A material–structure integrated design method for textile composite fire-resistant protection of bridge structural cables subjected to vehicle-induced fires

A textile composite fire-resistant design method of cables is proposed for cable protection structures subjected to vehicle-induced fires on three-tower cable-stayed bridges. The most unfavorable fire conditions are identified through Computational Fluid Dynamics (CFD)-Finite Element Method (FEM) coupled analysis, with heat release rates (HRR) ranging from 56 . 35 × 1 0 3 to 108 . 48 × 1 0 3 kW (corresponding to 15 m 3 tankers) and 79 . 02 × 1 0 3 to 152 . 98 × 1 0 3 kW (corresponding to 50 m 3 tankers) under wind speeds of 5-11 m/s. These HRR values are used to represent the severity of tanker fire scenarios and provide the thermal boundary conditions for subsequent design. To address these scenarios, the coupled optimization problem is solved by separating it into structural- and material-scale optimizations. At the structural scale, gradient-based optimization determines that effective fire protection can be achieved with thermal conductivities of 0.07 W/(m K) at 3 mm thickness and 0.05 W/(m K) at 5 mm thickness. At the material scale, optimization significantly reduces fiber consumption, with basalt fiber textile composites requiring as low as 10.3 and 14.3% fiber volume fraction and carbon fiber textile silica aerogel composites reduced to 39.5 and 40.6%. These results demonstrate that the proposed material-structure integrated design method not only ensures fire protection performance under severe fire conditions but also achieves substantial material savings. The study establishes a comprehensive framework for optimizing both structural and material aspects of textile composite fire protection systems for practical bridge engineering applications.