Arch First and Beam Later Technology: An Accelerated and Safe Construction for Tied Arch Bridges

The Taidong River Bridge, a 115 m tied arch bridge, was opened in 2021 over the Taidong River in Jiangsu, China. Due to the significant role of the Taidong River as a crucial navigation channel for local transportation, construction activities aimed to reduce the duration of river closure. The bridge construction employed the pioneering technique of arch first and beam later without support mechanisms in the river course. This method entailed the integral hoisting of arch ribs via a floating crane, and the tied-arch bridge's longitudinal deformation was temporarily consolidated with tension during construction phases. The investigation analyzes the hoisting point layouts, arch rib limiting devices, structural system transformations implemented, as displacement, and horizontal thrust of the arch foot during the temporarily consolidated tensioning construction stage of the bridge. The research results showed that the arch first and beam later method without support construction adopted in this project demonstrated impressive compliance with the navigation standards stipulated for the Taidong River. In addition, this study proposes a method that combines mechanical calculation formulas with the Midas model to determine the position of the arch rib suspension point and provide theoretical values for temporary consolidation forces during the construction stage. The findings of this study offer valuable practical guidance that can be applied to comparable bridge projects.