Abstract: The frequent conversion of erection load states of large prefabricated bridge components, together with the disturbance of local force flows on the circumferential full-scale geometric configuration of splicing interfaces, often induces local assembly failures at the bridge site, thereby reducing the timeliness and safety of modular bridge construction. To address this challenge, a two-stage virtual pre-assembly framework is established that incorporates erection load disturbances, enabling the prediction of downstream material adjustment or correction requirements for prefabricated components and ensuring rapid and accurate closure at the bridge site. A terrestrial laser scanning (TLS)–building information modeling(BIM)–finite element model(FEM) conversion interface is developed to quantify the erection load disturbances affecting the circumferential full-scale geometric state of splicing interfaces, and a TLS-based reshaped point-cloud model is constructed to represent the erection load state. Furthermore, a digital model–based splicing inspection method is proposed, in which the initial positioning and registration are performed using the keypoint-based 4-points congruent sets algorithm, refined registration is achieved through a K-dimensional tree–based iterative closest point algorithm, and circumferential full-scale deviations of the splicing interface are detected using the K-nearest neighbor algorithm. The method was applied to the assembly of a long-span steel arch rib. Considering erection load disturbances, the maximum circumferential trimming adjustment required for the closure splice was 48.60 mm. After the prefabrication of the arch rib segments accordingly, TLS-based reconstructed model inspections of the virtual pre-assembly revealed a maximum closure splice deviation of only 1.41 mm, requiring no corrective adjustment. The actual field assembly achieved circumferential deviations of less than 2 mm, enabling closure without additional trimming. The method reduced the closure construction period, improved assembly efficiency by approximately 50%, and ensured a precise, efficient, and safe on-site erection process.