A simplified frequency formula for post-tensioned balanced cantilever bridges

Abstract

The aim of this study is to develop a simplified natural fundamental frequency formula for the post-tensioned balanced cantilever bridges using the Operational Modal and Finite Element Analyses results. For this purpose, experimental and numerical studies were carried out on the five post-tensioned balanced cantilever bridges constructed in the city of Artvin, Turkey. First, the experimental and theoretical dynamic characteristics of the selected five bridges were determined using the ambient vibration-based Operational Modal Analysis and Finite Element Method, respectively. Then, the bridge model, which is given the highest correlation between the experimental and theoretical frequencies, was selected to determine the most important parameters that affected the modal behavior of the bridges. The most important parameters were determined as bridge length and pier height. Theoretical modal analyses were carried out for a series of bridge models with different lengths and heights. Finally, a simplified fundamental frequency formula was developed for the post-tensioned balanced cantilever bridges using the method of least squares considering the frequency values obtained from the theoretical modal analyses of the bridge models. The developed formula was checked with the experimentally obtained values, and it was observed that both sets of results were close to each other.