Vibration in non-linear stairs

[JDV22]

Hello!

I am trying to work my way through a vibration check for a staircase. Typically I just page my way through design guide 11 but in this case I am working with a stair that has a curve in it. Design guide 11 has a section that is labeled "Recommended Evaluation Criteria for Linear Monumental Stairs". Since my stair is technically not linear, does this mean these considerations do not necessarily cover my stair?

My question for all of you is: Can I still use DG11 for my vibration check and if not, can you recommend any technical papers or procedures I can reference to help me in my calculations?

Thanks!

 

[Lomarandil]

The research that backs the stair recommendations in the newest edition of DG11 (sorry, name is escaping me) is based on testing for one linear stair, and one stair with one main flight and two small flights on the wings. So not strictly linear in that sense.

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just call me Lo.

 

[JDV22]

Thanks for the response Lo!

DG 11 defines linear as "straight in plan view", so while the stair may be interrupted with landings, it is still a straight line when in plan view. My question is pertaining to what type of design considerations I need to take into account when analyzing a curved stair in regard to vibration. From what I have been reading in DG11, finite element analysis is recommended for non-linear stairs. What I would like to do is be able to use a numeric method rather than jumping into FEA since FEA is not readily available for me. Does anyone have any recommendations on what they have done in the past when analyzing non-linear stairs for vibration or some references to technical document that may assist in some calculations?

 

[glass99]

JDV22: most people just worry about hitting the 5Hz number, which is definitely the most important thing. If you want to do more you have to dive into FEA (which is a pain).

 

[Agent666]

I'd say in general the same limits apply to curved stairs, you'll just have more trouble meeting them due to a curved stair being invariably more flexible than a nice straight linear stair.