爆炸荷载下钢桁架桥梁生存能力评估研究

发布时间：2018-05-11 22:36

  本文选题：钢桁架桥 + 箱包炸弹　； 参考：《西南科技大学》2017年硕士论文

【摘要】：本文采用数值模拟方法,系统深入的研究了钢桁架桥梁在箱包炸弹作用下的动力响应、破坏模式,并基于承载能力对爆损桥梁的生存能力进行了快速评估。其研究成果能够为钢桁架桥梁的抗爆防爆设计以及后续的修复加固提供相关参考和依据。本文的主要成果如下:(1)箱包炸弹作用下,钢桁架桥梁的耗能方式为桁架梁与桥面板的塑性变形,桥面板和钢桁架梁塑性变形耗能之和约占总能量的90%左右。对于钢桁架桥梁,加强桁架梁与增强节点的连接,提高桥面板和钢桁架梁的塑性变形能力,将有助于提高桥梁结构在爆炸载荷作用下的生存能力。(2)在箱包炸弹作用下,钢桁架桥梁的破坏模式可归纳为3种:模式Ⅰ,桥面板发生塑性变形,钢桁架梁发生塑性变形。模式Ⅱ,桥面板发生塑性变形,钢桁架梁断裂损毁;模式Ⅲ,桥面板开裂破口,钢桁梁断裂损毁。药量、炸点位置均能影响结构的破坏程度、破坏模式,相对于炸药当量,炸点位置的改变对结构的破坏程度、破坏模式的影响更加敏感。(3)基于承载能力提出了一种生存能力评估方法,该方法采用LS-DYNA重启动功能,以设计荷载为控制荷载对爆损桥梁加载,获得爆损桥梁各控制截面力学参数。重点考校分析关键力学参数:应力、挠度、冲击系数是否超过规范规定的限值,从强度、刚度、稳定性3方面综合判断桥梁的生存能力是否满足现有荷载等级要求。(4)对发生破坏模式Ⅰ的爆损桥梁进行了生存能力评估,结果表明:工况1、工况2、工况5、工况9爆炸荷载作用下,桥梁的生存能力满足现有荷载等级的要求;工况3作用下,施加荷载后桥梁的竖向挠度超过限制,其生存能力不满足现有荷载等级的要求;工况4作用下,施加荷载后桥梁主桁的3根腹杆发生断裂破坏,结构丧失承载能力,不满足现有荷载等级,应进行修复加固。
[Abstract]:In this paper, the dynamic response and failure mode of steel truss bridges under the action of box and bag bombs are studied systematically and deeply by using numerical simulation method, and the survivability of damaged bridges is evaluated quickly based on load-carrying capacity. The research results can provide reference and basis for anti-explosion design and subsequent repair and reinforcement of steel truss bridge. The main results of this paper are as follows: 1) under the action of box bomb, the energy dissipation of steel truss bridge is the plastic deformation of truss beam and deck slab, and the sum of plastic deformation energy consumption of bridge deck plate and steel truss beam is about 90% of the total energy consumption. For steel truss bridges, strengthening the connection between truss beams and reinforced joints and improving the plastic deformation capacity of deck and steel truss beams will help to improve the survivability of bridge structures under explosive loading. The failure modes of steel truss bridges can be divided into three types: mode 鈪，

本文编号：1875939