预应力混凝土箱梁桥面近爆防护研究

STUDY ON PROTECTION OF PRESTRESSED CONCRETE BOX GIRDER UNDER NEAR EXPLOSION OF BRIDGE DECK

  • 摘要: 该文以1∶5缩尺比例设计预应力箱梁爆炸防护试验,研究钢板、UHPC(Ultra-high performance concrete)层和复合层对箱梁的爆炸防护性能。试验表明:未防护箱梁顶板损伤比防护箱梁严重,在桥面爆炸作用下箱梁顶板发生局部贯穿破坏,呈现冲切破坏特点,腹板和底板呈现弯曲受力特征。同时,根据试验数据分析不同防护层对箱梁各爆炸动力响应的影响。进行箱梁爆炸数值分析,结合试验数据验证数值模拟的准确性。基于数值结果,对不同防护层的能量吸收规律和爆炸耗能能力进行研究。研究显示:复合防护层耗能相对较大,而且延性较好的泡沫铝层耗能能力较强。研究防护层对箱梁动力响应的影响敏感性。结果显示:UHPC层对箱梁预应力变化量、爆炸损伤面积影响较为敏感,对钢筋应力影响较小。

     

    Abstract: This study designs prestressed box girder explosion protection tests with 1∶5 scale. The explosion protection properties of its steel plate, UHPC layer and, composite layer against one box girder are studied. The test results show that the unprotected box girder roof damage is more serious than protected box girders. The local penetrating failure occurs in the box girder top plate under deck explosion, and top plate presents the punching failure characteristics. The web and bottom plates exhibit bending stress characteristics. Meanwhile, the different protective layer influences on the box girder explosion dynamic response are analyzed upon test data. The box girder explosion numerical analysis is carried out, and the numerical simulation accuracy is verified by the test data. Based on the numerical results, the energy absorption law and explosive energy dissipation capacity of the different protective layers are studied. The research revealed that the composite protective layer energy dissipation is relatively large, and that the energy dissipation capacity of foam aluminum layer with good ductility is relatively strong. The protective layer sensitivity to the dynamic response of the box girder is studied. The analysis shows that: the UHPC layer is sensitive to the prestress change and to the box girder explosion damage area, but has little influence on the rebars stress.

     

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