With the rapid development of infrastructure in western China, numerous arch bridges have been constructed as vital transportation hubs spanning river canyons. Understanding the impact of canyon topography on the seismic response of long-span half-through arch bridges crossing canyons is essential. This study first establishes a seismic input method for oblique P-wave and SV-wave incidence, based on the viscous-spring artificial boundary theory, which transforms ground motions into equivalent nodal loads on artificial boundaries. The feasibility of this proposed method is systematically validated. Subsequently, parametric investigations are carried out to explore the effects of seismic wave incidence angle, canyon depth-to-breadth ratio and soil elastic modulus on the ground motion amplification characteristics in V-shaped canyons under oblique P-wave and SV-wave excitations. Finally, dynamic response patterns of the arch ribs and the stress-strain relationships at critical structural components are thoroughly analyzed. Key findings reveal that SV-waves induce significantly different ground motion amplification effects compared to P-waves, with the wave incidence angle and canyon width-to-depth ratio being crucial influencing factors. The connection between the arch footings and the concrete cross braces constitutes the most vulnerable region, frequently exhibiting maximum stresses that exceed the yield strength of C40 concrete under multiple scenarios. Notably, when the depth-to-breadth ratio (D/B) is 0.75, the peak stress at the arch footings reaches 5.18 x 10(7)kPa, surpassing the yield stress threshold of C40 concrete. These findings highlight the need for special seismic fortification measures at these critical connections during bridge design. This research offers valuable insights into the seismic design of long-span arch bridges in complex topographic conditions.

As critical lifeline projects, complex geological conditions affect urban buried pipelines, making their seismic safety particularly important. This study focused on a high-pressure gas pipeline project in a city to establish a static and dynamic joint analysis model of the pipeline foundation interaction system using ANSYS software. Considering various working conditions, the seismic response analysis of high-pressure pipelines under different laying methods, changes in buried depth, and bending angles was carried out. The results show the radial deformation peak of the deeply buried pipeline under the action of earthquake increases by 106.17%, which is more vulnerable to damage. The depth of soil cover significantly impacts the dynamic response of buried pipelines. Pipes should be buried shallowly, while meeting the minimum depth of soil cover and other specifications. The two 18 degrees bends are in the peak area of axial high strain, and the buried pipelines are more prone to stress concentration at the large angle bends, which should be primarily monitored. The research results can provide references for the seismic safety analysis of buried high-pressure gas long-distance pipelines in similar urban settings.