Floor modal mass identification using human-induced dynamic excitation

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.

Automated summary

Modal mass is a critical modal parameter that is difficult to obtain accurately from identification methods in structural modal testing. This study proposes a method using pressure insoles to measure human-induced loads and an iterative correction method to identify the floor 1st-order modal mass from resonant responses. The method iteratively calculates the modal mass by weighting the errors between the calculated and measured multi-point acceleration responses Fourier spectrum and correcting the natural frequency and damping ratio. Applying the method to two prestressed concrete floors resulted in a maximum identification error of 6%, providing a convenient and accurate way to obtain floor modal mass.