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大型缆索支撑桥梁遭受爆炸荷载作用的风险在不断增加,相关抗爆研究仍不足。本文采用数值模拟方法,研究了大跨度缆索支撑桥梁中的钢箱梁、钢筋混凝土主塔在不同当量爆炸荷载作用下的冲击响应,着重分析了桥面爆炸影响下钢箱梁、钢筋混凝土主塔的局部破坏特性,考虑多种爆炸当量在桥面的多种典型位置模拟爆炸作用。首先运用非线性有限元软件,基于CONWEP算法,通过数值模拟,深入分析了钢箱梁、钢筋混凝土主塔的爆炸动力响应、破坏模式、破坏参数及其主要影响因素。结果表明:钢箱梁顶板受近距离爆炸冲击波作用出现开裂破口,横隔板对破口有明显的约束作用;由于爆炸点与桥塔距离较远和主塔壁较厚,钢筋混凝土桥塔的局部破坏较小,桥塔不会在恒、活荷载作用下压溃。为了模拟爆炸对于全桥的影响,提出了全桥数值简化方法。
The risk of large-scale cable-supported bridges being exposed to explosive loads is increasing, and the related research on anti-blasting is still insufficient. In this paper, the numerical simulation method is used to study the impact response of steel box girder and reinforced concrete pylon under long-span cable-supported bridges with different equivalent explosive loads. The effects of steel box girder, reinforced concrete pylon The local damage characteristics of a variety of explosive equivalent to consider a variety of typical locations in the bridge detonation simulation. First of all, the dynamic response, failure mode, failure parameters and main influencing factors of steel box girder and reinforced concrete main pylon are analyzed by numerical simulation based on CONWEP algorithm using nonlinear finite element software. The results show that the crack of roof of steel box girder is caused by the shock wave of close-range blasting, and the diaphragm has obvious restraining effect on the breach. Because of the distance between explosion point and bridge tower and thicker main tower wall, The local damage is smaller, the bridge tower will not collapse under the constant and live load. In order to simulate the impact of explosion on the full bridge, a full bridge numerical reduction method is proposed.