How Reliable Are Dynamic Properties as Indicators of Bridge Reconstruction Success?

This paper presents an in-depth analysis of the experimental dynamic properties of a Croatian bridge before and after its reconstruction. Initially built as a three-span balanced cantilever bridge of the Gerber type, the bridge was recently transformed into a continuous static system during the reconstruction. To evaluate the impact and success of this transformation, dynamic tests were conducted to measure the bridge's natural frequencies and mode shapes both before and after reconstruction. The paper outlines the experimental methodologies employed to capture these dynamic properties and emphasizes their importance in validating the conformity of the reconstruction with the original design intent. A central focus is the use of dynamic testing as a tool to assess the structural changes and the effectiveness of the reconstruction. The findings provide critical insights into the alterations in dynamic behavior induced by the reconstruction process, underscoring the significance of dynamic properties in maintaining the structural integrity of reconstructed bridges. The results contribute to the field of bridge engineering by illustrating the essential role that dynamic testing plays in the lifecycle management and evaluation of bridge structures.