Structure-related damage analysis for civil-engineering structures
Break in prestressing steel, discovered using ZfP
The condition of bridges and other civil-engineering structures which adjoin paths and roads is recorded during the inspection of the structures. These inspections are carried out every six years; they mainly take the form of visual inspections. In the case of complex, serious or unclear damage, it may be necessary to carry out detailed, structure-related damage analyses (objektbezogene Schadensanalysen – OSA) which go into greater depth than the normal inspection of the structure. The competent administrations of the federal states decide on whether or not these analyses should be carried out. Information on the condition of the structure constitutes one of the essential input variables for the Structure Management System.
Guidelines were developed to ensure that OSA was applied uniformly as part of the Structure Management System (Bauwerks-Management-System – BMS); these guidelines were introduced for federal trunk roads by General Circular on Highway Construction Number 14/2004 of 24.06.2004.
Ultrasound Echo Principle
The ZfP processes - non-destructive material testing (zerstörungsfreie Materialprüfung) play an important role in these damage analyses. The BASt has for some time been working on the application of these processes. Particularly worthy of mention are the geo-radar, the potential-field measurements and the tunnel scanner.
The geo-radar enables bridge superstructures to be passed over with high-speed radar systems to produce rapid and extensive records of the surface. The interpretation of the results provides information on anomalies in the section where the surface joins the concrete and on anomalies in the concrete of the road plate.
The inspection of bridge superstructures using the potential-field process enables an in-depth examination to be carried out in a reasonable amount of time. The results of potential-field measurements make it possible to detect areas with active corrosion of the non-prestressed and the prestressed reinforcement.
Tunnel scanner: measuring principle Source: SPACETEC
The use of the tunnel scanner enables the condition of the inner shells of tunnels to be recorded in detail. Cracks, flaking and other damage can be localised on the surface by evaluating the images. Penetration of dampness and hollow areas can also be detected using a combined evaluation of visual and infrared images.