Shear behavior of RC members without shear reinforcement – development of a consistent experimental, analytical and numerical characterization methodology

• Applicants: Professor Dr. Rostislav Chudoba; Professor Dr.-Ing. Martin Claßen
• Subject Area: Structural Engineering, Building Informatics and Construction Operation ; Applied Mechanics, Statics and Dynamics
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 420545423

• Final Report Year: 2024

Final Report Abstract

Research into the shear-induced degradation of reinforced concrete sections has been a prominent focus since the mid-20th century. Despite significant advancements, no comprehensive model currently exists that fully captures the complex behavior of reinforced concrete members under shear loading. The primary objective of this project was to develop an integrated numerical and analytical framework to describe the shear behavior of reinforced concrete members lacking shear reinforcement. The project aimed to establish both analytical and numerical modeling approaches, striving for an optimal balance between accuracy and computational efficiency. Extensive experimental investigations were conducted involving 22 component tests, during which various parameters were systematically varied. Advanced monitoring methods, including digital 3D image correlation (DIC), were employed to monitor deformation fields and trace shear cracks. To enhance crack localization and detection, an automatic crack detection approach, incorporating constitutive models of crack localization, was developed. For automatically identified cracks, stress transfer mechanisms such as aggregate interlock and dowel action could be quantified, leading to refined models for improved predictive capabilities. This development led to enhancement of the novel Shear Crack Propagation Theory (SCPT), effectively capturing key aspects of shear force transfer. Validation against test results demonstrated strong agreement, offering valuable insights into the mechanics of shear force transfer. Overall, the smeared/discrete and numerical/analytical models and methods developed in this project can significantly improve the quality of evaluation and prediction of shear behavior and maximum shear capacity in reinforced concrete components. They provide a solid foundation for future investigations while highlighting new questions for follow-up research.

Publications

• Fictitious Rough Crack Model (FRCM): A Smeared Crack Modelling Approach to Account for Aggregate Interlock and Mixed Mode Fracture of Plain Concrete. Materials, 13(12), 2774.
  Ungermann, Jan; Adam, Viviane & Classen, Martin
  
• Shear Crack Propagation Theory (SCPT) – The mechanical solution to the riddle of shear in RC members without shear reinforcement. Engineering Structures, 210, 110207.
  Classen, Martin
  
• Mixed mode criterion for discrete crack propagation through RC shear zones, in: Júlio, E.; Valença, J.; Louro, A. S. (Hrsg.): Concrete Structures: New Trends for Eco-Efficiency and Performance: Proceedings of the fib Symposium 2021 held online from Lisbon, Portugal, 14-16 June 2021, (2021).
  Seemab, F.; Baktheer, A.; Hegger, J. & Chudoba, R.
  
• Shear Response of Members without Shear Reinforcement—Experiments and Analysis Using Shear Crack Propagation Theory (SCPT). Applied Sciences, 11(7), 3078.
  Schmidt, Maximilian; Schmidt, Philipp; Wanka, Sebastian & Classen, Martin
  
• On the existence of the center of rotation around a shear crack; numerical inspection of digital image correlation measurements, in: Stokkeland, S.; Braarud, H. C. (Hrsg.): Concrete Innovation for Sustainability. fib International Congress, (2022), digital proceedings.
  Seemab, F.; Schmidt, M.; Baktheer, A.; Hegger, J. & Classen, M.
  
• Automated detection of propagating cracks in RC beams without shear reinforcement based on DIC-controlled modeling of damage localization. Engineering Structures, 286, 116118.
  Seemab, Fahad; Schmidt, Maximilian; Baktheer, Abedulgader; Classen, Martin & Chudoba, Rostislav
  
• Evaluation of FRP-Reinforced Concrete Members without Shear Reinforcement - Analysis using Shear Crack Propagation Theory (SCPT), in: Proceedings of 11th International Conference on Fiber-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE 2023). 11th International Conference on Fiber-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE 2023), Rio de Janeiro, Brazil, (2023).
  Fattahi, M.; Schmidt, M.; Bosbach, S.; Noël, M.; Hegger, J. & Classen, M.
  
• Neue Perspektiven auf das Querkrafttragverhalten von Stahlbetonbauteilen ohne Querkraftbewehrung. Beton- und Stahlbetonbau, 118(7), 455-466.
  Schmidt, Maximilian; Seemab, Fahad; Chudoba, Rostislav & Claßen, Martin
  
• Evaluation of FRP-Reinforced Concrete Members without Shear Reinforcement: Analysis Using Shear Crack Propagation Theory. Journal of Composites for Construction, 28(6).
  Fattahi, Morvarid; Schmidt, Maximilian; Bosbach, Sven; Noël, Martin; Hegger, Josef & Classen, Martin
  
• Large-scale combined torsional and axial loading system (TorAx) – A new perspective on multiaxial testing of fracture and stress transfer in plain and reinforced concrete. Engineering Structures, 302, 117391.
  Becks, Henrik; Schmidt, Maximilian; Bosbach, Sven & Classen, Martin