Back when I first got in the business this issue came up. Not too far from you is a little 'ol institution of higher learning known as the University of Minnesota. I spoke with 2 PhD Professors and our own City SE. All were in agreement. The caveat is a truss with similar top chord and bottom chord construction. The truss does not care where you hang from. The load are transferred the same within the truss. That's the point of the truss. With that information while AHJ for the City I didn't care provided the chords were the same. And most of what we see is same top and bottom chords. As a contractor now it doesn't come up too often where there is even the opportunity to hang from the bottom so we just go along to get along and everything is top chord.
I did ask why some SE's and AHJ had issues hanging from the bottom. Lazy and/or ignorant was what I got back. You know how some PhD's can be, lol. Chris Cahill, P.E. Fire Protection Engineer Sentry Fire Protection, Inc. 763-658-4483 763-658-4921 fax Email: [email protected] Mail: P.O. Box 69 Waverly, MN 55390 Location: 4439 Hwy 12 SW Waverly, MN 55390 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Hinson, Ryan Sent: Thursday, January 28, 2010 4:54 PM To: '[email protected]' Subject: Hanging. bracing, or restraining from the bottom chord of a trussor joist I have always been instructed to hang, trapeze, or brace to the top chord of trusses, joists, and other structural members. I believe it is good practice to do so since the top chord is restrained via the attached roof from lateral movement whereas the bottom chord is not except where cross bracing is attached. That being said, is there any specific code reference that mandates this; or is it strictly up to the structural engineer to determine whether the bottom chord can handle the possible generated loads? Ryan L. Hinson, EIT, NICET III Fire Protection Systems Designer, Aviation and Facilities Group Minneapolis-St. Paul Office Burns & McDonnell 8201 Norman Center Drive, Suite 300 Bloomington, MN 55437 Direct: 952-656-6003 Ext 3662 Fax: 952-229-2923 www.burnsmcd.com<BLOCKED::www.burnsmcd.com> Proud to be one of FORTUNE's 100 Best Companies To Work For _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
