Analysis of the directional characteristics of near-fault ground motions and disaster manifestations: a case study of highway system damage during the Luding earthquake
摘要
The directional effects of near-fault earthquake motions significantly influence the extent of damage to buildings and infrastructure in areas with intense seismic activity, revealing clear directional characteristics. For transportation infrastructure, these directional characteristics are primarily manifested in subdisasters such as roadbed collapses, bridge displacements, and landslides. Therefore, researching the directional characteristics of near-fault ground motions in combination with strong motion records and specific seismic damage phenomena is crucial for the seismic design and disaster protection of highway systems. In this study, we first organized the fault distribution characteristics and selected several strong motion stations based on information about the Ms 6.8 Luding earthquake on September 5, 2022, in Sichuan Province, China. We attempted to capture the characteristics of the omni-directional response spectrum, directional indices of IMs, and distribution characteristics of sliding block displacements from the records at these stations. These phenomena and characteristics were subsequently compared and analyzed to assess the advantages of each indicator in studying the directionality of earthquakes. Subsequently, we integrated the phenomena observed at these stations to analyze the directional distribution characteristics of various indicators comprehensively. Finally, we perform a statistical analysis of seismic damage to highway systems in strong earthquake zones and discuss the reliability of seismic design codes for highway structures in near faults from multiple perspectives.