New utility model: waveguides for measuring the condition of steel strands in prestressed structures
Our scientists can boast another success - a newly registered utility model called "Assembly for measuring the condition of post-tensioned reinforcement of bridge structures using waveguides", which was registered on 31 January 2023 at the Industrial Property Office as utility model No. 36 800. In addition to the scientist from our faculty (Assoc. Prof. Monika Manychová), the workplace of the CDV - Transport Research Centre (with the researchers Dr. Josef Stryk, Msc. Aleš Frýbort and Assoc. Prof. Marta Kořenská).
Prestressed concrete is a widely used material in civil engineering and transport infrastructure. Over the past century, many bridge structures have been built around the world using post-tensioned steel strands (hereinafter referred to as reinforcement) and have been in service for many years. The most common cause of major failures, which can lead to bridge collapse, is corrosion of the this reinforcement. No sufficiently reliable non-destructive diagnostic method has yet been found for diagnosing the condition of prestressed reinforcement in-situ, so visual inspection combined with various non-destructive methods and inspection drilling is mainly preferred for assessing the existing condition of the structure. This opens up the possibility of applying methods that require direct contact with the reinforcement, in our case the method of non-linear ultrasonic spectroscopy (NUS). Access to the reinforcement for transmission of the excitation signal to the prestressing reinforcement and recording of the response to the excitation signal is enabled by probes and waveguides.
The necessity to access the reinforcement at several locations makes the NUS method particularly suitable for specific applications (it allows the evaluation of locations inaccessible to other methods, locations with a large concrete cover, or the condition of the reinforcement in locations above which it is not possible to drill to cover reinforcement).
The essence of the technical solution
In addition to the measuring apparatus, the assembly consisting of a harmonic signal generator, amplifiers and filters includes the following elements:
- probe for signal excitation (exciter)
- signal sensing probe (sensor)
- the first waveguide for connection of the excitation probe with the reinforcement
- a second waveguide to connect the response probe to the reinforcement
Two types of waveguides can be used:
- for freely accessible external prestressed reinforcement (sleeve waveguides)
- for built-in internal prestressed reinforcement routed in ducts, to which access for connection of the waveguides is provided by means of boreholes (rod waveguides).
Option to purchase a license
The utility model is hereby made available to potential licensees. Licensing is normally conducted under normal terms and conditions. Among the greatest advantages of the report is the possibility of applying it to specific situations where other common methods cannot be used. It is envisaged that the utility model could be used by companies specialised in carrying out diagnostic surveys of structures (not only bridges). In particular, the result is intended for the performance of detailed diagnostic surveys. It is applicable to firms engaged in the investigation and monitoring of reinforced concrete and prestressed concrete structures.
If you are interested in using it, please do not hesitate to contact the Technology Transfer Manager (MTT) who authored this article.
|doc. Ing. Michal Kriška, Ph.D.