Novel assessment of bridge retrofitting measures through Interface Efficiency Indices (InterFeis) using a Guided Wave-based monitoring method

Projektbeschreibung

Neue Wege zur Nachrüstungseinschätzung bestehender Brücken

Faserverstärkte Polymer-Verbundwerkstoffe, die ursprünglich für die Luft- und Raumfahrtindustrie entwickelt wurden, haben sich auch im Brückenbau bewährt. Sie haben herkömmliche Materialien für Konstruktionselemente wie Träger, Brückenfahrbahnen und Schrägseile ersetzt. Es gibt aber auch Faktoren, die den Grad der Integration des Systems aus faserverstärkten Polymer-Verbundwerkstoffen in der Brücke reduzieren können. Das EU-finanzierte Projekt BriFace wird Techniken zur strukturellen Zustandsüberwachung einsetzen, um die Effizienz von Verstärkungsmaßnahmen zu messen und diese mit Interface-Effizienzindizes (InterFeis) zu quantifizieren. Die Indizes werden im Projekt festgelegt. Für eine erste Brückeninneninspektion wird aus großer Entfernung eine Prüfmethode mit gelenkten Wellen eingesetzt. Die Ergebnisse werden für die Entwicklung von Leitlinien für das Brückendesign und für eine EU-Strategie zur Infrastruktursicherheit nützlich sein.

Ziel

Modernisation of our deficient transportation networks and in particular bridges is a pressing requirement imposed by the growing EU economy, vital to societal coherence and safety. Frequent retrofitting solutions include the use of versatile Fiber Reinforced Polymers systems (FRPs), which have been proven to enhance the capacity and deflections of bridges. Nevertheless, it is surprising that only a few, if any, research results are available with regard to the efficiency and appropriateness of FRP systems used on bridge retrofitting schemes, whilst international design guidelines neglect the level of integration of the measures with the existing bridge components. In practice, and especially in bridge decks were deterioration is expected, there is a number of limitations that reduce the level of integration of the FRP system with the bridge. This gave the BriFace project a strong motivation to utilise Structural Health Monitoring (SHM) techniques to assess the efficiency of the strengthening measure and quantify those, for the first time in the international literature, with the Interface Efficiency Indices (InterFeis), by measuring reliably the interface deflections and strains and by taking into account the failure modes and the limit stress states of bridge components. The novel objectives of BriFace are: 1) To define the Interface Efficiency Indices, 2) To utilize an expedient, long-distant inspection method of guided waves for the first time in bridge inspection, 3) To increase the interface efficiency by chemical means potentially by using nanoparticles and 4) To use InterFeis as a reliable indicator toward the quantification of the redundancy of the retrofitted bridge, as a means to assess its capacity and thus its resilience. The research outcomes will also benefit stakeholders and fuel bridge design guidelines and align them with the EU strategy on infrastructural safety and resilience.