Comparisons of measured modal properties and walking accelerations with analytical predictions for a slender monumental stair

Over the last few years, slender, clear-span monumental stairs have become increasingly popular in hotels, hospitals, and a variety of other structures. These stairs are vulnerable to annoying vibrations due to walking. Finite element modeling techniques may be used to predict the vibration response of a stair, but experimental verification of these procedures is not available. An experimental and analytical study was performed toward the goal of better understanding vibration characteristics of monumental stairs and to judge the accuracy of finite element modeling predictions. A monumental stair containing heavy glass treads and guardrails, supported by slender hollow structural section (HSS) stringers was used in the study. Experimental modal analysis techniques were used to estimate the stair's modal properties. Stair ascents and descents were also performed to determine the acceleration response. Finite element modeling techniques were used to predict the natural frequencies, accelerance FRF peak magnitudes, and acceleration response to walking. The experimental results are compared to the finite element modeling predictions to determine whether or not the finite element modeling techniques provided reasonably accurate predictions.