Advancements in design and construction of twin-I composite-girder cable-stayed bridges

Twin-I composite girder cable-stayed bridges (CSBs) are characterised by high overall rigidity, reduced self-weight, low construction cost and improved fatigue resistance. This structural design has been widely adopted in long-span bridges, with extensive design and construction experience accumulated over time. However, current research on long-span twin-I composite girder CSBs remains largely focused on the design and construction of individual bridge projects, with limited systematic studies on their structural design and innovative aspects. To address this gap, this paper compiles and analyses the design parameters of long-span twin-I composite girder CSBs worldwide, examining their structural system, span arrangement, key design parameters (main girder, pylons and stay cables) and innovative design and construction methods. This study aims to provide a comprehensive and valuable reference for the design and construction of twin-I composite girder CSBs worldwide.