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For the assessmentand for monitoring of timber structures there are numerous promising methods that enable the quantitative description of the current condition of construction elements or parts of a structure. This concerns material properties like modulus of elasticity, moisture content and density as well as structural properties like dynamic characteristics, localization of inhomogeneities, cracks, and biological attack. During the work in COST Action FP 1101, since 2012 the capability of experimental methods are discussed and compared. This covers electrical and electromagnetic wave methods (resistivity, microwave, Radar, X-Ray), elastic waves (ultrasound, pile testing) and mechanical testing (static and dynamic). Describing and collecting the use of the experimental methods for monitoring purposes was the objective of working group 3 "Monitoring of Timber Structures" of the COST Action. Monitoring capabilities will extend the use of timber structures to further applications in civil engineering. So far, no standard exists but collections of application examples and review papers representing the state of the art. From there needs for further developments regarding monitoring and NDT methods for timber structures can be identified and these are described in this paper.
The research project "Ultrasonic Net for Concrete Monitoring (UNeCOM)" aims at developing a methodology for an embedded ultrasonic network for the condition assessment of infrastructure constructions. Civil engineering structures made of concrete, which are located in tectonically active regions or undergo special loading conditions, may require continuous monitoring. It is important to assess the condition of the building and its stability to recognise and classify the effect of a seismic event or evolving damage at early stages before failure occurs. Embedded ultrasonic sensors offer the possibility to detect changes in the material and degradation mechanisms from inside the structure in areas which are difficult or impossible to inspect otherwise. In contrast to conventional ultrasonic testing methods, where the concrete surfaces are scanned with ultrasound probes, this new approach uses sensors, which are embedded into concrete, eliminating the effect of variable coupling conditions between sensors and concrete. This method allows an integral detection of changes in the concrete structure, for example due to seismic activities, to detect mechanical impacts, as well as degradation of the material due to overloading. Such methods have great relevance especially for the monitoring of constructions like power plants, bridges, offshore structures and other structures with high technical safety requirements. The sensor network can be controlled remotely through the internet which is also being used for data transfer. The embedded sensor network is designed to monitor structural damage and concrete degradation globally with high sensitivity.