TJI
https://parr.com/PDFs/TJ-4000_ijoist_guide.pdf

http://www.weyerhaeuser.com/woodproducts/engineered-lumber/tji-joists

 

Your going to need at least a center support on that 28' span. As for the other a 12" or 16" TJI will span but the I beam needs supported on both sides in the middle. Also what is going on the mezzanine? The weight of what is going to be there will make a difference.

I am willing to bet if you support that beam at just the ends it has at least an 1" of sag in the middle. But I could be wrong.

 

If the max span is 18', use 360 series TJI's that are 11 7/8 tall and do what you like up there.

 

Need to know the lbs/ft weight of the beam.... usually stated like W12x100 or whatever. That tells us how much it can support.

"12x15" isn't near enough info. If you have the flange and web thickness, it can be matched up to a chart.

Generally speaking you are looking for deflection loaded to be less than L (in) / 360. The joist calc is easy but your clear span beam needs calculated before doing anything else.

 

Dad got it off a road job his company did. It was used under a bridge on a dirt road.

Off the top of his head:

Top and Bottom Flange: 1/2" x 5" wide

Web: 15" outside measurement top of top flange to bottom of bottom flange x 1/2" thick

If he needs to go measure anything he will if the above numbers don't get us there.

 

What is going on that floor?

 

Storage mainly. He's 64 and not crazy strong so it'll be limited to stuff he can carry up stairs until he figures out how build a winch elevator and then starts bringing up parts or other random shit. he might put some metal drops up there or something I guess. Is there a standard for what the per square weight load should be for various types of purposes?

It is zoned commercial, so long term it could be sold or rented to someone for commercial purposes. Does that bump him into a different set of standards?

 

You can also look at putting the "end" support at the 2/3 span length instead of the very ends. The will reduce your unsupported length.

Of course, you really should know the maximum loads and have someone verify the design. Also if it's a mezzanine design, take into consideration what someone will hang/attach from the bottom side along with the weight on the floor above. Like a hoist of some kind?

By the way, when all is said and done there should be a lb/ft2 weight calculation that should be noted/posted somewhere so someone doesn't get crazy now or in the future. But I'm an Engineer so feel free to just ignore me....

 

I've tried to get him to offer up what he plans to put up there but he can't give a number. He says coolers, tackle boxes, just random crap. He said he doesn't plan to put any steel up there or store any metal drops. He's still got his bike he's own since the 70s but hasn't ridden since '83. He's just got your typical small town midwestern hoard that he's amassed over 50 years with nowhere to put it but he can't part with it for whatever reason.

If someone could give me a ballpark of "this is good for up to x lbs-ft" I'd at least feel better that he had an idea of what he had available to him.

I'm an engineer too, just the wrong damn kind. I figure out Erlang calculations for the number of phone calls generated by a population of people. Not how strong a floor is =\.

Absolutely appreciate everyone's feedback on this.

 

Some barn yard engineers up in this MF'er...

 

What I am reading from your post is a LOFT ...or am I missing something? ... from what I know a mezz is a floor OVER a room inside a building.

 

He calls it his mezzanine project. Loft is really more accurate. He's got an open pole barn with 16' walls and the back 20' of it have vaulted rafters for headroom of a 2nd floor back there.

Underneath this floor he is debating on if he'll put his tools and make it his work area or if he'll just store his boat, tractor, Dart, and other misc stuff. Either way, I'd prefer this thing not crush him or my future car .

 

OK, an "I" section beam measures as follows:

15" tall

I15x42.9: web thickness 0.411" flange width 5.501"

I15x50: web 0.550" thk Flange width 5.640"

Does that sound right?

 

I'm going to send him back down there to remeasure tomorrow. He swears the top and bottom flanges are 5" but I can't find anything that has a 15" section height with a 5" flange. Just the 2 you've posted that are 5.501" or 5.640".

Unless KDOT uses something crazy to build rural bridges in Kansas it should one of those. I've measured the section depth myself and know it's 15" because I double checked his math to make sure he cut his posts to the right height.

I'll post up again as soon as he has a chance to go down and measure them out and figure out which one he has. I really appreciate everyone's insight.

 

The only guy who knows what to do is a licensed engineer or architect who will put his "seal" on the calculations and plans....... Might cost a few $$$ but it will be worth it.

Spend the money and hire a PRO because your loss may be more than just financial.

 

I did something similar in a house, 2x12 syp will clear span 16' one end was supported on the wall, similar to your outside wall beam. The other end was on a 4.5 x 11.25 lvl, with a 20 foot span this was specd and signed of by an engineer. So this was a 16x20 clear span.

Just to give you an idea.

 

As a structural engineer who owns my own engineering company these threads always get interesting. One big item that needs to be addressed is not only how the floor live load will be supported vertically but the overall lateral stability of the new storage/mezzanine floor area. I believe I thought I saw in one post that this was a commercial building. If this is the case and if used and classified as light storage would require the floor to be rated at 125 psf. Or in some instances can be rated lower if posted as such with a supporting letter from an engineer. It isn't uncommon to have insurance companies request a load rating evaluation be done on older mezzanines that don't have any information on them. I just did a load rating on a parts storage mezzanine at the local town garage due to a state audit they had.

Using old beams is interesting as the designer would have to assume what kind of steel material the beam was made from and thus the yield stress of the material. Being an older beam chances are it was made from A36 steel but if it is really old could be A7. Ask around who is a good local structural engineer who isn't an egghead and that you can talk to on a common sense level and they will steer you in the right direction.

Paying a few hundred dollars to have a guy come out take a look at your situation and give you some guidelines on the feasibility of what you want to do is the best thing to do. If they think what you want to do is rational then you can pay him to design and detail it up for you and most importantly stamp & sign (certify) the drawings.

 

I'm still waiting for him to call me this morning. Appreciate the continued feedback.

I knew and expected the comments for call an engineer and do this by the book. I'm much more by the book than my father, which is why I'm asking the question and not him.

4 Speed Dave, right now this building is a personal storage barn for his hoard. However, the lot this building is on is zoned commercial and could, at some point in the future, be rented or sold as such.

Also, the steel is not old, it's brand new steel that was left over from the bridge construction last year that was going to be recycled and he was told to get it out of there before they hauled it off, so he did. The steel under the old bridge was recycled. I thought I took pics of the beams but apparently I didn't. You can see in the pics the vertical supports are tied into posts used for the main building verticals. They are lag bolted into the posts from 2 directions using welded on mounting tabs (fortunately, he didn't do the welding, the welder at the construction company he worked at did). The same welder welded the I beams to the posts when they were set a couple of weeks ago when a group of guys from work came down and helped him set them.

The main posts for the building are set 9' apart, thus sitting one I beam at the back wall and the other attached to the 2nd post the loft becomes 18 feet deep. The beam across the back wall already has a center support because it won't be in the way back there.

Found a couple of pictures that kinda show what he's trying to accomplish. You can see a couple of the vertical supports in the process of getting set in these pics.

Also, where those posts sit the concrete was poured thicker, though I can't recall the exact details of what they did. Dad told the builder he was going to put loft supports in those places so when they set the poles they dug out and created a bit of a footer for those posts to rest on thicker than the main slab. The majority of the slab is 4" thick.

If I don't get anywhere with the power of the internet then I'll pay for an engineer myself to go make sure what he's doing isn't going to get him or anyone else crushed. Like I said at the beginning, everything looks solid as hell, but I'm the wrong kind of engineer, and I know what looks strong may not actually be.

 

That sounds like a strange piece of steel.
Typically when the flange and web are the same thickness, it's an H-Pile, but then the flange width is close to the depth.
One clue to if it's an "S" (Standard) beam is if the flange thickness is actually tapered.

It's not a fabricated beam made from plate is it?
You can tell by looking at the joint of the web and flange.

 

Dad finally went and measured the beam and it matched exactly to the smaller beam.

I15x42.9: web thickness 0.411" flange width 5.501"

 

this is how I did it if the picture shows...

 

It's not a strange piece of steel. It's an I-beam.

Furthermore, as long as you run sensible calculations, everything will be kept far below the yield stress, so let's not get all wound tight about it.

Like I said before, a rule of thumb is to keep deflection to less than L/360 (length in inches divided by 360). In your case this is really easy because your beam is 360 inches long. So we need to keep that beam under 1" deflection, loaded.

So we start with the beam by itself. Its own load is 42.9 lbs/ft evenly distributed. Running the beam calc on that says that it's sagging 0.72" just of itself. So obviously......you MUST put support post(s) under it.

You figure out where you want them and we can keep on truckin'.

 

I'm guessing it's either going to be 1 or 2 posts. If a single center post is sufficient he'll go that route. He has to put 2 posts 10' in from each wall, he'll do that.

How does the math work out in either of those scenarios? Ultimately, he's got the beam, the beam is installed, so how many posts does it take to make is secure?

 

I'm guessing that building a mezzanine, to hold 6 cars, would scare some of you?

 

Wouldn't bother me a bit if the guy building it wasn't too stubborn to get it engineered correctly

 

What was alluded to earlier. I would be as concerned about angle bracing the legs to keep the house of cards effect from landing on him. Also when you are all done run a chain to the top rafter so it will fail slow if it fails. j/k Rod

 

Angle bracing was added once the beams were lifted in place, along with cross bracing between the beams to tie them together.

 

Plenty of things can, and are, built wrong...Plenty of times a person takes a half ass approach to doing something, and the results are catastrophic...

Mine will be built with 4 legs for each car, and that will all be tied together as one...It will also be tied into two walls of the building, with plenty of cross bracing...I have been told it is overkill, but IMO that is better than cutting corners.