在用市政桥梁基于位移的抗震安全评估

介绍了在用市政桥梁结构基于位移的抗震安全评估的步骤和方法。依据国内外普遍接受的结构抗震设计理念,以墩柱顶的位移延性系数、墩柱底截面钢筋的拉应变和混凝土的压应变为参数,通过比较结构的抗震能力和地震需求,提出了在用市政桥梁结构抗震安全评估标准。用基于位移的方法和评估标准,对北京5座在用市政桥梁进行了在设防烈度地震和罕遇地震作用下的抗震安全评估,为这些桥梁是否需要抗震加固提供了依据。

DISPLACEMENT-BASED SEISMIC SAFETY ASSESSMENT OF EXISTING MUNICIPAL BRIDGES

The basic procedure and method of the displacement-based seismic safety assessment of existing municipal bridges are introduced. Displacement ductility coefficient of pier, reinforcement tension strain and concrete compression strain at the bottom section of pier are adopted as assessment parameters. Based on the world- wide accepted structural seismic design philosophies and by comparing earthquake resistant capacity and earthquake demand of structures, principles of seismic safety assessment of existing municipal bridges are proposed. Using the displacement-based method and the assessment principles, seismic safety assessments of 5 Beijing existing municipal bridges were performed. The assessment results can serve as the bases for strengthen decision making of these bridges.