Structural reliability analysis and service life prediction for structural health monitoring

Abstract

Reliability-based safety assessment is used frequently in Europe and elsewhere to assess the need for maintenance and the remaining service life of structures. In order to assess the effect of corrosion, quantitatively, an experimental study was conducted using an accelerated corrosion testing technique. Vibration tests were carried out fortnightly to study its effect on the natural frequency of RC beams subject to corrosion. One beam was taken out and broken every four weeks. The mass losses of steel rebar were measured to determine the corrosion state. The experimental results are used to develop an empirical model that describes the relationship between natural frequency and corrosion loss. The statistics for model error for this relationship were then inferred. A spatial time dependent structural reliability analysis was developed to update the deterioration process and evaluate the probability of structural failure based on vibration results. The performance of RC beams is used to illustrate the reliability analysis developed in this paper. The inspection finding considered herein is the timing of test and the vibration results, which are used to provide an updated estimate of structural reliability. It was found that vibration test findings change, the future reliability predictions significantly. A description of structural reliability and reliability-based safety assessment is also provided, where failure probabilities are compared with a typical target failure probability to illustrate how condition assessment findings can be used to more accurately assess and often increase service life predictions.