Condition assessment of reinforced concrete structures using automated multi-sensor systems

Abstract

Infrastructure is subject to continuous ageing. This has given life cycle management of infrastructure an increasing role. Reliable inspection and monitoring tools are therefore increasingly requested. A reliable prognosis of the condition and behavior of a structure is an important basis for an effective service life management. In order to determine the most economic point in time for repair measures to be taken along the life-time of a structure, knowledge on the deterioration process at exposed regions as well as detailed knowledge about the current condition of the whole structure is essential. Different concepts were developed depending on the type of infrastructure and the construction material used. However, in general cracks and flaws, corrosion, information as well as the states of material degradation have to be retrieved. A combination of different nondestructive test methods is often a necessity to receive reliable results for material characterization, flaw detection and the determination of component specific geometry parameters. Therefore, a multi-sensor measurement approach is necessary with a high degree of automation. Otherwise a time consuming succession of manual measurements has to be performed which would prevent practical applications. The developments presented are results from two collaborative projects dealing with the development of an automobile robot system and a highly flexible scanner system. The BetoScan system consists of a self-navigating mobile robot which currently measures 8 parameters. The system is especially designed for the investigation of reinforced concrete floors exposed to deicing salts. Data acquisition of an alternative scanner-based multi-sensor monitoring system is performed through the aforementioned robot approach as well. These different applications are based on a similar kernel allowing the modular use of different contact and non-contact sensors. These applications are designed for the monitoring reinforced concrete and tendon ducts. The advantage of an automated multi-sensor analysis is that large surfaces can be investigated in comparatively short times and the measurements are of reproducible quality. This guarantees data quality for recurrent inspections