纵向地震作用下通航渡槽碰撞特征研究

通航渡槽与升船机是过坝的快速通道。通航渡槽具有墩高由高到低连续变化、升船机与相邻高墩区渡槽基本周期差异大的结构特点,属于地震下激烈碰撞易发结构。基于有限元模型,对通航渡槽进行碰撞特征、控制因素以及地震响应影响研究。研究结果表明:渡槽与升船机周期差异大是造成剧烈碰撞的主要因素,且此碰撞有明显的传递效应;具有大位移的高墩在相邻渡槽跨周期差异不大时也会造成剧烈的碰撞,是碰撞的另一主要控制因素;有别于桥梁结构中碰撞通常限制墩的位移,通航渡槽中靠近升船机的剧烈碰撞区域,出现了明显的槽墩位移放大现象;碰撞对支座剪力影响程度远大于墩底剪力、弯矩。

Research on pounding of navigable aqueduct subjected to longitudinal ground motion

Navigable aqueducts and ship lifts are water-traffic corridors for passing through dams. The piers with continuous varying height from high to low and eminent difference of fundamental period between ship lift and adjacent span, are the extraordinary structural characteristics of navigable aqueduct. These give rise to severe pounding under earthquake for navigable aqueducts and ship lifts. So the dynamic characteristics, control factors and effects in seismic responses of pounding of navigable aqueduct subjected to longitudinal ground motion are investigated using finite element analysis. The results show that the eminent difference of fundamental period between aqueduct and ship lift is the critical factor causing severe pounding, and the pounding has obvious transmission effect. Higher pier with large displacement will also cause strong pounding even the period difference between adjacent aqueducts is not obvious, and this is another critical factor. Different from the usual conception of pounding limiting displacement in bridge structure, there is obvious displacement amplification on the top of piers near ship lift in the severe pounding area. The effect on bearing shears caused by pounding is much greater than shear and bending moment on piers bottom.