三峡库区跨江桥梁宽体式扁平钢箱梁气动特性及风致振动研究

Wide-body flat box girder can well meet the construction needs of crossing Yangtze River bridge in Three Gorges reservoir area with many advantages such as wide bridge deck, large aspect ratio, excellent aerodynamic performance and easy maintenance.Three typical wide-body flat box girders are selected as study subjects. The research is carried out to grasp aerodynamic features of typical wide-body flat box girder and systematically summarize advantages and disadvantages of its aerodynamic performancewith the means of dynamic balance test, section model test and barcing model test. Static force coefficients, flutter derivatives and Strouhal number are measured in uniform flow while aerodynamic admittance and buffeting forcescorrelationalong span are surveyed under different turbulence flow.Meanwhile CFD numerical simulation method is adopted to reveal themechanismof how such type of beam differ from traditional flat box girderin aerodynamic performance.Further study is carried out to measure handrail, and other affiliated members’ influence on wide-body flat box girderaerodynamic performance.The optimal form and location of the affiliated members is proposed and aerodynamic model of wide-body flat box girderwith accessory structure is established from the existing model.Based on long-span bridge flutter and buffeting theories and acquired aerodynamic parameters, wind-induced vibrationcharacteristics of structure are studied under different aerodynamic parameters to reveal how the latter affect the former combined with the verificationof full bridge aeroelastic model test.

宽体式扁平箱梁能够很好满足三峡库区跨江桥梁的建设需求，具有桥面宽，宽高比大，气动性能优良，易于建造和维护等诸多优点。以三种典型的宽体式扁平箱梁为研究对象，借助高频天平试验、节段模型试验、拉条模型试验开展详细研究工作。包括均匀流下的三分力系数、颤振导数、斯托罗哈数的测试，获得一般性气动参数；根据实测的三峡库区桥址处典型风场参数，采用被动方式模拟紊流场，获得特定条件下的气动导纳和抖振力跨向相关性。借助CFD数值模拟技术，揭示不同梁体气动性能差异的机理，系统归纳总结不同梁型在气动性能上的优势与不足，以及在三峡库区跨江桥梁上的适用性。在此基础上，进一步开展栏杆及检修轨道等附属构件对宽体式扁平箱梁气动性能影响的研究，旨在提出基于不同梁型的附属构件的最优形式和位置，并借助已有气动力模型，提出考虑附属构件影响的宽体式扁平箱梁的气动力模型。最后，基于大跨度桥梁的颤抖振计算理论，采用试验获得的典型气动参数。

宽体式扁平箱梁能够很好满足三峡库区跨江桥梁的建设需求，具有桥面宽，宽高比大，气动性能优良，易于建造和维护等诸多优点。本课题采用现场实测、风洞试验、理论分析和数值计算相结合的方法，开展了三峡库区跨江桥梁宽体式扁平钢箱梁的气动力特性与风致振动特性研究，取得了以下五个方面的成果。1).通过现场实测，结合数值计算，总结归纳风场特性参数，建立了三峡库区典型山地地貌的风场模型，为后续的风洞试验研究和抖振计算提供必要参数。2).借助节段模型风洞试验，研究了典型宽体扁平箱梁的颤振和涡振性能，对比了不同外形箱梁的气动性能；量化了检修车轨道和栏杆等附属构件对扁平箱梁气动性能的影响；结合CFD数值模拟，揭示了不同梁体气动性能差异的机理；总结出不同梁体在气动性能上的优势与不足，以及在三峡库区跨江桥梁上的适用性。3).基于大跨度桥梁的颤、抖振计算理论，采用试验获得的典型气动参数和现场实测风参数，借助拉条模型和全桥气弹模型风洞试验，研究了不同气动参数条件下和特定紊流场条件下宽体扁平箱梁的抖振特性，并据此探索适合于三峡库区风场特点的梁型。4).根据三峡库区桥址处典型风场参数，采用被动方式模拟紊流场，结合高频动态天平对比并量化了气动外形对气动导纳的影响，提出了宽体扁平箱梁气动导纳理论计算的修正公式。5).开展了脉动风荷载作用下大跨悬索桥风-车-桥系统耦合振动仿真计算与分析，评价了车辆在风场中通过大跨度悬索桥的安全性。.本课题成果共计发表SCI/EI论文11篇，CSCD核心论文4篇，获批软件著作权、专利5项，出版专著1本，成功培养博士2名，硕士5名。成果应用于特大跨悬索桥寸滩长江大桥，提出了风致振动的控制措施，提供了行车交通管控措施的参考依据。