SHM trends and opportunities for the civil engineering sector

The structures, especially bridges, are strategic elements of a network of road, railway or inland waterway infrastructures. They are constantly exposed to aggressive environments, to the aging of their equipments and their constituent materials, to the degradation of their structural elements and to changes in operating conditions. These latter are characterized by an increase of the traffic, by heavier loads and by more abnormal loads. These factors amplify the effect of potential errors in design or construction, or the consequences of accidental damages such as vehicle impacts. The preservation of a long lasting patrimony of structures requires a management policy that includes not only actions of maintenance, repair, strengthening and rehabilitation, but also actions for limiting and even stopping the operation of structures, for installing a safety monitoring, or for immediate safeguarding. These actions are only relevant when appropriate procedures and methods exist to assess the residual load carrying capacity, the serviceability and durability of the structure. Structural Health Monitoring is one of the important tools available to the manager of a patrimony in order to evaluate the structural performance of the bridges, or alternatively to have an objective and relevant vision of their condition. Referring to the S3 project initiated by Ifsttar in 2007, Structural Health Monitoring can be divided into three themes: the monitoring by itself or operational monitoring which includes instrumentation, measurement and management of information; the diagnosis which consists of processing data collected during the monitoring phase (performance indicators, discrimination tests, alert thresholds,...); the structural identification whose objective is to provide predictive information on the structure behavior (resistance, life duration,...) which is integrated into the management system. Although the structural health monitoring is not yet common practice, it is already applied for exceptional structures (Normandy Bridge, Millau Viaduct) or for strategic structures (dams, nuclear power plants...) and it is developing for large structures. Weak maintenance budgets, often minimized to excess..., do not facilitate the deployment of this approach, but a significant growth in the market for structural health monitoring has still been felt in recent years. However, recent advances in SHM concepts and technologies pave the ground to large-scale deployments by just providing increasingly affordable monitoring capabilities and services. Actually, multiscale monitoring, low(er) cost fiber optics, nanosensing construction materials or nanoelectronics as well as embedded computing for damage detection and SHM at large will change the perspective to effective deployment. Moreover, new markets for SHM technologies with higher pay-off expectations and more convincing RoI are emerging as potential key-drivers. From the theoretical point of view, potential large-scale deployments also raise new questions and opportunities at the frontier of state, data, and parameters. The talk will report on a combined view of SHM trends and opportunities for transportation and other infrastructure networks.