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Concrete Infrastructure Research Group (CIRG)


Reinforced concrete crack analysis




Due to rapid advances in the development of techniques for monitoring and retrofitting concrete, there is a need to revisit and generalise classical theories in order to better assess the strength of existing reinforced concrete (RC) structures and to inform the design of strengthening systems. An improved understanding of concrete cracking is an implicit requirement to achieve these aims. Cracking is a major deterioration mechanism when considering the durability and service life of concrete and it involves diverse phenomena such as the formation of cracks, crack propagation, the existence of micro-cracks, interactions between the reinforcement and the concrete, and the concrete microstructure. Over the past decades various models were developed to simulate the cracking process in reinforced concrete beams. These models can broadly be classified as plasticity based models which are justified in the case of ductile behaviour e.g. beams with sufficient internal steel, and fracture mechanics based models which do not treat fracture as a point phenomenon but use fracture mechanics principles to explain the crack propagation. This research seeks to identify the criteria that relates to the transition between these two perspectives and to generalize the modelling of the cracking process to explicitly include different reinforced concrete parameters.


Selected references

Fayyad, T.M. and Lees, J.M. (2018) "Integrated fracture-based model formulation for RC crack analysis". ASCE Journal of Structural Engineering, 144(7). (accepted version) (doi) 

Fayyad, T.M. and Lees, J.M. (2017) "Experimental investigation of crack propagation and crack branching in lightly reinforced concrete beams using digital image correlation". Engineering Fracture Mechanics,  182:487-505 (accepted version) (doi

Fayyad, T.M. and Lees J.M. (2015) "Evaluation of a minimum flexural reinforcement ratio using fracture-based modelling" Proceedings of the IABSE2015 Conference: Providing solutions to global challenges, Geneva, Switzerland pp. 735-742

Brault, A., Hoult, N.A. & Lees, J.M. (2015)"Development of a Relationship between External Measurements and Reinforcement Stress"Proc SPIE 9435, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2015, 943519 (March 27, 2015); doi:10.1117/12.2175830 (published copy) (doi)

Fayyad, T.M. and Lees, J.M. (2014) "Application of Digital Image Correlation to Reinforced Concrete Fracture" Procedia Materials Science - 20th European Conference on Fracture, Eds Z. Zhang, B. Skallerud, C. Thaulow, E. Østby and J. He, Elsevier v. 3 , pp. 1585–1590 (published copy)(doi)



The Concrete Infrastructure Research Group develops sustainable infrastructure, through an improved understanding of existing infrastructure assets, the use of new materials, and the creation of innovative structural solutions.


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