Optimum maintenance strategy for CRTS II slab track based on time-dependent system reliability

Abstract

CRTS (China Railway Track System) II slab track is a vertical multi-layer and longitudinal anisotropic strip system, which has been widely constructed in China’s high-speed railway. In this study, an innovative optimum maintenance strategy is proposed for CRTS II slab track, based on the concept of time-dependent system reliability and life-cycle cost analysis. System limit state function of the track structure is constructed with consideration of important serviceability failure modes. The time-dependent system reliability of the track structure is investigated and utilized as the indicator of track performance, which is estimated by an innovative outcrossing method based on the system limit state function considering time-dependent correlation among failure modes. At each maintenance time, all critical failure modes and components are identified and repaired to decrease the system failure probability under the acceptable level. Application of the proposed maintenance strategy is demonstrated by a worked example of a track structural system on bridge. It is found that: (1) appropriate maintenance strategy is important to ensure service reliability of the track system and extend the service life; and (2) the proposed maintenance strategy can be utilized to predict when, where, and what failure mode for maintenance and it can help to minimize the expected life-cycle cost without compromising the service reliability of the track structure.