Monitoring, modelling and assessment of structural deterioration in marine environments

Many transport infrastructures, historic buildings and other constructions of varying materials are located in coastal or marine environments. These constructions are very relevant to the economic life/sustainability of the countries and regions which they serve and therefore represent construction heritage. Common pathologies of construction materials in coastal and marine environments (by corrosion, biological attack, leaching and other chemical reactions) lead to aesthetic, functional or structural degradation of these structures. Such degradation, in most cases, results in a loss of serviceability at an elemental or global level. Owners/managers are therefore confronted with questions concerning the time to initiate maintenance/ rehabilitation and the extent to which these actions should be carried out. To properly address these questions, owners/managers of structures must be provided with tools for diagnosing damage, for modelling damage and for optimising expenditure with respect to the extent of the repair/rehabilitation works. Such tools must also allow owners/managers to decide about the time to intervention in order to optimise the whole life cost of structures. In order to present recent developments in the Monitoring, Modelling and Assessment of Structural Deterioration in Marine Environments this Special Issue has been assembled. It consists of seven self-contained papers, which present state-of-the-art advances and applications as briefly described subsequently. The papers are extended and revised versions of those presented at the International Conference: MEDACHS08 Construction Heritage in Coastal and Marine Environments – Damage, Diagnosis, Maintenance and Rehabilitation which was held at the Portuguese National Civil Engineering Laboratory (LNEC) in 2008. The conference was organised at the conclusion of MEDACHS – Marine Environment Damage in Atlantic Coast Heritage Structures, an EU Atlantic Area Programme – Interreg iiib project. The contributions presented herein were selected from amongst the six keynote and 80 oral presentations as they provide an overview of present thinking as well as some important research findings related to Monitoring, Modelling and Assessment of Structural Deterioration in Marine Environments. The work by Schoefs et al. presents probabilistic methods for characterisation of the performance of non-destructive test (NDT) methods through the use of receiver operating curves, and for combination of the results of multiple inspections/inspection techniques to minimise the uncertainty in the resulting condition prediction. On a similar note, Breysse et al. demonstrate the kind of improvement which can be expected from combination of multiple NDT techniques. Examples are presented from a series of on-site case studies and laboratory experiments. Sheils et al. present an investigation of the effect of the quality of inspection techniques on the optimal inspection interval for structures. This paper proposes the development of a two stage inspection based maintenance management framework which by modelling the detection and sizing stage of an inspection separately, allows the optimum combination of techniques to be determined. Val and Chernin consider analytical modelling of crack initiation in the concrete cover caused by corrosion of reinforcing steel. A new analytical model proposed by the authors is presented and calibrated against available experimental data. Considering real structures: Salta et al. present the result of extensive experiments conducted on a marine structure to identify chloride profiles whilst Padgett et al. discuss the performance of coastal bridges during Hurricane Katrina. Case studies are presented which highlight the constructed details of the bridges which contributed to their success or poor performance in the hurricane, contrasting the damage to bridges in geographically similar regions. Finally from a budget optimisation viewpoint Stewart reviews how spatialand time-dependent modelling of deterioration processes can be used to provide a more realistic assessment of the reliability, safety and maintenance options for reinforced concrete structures. The Guest Editors would like to express their deep gratitude to all of the authors for the time and effort Structure and Infrastructure Engineering Vol. 8, No. 6, June 2012, 529–530