Investigation Of The Effect Of Construction Sequence On The Flutter Of Suspension Bridge

With the continuous increase in the span length of suspension bridge in recent years, the structure overall stiffness and damping ratio are abated. The bridge will expose to more severe wind induced vibration. Thus the structure wind resistance stability has become the dominant factor in the long span bridge design and construction. As a severe divergent vibration, the flutter will cause significant damage. In the suspension bridge construction phase, the torsional stiffness is much less than that in the completed phase, especially in the inception of construction phase. Therefore the flutter critical wind speed is lower than in the completed phase and the bridge will expose to flutter response. In this way, the issues of how to improve the flutter stability in the construction phase have been an imperative study subject.Based on a suspension bridge with main span1130m, and the established research findings, the suspension bridge flutter response was studied by calculation and wind tunnel testing analysis.The key content of this paper is as follows:The bridge flutter theory, i.e. three dimensional multi-modal coupling flutter analysis theory, is introduced. Then the calculation program by numerical software was compiled and the correctness and reliability were verified by the typical calculation example.The flutter response of the bridge in the typical construction phase and completed phase was analyzed and thevariation pattern of flutter response with the construction of suspension bridge was explored. Also the influential factors of flutter stability were studied and the effect of the reduction of girder stiffness and decreasing of structure damping ratio were investigated.The flutter critical wind speed of various construction sequence of the suspension bridge was researched and the influence of adopting different eccentricity ratio in the asymmetric circumstance was studied. Some measures regarding increasing the flutter stability in the construction phase were obtained by investigating the variation pattern of critical flutter wind speed for different construction sequences.