Abstract:Aiming at the problems of disease compounding, structural deterioration and surging maintenance costs of old bridges in cold northern China, the limitations of traditional short-term fragmented maintenance is broken through and a systematic long-term maintenance scheme is proposed. Based on the trinity monitoring data of 58 national and provincial highway bridges and 151 culverts in Baicheng City from 2023 to 2025, a linear regression prediction model with back-substitution error ≤ 5% is constructed, and a long-term maintenance mode featuring “data-driven, smart empowerment, full-chain integration, scenario adaptation and performance orientation” is designed. And its feasibility is demonstrated from three aspects of technology, economy and operation. Through the coordinated operation of differentiated monitoring, systematic disposal and performance-based assessment, the mode can achieve a disease disposal qualification rate ≥ 98%, a 17.1% reduction in annual maintenance cost per unit bridge length and a 53.3% reduction in cross-railway maintenance coordination time. In 2028, the incidence of composite diseases will drop from 96.6% to 40%, and the incidence of structural cracks to below 25%, which can provide a technical framework and management paradigm for the maintenance of similar bridges in cold northern China.