Reinforcing Existing OW Steel Joist

[BurgoEng]

I am trying to find info(methods, details) for reinforcing existing open web steel joists. My situation is that we are adding a 2nd floor to an existing building and the existing rood joists will become overstressed in shear at the end supports with the new loads. Thoughts, ideas? Capacity is 6kips, new loads bring the end reactions to about 7+kips

I understand a paper was published in the Engineering Journal by James Fisher discussing this topic. Can I find this on the web somewhere?

 

[JAE]

If you join AISC you can get it online free.

http://www.steel.org

Also check out these threads
--->
thread507-102327
thread507-17645
thread507-6993

 

[haynewp]

There is a book "Designing with steel joists, joist girders, and steel deck" that explains and gives examples of reinforcing joists. Fisher is one of the authors.
But if there is a whole floor that will be overstressed at the ends of the joists, I would consider sistering in new joists beside the existing rather than all the modifications that will be required. But it may not be that much to do if the joists are within a kip of working for shear.

 

[nutte]

http://www.steel.org

is AISI.

http://www.aisc.org

is AISC's website.

 

[DaveAtkins]

The likely solution is adding angles to the web members (since shear is your problem). If a web member is round, an angle fits around it and is welded to it.

DaveAtkins

 

[structural01]

There's an example calculation at buildabout.com you can download.

 

[connect2]

Same on the DaveAtkins solution to the shear problem wrt. the webs where feasible. With regards to the tension and compression in the top and bottom cords, and deflection, we add round bars to the top and bot. chords at the junction of the two legs were feasible from a construction and analysis point of view. Neither simple nor quick from from an analysis or constructability point of view, 'proprietory' joists aside. Its a job trying to 'beef' up existing open web steel joists.

 

[JAE]

nutte - thanks for pointing out the incorrect link - I copied the one next to AISC on my Favorites sidebar.