Human-induced vibrations in light-gauge steel floors: tests, finite-element analysis and design guides

This study examines the dynamic response of light-gauge steel (LGS) floor systems subjected to human-induced vibrations, with emphasis on occupant comfort and serviceability. A full-scale LGS floor was experimentally tested using heel-drop and fast-walking excitations to identify its fundamental frequency and acceleration response. The heel-drop test provided natural frequency and damping characteristics, while fast-walking tests represented realistic occupant activity. A detailed finite-element model was developed to perform modal and time-history analyses, and numerical results were compared with predictions from the American Institute of Steel Construction design guide 11 (DG11). Experimental measurements indicated a fundamental frequency of 6.25 Hz and root mean square (RMS) acceleration responses between 5.47%g and 5.58%g. Numerical simulations showed that assuming a 20% live load contribution yielded a fundamental frequency of 6.23 Hz, which closely matched the experimental results. Time-history analyses predicted RMS accelerations ranging from 5.18%g to 7.10%g, with damping ratios of 3–4% providing the best agreement with measured data. In contrast, DG11 significantly underestimated vibration response, predicting only 1.1%g. The findings demonstrate the limitations of current guideline-based approaches and support the adoption of distributed walking load models, RMS-based performance metrics and validated time-history analysis for reliable serviceability assessment of LGS floor systems.