Beam Size for Supporting Double TJI230 2-5/16 by 11-7/8 1

[aokamura]

Hi,

I was wondering if anyone could help me with this small problem...

I'm trying to come up with the most economical solution for a beam that needs to be put under double TJI230 2-5/16 by 11-7/8 members that are taking 320 PLF dead and 280 PLF live loads. Simply supported.

An alternative to placing a beam under the double joist is to add additional joists to the double, making it a triple or quadruple joist... which is highly unlikely.

The project is already under construction, so removing the double TJIs is the last resort.

Thanks!

 

[msquared48]

Why not use double 1.75 X 11.875" microlams - one each side if necessary. Probably an overkill, but could work.

I assume you are needing to place the new beams parallel to the existing joists.

If you need to support the joists in the transverse direction, you can shore and cut the existing joists to receive the new beam with the top flush with the underside of the plywood, and hang the joists off the beam. This will increase the capacity of the joists due to the shorter span, but the beam will have to be sized to take the load.

Mike McCann
MMC Engineering

 

[aokamura]

msquared48,

Thanks for your reply. Actually, double 1.75x11.875 microllams don't work... the bending moment is too large and the total deflection is way over the L/240 limit.

Based on my calculations, I came up with either a double 3.5x11.875 parallams or a single 7x11.875 parallam. Would taking out the double joists be the optimal choice? I'm not familiar with the parallam costs, so I don't know if single 7x11.875 is cheaper than 3.5x11.875 either. Would you happen to know?

I guess I'll have to cut the double joists like you suggested...

Thanks!

 

[frogit22]

could do LVL with steel flitch plates, possibly?