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(HSS Sections imported from China) porches in seismic areas

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Talking about HSS sections, there are problems related to the HSS tube sections manufactured in China. This issue pertains to the defective HSS Seam Welds due to lack of fusion, cracks and splits.
You may look at DSA Bulletin 07-03 on and photographs on DSA web site:
http://www.documents.dgs.ca.gov/dsa/bulletins/BU_07-03_UPDATE2_3-7-08.pdf
There are also Visual Guides on http://www.dsa.dgs.ca.gov/Labs/hss_pictures.htm identifying the problems.
 
Regards
Casey K. Hemmatyar, SE


 
_________________________________________________________________________________________________________________
Chris,
May want to look at the plate forces a bit closer.  I may not have looked close enough at the forces at the plates which may be larger due to the moment from the column moment.  I was winging it without sketches.  I'll look at it a bit more this evening also.
Joe
 
-----Original Message-----
From: chris.slater(--nospam--at)gmail.com [mailto:chris.slater(--nospam--at)gmail.com] On Behalf Of Chris Slater
Sent: Thursday, May 15, 2008 4:48 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: porches in seismic areas
 
That makes sense.  One more option to put in the holster.
 
Thanks!
 
On Thu, May 15, 2008 at 4:35 PM, Joseph R. Grill <jrgrill(--nospam--at)cableone.net>
wrote:
> Yes, I was thinking lighter loads. Also, only "similar" to a Simpson base.
> If the side plates are taller, say 12", then the bolts could have a 9"
> spacing.  A 5/8" bolt in a 6x6 DF would give you 1420x1.6=2272 lbs per
bolt.
> At 9" couple that would give a 1704 ft-lb moment resistance.  At 7'
> you could restrain a 240# lateral load. That would be for the bolts
> only.  At
90
> degrees that same 240 lbs applied at the top (I'm being kind of
> general
> here) of two 3" wide plates produces a moment at the bottom of the
> plates
of
> 1440 in-lbs (if I'm correct). Looks like 2-3/8" plates might work at
> the
90
> degree situation.  Depends on how big the porch and how many posts
resisting
> the seismic or wind. If deflections at the top of the post are
> agreeable,
if
> may be work.
> Joe
>
> -----Original Message-----
> From: chris.slater(--nospam--at)gmail.com [mailto:chris.slater(--nospam--at)gmail.com] On Behalf
> Of Chris Slater
> Sent: Thursday, May 15, 2008 4:00 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Re: porches in seismic areas
>
> I think the loads would have to be incredibly light.
>
> Given a 7' column, with only 500# of lateral load, you get 3500 #-ft.
> That's resisted by the couple in the bolts, at 3" apart.  So each bolt
> winds up needing to be able to resist 14 kips.  Pretty sure NDS values
> for through bolts in double shear are at the most in the 4 kip range.
> Maybe less...
>
> Am I missing something?
>
> On Thu, May 15, 2008 at 3:14 PM, Joseph R. Grill
> <jrgrill(--nospam--at)cableone.net>
> wrote:
>> Another option?  But, probably for lighter laterally loaded columns.
> Using
>> a column base, shaped similarly to a Simpson CB or LCB but heavier
>> plates and bolts.  For loads in one direction the side plates resist
>> the column base moment by bending.  For loads in the perpendicular
>> direction the
> bolts
>> resist the column base moment in bolt values perpendicular to grain. 
>> Any thoughts?
>>
>> Joe Grill
>>
>>
>>
>> From: Jnapd(--nospam--at)aol.com [mailto:Jnapd(--nospam--at)aol.com]
>> Sent: Wednesday, May 14, 2008 12:43 PM
>> To: seaint(--nospam--at)seaint.org
>> Subject: Re: porches in seismic areas
>>
>>
>>
>> Andrew
>>
>>
>>
>> You are correct steel tubes are not that expensive and I use them all
>> the time.  Contractors and home owners freak out when you mention
>> steel. They don't understand where to buy, how to use and therefore
>> it must cost way
> to
>> much is the normal response.
>>
>>
>>
>> I tell clients all the time you can use the City or County spec for
>> knee braced patio supports; but if you go beyond the size they
>> recommend I
will
>> not sign or approve any knee-braced wood post..no exceptions.
>>
>>
>>
>> Dennis and I do most of our work within 0-15 km of the San Andreas Fault.
>> Our area has been expecting a 6.5 - 7.5 Quake for the last 20 years.
>> Landers and Big Bear quakes were not on the main fault branch.
>>
>>
>>
>> What I do when requested is install a 6x6 post inside a HSS6x6x.25
column.
>> The tube extends 2-3 ft above ground with the post embedded 12' into
steel
>> tube. Clients put stone or brick around the tube so you see just the
wood.
>> The height of the wood depends on how many post are available.
>>
>>
>>
>> I always consider a trellis roof as a solid roof..because within 5
>> years
> it
>> usually is.
>>
>>
>>
>> I sleep quite well at night.
>>
>>
>>
>> Joe Venuti
>> Johnson & Nielsen Associates
>> Palm Springs, CA
>>
>> ________________________________
>>
>> Wondering what's for Dinner Tonight? Get new twists on family
>> favorites
at
>> AOL Food.
>
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