Abstract:
To analyze the seismic response of different forms of long-span arch bridge-track systems, four different forms of arch bridges, namely 112 m basket handle arch bridge, 140 m steel box tied arch bridge, (24+160+24) m tied arch bridge and (52+382+52) m steel box arch bridge, are used as examples. The study revealed the dynamic characteristics of long-span arch bridge-track systems under seismic action and explored the effects of seismic waves, seismic intensity, and traveling wave speed on the seismic response. The results show that the stress envelope of the rail under seismic uniform excitation is antisymmetrically distributed, with the maximum value appearing near the end of the beam and the maximum axial force of the arch rib at the arch foot. There are large differences in the dynamic characteristics of the system under different spectral characteristics of seismic wave excitation. The change in seismic intensity mainly affects the rail stress near the end of the beam, and has less effect on the middle beam section. The traveling wave effect has a significant impact on the seismic response, with a significant increase in the axial force of the arch rib. The maximum stress in the rail increases by 149.2% compared to the seismic uniform excitation, and the longitudinal force in the rail at the middle of the span increases significantly, up to 503.4 MPa. Furthermore, the stress in the rail is greater when the apparent wave speed is smaller. Similarily, the stress on the rail increases as the traveling wave speed decreases. As the traveling wave speed increases, the stress distribution on the rail gradually approaches that of consistent excitation.