Performance Optimization Strategy for Steel-Concrete Composite Structures: Post-Fire Load-Bearing Capacity and Deformation Control

Abstract

Concrete-filled steel tube structures are widely used in industrial plants, large commercial buildings, infrastructure projects, antenna-supporting facilities, and electromagnetic-shielded spaces because of their strong mechanical performance and economic efficiency. Fire is a serious threat to structural safety. Under high temperatures, the load-bearing capacity and deformation control level of concrete-filled steel tube structures decrease significantly, while material strength loss, weakened interfacial bonding, and residual deformation develop simultaneously. These changes may not only reduce structural reliability but also affect the geometric stability required for antenna alignment and controlled electromagnetic environments. This paper focuses on the post-fire performance of concrete-filled steel tube structures and systematically discusses how high-performance fiber-reinforced composite wrapping and constraint enhancement can mitigate material degradation and preserve load-bearing capacity under extreme thermal stress. By analyzing the relationships among temperature-induced material deterioration, residual deformation, stiffness reduction, and reinforcement strategies, the study evaluates load-bearing capacity attenuation and deformation control in fire-exposed composite systems. The proposed optimization strategy provides technical support for post-disaster assessment, structural strengthening, and the safe reuse of steel–concrete composite structures in industrial buildings and electromagnetic functional facilities.