Search

Residual Service Life of Existing Concrete Structures – Is it Useful in Practice?

Gulikers, Joost J. W. / Groeneweg, Tom W.

Abstract An increasing number of existing reinforced concrete structures are approaching their intended design service life. The common assumption is that these structures will thus soon require more maintenance cost and attention from their owners. In order to manage and plan maintenance activities in a predictable and transparent way asset owners desire quantitative information on their structures’ actual condition. Periodically performed visual inspections don’t provide unambiguous quantitative figures that support decisions for maintenance activities on the long-term. Consequently the residual service life was identified as an alternative to indicate the condition. The involvement of numerous experts has resulted in a scientific approach on service life prediction in which mathematical models to describe a time-dependent deterioration process dominate. From an asset owners point of view such an approach introduces uncertainties and questions. As a result predictions of the residual service life based on a modelling approach generally don’t significantly affect the conservation and maintenance strategy of Rijkswaterstaat for concrete structures. These questions are raised because of the high latent variability of the outcome of these predictions that makes decision making by asset owners, based on this result, more obscure instead of more transparent. In this paper the origin of the variability will be demonstrated to critically discuss the usefulness in practice of service life predictions based on a modelling approach from an asset owner’s point of view. Simple examples of situations encountered in practice will be presented to elucidate the actual problems. It will be demonstrated that the modelling approach is not considered suitable to quantify the condition of an individual structure to make asset management more predictable and transparent. The authors would like to open a discussion on alternative and more practical methods to keep the stock of existing structures in a serviceable and structurally safe condition in a predictable and transparent way.