Fatigue Analysis and Life Prediction of Bridge with Health Monitoring Data – Part I: Theory and Strategy

This paper is aimed at developing a methodology and strategy for fatigue damage assessment and life prediction of bridge-deck sections of existing bridges with online structural health monitoring data. A fatigue damage model based on the continuum damage mechanics (CDM) is developed for evaluating accumulative fatigue damage of existing bridges. A structural model for the fatigue stress analysis of bridge-deck structures is proposed, in which structures are modeled by elastic members and welded connections with possible accumulative damage. Based on the proposed model, an analytical approach for evaluating the fatigue damage and service life of bridge-deck sections based on strain history data from an online structural health monitoring system and the CDM fatigue model are suggested. The updating of the representative block of cycles of the local stress by online monitoring data in the future is included in the computational approach. In order to compare results of fatigue damage and service life prediction evaluated by the CDM fatigue damage model, a modified Palmgren-Miner rule is developed for the same fatigue problem