Abstract：A massive falling cargo from passing trucks causes serious cracks and even damage of reinforced concrete box girders, which has the characteristics of localization and shear failure. The finite element software LS-DYNA was used to carry out the numerical simulation of the impact load acting on different positions of the box girder. Combined with the damage situation of a reinforced concrete box girder bridge under the impact of vehicle falling objects, the transfer law and failure mode of impact force effect were studied. Research results show that the dynamic response and failure mode of the box girder impacted by falling objects show obvious shear failure characteristics; the effect of impact force is transferred from the top plate position to the web plate and the bottom plate in turn; the local shear failure occurs when the impact load acts on the roof, and the bending shear oblique cracks may occur after the impact load is transferred to the web.
琚利平1，王银辉2，陆晓宏3，单继栋4. 行车落物作用下钢筋混凝土箱梁破坏形态分析[J]. 重庆交通大学学报（自然科学版）, 2021, 40(01): 72-78.
JU Liping1, WANG Yinhui2, LU Xiaohong3, SHAN Jidong4. Failure Mode Analysis of Reinforced Concrete Box Girder under Impact of a Falling Cargo from Passing Truck. Journal of Chongqing Jiaotong University(Natural Science), 2021, 40(01): 72-78.
［1］ 罗征，王银辉.滚石撞击桥墩动力响应试验［J］.中国公路学报，2017，30(9)：78-85.
LUO Zheng, WANG Yinhui. Experiment on dynamic response of piers subjected rolling stone impacting ［J］. China Journal of Highway and Transport, 2017, 30 (9): 78-
85.
［2］ 何思明，庄卫林，张雄，等.都汶公路彻底关大桥桥墩抗滚石冲击防护研究［J］.岩石力学与工程学报，2013(增刊2)：3421-3427.
HE Siming, ZHUANG Weilin, ZHANG Xiong, et al. Research on rockfall impact prevention of Chediguan bridge pier, Duwen road ［J］. Chinese Journal of Rock Mechanics
and Engineering, 2013 (Sup 2): 3421-3427.
［3］ 邹毅松，谷志敏，王银辉，等.滚石撞击下混凝土桥墩损伤仿真模拟［J］. 重庆交通大学学报(自然科学版)，2015，34(6)：27-31.
ZOU Yisong, GU Zhimin, WANG Yinhui, et al. Damage simulation of concrete pier under impact of rolling stones ［J］. Journal of Chongqing Jiaotong University
(Natural Science), 2015, 34 (6): 27-31.
［4］ 周晓宇 马如进 陈艾荣. 行车落物冲击下钢筋混凝土桥面板的安全性能［J］.华南理工大学学报, 2018, 46(4): 137-145.
ZHOU Xiaoyu, MA Rujin, CHEN Airong. Safety performance of a bridge deck under impact of a massive falling cargo from passing truck ［J］ .Journal of South China
University of Technology (Natural Science), 2018, 46(4): 137-145.
［5］ 王明洋，王德荣，宋春明.钢筋混凝土梁在低速冲击下的计算方法［J］. 兵工学报，2006，27(3)：399-405.
WANG Mingyang, WANG Derong, SONG Chunming. A calculation method of reinforced concrete beam under low velocity impact ［J］. ACTA Armamentarii , 2006, 27 (3): 399
-405.
［6］ 邹毅松，刘磊，王银辉，等.接触面对驳船撞击桥墩动力响应的影响［J］.重庆交通大学学报，2018，37(9)：7-15.
ZOU Yisong, LIU Lei, WANG Yinhui, et al. Influence of contact surface on dynamic response of barge impacting pier ［J］. Journal of Chongqing Jiaotong University
(Natural Science), 2018, 37 (9): 7-15.
［7］ 霍静思，胡开赢. RC梁冲击破坏机理试验研究与残余变形预测方法探讨［J］.湖南大学学报（自然科学版），2017，44(1)：112-117.
HUO Jingsi, HU Kaiyin. Failure mechanism of RC beams under impact loading and discussion on prediction methods of residual deflection ［J］. Journal of Hunan
University (Natural Science), 2017, 44 (1):112-117.
［8］ SAATCI S, VECCHIO F J. Effects of shear mechanisms on impact behavior of reinforced concrete beams ［J］. ACI Structural Journal, 2009,106 (1):78-86.
［9］ 许斌，曾翔. 冲击荷载作用下钢筋混凝土梁性能试验研究［J］. 土木工程学报，2014,47(2)：41-51.
XU Bin, ZENG Xiang. Experimental study on the behaviors of reinforced concrete beams under impact loadings ［J］. China Civil Engineering Journal, 2014, 47(2): 41
-51.
［10］ 窦国钦，杜修力，李亮.冲击荷载作用下高强钢筋混凝土梁性能试验［J］. 天津大学学报，2014，47(12)：1072-1080.
DOU Guoqin, DU Xuli, LI Liang. Experimental study on the behavior of high strength reinforced concrete beams under impact load ［J］. Journal of Tianjin
University, 2014 (12): 1072-1080.
［11］ PHAM T M , HAO H . Plastic hinges and inertia forces in RC beams under impact loads ［J］. International Journal of Impact Engineering, 2017, 103（5）:1-11.
［12］ 梅福林，董新龙，俞鑫炉.不同落锤速度冲击下混凝土和RC梁破坏研究［J］.宁波大学学报(理工版)，2017，30(5)：83-88.
MEI Fulin, DONG Xinlong, YU Xinlu. Failure of concrete and RC beams under impact of different drop hammer speeds ［J］. Journal of Ningbo University (Natural
Science and Engineering), 2017, 30 (5):83-88.
2021, Vol. 40 
