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为正确估计滚石撞击山区桥梁结构的动力响应,以中国西部山区中广泛采用的矩形桥墩为对象,利用45°,90°,135°不同高度重力摆锤下落,对3种不同截面尺寸(20cm×20cm,30cm×30cm,40cm×40cm)矩形墩柱进行冲击试验,从动态损伤扩展、墩柱撞击力及墩顶动力响应等方面研究矩形墩柱的冲击响应过程和破坏机理,并将墩柱撞击力时程曲线与中国《公路路基设计规范》(JTG D10—2016)及日本道路公团给出的等效静力撞击力计算公式进行对比和讨论。研究结果表明:冲击荷载作用下,墩柱可能出现整体损伤及局部损伤2种损伤形态,其中局部损伤出现在墩柱撞击区域,主要为剪切裂缝,整体损伤出现在墩底,主要为弯曲裂缝;墩柱整体刚度的提高对撞击区域混凝土局部损伤影响不大,但能减小墩顶位移,增大撞击力峰值;随着重力摆锤下落高度的提高,撞击初始动能越大,墩柱的墩顶位移及撞击力峰值都将增大;中国《公路路基设计规范》撞击力计算公式与试验平均撞击力接近,计算结果偏小,设计不安全,日本道路公团公式的分析结果与实测墩柱撞击力峰值吻合良好,建议工程设计予以采用。
In order to correctly estimate the dynamic response of the roller-impact bridge structure in mountainous area, the rectangular bridge piers widely used in the mountainous area of western China were used as the object. The gravity pendants at different heights of 45 °, 90 °, 20cm, 30cm × 30cm, 40cm × 40cm) rectangular column, the impact response process and failure mechanism of rectangular column are studied from dynamic damage expansion, pier impact force and pier top dynamic response, Force time history curve is compared with the equivalent static impact force formula given by China Highway Subgrade Design Code (JTG D10-2016) and Japanese road corps. The results show that under impact load, the pier may have two kinds of damage patterns, one is the whole damage and the other is local damage. The local damage occurs in the impact area of the pier, which is mainly the shear fracture. The overall damage occurs at the bottom of the pier, ; The increase of the overall stiffness of the pier has little effect on the local damage of the concrete in the impact area, but it can reduce the displacement of pier top and increase the peak value of the impact force; as the drop height of the gravity pendulum increases, the initial impact energy of the pier increases, The displacement of pier top and the peak value of impact force will all increase. The calculation formula of impact force of China’s Highway Subgrade Design Code is close to the average impact force of the test, the calculation result is too small and the design is unsafe. The analysis result of Japan Highway Corporation Formula and the measured piers The column impact peak coincide with the good, it is recommended to use engineering design.