In mountainous areas, more challenges are expected for the construction of long-span bridges. The flutter instability during erection is an outstanding issue due to flexible structural characteristics and strong winds with large angles of attack. Taking the suspension bridge as an example, the flutter stability of the bridge with different suspending sequences was investigated. First, the dynamic characteristics of the bridge during erection were computed by the finite element software ANSYS, along with the effects on flutter stability discussed. Then, different aerodynamic shapes of the bridge girder during erection were considered. The aerodynamic coefficients and the critical flutter state were determined by wind tunnel tests. Based on the above analysis, some structural measures are proposed for improving the flutter stability of the bridge during erection. The results show that the flutter stability of the bridge during erection is related to the suspending sequence and the aerodynamic shape of the girder. Owing to the structural dynamic characteristics, the bridge has better flutter stability when the girder segments are suspended symmetrically from the two towers to the mid-span. Considering the construction requirement that the bridge deck should be laid without intervals, this structural superiority is seriously weakened by the unfavorable aerodynamic shape of the girder. In order to improve the flutter stability of the bridge during erection, an effective way is to adopt some temporary structural strengthening measures.

中文翻译：

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山区大跨度悬索桥架设时的颤振稳定性

在山区，大跨度桥梁的建设预计将面临更多挑战。由于灵活的结构特性和大迎角的强风，架设过程中的颤振不稳定性是一个突出的问题。以悬索桥为例，研究了不同悬吊顺序下桥梁的颤振稳定性。首先，通过有限元软件ANSYS计算了桥梁在架设过程中的动态特性，并讨论了对颤振稳定性的影响。然后，考虑了桥梁在架设过程中的不同气动形状。通过风洞试验确定了气动系数和临界颤振状态。基于以上分析，提出了一些结构措施，以提高桥梁在架设过程中的颤振稳定性。结果表明，桥梁架设过程中的颤振稳定性与悬垂顺序和主梁气动外形有关。由于结构动力特性，当梁段从两塔到跨中对称悬挂时，该桥具有较好的颤振稳定性。考虑到桥面应无间隔铺设的施工要求，这种结构优势被梁的不利气动形状严重削弱。为了提高桥梁架设时的颤振稳定性，一种有效的方法是采取一些临时的结构加固措施。结果表明，桥梁架设过程中的颤振稳定性与悬垂顺序和主梁气动外形有关。由于结构动力特性，当梁段从两塔到跨中对称悬挂时，该桥具有较好的颤振稳定性。考虑到桥面应无间隔铺设的施工要求，这种结构优势被梁的不利气动形状严重削弱。为了提高桥梁架设时的颤振稳定性，一种有效的方法是采取一些临时的结构加固措施。结果表明，桥梁架设过程中的颤振稳定性与悬垂顺序和主梁气动外形有关。由于结构动力特性，当梁段从两塔到跨中对称悬挂时，该桥具有较好的颤振稳定性。考虑到桥面应无间隔铺设的施工要求，这种结构优势被梁的不利气动形状严重削弱。为了提高桥梁架设时的颤振稳定性，一种有效的方法是采取一些临时的结构加固措施。当梁段从两塔对称悬挂到跨中时，桥梁具有更好的颤振稳定性。考虑到桥面应无间隔铺设的施工要求，这种结构优势被梁的不利气动形状严重削弱。为了提高桥梁架设时的颤振稳定性，一种有效的方法是采取一些临时的结构加固措施。当梁段从两塔对称悬挂到跨中时，桥梁具有更好的颤振稳定性。考虑到桥面应无间隔铺设的施工要求，这种结构优势被梁的不利气动形状严重削弱。为了提高桥梁架设时的颤振稳定性，一种有效的方法是采取一些临时的结构加固措施。