Engineering questions - steel laminate beams

[BHD]

I was in a building one time and they sistered up trusses in groups of 4 or 5, and it looked a lot like post and beam, and they were spaced for T&G roof decking.

from my beam calculator (a paper slide rule type from western wood products) a Douglas fir 2x14 joist, 16" oc., spanning 24', should carry a 46pound sq. ft. load, and at 12"OC about 62 pounds SQ. ft.,

Hemlock 2x14", 12" OC., 24 foot span, should be 50 psf.

Both were figured using construction grade (low grade lumber), select structural would be a lot stronger yet,

DO not take this as gospel but get you own engineering done, but this should be close, if one sisters up the joists one should be able open up the spacing, so a 4"x14", on 24" OC, I would think would carry the same load,

I do not have a calculator for steel but I would think if one laminated a steel plate in between two wood joists, one would increase the strength of it greatly, but I can not tell you how much.

in a span the depth of the beam is more important than the width of it, up to a point,

 

[notme]

i looked into this at one point, if i remember i found some information under "filch beam" wood on both sides steel flat bar down the middle don't be cheap with the bolts going thru... cant help you with with loads or spans i did make one with steel on the outside of the beam to open up a span and remove a loly column worked great so far ;p

 

[Jim Timber]

I have about 5 red pines on my property, and only one of them is big enough to mill. The wood I have that's construction grade is red maple and red and bur oak, which I have an abundance of (my clearing projects will result in sufficient wood to build everything I want, and then some). Since I can choose my trees, there's no reason to use inferior wood. The tree I hunted out of this fall was 17" DBH and clear to 30' where I stopped climbing. This is not an unusual red oak, that's quite typical of my stand. My concern is with what's inside them though, since heart rot can be present in anything, and I do have some wetter soils where I'm going to be clearing. Most of the larger trees I've dropped so far have been sound, so that's a plus.

I have an excess of quaking and big tooth aspen as well, but their lack of dimensional stability in drying, has me reluctant to try building large scale with them. I'll either try to sell them to Sappi again (my 100 cord contract offer was too small for their needs last time I asked), or mill them into small accessory structures for sale.

I'd like to make this something special instead of just using off the shelf trusses. I suppose if it came down to it, I could go that route and it would probably be cheaper (man-hours wise it would be). I'd rather have an angle iron truss I built than a wood one I bought.

 

[Jim Timber]

Think these'd work? :laughing:

 

[Jim Timber]

Maximum Span Calculator for Wood Joists and Rafters

That is a site that does span tables for different kinds of woods depending on the species and grade of the wood. Add your spacing and what load you want and it will tell you how far you can go. From what I just looked at, you can use Number 1 Red Oak 2x12's on 16 inch centers for a 50 lb load and only span 15ft 10 inches.

I've yet to find a calculator that'll do anything but 2x12 as a max size for a joist.

 

[Billrog]

The code here at one time you could span 24' with fir 2x10's 12" centers but some will sag 2.5" over time under their own weight , I've done quite a few with fir 2x12's on 12" centers and up to 28' with 2x14's but there is some bounce at those spans none have ever come down. If your have your own wood no need to buy LBL's or other manufactured beams. Make your own with 2- 2x12's or if you feel you need then stronger go 3-2x12's and use 1/2" or larger plywood ripped to the same size and nail it in between. Then hang your joist the other direction in between or on top with 12' spans.

 

[Jim Timber]

Ideally, I want a beam that can support the floor joists for a more typical 8-10' span. So I'd like "I=I=I" with the I's being my beams and the = being my floor joists. 12" centers is not going to work. I only need two of them if I have a 10' deep bay, because the outside wall will hold the other end of the first section.

I'm thinking a wood truss is needed to get this level of load supported, or a tall gluelam, but I'd have to purchase dried wood for those to be safe.

 

[Mysfyt]

You mentioned that a bridge crane is in the future. Would it make sense if you incorporated that as a support structure?

 

[Jim Timber]

So, what if I took (2) 8x8x24" red oak cants and used those for my top and bottom chords, then connected them with vertical columns of 6x6 red oak every 2' OC with M&T connections at every joint? If I made the truss 24" deep, that'd leave an 8" long 6x6 between the top and bottom. If I did this, would I have enough strength to support the floor with another truss at 10' and traditional sized joists between them? And would I need diagonals to convert the load to tension with that thick of a vertical web member and that small of gap between chords?

 

[Jim Timber]

You mentioned that a bridge crane is in the future. Would it make sense if you incorporated that as a support structure?

The crane will go under this floor, thus the clear span requirement. I already have the crane in place in my current shop, so the width is what's there now.

I actually plan to have two cranes in this building, but the second one will be in the two story open end supported by the roof trusses, and the main floor one will run the entire length of the center bent and run along the side of the first floor posts.