The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite...The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite element simulations, the static deformations of different components, stress increments and distributions of the girder, as well as the vibration characteristics and damping ratio of the Hunan Road Bridge were analyzed, which is the widest self-anchored suspension bridge in China at present. The dynamic responses were calculated using the Newmark-β integration method assisted by the simulation models of bridge and vehicles, the influences on the dynamic impact coefficient(DIC) brought by the vehicle parameters, girder width, eccentricity travel and deck flatness were also researched. The spatial effect of the girder is obvious due to the extra width, which performs as the stress increments distribute unevenly along the transverse direction, and the girder deflections and stress increments of the upper plate change as a "V" and "M" shape respectively under the symmetrical vehicle loads affected by the shear lag effect, cross slope and local effect of the wheels, the maximum of stress increments are located in the junctions with the inner webs. The obvious girder torsional deformation and the apparent unevenness of the hanger forces between the two cable planes under the eccentric vehicle loads, together with the mode shapes such as the girder transverse bending and torsion which appear relatively earlier, all reflect the weakened torsional rigidity of the extra-wide girder. The transverse displacements of towers are more obvious than the longitudinal ones. As for the influences on the DIC, the static effect of the heavier vehicles plays a major role when pass through with a higher speed and the changes of vehicle suspension stiffness generate greater impacts than the suspension damp. The values of DIC in the vehicle-running side during the eccentric travel, affected by the restricts from the static 展开更多
为了研究近场爆炸作用下单箱三室混凝土箱梁的动力响应和破坏特征,开展了缩比试件爆炸试验和数值模拟。以原型桥梁主梁截面按1∶3缩比设计和制作了箱梁试件,测量了3 kg TNT药柱爆炸作用下试件的反射超压、钢筋应变、竖向位移及破洞形态...为了研究近场爆炸作用下单箱三室混凝土箱梁的动力响应和破坏特征,开展了缩比试件爆炸试验和数值模拟。以原型桥梁主梁截面按1∶3缩比设计和制作了箱梁试件,测量了3 kg TNT药柱爆炸作用下试件的反射超压、钢筋应变、竖向位移及破洞形态;采用LS-DYNA软件进行了箱梁爆炸响应模拟,结合试验数据验证了数值模拟方法的可靠性;分析了TNT当量、起爆位置、混凝土强度、配筋率对箱梁抗爆性能的影响。结果表明:3 kg TNT药柱于箱梁中间箱室中心正上方0.4 m处起爆时,在中间箱室顶板中心形成一个椭圆形的贯穿破口,破口沿横、纵桥向长度分别为41.50、45.50 cm;中间箱室顶板底面的混凝土发生大面积剥落,呈现喇叭状冲切破坏特征;多室箱梁的超宽截面形式使得其爆炸响应沿横桥向分布不均匀;箱梁底板竖向位移峰值和钢筋应变峰值随药量的增大而增大,采用最小二乘法得到了对应的拟合曲线表达式;不同起爆位置下,中间箱室底板中心的竖向位移均大于两侧箱室中心的。展开更多
为研究爆炸荷载作用下涂覆聚脲混凝土自锚式悬索桥主梁的抗爆防护效果,以山东湖南路大桥为背景,通过试验和数值模拟结合的方法对自锚式悬索桥主梁的爆炸破坏特征和动力响应进行研究。采用2发3 kg TNT和1发5 kg TNT药柱,开展1∶3缩尺节...为研究爆炸荷载作用下涂覆聚脲混凝土自锚式悬索桥主梁的抗爆防护效果,以山东湖南路大桥为背景,通过试验和数值模拟结合的方法对自锚式悬索桥主梁的爆炸破坏特征和动力响应进行研究。采用2发3 kg TNT和1发5 kg TNT药柱,开展1∶3缩尺节段箱梁试件的2发单次爆炸试验和1发重复爆炸试验,分别编号为G(未涂覆聚脲箱梁)、PCG(涂覆聚脲箱梁首次起爆)、PCGR(涂覆聚脲箱梁二次起爆),试件顶面涂覆聚脲厚度为1.5 mm。通过LS-DYNA软件进行试件爆炸响应数值模拟及验证。研究结果表明,聚脲涂层可有效增强混凝土箱梁的抗爆性能,3 kg TNT在中间箱室上方0.4 m处首次起爆时,试件G中间箱室顶板形成贯穿性椭圆形破洞;试件PCG中间箱室顶板未贯穿,仅发生轻微的局部凹陷;5 kg TNT二次起爆后,试件PCGR中间箱室顶板出现近似圆形贯穿性破洞,1号和3号箱室在支撑处出现明显裂缝。涂覆聚脲后自锚式悬索桥主梁抗爆性能得到至少20%的提升,300 kg、500 kg、800 kg、1000 kg TNT当量作用下,未涂覆聚脲主梁顶板混凝土均出现贯穿性破洞;涂覆聚脲后仅在TNT当量为1000 kg时发生轻微贯穿。展开更多
基金Project(51278104)supported by the National Natural Science Foundation of ChinaProject(2011Y03)supported by Jiangsu Province Transportation Scientific Research Programs,China+1 种基金Project(20133204120015)supported by the Research Fund for the Doctoral Program of Higher Education of ChinaProject(12KJB560003)supported by Jiangsu Province Universities Natural Science Foundation,China
文摘The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite element simulations, the static deformations of different components, stress increments and distributions of the girder, as well as the vibration characteristics and damping ratio of the Hunan Road Bridge were analyzed, which is the widest self-anchored suspension bridge in China at present. The dynamic responses were calculated using the Newmark-β integration method assisted by the simulation models of bridge and vehicles, the influences on the dynamic impact coefficient(DIC) brought by the vehicle parameters, girder width, eccentricity travel and deck flatness were also researched. The spatial effect of the girder is obvious due to the extra width, which performs as the stress increments distribute unevenly along the transverse direction, and the girder deflections and stress increments of the upper plate change as a "V" and "M" shape respectively under the symmetrical vehicle loads affected by the shear lag effect, cross slope and local effect of the wheels, the maximum of stress increments are located in the junctions with the inner webs. The obvious girder torsional deformation and the apparent unevenness of the hanger forces between the two cable planes under the eccentric vehicle loads, together with the mode shapes such as the girder transverse bending and torsion which appear relatively earlier, all reflect the weakened torsional rigidity of the extra-wide girder. The transverse displacements of towers are more obvious than the longitudinal ones. As for the influences on the DIC, the static effect of the heavier vehicles plays a major role when pass through with a higher speed and the changes of vehicle suspension stiffness generate greater impacts than the suspension damp. The values of DIC in the vehicle-running side during the eccentric travel, affected by the restricts from the static
文摘为了研究近场爆炸作用下单箱三室混凝土箱梁的动力响应和破坏特征,开展了缩比试件爆炸试验和数值模拟。以原型桥梁主梁截面按1∶3缩比设计和制作了箱梁试件,测量了3 kg TNT药柱爆炸作用下试件的反射超压、钢筋应变、竖向位移及破洞形态;采用LS-DYNA软件进行了箱梁爆炸响应模拟,结合试验数据验证了数值模拟方法的可靠性;分析了TNT当量、起爆位置、混凝土强度、配筋率对箱梁抗爆性能的影响。结果表明:3 kg TNT药柱于箱梁中间箱室中心正上方0.4 m处起爆时,在中间箱室顶板中心形成一个椭圆形的贯穿破口,破口沿横、纵桥向长度分别为41.50、45.50 cm;中间箱室顶板底面的混凝土发生大面积剥落,呈现喇叭状冲切破坏特征;多室箱梁的超宽截面形式使得其爆炸响应沿横桥向分布不均匀;箱梁底板竖向位移峰值和钢筋应变峰值随药量的增大而增大,采用最小二乘法得到了对应的拟合曲线表达式;不同起爆位置下,中间箱室底板中心的竖向位移均大于两侧箱室中心的。
文摘为研究爆炸荷载作用下涂覆聚脲混凝土自锚式悬索桥主梁的抗爆防护效果,以山东湖南路大桥为背景,通过试验和数值模拟结合的方法对自锚式悬索桥主梁的爆炸破坏特征和动力响应进行研究。采用2发3 kg TNT和1发5 kg TNT药柱,开展1∶3缩尺节段箱梁试件的2发单次爆炸试验和1发重复爆炸试验,分别编号为G(未涂覆聚脲箱梁)、PCG(涂覆聚脲箱梁首次起爆)、PCGR(涂覆聚脲箱梁二次起爆),试件顶面涂覆聚脲厚度为1.5 mm。通过LS-DYNA软件进行试件爆炸响应数值模拟及验证。研究结果表明,聚脲涂层可有效增强混凝土箱梁的抗爆性能,3 kg TNT在中间箱室上方0.4 m处首次起爆时,试件G中间箱室顶板形成贯穿性椭圆形破洞;试件PCG中间箱室顶板未贯穿,仅发生轻微的局部凹陷;5 kg TNT二次起爆后,试件PCGR中间箱室顶板出现近似圆形贯穿性破洞,1号和3号箱室在支撑处出现明显裂缝。涂覆聚脲后自锚式悬索桥主梁抗爆性能得到至少20%的提升,300 kg、500 kg、800 kg、1000 kg TNT当量作用下,未涂覆聚脲主梁顶板混凝土均出现贯穿性破洞;涂覆聚脲后仅在TNT当量为1000 kg时发生轻微贯穿。
基金Project (BK20200494) supported by the Natural Science Foundation of Jiangsu Province,ChinaProject (2021M701725) supported by the China Postdoctoral Science Foundation+1 种基金Project (2021K522C) supported by the Jiangsu Postdoctoral Research Funding Program,ChinaProject (30919011246) supported by the Fundamental Research Funds for the Central Universities,China。
