Evaluation of flexural deformation of a lightweight fabricated GFRP emergency bridge with a novel broken-line prestressed cable system

Abstract To address the urgent need for rapid traffic restoration after bridge collapse, a novel lightweight fabricated GFRP (Glass Fiber-Reinforced Polymer) emergency bridge with a broken-line prestressed cable system was developed. Full-scale four-point bending tests and initial deformation measurement tests caused by dead load and clearance effect were conducted to determine the flexural deformation of the bridge. It was demonstrated that the broken-line prestressed cable system substantially enhances the structural stiffness while maintaining the advantages of modular assembly. The experimental results revealed that SLYP (Single Lug and Yoke Plate) joints serve as critical load transfer components, and the deformation caused by the clearance effect of SLYP joints cannot be ignored. The calculation method for the equivalent flexural stiffness, distinguishing GTAL (GFRP tube and aluminum alloy deck) part and SLYP joint part, was given. The flexural deformation caused by dead load, live load, prestressing, and clearance effect, considering the axial deformation and spatial angle reduction effect of the steel wire cables, was proposed based on the flexibility method. The validated analytical model exhibited excellent agreement with experimental data. The main parameters influencing the flexural deformation, such as the equivalent flexural stiffness, clearance between the pin and pinhole, height of the segment, length of the vertical stay and turning component, and SLYP joint arrangement, were discussed in detail based on the proposed method.