Steel I-BEAM equivalent to a 2"by10" hardwood beam

[JohnnyVolvo]

Gentlemen,

I need to replace a cracked floor joist under my
dining room.

What size of commercially available I-Beam should I use
that will be equal in strength to a 2" by 10" wooden beam?

The span length is 14'-6". I plan to wedge it under the floor on the cross joist at one end and jack it up into place at the other.

 

[Ron]

Same post in AISC forum....

Assuming the joist is fractured as you described it can likely be repaired in place which would be lot easier than removal and replacement. If you want to repair it in place, consider using a piece of 6-inch wide steel flat bar, 3/16 of an inch thick, for the full span. Drill a 5/16-inch diameter hole, 1-inch of the edge of the plate every 6 inches, top and bottom, staggering the holes by 3 inches from the top and bottom (start the top holes at 3 inches from the end, then drill one hole every 6 inches, and start the bottom holes at 6 inches from the end, then every 6 inches).

Jack the joist back into place and put the plate on one side of the joist with the bottom edge of the plate flush with the bottom of the joist. Clamp everything in place and drill corresponding 5/16-inch holes in the wood joist, inserting a 5/16-inch corrosion resistant bolt in each hole as drilled. You will likely need to hammer the bolt through, but this is intentional as you need the fit to be tight. Place the head of the bolt through the plate side and place a 5/16-inch fender washer on the wood side followed by a lock washer and nut. Tighten the bolts until the wood fiber starts to compress.

This process is called flitching or flitch-plating the joist.

If the joist is beyond repair, replace it with another wood section. The steel as a retrofit will be difficult.

 

[LPPE]

Why not just sister a new 2x10 to the cracked one? Or if your really concerned, sister a 2x10 to each side of the cracked joist. Probably cheaper than finding a steel plate, making holes, and bolting.

 

[dik]

JohnnyV...
Any idea of why it broke? Can you describe the type and location of cracking (midspan, end, horizontal split, shattered, bottom broken (shredded appearance) andy knots, etc.)?

FYI, the joist is likely a softwood member (fir, pine, spruce, etc.). Funny that well seasoned Douglas Fir is so hard that you can barely drive a nail into it is a softwood and that Balsa, the model airplane stuff is a hardwood... gymnosperms (conifers, or needle trees) are softwoods, and angiosperms (deciduous, or leaf trees) are hardwoods.

 

[idl]

Double-up the existing wood joists as required. Forget the steel beam.