Simplified Experimental Evaluation of Floors Subject to Walking-Induced Vibration

When occupants complain of lively floor motion due to human activity, it is often necessary to estimate the dynamic properties of the floor and ascertain the form and level of vibration response toward the goal of designing an effective retrofit solution. The most detailed and accurate experimental method is to determine the natural vibration modes using full experimental modal analysis, which requires substantial equipment including at least one floor shaker, and then determine the acceleration due to walking. However, due to cost and time constraints and possible unacceptable occupant disruption, it may not be possible to perform a full experimental modal analysis. An alternative testing procedure is to use a handheld spectrum analyzer to record floor accelerations due to heel drop and timed walking excitations. These measurements are then used to estimate the natural frequencies and vibration response level, respectively. This paper describes the procedure and compares results with experimental modal analysis techniques. The method is illustrated by a case study of an in-service floor and is shown to be economical, convenient, and effective. (C) 2014 American Society of Civil Engineers.