重载车辆作用下UHPC桥墩防撞性能研究

Study on impact resistance performance of UHPC pier under collision of heavy-loaded vehicle

普通混凝土NC(normal concrete)桥墩在遭遇车辆撞击时往往表现出承载能力不足,可能导致严重的结构破坏甚至人员伤亡。为此,基于超高性能混凝土UHPC(ultra-high performance concrete)良好抗冲击性能和超高强度,对UHPC桥墩的防撞性能进行研究。采用ANSYS/LS-DYNA建立车-桥碰撞有限元模型,对UHPC桥墩的撞击过程、耗能特性和碰撞力进行对比研究。研究结果表明:相比NC桥墩,UHPC桥墩具有较强的抗损伤能力和优异的抗冲击性能;在重载车辆撞击下,UHPC桥墩的破坏仅以轻微混凝土剥落和柱脚剪切损伤为主,而NC桥墩出现较严重的混凝土开裂和剥落现象;在重载车辆撞击时,NC和UHPC桥墩均产生2个峰值碰撞力,且UHPC桥墩的2个峰值力均明显比NC桥墩的峰值力大。

The normal concrete(NC) piers may lead to serious structural damage and even casualties due to its low crash worthiness when it is impacted by vehicles, the collision performance of ultra-high performance concrete(UHPC) bridge piers impacted by heavy-loaded vehicles was investigated considering the excellent impact performance and higher strength of UHPC. The impact progress, energy-dissipation capacity and impact force characteristic of the UHPC pier were investigated by using the ANSYS/LS-DYNA software. The results show that the impact performance and anti-damage capacity of UHPC piers are substantially higher than those of NC piers. In heavy-loaded vehicle collisions, the damage pattern of UHPC piers is just slight concrete spalling and shear damage of the pier bottom, while NC piers present severe concrete cracking and spalling. Two peak forces ocure when NC and UHPC piers are impacted by heavy-loaded vehicles, and the two peak forces of UHPC piers are higher than those of NC piers.