基于改进的模态往复pushover法的拱桥抗震性能评估

Research on the anti-seismic assessment of Arch bridge based on modified modal cyclic pushover method

针对目前拱桥抗震性能评估方法的不足以及抗震设计规范的局限性,引入改进的模态往复pushover分析,利用Ghobarah隐式双参数指标进行拱桥结构损伤评估.建立了3组刚架拱结构的有限元模型,拱肋均采用跨度为5.4 m的钢管拱肋,桥墩分别为钢筋、钢骨以及钢管混凝土桥墩.对3组刚架拱结构采用倒三角荷载分布形式的侧向力,进行了OBG、SFS、TAR等3条地震波的MMCP法分析和动力时程分析,得到墩顶位移、滞回耗能和损伤指标曲线.研究结果表明:1MMCP法可用于拱结构的抗震性能评估;2MMCP法能够准确地预测拱结构整体的损伤情况;3MMCP法可与桥梁规范的设计反应谱相联系,使评估结果具有一定的普适性、安全度.

In view of the limitations of current seismic performance assessment methods and the seismic design specifications , a modified modal cyclic pushover （ MMCP ） analysis is introduced in this paper for damage assessment in the arch bridge structure by using Ghobarah implicit two-parameter indicator .The finite element （FE） models of three different rigid frame arch structures （ span of arch ribs is 5.4 m） are established, in which the piers are reinforced , steel and concrete , respectively .The lateral force which is distributed as inverted triangle is added on the three arc structure FE models and MMCP analysis as well as the dynamic analysis process are performed to analyze three earthquake waves including OBG , SFS, TAR, to obtain the vertex displacement , hysteretic energy , and damage indicators curves .The results show that：①MMCP can be applied in seismic performance evaluation of arch structures; ②MMCP can predict the overall damage situation of arc structures accurately;③MMCP can be related to the design response spectrum of bridge specifications , indicating that to a certain extent , the assessment results own universality and safety .