W8 x 28 structural beam for girder, need to pack out with 2x..

[compman723]

I am wondering what size bolts and at what pattern are needed. Because of height restrictions I can't use top hung joist hangers so that is why I need to pack out the web.

Thanks

 

[ishvaaag]

Without further info (some sketch and info on loads, spans would be welcome) it is hard to say, since design uses to be closely related with analysis.

 

[DLBennett]

You could use the same resources as multi ply wood members. The bolt pattern will depend on the side load PLF. Here is a chart

http://woodbywy.com/literature/TB-500.pdf

that you could use. Most LVL manufacturers will have them in their product tech literature.

DBennett
Lone Star Engineering, PC

http://www.lonestarengineeringpc.com

 

[compman723]

The span is 19.5 ft with 14ft till exterior wall on each side. The load is holding one floor no attic weight so I was using 40 psf live 15 psf dead to be safe. Let me know if any more info would help. I have done these before but always had room for a top plate and top joist hangers but because of height restrictions, cause we want it flush in a 2x10 ceiling that I have to pack out web and use normal hangers.

 

[ToadJones]

Even if you just carriage bolt some 2x's into the web of the W8 you can just cope the top of the floor joists that are framing in to the girder so they miss the top flange of the W8...should be small cope. Then just use regular joist hangers.
I did it many times in my bob-the-builder days.

 

[ToadJones]

This is very basic as far as the bolt design goes....figure out your floor joist reactions at your "pack out" ledger and size bolts to transfer the loads to the W8. If you are thru-bolting and there are floor joists on either side of the W8, make sure you account for loads from both sides on the bolts.
As far as checking the wood "pack out" itself, that is not my area of expertise (if I even have one)

 

[compman723]

Sounds good that seams like a good idea... Also I was wondering is there a spot where I can find the compression strength of a 4x6 or maybe I need a 6x6. I have heard people using these for end posts but I just want to make sure they are strong enough. I have calculated about 29,000 lbs over the beam so probably each post needs to be able to handle half that.

Does anyone have any insight on this? Or is a steel permanent post really the best option?

 

[msquared48]

If this is a residence with sheetrock walls, I would try to stay with wood columns considering differential vertical shrinkage. 15 kips is doable with a wood column, however, depending on the location, it's presence may be readable depending on the size and orientation. You will have to be the judge of that.

Other than that, a 3.5" standard pipe column would be normal to use, depending on the unsupported lengths of the columns.

As for "packing" the W8, I thought that Simpson made weldable top flange hangers so that this was not necessary. Hate to weld in the field, but...

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[MiketheEngineer]

I like to use steel columns in concrete basements and then switch to wood above where wood is generally used in the walls.

 

[wannabeSE]

Have you considered welding the hangers to the top of the beam (

http://www.strongtie.com/FTP/bulletins/T-WELDUPLFT10.pdf

)? Or does this add a different trade to the project that you would like to avoid?

 

[hokie66]

Why would the web bolts have to carry the load? The packers would sit on the bottom flange, and the bolts would just need to tie it all together.

 

[msquared48]

Hokie is correct, assuming that the packing does not shrink over time, which would load the bolts.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[compman723]

Would a 4x6 on each end be strong enough to hold this load? I calculated the load at almost 30,000 lbs. Or if not would a 4x8 or what would I need to hold this?

 

[msquared48]

What you could do to mitigate any shrinkage effects for the wood would be to install vertically elongated holes for the bolts in the wood member, and mount the bolt low on the hole to allow for vertical settlement. Stagger the holes vertically to minimize horizontal splitting and use washers on both ends.

I would also provide a 1/2" gap between the top of the steel beam and the underside of any diaphragm sheathing, if that is possible, otherwise shrinkage will cause the wide flange to be read on the surface of the diaphragm.

Finally, the infill here should be done with a 4X8 ripped to size, not a 4X6. It should be a tight fit in order to engage the bottom flange in bearing. The vertically slotted holes will keep it that way.



Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[compman723]

Thanks for everyone's input I think I have everything solved except how big of wood posts I need to hold up the beam on each side? Is a 4x 8 big enough ?

 

[msquared48]

Depends on the load, grade, and unsupoported length. What do you have?

You can always check the allowable bearing using .3E/(l/d)^2.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[compman723]

The unsupported length will be 19.5 ft
the load I calculated to be 29000 lb
not sure on grade I think you mean wood and that would just be douglas fir or pine....

If anyone can point me in the right direction for this I would greatly appreciate it.

Thanks again everyone!

 

[msquared48]

he formula and method are in the AITC manual.

Basically, calculate the allowable bearing stress in psi on the column using the formula I gave you, and multiply that figure by the area of the column to get the capacity.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[BAretired]

compman,

I am wondering why you are undertaking this project when you do not know how to size a wood column. You seem to be asking us to size your wood column for you. That is not what we do on this forum.

Assuming you are correct in your calculation of 29,000#, it is a substantial load, much more than the capacity of an ordinary telepost of about 8,000#. It seems to me that you should be engaging the services of a structural engineer because you clearly do not know what you are doing.

BA

 

[jdgengineer]

I couldn't agree with BAretired more. If you can't size a simple wood post you shouldn't be doing what you are doing. I'm not trying to be rude but you clearly seem out of your area of expertise, and in my opinion you should be seeking the assistance of someone else to help you.