Aerodynamic stability of long-span suspension bridges under erection

The aerodynamic instability of a long-span suspension bridge with a shallow streamlined box girder is a serious engineering concern, particularly duri ng the early deck erection stage. Its characteristics are significantly inf luenced by the sequence of deck erection. Using the Hoga Kusten Bridge in S weden as an example, this paper presents an analytical and experimental dis cussion regarding the evolution of flutter characteristics for a long-span suspension bridge, and a comparison of different erection sequences and ana lytical prediction of more stable configurations. The general feature of th e flutter limit evolution with the erection program of midspan to pylons, w hich was previously evidenced by wind tunnel tests, has been successfully r eproduced analytically, and the advantages of keeping nonsymmetric deck con figurations were confirmed. The pylon to midspan program has never been emp loyed for long-span girder bridges, but it was found to be, at least, aerod ynamically favorable.