CONDITION ASSESSMENT OF STAY CABLES BASED ON STRUCTURAL HEALTH MONITORING TECHNIQUES

Structural health monitoring (SHM) system provides an efficient way to the diagnosis and prognosis of critical and large-scale civil infrastructures like long-span bridges. This paper presents a long-term condition assessment approach of cables under in-service loads based on SHM technique. For the cables of the bridge, the stochastic axial force response can be collected by the SHM system and described by a filtered Poisson process, through which the maximum value distribution of axial forces in its design reference period can be derived using Poisson Process theory. The long-term deterioration process of steel wires in the cables considers simultaneously the uniform and pitting corrosion due to environmental attack and the fatigue propagation induced by cyclic stress. By employing first order reliability method, the reliability of the cables under the monitored responses is further estimated in terms of the safety under the extreme traffic load distribution in the design reference period and the serviceability specified in the design specification. The discussions of the life-cycle condition assessment of the cable stayed bridge provide guidance to the future decision making related to maintenance and replacement, and it may also shed light on the long-term condition assessment of other structures.