Jintrakham K.Mahasuwanchai P.Wararuksajja W.Athisakul C.Ornthammarath T.Jongpradist P.Leelataviwat S.Mahidol University2026-05-252026-05-252026-06-01Results in Engineering Vol.30 (2026)https://repository.li.mahidol.ac.th/handle/123456789/116835This research investigates the seismic performance and potential damage scenarios of the ancient Wat Chedi Luang pagoda in Chiang Saen, Thailand. The study integrates 3D laser scanning for high-fidelity finite element model reconstruction with nonlinear time-history analysis. The Concrete Damage Plasticity (CDP) model was employed to simulate masonry nonlinear behavior. The reliability of the finite element model was validated against on-site ambient vibration measurements; the fundamental period derived from the analysis (0.441 s) exhibited excellent agreement with the field-measured period of 0.448 s obtained via the horizontal-to-vertical spectral ratio (HVSR) method. The current geometry of the point cloud reveals a structural tilt of 0.398 degrees to the northwest. Material testing reveals significant compressive strength variations (1.89–12.79 MPa), necessitating a sensitivity analysis across different material models. The probabilistic seismic hazard analysis (PSHA) determined the peak ground accelerations (PGA) to be 0.048 g for frequent earthquakes (50% PE in 30 years), 0.1–0.15 g for occasional earthquakes (10% PE in 50 years), and 0.30–0.35 g for rare earthquakes (2% PE in 50 years). The analysis indicates a progression of damage, consistently initiating at the pinnacle before extending to the bell and upper base. The pagoda is susceptible to partial collapse under rare earthquakes, with a damage volume reaching 6.99% (exceeding the global instability threshold). The results identify the pinnacle as the most vulnerable component. Therefore, targeted reinforcement using an embedded deformed steel core is quantitatively verified to prevent a collapse mechanism at the pinnacle.EngineeringArticleSCOPUS10.1016/j.rineng.2026.1108212-s2.0-10503883396925901230