Samir Dirar graduated from the University of Khartoum (U. of K.) with a First Class BSc (Hons) in Civil Engineering in 2002. He spent his first year after graduation working as Graduate Engineer for a couple of private firms and assisting with teaching undergraduate students at U. of K.
In 2003, Samir joined the Department of Engineering at the University of Cambridge to study for the degree of MPhil in Engineering, thanks to a Shell Centenary Scholarship. In 2004, he was awarded an EPSRC PhD Studentship, together with a Trinity College Overseas Fees Bursary, to study the behaviour of reinforced concrete structures strengthened in shear with un-bonded pre-stressed and bonded passive carbon fibre reinforced polymer (CFRP) systems.
After the successful completion of his PhD degree, Samir joined the Civil and Computational Engineering Centre at Swansea University where he worked as Post-doctoral Research Assistant until 2010.
In 2010, Samir was appointed as Lecturer in Structural Engineering at the University of Birmingham where he is currently actively involved in both teaching and research.
Resilience and Sustainability of Reinforced Concrete (RC) Structures
Shear Strengthening of Existing RC Structures
The strength enhancement of existing RC infrastructure is an application of considerable economic and strategic importance, and of notable complexity. Samir’s work represents the first time that the influence of pre-existing damage has been investigated in the context of carbon fibre reinforced polymer (CFRP) shear-strengthened RC beams, elucidating the important interactions between cracking, load sharing and the CFRP strengthening system. The effects of load history, type of shear strengthening system, beam depth and percentage of longitudinal steel reinforcement on the strengthened behaviour have also been examined. The experimental results indicated that the contributions of the external CFRP systems to the shear force capacity can be significant and depend on most of the investigated variables.
Nonlinear Finite Element (NLFE) Analysis of RC Structures
Samir has been involved over the last 8 years in studies providing detailed analysis of the nonlinear behaviour of complex RC structural elements such as RC deep beams and FRP-strengthened RC structures. The main emphasis of his work has been on the development of NLFE predictive tools using advanced phased analyses and representative material models. The numerical investigations provided valuable insight into the constitutive models; in particular material models for the behaviour of concrete in shear, and the modelling techniques used in NLFE analysis of RC structures and highlighted their advantages and limitations.
Development of Design Guidelines for Shear Strengthening of Existing RC Structures
Samir’s work in this area aims to formulate design models that can predict accurately the shear force capacity of FRP-strengthened RC members. To this end, Samir has drawn together existing design proposals, previously distinct work on modelling FRP-to-concrete bond, and his own work to produce a new design model that is explored and demonstrated to be an improvement upon current design practice. Key advances include: (i) the identification of limitations in current design practice; and (ii) the quantification of the design of externally bonded shear strengthening systems to extend the lifetime of existing RC infrastructure.
Dirar, S., Lees, J., and Morley, C., 2011, Precracked RC T-Beams Repaired in Shear with Externally Bonded CFRP Sheets, ACI Structural Journal (under review).
Hassan Dirar, S., Morley, C., and Lees, J., 2007, Effect of Effective Depth and Longitudinal Steel Ratio on the Behaviour of Pre-cracked Reinforced Concrete T-Beams Strengthened in Shear with CFRP Fabrics, Proceedings of the 8th International Symposium on Fibre Reinforced Polymer Reinforcement for Concrete Structures (FRPRCS-8), Patras, Greece, 10 pp.
Hassan Dirar, S. M. O., Morley, C. T., and Lees, J. M., 2007, Effect of Load History on the Behaviour of Reinforced Concrete Beams Retrofitted in Shear with CFRP Systems, Proceedings of the 3rd International Conference on Advanced Composites in Construction (ACIC 07), Bath, United Kingdom, pp. 292 – 300.
Hassan Dirar, S. M. O., Hoult, N. A., Morley, C. T., and Lees, J. M., 2006, Shear Strengthening of Pre-cracked Reinforced Concrete Beams Using CFRP Straps, Proceedings of the 2nd fib Congress, Naples, Italy, 10 pp.
Hassan Dirar, S. M. O., and Morley, C. T., 2005, Nonlinear Finite Element Analysis of Reinforced Concrete Deep Beams, Proceedings of the 8th International Conference on Computational Plasticity Fundamentals and Applications (COMPLAS VIII), Barcelona, Spain, Part 1, pp. 209 – 212.