deep steel beam to shallow steel beam framing

[redun]

I have a 27 ft span. calcs. shows that a W12x14 should be ok.this W12 would frame into a W8x10 that only spans 5 ft. I am thinking about making the W8x10 a W 10x12 just so they dont have to cut out so much of the W12 to fit it to the W10. But I dont think its really necessary -just looks kinda strange to have a W12 connected to a W8 (TOS=TOS).
Just curious is there some rule of thumb, or usual, or standard, practice regarding beam to beam connections and depth ratios? Is there any problem framing a W12 to a W8 ? I figure theyll be able to get 2 bolts in so shear is no problem not a problem with the net web remaining either. But I'm just wondering if I missed anything.

 

[AVak]

Unless you want to answer some questions from the owner about this situation, I would suggest up-sizing the W8x10 to a W12x14. I had a similar situation a few years ago and the owner asked me why a small beam was used to support a larger beam. Since that time I have always tried to use at least the same depth for my supporting beams as the supported beams. Ideally for a beam to girder connection, I like to use a girder depth deeper than the supported beam(s).

Adam Vakiener, P.E.

 

[nutte]

Beam is 5 ft long. W12x14 is 4 #/ft heavier than a W8x10. You're adding 20# of steel while simplifying the connection and keeping it from looking weird. Nothing to even think about here.

 

[redun]

Thanks AVak and nutte. Good points. This detail occurs over and over,not just once so I didnt want to just upsize the W8 arbitrarily, but could be the extra cutting out of the W12 to connect to the W8 would be more expensive than just using a W12 short beam as well. I think I may upsize the 5 ft beams as you suggest.

 

[azcats]

The fab shop can also use the drops from the 27' beams to make the 5' beams saving the owner from having to buy additional 8x10 material. Depending on the size of the job, shops don't always eat the drops from cutting 40' or 50' beams.

 

[redun]

azcats Thanks -another good point-

 

[JedClampett]

My personal preference is to not use those little 4 inch flange members, like W8 x 10's and W12 x 14's. It just seems like anytime I've had an issue, it was with one of those tiny sections. I guess you've checked the beam and the loads are small, but I'd rather overdesign a little, and use a W12 x 26.
One thing to think about is that if these are roof members and you're welding steel deck to them, it's harder for the spot welder to hit the beam with a 4 inch flange.

 

[MiketheEngineer]

Just keep it the same - done all the time. Probably save labor costs??

 

[msquared48]

I agree too with the 12X14. KISS.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[hokie66]

Don't know what you are designing, but be sure to check that deflections of the W12x14 are satisfactory. I always like to keep the span/depth ratio to 24 or below.

 

[LSPSCAT]

Same thought as hokie66 - W12X14 seems light for a 27 foot span...

 

[JAE]

I once saw an elder engineer yell at younger engineer once when they were out on a job site and a W24 was framing into a W10. It looked really stupid and the older engineer let them have it.

Mathematically it works. Visually....it looks stupid.

 

[msquared48]

The older ehgineer should have screamed at himmself JAE for not checking the drawings...

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask