shoring an open web floor truss
shoring an open web floor truss
(OP)
What's a biomed guy doing in here? (hopefully not getting into trouble)... I have a 2 story home with open web floor trusses spanning 40ft bearing on front and rear walls; 24"oc. Trusses have settled (26yrs old) onto an interior nonloadbearing wall. Deflection of 2.25in now exists midspan on second floor over 4 trusses with drywall cracks and separation along 2nd floor ceiling and buckling/pop-up of 3/4"TG subfloor. I glued&nailed 1/2" plywood gussets over front 26ft last summer from below(remaining 14ft inaccessible)but problem has progressed since. Can I hang a beam under the bottom cord of the gusset section and jack-up sagging members or will I need to put additional vertical bracing between top and bottom cords at the site of the new beam. Section is over a garage so posts/footers not a problem. It's been a while since eng.mech. course but I do know bottom cord isn't designed for vertical forces.





RE: shoring an open web floor truss
Most likely you'll need a vertical member at the concentrated load of the support....
I'd talk to a local truss fabricator and see if they have someone who can come out and take a look.
RE: shoring an open web floor truss
I would hire a structural engineer to provide recommended fixes and then adhere to them. You wouldn't want to have that liability on your head should something go wrong, and if you want to sell your house down the road you will need a professional fix anyway.
RE: shoring an open web floor truss
Typical max truss delfection I use is limited to L/480 or one inch under live and dead load, you indicate 2.25 inches under dead load.
RE: shoring an open web floor truss
RE: shoring an open web floor truss
If, as was previously mentioned, the original designer assumed interior walls were bearing, then those wall locations would seem to be the best locations for introducing support now.
RE: shoring an open web floor truss
Hope this is helpfull
Boo1
RE: shoring an open web floor truss
I would contact a truss plant and talk to them as if you are building a new home. Tell them the span you have (40') and where you are proposing the beam. I am still surprised that 40' floor trusses are 24" o.c. Any good designer would have noticed the span and NOT just design with ALL walls as being bearing (per UcsfSe). I designed roof and floor trusses for 10 years. The main detail I was taught was to insure there was a beam or post or concrete wall under any bearing point. Now maybe the orginal plans called for a beam and posts, but the builder decided to eliminate them to make the space more open, and failed to inform the truss designer.
Anyway, I would definitely contact a truss plant. Talk to them and find out your options. Most plants might even put you in touch with an engineer.
RE: shoring an open web floor truss
If you contact a local truss company after describing your problem you might ask them to reccomend a structural engineer.