Estimating fundamental frequency of masonry arches under elevated temperature: numerical analysis and validation using ambient vibration tests

In this study, the changing of dynamic characteristics of masonry arches at varying geometric parameters and temperature histories was investigated through a combination of experimental and numerical methods. First, the dynamic characteristics of laboratory-built arch models were determined both pre- and post-high-temperature test using ambient vibration testing. Then, the finite element (FE) models of the arches were developed for both, allowing for dynamic characteristics to be assessed numerically. To refine the accuracy of numerical models, FE analyses were adjusted based on experimental data. These updated FE models were used to investigate the dynamic characteristics of arches with different spans, heights, widths, and thicknesses under different temperature history scenarios. Finally, utilizing the data repository obtained, formulation and graphs/charts, providing valuable insights into the dynamic response of masonry arches under fire conditions, were developed and presented for practical application. The experimental study revealed that the natural frequencies of arches decreased by 55% with increasing temperature exposure.