Feasible deck erection schedules of long-span suspension bridges considering flutter safety

This paper proposes a method of conducting flutter safety inspections for suspension bridges during deck erection stages. Historical extreme wind speed data spanning 30 years (1983–2012) from six regions in China were collected. By utilizing the start date and reference period of deck erection as parameters, the extreme wind speeds were divided into distinct stages. A staged extreme wind speed probability distribution model was introduced, and the staged wind speed with a non-exceedance probability was calculated while accounting for finite sample size effects. The staged flutter-check wind speed was derived, and flutter inspections were carried out for each erection stage. Taking the target flutter safety assurance rate (Pt0) as the benchmark, the flutter safety of various deck erection schedules for a long-span suspension bridge with flat box girder (represented by the Severn Bridge with a main span of 988 m in UK) and a long-span suspension bridge with central-slot box girder (represented by the Xihoumen Bridge with a main span of 1650 m in China) was evaluated in different bridge locations and terrain conditions. The results indicate that both the bridge location and the terrain roughness significantly influence the feasible start date for erection. Properly selecting the erection start date to avoid strong-wind periods can substantially enhance safety during construction. Furthermore, the impact of different target flutter safety assurance rates on the proportion of schedules passing the inspection was examined. The findings show that the pass rate can differ by up to 40% when Pt0 values of 0.8 and 0.95 are compared. Finally, the weighted overall flutter safety probability was proposed to evaluate the flutter safety throughout the entire deck erection process. The results indicate that longer construction durations lead to lower overall flutter safety probability.