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RE: FW: Q: Weld QA/QC per FEMA 350

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Thank you for your comments and consideration of my question.
Catherine

-----Original Message-----
From: THunt(--nospam--at)absconsulting.com [mailto:THunt(--nospam--at)absconsulting.com]
Sent: Tuesday, April 13, 2004 12:29 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: FW: Q: Weld QA/QC per FEMA 350



Catherine, 

I have used both the FEMA 350 welded WUF-W and the bolted end plate WFP
moment connections.  My experience is that it is more a construction
preference more than anything else.  In heavy industrial work, especially
petrochemical and power, most of the moment connections are bolted end
plate.  I used this on a large power plant facility and the field loved it.
The structures went up very fast and the critical welds were made in the
shop under potentially better quality control measures.  We used twist-off
bolts and every morning the field engineer tested a random sample of bolts
in a Skidmore to provide documented QC.  In the commercial (buildings) world
they almost exclusively use welded connections.  I once suggested a bolted
moment connection for a large bay single story building structure and all I
got was an open jaw and bug eyed response. 

Just to clarify my previous response, FEMA 350/353 are not part of the code.
However some jurisdiction, but not all, will accept the FEMA 350 connections
as meeting the UBC requirements for "tested" connections.  Be sure and
verify which ones, if any, of the FEMA 350 connections are acceptable to
your building official. 

If you choose to use the bolted end plate (WFP) connection, note that there
were a lot of bugs in the original equations.  Be sure and get the errata. 

Thomas Hunt, S.E. 
ABS Consulting 




Catherine Pagni <CPagni(--nospam--at)pacecivil.com> 
04/13/2004 12:03 PM Please respond to
<seaint(--nospam--at)seaint.org>

To"'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org> 
cc
SubjectFW: Q: Weld QA/QC per FEMA 350







Thank you Tom.

Regarding the same WUF- welded web connection, the beam has a very shallow
depth. Would a bolted web connection be a better choice? Advice on selecting
between these connection is appreciated.

Thanks, Catherine


-----Original Message-----
From: THunt(--nospam--at)absconsulting.com [mailto:THunt(--nospam--at)absconsulting.com]
Sent: Tuesday, April 13, 2004 11:12 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: Q: Weld QA/QC per FEMA 350



Catherine, 

The L and T indicate whether the weld is loaded Longitudinally or
Transversely.  This may change the NDE requirements as shown in Table 6.3 of
FEMA 353. 

As to whether you are allowed to use Omega forces or Beam Capacity will
depend on the Building Official.   I suggest you have a long talk with them.


Thomas Hunt, S.E. 
ABS Consulting 





Catherine Pagni <CPagni(--nospam--at)pacecivil.com> 


04/13/2004 10:51 AM 


Please respond to
<seaint(--nospam--at)seaint.org>



To
"'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org> 

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Subject
Q: Weld QA/QC per FEMA 350

                




The engineer is required to specify the Seismic Weld Demand Category per
FEMA 350. Using the detail for WUF-W, the category is given for each weld as
QA/QC Category AH/T or BH/L or sim. I understand the BH indicates the
seismic demand/consequence category per table 6-1 FEMA 353. What does the T
or L indicate?

Second question; Where this building is located, the governing code is the
97 UBC. Can I detail the connection using the reacting moments due to the
lateral forces increased by Omega, 2.8, or must the internal forces be
calculated using the equations in FEMA 350 Section 3.2?

Your help is very much appreciated,
Catherine A Pagni, MSCE
PACE Civil, Inc.
Staff Engineer
1730 South St.
Redding, CA 96001
(530) 244-0202



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