Determination of the Modal Parameters of the Historical Elevated Water Tank Using Experimental and Numerical Methods

Abstract

Determining the modal parameters of historical buildings is crucial for understanding their dynamic behavior, which is essential for their preservation and safety for future generations. Experimental and numerical studies are commonly used to characterize modal properties such as natural frequencies and mode shapes. Experimental studies typically employ the operational modal analysis method, while numerical studies employ the finite element method. Vibration measurements of the structure under various environmental conditions, including wind and traffic, were used to determine the modal parameters. However, discrepancies often arise between modal parameters obtained from experimental research and those assessed by finite element models, primarily due to unknown factors like boundary conditions and material properties. The purpose of this study was to measure the vibrations of a historic elevated water tank a 150-year history under ambient conditions to determine its modal characteristics. Comparing the modal parameters obtained from numerical and experimental investigations revealed that the water tank's finite element model requires updating to align with the findings of the experimental modal study. Using the updated finite element model in future evaluations or assessments of the structure can lead to a better understanding of the behavior of the structure.