Aerodynamic Stability of Long-Span Suspension Bridges under Erection

Abstract

The aerodynamic instability of a long-span suspension bridge with a shallow streamlined box girder is a serious engineering concern, particularly during the early deck erection stage. Its characteristics are significantly influenced by the sequence of deck erection. Using the Höga Kusten Bridge in Sweden as an example, this paper presents an analytical and experimental discussion regarding the evolution of flutter characteristics for a long-span suspension bridge, and a comparison of different erection sequences and analytical prediction of more stable configurations. The general feature of the flutter limit evolution with the erection program of midspan to pylons, which was previously evidenced by wind tunnel tests, has been successfully reproduced analytically, and the advantages of keeping nonsymmetric deck configurations were confirmed. The pylon to midspan program has never been employed for long-span girder bridges, but it was found to be, at least, aerodynamically favorable.