大跨劲性骨架拱桥混凝土外包过程动力特性及抗风性能研究

研究劲性骨架拱桥混凝土外包过程中的动力特性和抗风性能对其施工具有重要的指导意义.本文以天峨龙滩特大桥为例，采用有限元分析软件MIDAS/Civil,建立了实桥空间有限元模型，研究了在三种不同工作面条件下，不同施工阶段桥梁的自振频率以及抗风能力的变化规律.结果表明：在外包混凝土的过程中桥梁横向频率呈现单调上升的趋势，而竖向频率却呈现先下降再上升的趋势，并且会出现veering现象；抗风能力呈现出先提高，再降低，最后再提高的变化趋势；抗风性能也会受到工作面数量的影响，工作面越多，结构的横向抗风性能越弱.

Dynamic Characteristics and Wind Resistance of Concrete Encasement

The study on dynamic characteristics and wind resistance performance of concrete encasement stage of arch bridge with stiff skeleton has great guidance for its construction. Tian''e Longtan Bridge serves as the research model here. With the aid of FEM software MIDAS/Civil, three dimensional finite element models of Tian''e Longtan Bridge are set up. Then, the change laws of natural frequency and wind resistance performance of the bridge in different construction stages under three different working platform conditions is investigated. The results show that the lateral frequency of the bridge shows a monotonically upward trend in the process of encasing concrete, while the vertical frequency is decreased first and then increased, and the phenomenon of veering will occur. the wind resistance performance is increased first, then decreased and finally increased again. The wind resistance is also affected by the number of working platforms. The more working platform there are, the weaker the lateral wind resistance of the structure.