土木工程结构地震入射方向性效应研究进展

STATE-OF-THE-ART OF RESEARCH ON SEISMIC INCIDENT DIRECTIONALITY EFFECT OF CIVIL ENGINEERING STRUCTURES

  • 摘要: 多维地震动对土木工程结构的入射方向具有高度不确定性,而传统抗震设计方法未考虑地震入射方向性,将导致结构在地震中易出现入射方向性震害,如何保证结构在任意入射方向下的地震安全,是国内外学者十分关注的问题。利用考虑入射方向的地震动强度参数,多种地震动预测模型被提出,并应用于规范,但规范的措施可靠性低,需要对其做出调整。在建筑结构、桥梁结构和一些特种结构领域,地震入射方向性效应已被广泛研究,结果表明入射方向的影响是显著的,对结构抗震设计具有一定参考意义,但仍存在不足。为了改善土木工程结构的抗震设计方法,多种最不利入射方向求解方法被提出,但适用性低,而利用统计学方法研究入射方向的不确定性是有效的措施,未来需要将其推广应用于不同的土木工程结构,以优化抗震设计方法。此外,以地震动强度和入射方向同为随机变量的四种联合概率地震易损性模型被建立,对多种土木工程结构的地震风险进行了评估,但其分析效率低,有待提高,以实现结构快速风险评估。目前相关研究偏向于采用数值方法研究现象,未来应利用理论和试验技术,实现从现象到机理和理论的突破,最终进行工程应用,为完善抗震规范创造条件。

     

    Abstract: Multi-dimensional ground motion has a high degree of uncertainty on the incident direction of civil engineering structures, and the structure designed upon the traditional method without considering the incident directionality is prone to incident directional seismic damage in earthquakes. How to ensure the seismic safety of structures in an arbitrary direction of incidence is a problem that scholars at home and abroad are very concerned with. A variety of ground motion prediction models are proposed and applied to specifications using ground motion intensity measures considering the incident directionality. The reliability of the measures in the specifications is low and some adjustments need to be made. Moreover, the directionality effect of seismic incidence has been widely studied in the fields of building structures, bridge structures and some special structures, and the results show that the effect of incident direction is significant and have certain reference significances for structural seismic design, but there are still some shortcomings. In order to improve the seismic design method, a variety of methods solving most unfavorable direction of incidence are proposed, but their applicability is low, and it is an effective measure to use statistical methods to investigate the uncertainty of incident direction. In the future, it is necessary to promote its application to different civil engineering structures to optimize seismic design methods. In addition, four joint probability seismic fragility models with ground motion intensity and incident direction as random variables are developed, and the seismic risk of various civil engineering structures is evaluated. However, their analysis efficiency is low and needs to be improved to achieve rapid structural risk assessment. At present, the relevant researchers mainly focus on using numerical methods to study some phenomena. In the future, theoretical and experimental techniques should be used to achieve breakthroughs from phenomena to mechanisms and theories, and finally engineering applications should be carried out to create conditions for improving seismic specifications.

     

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