When existing sewer, waterway, and bridge structures deteriorate and no longer function properly, or when changes in surrounding conditions make it impossible to ensure safety within the existing structural cross-section, the existing structure must be demolished and reinstalled, or repaired and reinforced. Existing repair and reinforcement methods include assembling rebar internally, installing formwork and shore supports, and then pouring concrete, or installing precast concrete internally. However, the confined workspace during internal construction increases the risk of safety accidents. Furthermore, quality control and construction supervision make it difficult to effectively manage quality and schedule. Furthermore, in the case of on-site casting, the installation of shore supports hinders internal passage for existing pedestrians, leading to complaints. Furthermore, the lengthy construction period often leads to unexpected additional costs, frequently leading to conflicts between the client and the contractor.