Discussion: View Thread

  • 1.  Design of Stair Members - Deflection Criteria References

    Posted 03-05-2020 03:32 PM
    I am looking for some references related to "industry standard" for stair deflection criteria.

    At a previous employer, I remember doing a deep dive into the (very limited) research available from a practical standpoint (i.e. if you are practicing engineer designing stiar support members). I no longer have access to that list of resources for obvious reasons. If I recall correctly, one or more of those references came from an AIA-related article/guideline.

    Particularly for monumental stairs, we found the ASCE-7 deflection criteria were insufficient when it came to keeping occupants from complaining about the vibration of the stair. I am well aware of what is in the code, but am looking for recommended references/criteria beyond the code. Thanks in advance for your help!

    Stephanie Slocum P.E., M.ASCE
    Engineers Rising LLC

  • 2.  RE: Design of Stair Members - Deflection Criteria References

    Posted 03-06-2020 08:37 AM
    The work of Thomas Murray on floor vibration is a very good source on floor vibrations and the sensitivity of people to them.  You are right to be concerned because in one of his publications he notes that he has never seen a successful field retrofit.  I distinctly remember a chart that showed a demarcation between perceptible and non-perceptible.  If you google his name numerous references will pop up.  I am not necessarily  a fan of "industry standard" because all to often it is biased to the lowest common denominator of least cost.  Damping also is a big factor.
    Don Lee, SE

    Donald Lee M.ASCE
    Struct Engr
    Don Lee Engineering
    Lakewood CA

  • 3.  RE: Design of Stair Members - Deflection Criteria References

    Posted 03-06-2020 10:32 AM
    Basic stair design criteria for deflection can be found in NAAMM AMP 510.
    Yes it is dated but the 1/4" deflection limit is used commonly in design specifications.
    I don't know that I have ever had a complain about stair vibration issues using this design limit.

    Timothy Schroder P.E., M.ASCE
    Canaan NY
    United States

  • 4.  RE: Design of Stair Members - Deflection Criteria References

    Posted 03-06-2020 12:24 PM
      |   view attached
    Go to the NAAMM website and download AMP-510 Metal Stairs Manual.  The latest version was published in 1992, but is still relevant.  The manual provides all kinds of information related to stair design, including landing design and handrail design.  If the stair is extremely long and not very heavy, you might need to add some weight to the stair to dampen the vibrations, assuming the structural components can support the added weight.

    Dennis Young P.E., M.ASCE
    Young Engineering, LLC
    Omaha NE