爆炸作用下超宽自锚式悬索桥动力响应研究  

Dynamic Responses of Super‑Wide Self‑Anchored Suspension Bridge under Blast Loading

作　　者：周广盼[1] 林志成 范进[1] 王明洋[2,3] ZHOU Guangpan;LIN Zhicheng;FAN Jin;WANG Mingyang(School of Safety Science and Engineering,Nanjing University of Science and Technology,Nanjing,Jiangsu 210094,China;School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing,Jiangsu 210094,China;State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact,PLA Army Engineering University,Nanjing,Jiangsu 210007,China)

机构地区：[1]南京理工大学安全科学与工程学院,江苏南京210094 [2]南京理工大学机械工程学院,江苏南京210094 [3]陆军工程大学爆炸冲击防灾减灾国家重点实验室,江苏南京210007

出　　处：《中外公路》2024年第3期153-163,共11页Journal of China & Foreign Highway

基　　金：江苏省自然科学基金资助项目(编号:BK20200494);中国博士后科学基金资助项目(编号:2021M701725);江苏省博士后科研资助项目(编号:2021K522C);中央高校基本科研业务费专项资金资助项目(编号:30919011246)。

摘　　要：为研究超宽混凝土自锚式悬索桥在爆炸荷载作用下动力响应和毁伤特征,以某超宽混凝土自锚式悬索桥为工程背景,采用数值模拟文法,分析桥面近距爆炸作用下超宽箱梁顶面破口形态、底板竖向位移等动力响应。首先,利用Solidworks软件和Hypermesh软件建立整体桥梁的精细化有限元模型;其次,采用Ansys/LS-DYNA软件和*LOAD_BLAST_ENHANCED(LBE)方法施加爆炸荷载,并结合文献中混凝土构件爆炸试验结果验证计算方法的可靠性;最后,参数化分析不同炸药当量和沿横纵桥向不同爆炸位置工况下桥梁的动力响应。结果表明:当TNT当量为300 kg时,爆心正下方混凝土单元应力达极限值发生失效,形成椭圆形贯穿破口。随着TNT药量的增大,爆心正下方底板中心处的竖向位移峰值不断增大,1 000 kg药量工况下爆炸50 ms后竖向位移达135.9 mm。随着至爆心的距离增大,底板竖向位移减小,且竖向位移的增大速度减缓。吊杆内力变化与相连的箱梁底板竖向位移具有相关性,箱梁底板竖向位移越大,吊杆内力变化达到第一峰的峰值越高。相同爆炸当量工况下,爆心处于横、纵桥向不同位置时,超宽箱梁动力响应和破口形态的区别主要由横隔梁、腹板的支撑和约束作用不同引起。研究结果可为混凝土自锚式悬索桥的抗爆防护与加固提供重要依据。To study the dynamic response and damage characteristics of the super-wide concrete self-anchored suspension bridge under the blast loading,a real bridge with these characteristics was selected as the background,and the numerical simulation was used to analyze the dynamic response of the top surface crack shape and the vertical displacement of the bottom plate of the super-wide box girder under the close blast of the bridge deck.Firstly,the refined finite element model of the whole bridge was established by using SolidWorks and HyperMesh.Secondly,the blast loading was applied by Ansys/LS-DYNA and*LOAD_BLAST_ENHANCED(LBE)method,and the reliability of the calculation method was verified by combining the blast test results of concrete members in the literature.Finally,the dynamic response of the bridge under different explosive equivalents and different lateral and longitudinal blast positions was analyzed parametrically.The results show that when the TNT equivalent is 300 kg,the stress of the concrete unit right below the blast center reaches the limit value and fails,forming an elliptical crack.With the increase of TNT charge,the peak value of vertical displacement at the center of the bottom plate directly below the blast center increases continuously,with the vertical displacement reaching 135.9 mm after 50 ms of blast under 1000 kg charge.With the increase of the distance to the explosion center,the vertical displacement of the bottom plate decreases,and the increase speed of the vertical displacement slows down.The internal force change of the suspender correlates with the vertical displacement of the bottom plate of the connected box girder.The larger the vertical displacement of the bottom plate of the box girder,the higher the first peak value of the internal force change of the suspender.Under the same explosive equivalent,when the explosion center is at different positions in the lateral and longitudinal directions of the bridge,the difference in the dynamic response and crack shape of the super-wide box

关 键 词：自锚式悬索桥 爆炸荷载 混凝土 动力响应 数值模拟 

分 类 号：U446.1[建筑科学—桥梁与隧道工程]