Escalator support design criteria

[MitchelLH]

I am designing the structure to support an escalator in a shopping mall. Is there a code based allowable deflection criteria for the beams supporting escalators?
I have heard that the deflection of the supporting element should be limited to L/1666. However I can not find a reference.
Any help is appreciated.

 

[KootK]

You need ASME 17.1 Safety Code for Elevators and Escalators. It's a pretty dry read.

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.

 

[KootK]

This book has some decent info too: Link

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.

 

[MitchelLH]

Thank you for your reply KootK. I did spend some time reading ASME 17.1 on this issue. I was unable to find a specific allowable deflection design criteria for escalator support structure. There is allowable deflection criteria for elevator guiderails, but not escalators. If you know of a specific section could you please provide?

 

[EngineeringEric]

I do always love the response of manufacturers who state "No Deflection"

Ina document from Washington Metropolitan Area Transit Authority...

1.02 GENERAL DESCRIPTION OF ESCALATORS TO BE REPLACED
A. Structural requirements: Escalator truss structures shall be designed for a maximum deflection less than 1/1000 of the span between supports. Deflection calculations shall be based on the escalator component weights, including truss structure and truss cladding, combined with the passenger design load stipulated in this section.

 

[KootK]

Nicely done Eric. That's been saved to the KootK archives. Technically the L/1000 is for the trusses comprising the escalator rather than the supporting beams. Although, I think that we get the idea: deflection should be non-existent. Maybe L/1666 comes from the elevator code. It kind of makes sense that what is good for one machiney thing would be appropriate for another, particularly when both are referenced in the same standard. I feel that an absolute deflection criteria would be the way to go.

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.