Fatigue of structural concrete driven by a cumulative measure of shear strain

• Applicants: Professor Dr. Rostislav Chudoba; Professor Dr.-Ing. Josef Hegger
• 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 412131890

• Final Report Year: 2022

Final Report Abstract

Despite the remarkable progress made in recent years in modeling and characterizing the fatigue behavior of concrete, many open questions still need to be fundamentally addressed in order to gain a deep and general insight into the fatigue phenomenology of concrete. In this project, a modeling framework for the analysis and characterization of the fatigue behavior of concrete was developed to improve the understanding of fatigue phenomenology in terms of the fundamental fatigue damage mechanisms that occur at subcritical load levels. The developed modeling framework within this project was based on an enhanced fatigue modeling hypothesis that consistently represents the dissipative mechanisms associated with cumulative cyclic shear deformation at subcritical loading levels. The components of the modeling framework were formulated within the thermodynamic framework. The refined fatigue hypothesis was applied within the context of bond fatigue to describe the bond deterioration under fatigue loading. Further enhancement of the one-dimensional interface model was provided to consistently capture the 3D kinematics of zero-thickness interfaces response under monotonic and fatigue loading and providing a generic fatigue constitutive law that can be applied in a wide range of structural applications. To capture the tri-axial stress redistribution within the concrete structure under compressive fatigue loading, a novel microplane fatigue model was developed that employs the introduced fatigue hypothesis with cumulative fatigue damage due to sliding. A systematic calibration and validation procedure of the model response was provided based on the accompanying performed experimental program including normal- and high-strength concretes subjected to several loading scenarios of compressive loading. The developed modeling framework, supported by experimental studies, provides an improved framework for characterizing and analyzing the fatigue behavior of plain and reinforced concrete. Compared to current fatigue characterization methods that require a large number of expensive experiments, within the project a combined numerical, experimental and theoretical methodology was applied to characterize the effects of load following on the fatigue behavior of concrete. As a result, an enhanced assessment rule for predicting the fatigue life of concrete under compression was proposed that takes into account the effects of load sequence which provides an example of the potential contribution of advanced and efficient numerical modeling approaches to the formulation of reliable design concepts related to the fatigue behavior of materials and structures.

Publications

• Classification and evaluation of phenomenological numerical models for concrete fatigue behavior under compression. Construction and Building Materials, 221, 661-677.
  Baktheer, Abedulgader & Chudoba, Rostislav
  
• Combined numerical experimental methodology for characterizing the concrete fatigue behavior considering the loading sequence effect. In: VI International Conference on Computational Modeling of Fracture and Failure of Materials and Structures (CFRAC), Braunschweig, Germany.
  Baktheer, A.; Hegger, J. & Chudoba, R.
  
• Enhanced assessment rule for concrete fatigue under compression considering the nonlinear effect of loading sequence. International Journal of Fatigue, 126, 130-142.
  Baktheer, Abedulgader; Hegger, Josef & Chudoba, Rostislav
  
• Microplane damage plastic model for plain concrete subjected to compressive fatigue loading. Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures. IA-FraMCoS.
  Baktheer, A.
  
• Simulation of stress redistribution effect in concrete under cyclic compression: lattice discrete model vs. microplane model. In: 14th World Congress on Computational Mechanics (WCCM), Online.
  Aguilar M., Baktheer, A., Kveton, J., Masek, J., Elias, J., Vořechovský, M. & Chudoba, R.
  
• Experimental and theoretical evidence for the load sequence effect in the compressive fatigue behavior of concrete. Materials and Structures, 54(2).
  Baktheer, Abedulgader & Chudoba, Rostislav
  
• Fracture mechanics based interpretation of the load sequence effect in the flexural fatigue behavior of concrete using digital image correlation. Construction and Building Materials, 307, 124817.
  Baktheer, Abedulgader & Becks, Henrik
  
• Microplane fatigue model MS1 for plain concrete under compression with damage evolution driven by cumulative inelastic shear strain. International Journal of Plasticity, 143, 102950.
  Baktheer, Abedulgader; Aguilar, Mario & Chudoba, Rostislav
  
• Coupled sliding–decohesion–compression model for a consistent description of monotonic and fatigue behavior of material interfaces. Computer Methods in Applied Mechanics and Engineering, 398, 115259.
  Chudoba, Rostislav; Vořechovský, Miroslav; Aguilar, Mario & Baktheer, Abedulgader
  
• Monotonic and fatigue behavior of cementitious composites modeled via a coupled sliding-decohesioncompression interface model, in: Computational Modelling of Concrete Structures, EURO C-2022, Vienna, Austria.
  Baktheer, A., Vořechovský, M., Aguilar, M. & Chudoba, R.