Sub-project title: Towards more sustainable FRP strengthened concrete structures through novel strategies preventing flexural debonding. Effect of temperature & load distribution conditions (Subproject)
Period: 09/2024 – 08/2027 (36 months)
Principal Investigators of AMADE:
Cristina Barris Peña cristina.barris@udg.edu (IP1)
Marta Baena Muñoz marta.baena@udg.edu (IP2)
Other AMADE researchers involved in the project:
Lluís Torres, Alba Codina, Xavier Cahís, Miquel Llorens
Project Partners:
Universidad Politécnica de Madrid (UPM) (Coordinator)
Instituto Eduardo Torroja de Ciencias de la Construcción (IETcc-CSIC)
Grant agreement number: PID2023-150934NB-C32
Funded by: «Agencia Estatal de Investigación” (AEI), “Ministerio de Ciencia e Innovación” (MCIN) and confunded by the European Union under reference PID2023-150934NB-C32
DESCRIPTION
The retrofitting and strengthening of civil and building infrastructure significantly contribute to extending their service life and promoting global sustainability. This aligns with the principles of circular economy and reduces the environmental impact associated with raw material consumption. Fibre Reinforced Polymers (FRP) have emerged as excellent materials for strengthening concrete structures due to their attractive combination of mechanical properties, ease of assembly and durability. Evidence of their effectiveness is seen in the inclusion in an informative annex of the recently approved versions of new Eurocode 2 and new fib Model Code for Concrete Structures 2020. However, the behaviour of flexural concrete elements strengthened with FRPs greatly depends on the bond performance between concrete, adhesive and FRP. Using the most common strengthening techniques, premature debonding of FRP usually takes place, resulting in a severe underutilization of the mechanical properties of the FRP. The project seeks to optimize the use of FRP laminates in strengthening RC structures in flexure by improving the bond performance through innovative strengthening techniques not covered in current existing guidelines. In particular, the project will focus on grooving methods such as the externally bonded reinforcement on grooves (EBROG) and in grooves (EBRIG). The project will first concentrate on an extensive experimental evaluation of the bond behaviour of innovative configurations through single-shear tests, in order to: i) determine the most critical parameters in the design of such strengthening techniques, and ii) obtain analytical bond-slip laws that can be later be used in design provisions. In a second stage, an experimental programme on flexural beams will be designed and executed, where the same strengthening techniques tested in the previous step will be used with the optimized parameters. Numerical models will be implemented and analytical provisions developed able to be used for design purposes. Within the framework of the activities of the coordinated project, it is foreseen to use different structural health monitoring systems in conjunction with machine learning and deep learning strategies so as to enhance the level of knowledge and safety of FRP strengthened structures. Likewise, the interaction between flexural and shear debonding will be theoretically and experimentally studied to better understand the role of the different influencing factors when both types of strengthening are applied simultaneously and see the implications for the design. The aim of the project is also to foster the use of more sustainable materials for these strengthening systems. In that sense, basalt-FRP will be explored as an alternative to Carbon-FRP. To ensure that the project’s outcomes align with realistic environmental situations, the effects of temperature on the bonding system will be evaluated through experimental programmes on both bond single-shear and flexural tests. Finally, recognizing that flexural debonding is noticeably influenced by the load distribution, which is not accurately represented by the typical four-point loading test, a study on elements subjected to distributed load is anticipated. The project combines innovative flexural strengthening techniques, sustainability considerations and thorough evaluation of environmental factors to contribute to the advancement of FRP-based strengthening methods for civil structures.
