爆炸荷载作用下斜拉桥动力响应分析 胡志坚,李杨 武汉理工大学交通学院,湖北武汉430063) 摘要:爆炸荷载作为一种极限荷载,在一些重要的结构如斜拉桥的设计中必须被考虑到 本文用LS-DYNA建立斜拉桥实体模型,选取1814kg当量的TNT,分别在主跨跨中截面横桥 向对称加载和偏载加载,分析斜拉桥主梁、桥塔以及斜拉索的动力响应,结果表明:1) 1814 kgTNT在斜拉桥主跨跨中截面爆炸时,斜拉桥主要表现为局部损伤,并不会出现桥梁 连续性倒塌的现象;2)斜拉索的应力变化是主梁与主塔间锚固区的相对位移导致的。锚固 在桥塔顶端的斜拉索应力增量较大,比起其他斜拉索更容易失效;3)斜拉桥主跨跨中截面 爆炸时,主塔会向主跨跨中竖弯。徧载爆炸时,近爆点桥塔的竖弯效应大于远爆点桥塔。 关镳词:爆炸荷载;斜拉桥;LS-DYNA Dynamic response of cable-stayed bridge under blast load HU Zhi-jian, LI Yang Abstract: Blast loads have been recognized as one of the extreme loading events that must be considered in the design of important structures such as cable-stayed bridges. In this paper, a solid model of cable-stayed bridge is built by LS-DYNA. The blast size of 1814kg TNT is considered and placed at two different locations at mid-span: one at the middle of the section and another one close to the cable anchorage to analyze the dynamic response of main girder, bridge tower and cables of the cable-stayed bridge. The results show that: 1)when 1814kg TNT explodes at mid- span, the cable-stayed bridge is mainly characterized by local damage, and the damage does not cause global progressive failure of the bridge; 2)The change in cable stress is caused by the relative displacement of the anchorage zone between the main girder and the tower. Cables anchored to the top of the bridge tower have large increment of stress and are more vulnerable to rupture compared to other cables; 3 )when the blast location is at mid-span, the main tower will bend to the main span. The deflection of tower when the blast location is close to the cable anchorage is bigger than when the blast location is at the middle of the sectior Keywords: blast load: cable-stayed bridge: LS-DYNA 、引言 911事件后,爆炸荷载对结构物的破坏作用越来越被人们所重视。而桥梁作为重要的公 共交通枢纽,其在爆炸荷载作用下的表现出来的脆弱性也越来越被人们所重视。无论是我国 还是国外的桥梁设计,几乎都不会对桥梁进行抗爆设计,但近年来桥梁在车载爆炸以及恐怖爆炸荷载作用下斜拉桥动力响应分析 胡志坚，李杨 （武汉理工大学 交通学院，湖北 武汉 430063） 摘 要：爆炸荷载作为一种极限荷载，在一些重要的结构如斜拉桥的设计中必须被考虑到。 本文用 LS-DYNA 建立斜拉桥实体模型，选取 1814kg 当量的 TNT，分别在主跨跨中截面横桥 向对称加载和偏载加载，分析斜拉桥主梁、桥塔以及斜拉索的动力响应，结果表明:1） 1814kgTNT 在斜拉桥主跨跨中截面爆炸时，斜拉桥主要表现为局部损伤，并不会出现桥梁 连续性倒塌的现象;2）斜拉索的应力变化是主梁与主塔间锚固区的相对位移导致的。锚固 在桥塔顶端的斜拉索应力增量较大，比起其他斜拉索更容易失效;3）斜拉桥主跨跨中截面 爆炸时，主塔会向主跨跨中竖弯。偏载爆炸时，近爆点桥塔的竖弯效应大于远爆点桥塔。 关键词：爆炸荷载；斜拉桥；LS-DYNA Dynamic response of cable-stayed bridge under blast load HU Zhi-jian, LI Yang Abstract：Blast loads have been recognized as one of the extreme loading events that must be considered in the design of important structures such as cable-stayed bridges. In this paper, a solid model of cable-stayed bridge is built by LS-DYNA. The blast size of 1814kg TNT is considered and placed at two different locations at mid-span: one at the middle of the section and another one close to the cable anchorage to analyze the dynamic response of main girder, bridge tower and cables of the cable-stayed bridge. The results show that :1) when 1814kg TNT explodes at mid￾span, the cable-stayed bridge is mainly characterized by local damage, and the damage does not cause global progressive failure of the bridge; 2)The change in cable stress is caused by the relative displacement of the anchorage zone between the main girder and the tower. Cables anchored to the top of the bridge tower have large increment of stress and are more vulnerable to rupture compared to other cables; 3)when the blast location is at mid-span, the main tower will bend to the main span. The deflection of tower when the blast location is close to the cable anchorage is bigger than when the blast location is at the middle of the section. Keywords：blast load；cable-stayed bridge；LS-DYNA 一、引言 911 事件后，爆炸荷载对结构物的破坏作用越来越被人们所重视。而桥梁作为重要的公 共交通枢纽，其在爆炸荷载作用下的表现出来的脆弱性也越来越被人们所重视。无论是我国 还是国外的桥梁设计，几乎都不会对桥梁进行抗爆设计，但近年来桥梁在车载爆炸以及恐怖