Have you ever encountered resonance in stairs? AISC Design Guide 11 - Vibrations of Steel Framed Structural Systems Due to Human Activity provides parameters for checking resonance of monumental stairs when subjected to walking - considered at a period of 5 Hz. Other parameters based on an observer standing on the stairs while someone descending are also given. Design Guide 11 provides limited guidance for rectifying vibration in stairs, just recommending stiffeners.
What would be the best approach to correcting any issues encountered in field? Consider that the factors that impact vibration include: span, moment of inertia, and weight. Possible remedies include cross bracing, adding weight, stiffeners, or adding depth to the stringers.
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Chad Morrison P.E., M.ASCE
Professional Engineer
Greenville RI
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