Abstract: This paper presents a numerical investigation of fire-induced collapse behavior of a tied-arch bridge subjected to fire exposure on tie rods and hangers. A finite element (FE) model was developed in LS-DYNA using an implicit-to-explicit procedure to capture multiple cable ruptures and onset of bridge collapse under combined structural and thermal loading. The model was validated against a steel box girder fire test involving elastomeric bearing failure, and a single wire transient-state test for cable rupture. The validated model was then used in a parametric study to investigate the effects of fire scenarios and assess the effectiveness of aerogel fire protection. Cable rupture was governed by temperature-induced material degradation and the cable stress level, with rupture occurring at 411℃ and 526℃ at stress levels of 0.78 and 0.41, respectively. Collapse of the tied-arch bridge was initiated by the dynamic effects resulted from sudden hanger rupture, which caused shear failure in the concrete stringer joints under combined shear and axial tension. The dynamic amplification factor of the shear force reached 3.1, exceeding the recommended value of 2.0. Aerogel fire protection effectively slowed the temperature rise in the cables and reduced the risk of collapse.