Mechanical behaviour and spatial effect of a wide composite Pasco–Kennewick girder cable-stayed bridge

The composite Pasco–Kennewick girder (CPKG) features a super-wide design, strong transverse stiffness and excellent wind resistance, making it a formidable choice for cable-stayed bridges (CSBs) spanning 200–800 m. However, due to the unique shape and size of super-wide CPKGs, rigorous computational analyses must be conducted prior to construction to ensure that the designed alignment is achievable in the completed bridge. Furthermore, CPKG CSBs feature a super-wide main girder, which results in significant spatial effects. The wide and slender concrete slab exhibits a pronounced non-uniform transverse stress distribution under combined axial forces and bending moments. If spatial effects are not adequately considered, the load-carrying capacity of the main girder may be overestimated, potentially causing cracks in the concrete slabs and posing severe safety risks. In this work the mechanical behaviour and spatial effects of a real-world super-wide CPKG CSB was investigated. A global finite-element (FE) model of the bridge was established to examine its reasonable internal forces, deformations and cable forces during construction and after completion. Subsequently, a refined three-dimensional FE model was developed to perform a local analysis of the main girder, determining its actual transverse stress and shear lag effect.