Effect of temperature on the modal parameters of continuous rigid frame bridge

The temperature effect on modal parameters such as natural frequencies, mode shapes, and damping ratios is critical for precisely determining the health of a bridge. This is the first study investigating how temperature affects the modal properties of a large continuous rigid-frame bridge. The vibration experiment data was collected and analyzed 39 times within a year's maximum and minimum temperatures. The frequency has been analyzed using the Fast Fourier transform (FFT) algorithm. Mode shape and damping ratio were analyzed using MATLAB software using the covariance-driven stochastic subspace identification method (SSI-COV) and the logarithmic decrement method. Due to the unique shape of the bridge, numerical simulations were performed using Midas Civil software to validate the results. Moreover, the correlation coefficients of frequencies and damping ratios at different temperatures have been evaluated by this observation, which will assist in identifying the large continuous rigid frame bridge's health at various temperatures.