桩-土-结构相互作用与自锚式悬索桥桥塔顺桥向破坏相关性研究

Correlation study on pile-soil-structure interaction and failure pattern of self-anchored suspension bridge tower along bridge

悬索桥主塔作为核心支撑构件,在地震作用下特别是罕遇地震作用下其结构破坏模式就显得尤其重要,也是保证生命线工程结构震后安全的基础,而目前对大跨度悬索桥破坏模式的研究还很不完善。本文借助Open Sees有限元分析程序,以哈尔滨阳明滩大跨度悬索桥的设计方案为背景,以悬索桥的钢筋混凝土桥塔为研究重点,分析三维罕遇地震作用时,桩-土-结构的动力相互作用对大跨度悬索桥桥塔顺桥向破坏模式的影响。文中以在三维地震作用下塔底截面曲率达到等效屈服曲率,从而桥塔产生具有同时性特征的双塑性铰为破坏基准。分析发现在顺桥向罕遇地震作用下,悬索桥塔结构往往在桩基产生塑性屈服后塔底截面再出现塑性;同时发现考虑桩-土-结构相互作用可以延缓塔底截面进入塑性的时间,但会加大塔底截面的地震反应。

As a key supporting element,the failure mode of the main tower under earthquake,especially the rare earthquake seems to be quite important,and is the foundation to ensure the safety of the,which has not been well studied until now. Taking the design of Yangmingtan suspension bridge in Harbin as the research background,and the reinforced concrete tower of this bridge as the research point,we analyze the failure mode and the development of plasticity of the bridge tower of the large span suspension bridge under three-dimensional seismic motion,and also consider the dynamic interaction of pile-soil-structure,by using the finite element software of Open Sees. We take the section moment of the bridge tower or the piles that reaching the equivalent yield moment as the failure condition under three-dimensional seismic motion. Research shows that the failure mode is that the piles first enter the plastic yield condition,and then the bridge tower comes to the double plastic hinge damage. The plastic performance after entering the yield condition should be determined by the plastic dynamic stability of the bridge tower.