Floor modal mass identification using human-induced dynamic excitation

Abstract

Modal mass is the mass that is activated in a certain vibration mode, which is an essential modal parameter. It is difficult to obtain precise modal mass from identification methods because accurate measurement of external excitation is not easy in structural modal testing. Hence, the study uses the pressure insoles to easily and precisely measure the human-induced loads, and proposes a corresponding iterative correction method to identify the floor 1st-order modal mass from its resonant responses caused by single person dynamic loads. The method identifies the modal mass by weighted nonlinear least-squares iterating the errors between the calculated and measured multi-point acceleration responses Fourier spectrum, and corrects the natural frequency and damping ratio to ensure the accuracy of the identified modal mass. Applying the method to two actual prestressed concrete floors with maximum identification error of 6%. It provides a convenient and accurate way to obtain the floor modal mass.