Determining the dynamic amplification factor of multi-span continuous box girder bridges in highways using vehicle-bridge interaction analyses
Determining the dynamic amplification factor of multi-span continuous box girder bridges in highways using vehicle-bridge interaction analyses
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DOI：
10.1016/j.engstruct.2018.11.059
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发表时间：
2019-02
影响因子：
5.5
通讯作者：
L. Ma;Wei Zhang;W. Han;Jian-Xin Liu
中科院分区：
文献类型：
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作者：
L. Ma;Wei Zhang;W. Han;Jian-Xin Liu
公路多跨连续箱梁桥的冲击系数受路面不平度、车桥相互作用和行车速度等多种因素的影响。目前，桥梁设计规范规定的经验公式是基于单一因素（桥梁长度或基频）。这些公式产生的结果不一致，可能相差很大。本文选取15座连续梁桥进行了动力特性分析，研究了连续梁桥动力放大系数的变化规律。结果表明，连续梁桥发生共振时，结构的动态响应系数显著增大。车桥共振与车辆频率、桥梁频率以及车辆运动引起的扰动频率密切相关。运动速度对共振有重要影响。在大多数情况下，连续梁桥的最大速度范围为40-60 km/h。车桥共振可能由桥梁的一阶或二阶模态引起。二阶曲率模态在内支承处的负弯矩的消除中起着至关重要的作用。现行桥梁设计规范中采用的经验公式未能考虑共振和行车速度对桥梁动力响应函数的影响。连续梁桥内支座处的最大挠度可超过1.7。
The impact factors of multi-span continuous box girder bridges in highways are influenced by many factors, including road roughness, vehicle-bridge interactions (VBIs), and travelling velocity. Currently, the empirical formulas specified by bridge design codes are based on single factors (bridge length or fundamental frequency). These formulas yield inconsistent results that can differ widely. In this paper, the regularity of the dynamic amplification factors (DAFs) of continuous beam bridges is investigated by selecting 15 continuous beam bridges and conducting VBI analyses. The results indicate that the DAFs of the continuous beam bridges increase dramatically when resonance phenomena occur. The vehicle-bridge resonance is closely related to vehicle frequency, bridge frequency and the disturbance frequency caused by vehicle movement. The travelling velocity exerts an important influence on the resonance. In most cases, the DAF of a continuous beam bridge peaks at the velocity range of 40–60 km/h. Vehicle-bridge resonance may be caused by the first-order or second-order mode of a bridge. Second-order curvature modes exert an especially crucial influence on the DAF of the negative moment at the interior supports. The empirical formulas used in current bridge design codes fail to account for the influence of resonance and travelling velocity on the DAFs of bridges. The maximum DAF at the interior supports of the continuous beam bridges may exceed 1.7.