Smoothed Particle Hydrodynamics Simulation of the Dynamic Water Pressure inside an Arch Rib of an Arch Bridge Subjected to Seismic Excitation

The dynamic pressure exerted on an arch rib by inner water under seismic excitation was studied based on the smoothed particle hydrodynamics (SPH) numerical model. Numerical cases of different seismic excitations in both the horizontal and vertical directions and different water depths were carried out. The fast Fourier transform (FFT) of dynamic pressure exerted on the arch rib showed that the spike frequency is related to the water depth. The surface wave frequency of inner water is very close to the first spike frequency. The first spike frequency comes close to the second and fourth vibration frequencies when the inner water reaches the depth of 18 m and 11.3 m, respectively. This will likely lead to the resonance of the entire arch rib. By considering barely the first spike frequency, when designing a new arch bridge, the possibilities of resonance in its second and fourth modes under seismic excitation cannot be ruled out. Based on the findings of this investigation, the inner water effect should be considered during the arch bridge design stage.