Traditional reinforced concrete frame structures suffer from insufficient seismic ductility and brittle continuous collapse under strong earthquakes, while existing research on high-ductility fiber-reinforced concrete (HDC) only optimizes single component performance, lacking integrated overall seismic design theory and quantitative anti-collapse mechanism evaluation method for frame systems. To fill this research gap, this paper takes HDC frame structures as the research object, combines micromechanical fiber bridging constitutive modeling, quasi-static cyclic loading tests and elastoplastic time-history finite element simulation. It systematically analyzes the synergistic mechanical performance of HDC beams, columns and integral frames. On this basis, a complete set of seismic design calculation formulas and three-level progressive anti-collapse judgment criteria considering fiber bridging effect and beam-column synergistic coefficient is established. Test results indicate that ordinary RC specimens show severe hysteresis pinching effect, with peak bearing capacity of 82.1 kN and rapid strength attenuation after 14 mm displacement. HDC specimens achieve full spindle-shaped hysteresis curves with significantly suppressed pinching; its peak load reaches 145.2 kN (76.9% higher than RC specimens), and stable load-carrying capacity is maintained at 28 mm displacement, accompanied by gentle stiffness degradation and greatly improved energy dissipation capacity. The proposed design system innovatively integrates fiber strain-hardening characteristics into “strong column-weak beam, strong shear-weak flexure” seismic design principles, which enriches the seismic resistance theoretical system of HDC structures and provides quantitative theoretical basis and engineering reference for anti-collapse design of frame buildings located in high-intensity seismic zones.
