Elevator Guide Rail Supports_Cont'd

[JustAnArchitect]

RE: thread507-347179
This same solution - supporting elevator guide rails from metal stud framed hoistway walls - is being recommended to us by the elevator contractor/installer for a new 2-story office building. The 6" stud hoistway walls would be engineered to accomodate the guide rail loading by a structural engineer. We have always used HSS tubes to support elevator guide rails on similar previous projects, so I'm unfamiliar with using engineered metal stud framing in lieu of the steel tubes. Has anyone out there done this recently? Or seen it done? Thank you.

 

[KootK]

I've done this often in wood stud and see no ready why it could't be done with CFM studs. Can you elaborate on your particular concerns?

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.

 

[TehMightyEngineer]

I have also done it with wood studs. Deflection will likely control. Overall I didn't get the impression it would be cheaper to try to use anything other than the normal "heavy" steel framing or CMU walls.

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com

 

[jayrod12]

The one time I almost had one done out of wood the process went something like this:

Contractor: If we could change the elevator shaft from masonry to wood it would allow us to remove an entire trade from the job
Me: This is certainly an option however it may require some significant stud backing behind the rails
Architect: Will this be cheaper?
Contractor: Yes it will for sure be cheaper regardless of number of studs

So we go ahead and modify all of the drawings and details last minute in order to meet the submission deadlines. And then....

Architect to Elevator sub: Can you provide shop drawings showing wood stud backing as opposed to Masonry?
Elevator sub: No way, we do not recommend using wood, we have had nothing but issues with shifting.
Architect: Ok we'll go back to Masonry.
Me:

 

[JohnnnyBoy]

All,

Please take my advise with a grain of salt as I am still an EIT. I've worked a few separate elevator designs with Thyssen Krupp and throughout the design they had no issue with the wood stud post to support the guide rails. According to the elevator drawings we received there is also seemingly a very small amount of loading on them. In the case of a 2 story building it was calculated as 620lbs against the rail and 716lbs acting laterally on the rail which can be easily supported by wood posts.

I can't comment on the serviceability of the elevator and it was obviously not recommended by your elevator designer but in my experience there has been no issue.

 

[KootK]

It's worth noting that a CFM system would not be prone to the same shrinkage issues that plague wood shafts.

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.