Synchronous Multi-Span Closure Techniques in Continuous Rigid-Frame Bridges: Research and Implementation

This study investigates the Huangdong Daning River Bridge project in Guangxi, where the innovative side-span and mid-span synchronous closure technology for continuous rigid-frame bridges (CRFB) was systematically implemented for the first time in this region of China. A comparative finite element model developed in MIDAS Civil 2024 was employed to analyze the mechanical behavior mechanisms of main girders under span-by-span closure and synchronous closure processes. The numerical simulation results demonstrate that the stress distribution in main girders shows no significant sensitivity (<3%) to closure method differences during both the bridge completion phase and 10-year shrinkage-creep cycle. However, distinct closure sequences (asynchronous vs. synchronous) exhibited notable impacts on the girder alignment at the completion stage. The cumulative deviation induced by differential installation elevations of formwork segments necessitates precise dynamic control during construction monitoring. Furthermore, shrinkage and creep effects manifested differential influences on pier top horizontal displacements and bending moments when employing different closure methods, though all variations remained within 5%. The synchronous multi-span closure technology effectively mitigates structural mutation risks during construction while achieving superior alignment accuracy, rational stress distribution, and accelerated construction progress as verified by field implementation.