Flutter performance and improvement for a suspension bridge with central-slotted box girder during erection

摘要

Aerodynamic instabilities of super long-span bridges have always been the essential issue in design and construction, especially during the deck erection process. Based on the Xihoumen Bridge, this paper presents a particular insight into the flutter performance of a mega-bridge with a central-slotted box girder while in construction. Numerical analyses and full-model wind tunnel tests are conducted to explore the evolution of dynamic properties and flutter limits as erection proceeds. It is shown that favorable effects on aeroelastic stability are guaranteed following a symmetric deck erection sequence, but appropriate improvements are still required to ensure the safety of the structure under construction. The efficacy of different improvement methods, both structural and aerodynamic, are systematically examined, among which individual and conjoint applications of storm ropes are elaborated. The results indicate that single storm rope outperforms the combined application. In particular, one with 10% of the cross-section area of the main cable anchored at 1/8 of the midspan is especially effectual in improving the aerodynamic stability during erection.