独立式桥墩防撞结构防撞性能研究

Research on Performance of Independent-Pier Type Collision Protection Structures

为了解独立式桥墩防撞结构(由钢管混凝土立柱、钢横梁等结构组成)抵御船舶撞击的能力,并选取合适的结构方案,以广州明珠湾大桥为背景进行研究。采用显式动力软件LS-DYNA建立船舶与独立式桥墩防撞结构计算模型,分析立柱间距4.8 m且不设防撞套箱(方案1)、立柱间距6.7 m且不设防撞套箱(方案2)、立柱间距6.7 m且设防撞套箱(方案3)3种独立式桥墩防撞结构方案在3000 DWT船舶中心碰撞和偏心碰撞下的结构动力响应和船舶损伤。结果表明:在中心碰撞下,方案2较方案1能有效减少撞击时迎撞立柱的位移和轴向拉力峰值,提高了独立式桥墩防撞结构的防护性能和承载能力,方案3的防撞套箱能起到缓冲消能的作用;在偏心碰撞下,方案3防撞套箱的旋转能够使船舶远离桥墩,保护桥墩和拱脚下弦杆不受船舶的撞击作用,具有良好的导向能力。设防撞套箱的独立式桥墩防撞结构已在广州明珠湾大桥中应用。

This paper studies the mechanical property of the independent-pier type collision protection structure that is mainly composed of concrete-filled steel tubular columns and steel cross beams.Based on the Mingzhu Bay Bridge in Guangzhou,calculation models of three sorts of independent-pier type collision protection structures were developed in the explicit dynamic analysis software LS-DYNA to analyze the dynamic responses of the protection structures and the damages of the vessel,in the events of center collision and eccentric collision of the 3000 DWT vessel,including the independent pier with two columns spaced at 4.8 m and without protection box(Option 1),the independent pier with two columns spaced at 6.7 m without protection box(Option 2),and the independent pier with two columns spaced at 6.7 m and with protection box(Option 3).As per the analysis,in the center collision event,Option 2 is superior to Option 1,where the displacements and the peaks of the axial tension of the collision-resistant pier columns are effectively reduced,indicating improved performance and load bearing capacity of the collision protection structures.The protection box in Option 3 can buffer and dissipate collision forces in the center collision event,while in the eccentric collision event,the protection box in Option 3 is able to rotate to steer the vessel away from the pier,so that the permanent pier of the bridge and the lower chords of the arch at the arch springing are protected from the collision.The Mingzhu Bay Bridge is a typical engineering practice of the independent pier with protection box for collision prevention.