Connections Design and Shop Drawings

[Heldbaum]

Hello folks,
I've received a project where I was asked by the contractor for steel shop drawings and connections design (EOR requires signed and sealed calculations and SD). Please see attached framing plan. It's a 6-story building, first floor is commercial and residential floors are above. I am attaching here first floor (commercial) framing plan. EOR design loads is LL 100 psf for this floor and DL as per material (he calls for 4" LWC) so let's say overall DL is around 65 psf. so it's roughly 170 psf for 14' long w8x15..Seems too small for me. He calls for shoring of beams while concrete is being poured. but still, taking into account composite action, I wouldn't feel comfortable with W8x15..Plus construction wise, connection won't be easy to do in field. What do you think ?
Thank you for your input.

 

[WARose]

This may be a question to raise with the EOR. What is your role in this? Steel fabricator?

If you have design software, you may want to run a few beams with it unbraced and a reasonable construction load and see what you get.

 

[dik]

That framing looks very light (without running any numbers) have you considered using 2x10 @ 16?... just curious.

You will have lots of fun providing connections... maybe a 3/8 endplate welded to the beams with a couple of bolts... one on ea side since you will have difficulty in getting 2 lines of bolt holes in an 8" deep member.

Dik

 

[Heldbaum]

Yes steel fabricator. Yes I am going to contact EOR, just was curious what smart ppl here think

 

[WARose]

Good. By the way, what is that notation in ( ) behind the member sizes? It says stuff like: "W8x15 (2,2,3)".

I'm use to seeing only elevation differences between top of steel and finished floor in ( ) behind sizes.

 

[Heldbaum]

WARose - shear studs..

Dik - yes that's what I thought, that connections will be difficult with W8..Steel manual doesnt even have W8 in its tables with composite members capacity..

 

[DETstru]

For those short spans and small tributary areas the framing seems fine. You can always call the EOR though.

W8's always make for tough connections so there must have been ceiling height issues that forced the (relatively) heavier W8 choice over lighter W10's, especially for the girders. Would've been nice to avoid coping the bottom flange of the W8 beams that frame into the girders had the girders been W10's.

 

[dik]

3 shear studs is silly... you may as well miss the middle one, it doesn't do very much; you effectively have one shear stud working at each end...

You may want to add a C4 where the deck changes span direction... and keep the span direction the same.

...and don't forget L1x1s at the columns where they poke through the deck to provide support for the deck...

Dik

 

[KootK]

Is a W8x15 really all that hard to connect? Seems to me you've got 6.5" where you're trying to get a 6" tab or angle in there. And you can probably tighten up the bolt gauge too to give it a bit more room.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[DETstru]

Koot, it's not that hard to connect but having to cope both flanges out to connect it to the girder makes it tight.

They could use an extended tab but that's more work to design.

 

[KootK]

Yeah, beam to girder isn't optimal. I was thinking of the girders to the columns.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.