Rest of Example Problem ...

 ...

So, yeah, here is the rest of that example problem. 

Recall we found that to satisfy the Live load deflection criterion we needed EI = 320 million lb-sq.in. ... we got it with the TJI-110 14" EI = 392 million ... good! ... and the TJI 210 16" 629 million ... WAY GOOD!

( ... whoa, there isn't a 110 series joist in the 16")

The we checked Moment (`flexure') ...

area load = 40 psf Live + 45 psf Dead ... the Dead being 15 psf from framing and 30 psf for 3 in. lightweight conc.

w = area load x spacing = (40 + 45 psf) x 16/12 ft = 113.3 plf

M = 113.3 lb/ft (17 ft) squared / 8 = 4094 lb-ft ... NEEDED!!!

p. 3 of the brochure (http://www.woodbywy.com/literature/TJ-4000.pdf) ...

TJI 110 14" M = 3740 ... NOT GOOD!

TJI 210 14" M = 4490 ... OKAY!

TJI 16" 210 Series ... M = 5140 GOOD!  BABY!


 ... now ... SHEAR!!!

V = wL/2 = 113 lb/ft (17 ft) / 2 = 960 lb.

p. 3 of the brochure ...

TJI 210 14" ... V = 1945 lb ... GOOD!

TJI 210 16" ... V = 2190 lb ... GOOD!


So, the 210 Series works, in both the 14 in. and 16 in. depths.


BEARING ...

R = V = 960 lb

End ... p. 3 ... 14" 210 Series ... 1005 lb for 1-3/4 in. of bearing.

Assuming 2 x 6 walls that will have 5-1/2 in. top plates ... and that the rim will take up about 1-1/4 of the 5-1/2, leaving over 4 in. ... good!

We'd be good even if we dropped down to 2 x 4 framing ... 3.5 in. minus 1-1/4 gives 2-1/4 ... good.

FOR THE INTERMEDIATE BEARING - INT. BEARING WALL ...

 ... we'd probably have a 2 x 4 wall, at least ...

 ... if the joists end/start over the wall ... they need 1-3/4 in. each ... 2 x 1-3/4 = 3.5 ... perfect!

16" ... same ... good!


If the joists span continuously over the interior support ... we'll address that on another post! (or in class)


ANSWER: TJI 210 SERIES JOISTS IN EITHER 14 IN. OR 16 IN. DEPTHS ... WILL DO IT!