Parametric analysis on flutter performance of a long-span quadruple-tower suspension bridge

Abstract

Flutter is a critical point of concern in the wind-resistant design of long-span suspension bridges. As a novel realization, the multi-tower suspension bridge is becoming more and more popular in engineering communities. The aeroelastic stability of this kind of bridge attracts intensive attentions. To better understand the flutter performance of multi-tower suspension bridges, a long-span quadruple-tower suspension bridge (QTSB) with three main spans is designed in this study by extension from Taizhou Bridge, which is a triple-tower suspension bridge (TTSB) with double main spans. Considering the role of some important structural parameters in flutter performance, a parametric analysis is carried out for the long-span QTSB with comparisons to the TTSB that has the same length in each main span. The parameters of focus include sag-to-span ratio of the main cable, vertical and torsional rigidities of the girder, mass of the girder as well as longitudinal rigidities of middle towers. The analytical results indicate that increasing the torsional rigidity of the girder and longitudinal rigidities of middle towers can effectively improve the critical wind velocities. Changing the sag-to-span ratio or the mass of girder would cause complicated results, in which the transition of the dominant mode is observed. The mode transition phenomenon can be reasonably utilized in the wind-resistant design of a long-span QTSB.