Abstract: To investigate the load-resisting mechanism of U-shaped beam trough assembled monolithic precast concrete beam-column structures during the progressive collapse triggered by middle column removal scenario, two two-span, half-scale beam-column structural models were fabricated in this study. Using a pushdown loading method, a systematic examination of the mechanical properties and failure modes of this type of structure during collapse was conducted. The experimental results indicate that as the span-depth ratio increases, the plastic rotation rate at the beam-column joint gradually decreases, effectively delaying the rupture of strands in the tension zone. Additionally, a smaller span-depth ratio results in a higher first peak load under the influence of compressive arch action, but has a limited impact on the ultimate load capacity of the structure. To further explore the parameters which were not considered in the experiments but have a significant influence on the structure, modeling and parametric analysis were performed using the finite element software LS-DYNA. Based on the verified finite element model, extended parametric analysis was conducted on different types of post-cast concrete and different number of U-shaped reinforcements in the U-shaped beam trough. The analysis results show that when ultra-high-performance concrete is used for the post-cast layer, the first peak load during the compressive arch action phase and the maximum horizontal pressure increases by 16% and 26%, respectively. As the number of U-shaped reinforcements in the middle joint's U-shaped beam trough increases, the first peak load during the compressive arch action phase and the ultimate load capacity during the catenary action phase increases by 4% and 18%, respectively, while the maximum horizontal tension also increases by 11%. It is worth noting that as the number of U-shaped reinforcements increases, the ultimate failure mode of the structure shifts from the rupture of the U-shaped reinforcement to bond failure of the U-shaped beam trough. However, increasing the number of U-shaped reinforcements at the peripheral joints has minimal impact on the overall load-resisting capacity of the members.