Dynamics Properties and Seismic Response of Phra Prang Wat Ratchaburana, Phra Nakhon Si Ayutthaya Province

This paper investigates the dynamic properties and seismic response of the Phra Prang of Wat Ratchaburana, a significant heritage and tourist site in Phra Nakhon Si Ayutthaya Province. The architecture of Wat Ratchaburana exhibits notable visual characteristics, utilizing brick and laterite as primary materials, which pose complexities for engineering analysis. Therefore, studying the structural behavior and engineering properties in response to seismic forces is essential for the long-term preservation of this site. The research employs terrestrial laser scanning technology to capture high-resolution point cloud data, providing detailed surface coordinates of the structure. This data facilitates accurate assessments of dimensions and the creation of a 3D model for structural analysis using the finite element method. Nonlinear material properties are assigned for both brick and laterite, followed by nonlinear dynamic analysis under seismic forces through time integration to assess tensile stress damage incurred during earthquakes. Findings indicate that the fundamental frequency of the Phra Prang is 1.735 Hz, and under seismic vibrations with a peak ground acceleration of 0.166 g, tensile stress damage was observed at the entrance arch of the prang. The results of this study can serve as a guideline for the preservation of other historical sites in the future.