.com]
>Sent: Wednesday, March 10, 1999 1:30 AM
>To: seaint(--nospam--at)seaint.org
>Subject: Re: Crane Design; SE v. ME
>
>
>Drew ---
>
>In general, cranes are cranes, not building structures.  The 
>manufacturer
>certifies complience with Crane Manufacturers Association of America
>(CMAA), ANSI, and OSHA requirements, including installation (if within
>contract scope).  None of these codes and standards address earthquake
>loads and seismic design.  CMAA even states that the owner must look
>elsewhere for seismic design of cranes.  AISC attempts to elucidate
>somewhat, but is too simplified, and is not invoked by the crane codes
>and standards.  Bottom line is that the crane manufacturer needs NO
>ENGINEERING LICENCES to build and sell a crane.  The California
>certifier, licensed by CalASHO, needs to have a licensed ME or CE on
>staff in order to certify the final installation.  This requirement
>varies by state, and is different for federal installations.
>
>In general, most building cranes will withstand zone 4 seismic loads, 
>but
>the attachments to the building will not, if designed per crane 
>standards
>(not even close).  Also suspect might be the runway beams.  The crane
>codes and the building codes are truely disconnected, as are the
>practices of engineering of cranes vs. engineering their 
>installations. 
>The loads you have been supplied by the crane engineer do not include
>seismic, as you have suspected.  That disconnect was directly 
>responsible
>for industrial bridge cranes failing and falling to the floors below
>during the 1994 Northridge Earthquake.
>
>I will repeat my offer from a few months ago.  I wrote and published a
>paper on this subject , delivered at the 1996 ASCE Natural Disaster
>Reduction Conference.  I will send the paper and other enlightening
>material to anyone is interested and  who send me thier name and 
>mailing
>address.
>
>Russ Nester, SE, GE
>rnester(--nospam--at)juno.com
>
>On Tue, 9 Mar 1999 19:28:30 -0500 "Drew A. Norman, S.E."
><DNormanSE(--nospam--at)email.msn.com> writes:
>>An appeal to the voice of my colleagues' experience.  Is there anyone 
>
>>out
>>there with crane design experience, or anyone from BORPELS and/or 
>>CAL-OSHA,
>>who could shed some light on the following situation?
>>
>>My office has designed a building to support a thirty ton bridge 
>>crane.  The
>>hoist runs along a bridge spanning 54' between trolleys which in turn 
>
>>run on
>>rails spanning 27' between supports points where they are hung from 
>>our roof
>>structure.  Reactions at these suspension points were provided to us 
>>by the
>>crane supplier.  The installation will be in California, in seismic 
>>zone 4.
>>Laterally, the two bridge beams are (we think) interconnected as a 
>>truss to
>>resist horizontal inertial forces created by acceleration or 
>>deceleration of
>>the mass of hoist, bridge and load (whether due to earthquake or 
>>normal
>>operations).  Lateral loads along the axis of the bridge are 
>>presumably
>>transferred to the rails, which must span horizontally between 
>lateral
>>bracing we provide at the supported points.
>>
>>We have asserted that the bridge crane and its rails, which are to be
>>designed by their supplier, are a substantial structure.  Our 
>>documents call
>>for the design to be submitted to us (for verification of consistency 
>
>>with
>>our design of the supporting structure) under the seal and signature 
>>of a
>>licensed SE.  We were recently advised that the crane supplier 
>asserts 
>>that
>>the crane is a machine, not a structure, and that an SE signature is 
>>not
>>required (they have an ME who proposes to sign the documents).
>>
>>We have been asked to assist our client in responding to this 
>>situation.
>>Because the cost of proper engineering is not insignificant, the 
>issue 
>>is
>>not immaterial, and there is some pressure to accept an ME signature.
>>
>>Does anyone know if the Professional Engineers Act or the BORPELS 
>>Rules
>>address the issue of when a machine becomes a structure?
>>
>>Does anyone know if CAL-OSHA or any regulatory agency has policy on 
>>when a
>>crane requires structural (v. mechanical) design?
>>
>>Does anyone have any useful suggestions or relevant information that 
>I 
>>could
>>pass on to my client?
>>
>>Drew Norman, S.E.
>>Drew A. Norman and Associates
>>
>>
>>
>>
>>
>>
>>
>
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>
>
>
>
>
>

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