Dr Marios Theofanous Dipl. Ing., MSc, PhD

Dr Marios Theofanous

Department of Civil Engineering
Lecturer

Contact details

Address
University of Birmingham
Edgbaston
Birmingham
B15 2TT
UK

Marios Theofanous is Lecturer in Structural Engineering. His main research interests, in respect of which he has co-authored more than 25 papers in peer-reviewed academic journals and conferences, include experimental and numerical research of structural steel, stainless steel and high strength steel structures at cross-sectional, member and system level. Other research interests include FRP-strengthened concrete structures, structural fire engineering and semi-rigid connections.

Qualifications

  • PhD in Structural Engineering, Imperial College London, 2010
  • MSc, DIC in Structural Steel Design and Business Management (with distinction), Imperial College London, 2006
  • Dipl. Ing. (8.32/10), Aristotle University of Thessaloniki, 2005.

Biography

Marios Theofanous completed his undergraduate studies in Civil Engineering at the Aristotle University of Thessaloniki, Greece in 2005. After obtaining an MSc (with distinction) in Structural Steel Design and Business Management from Imperial College London in 2006, he worked for the Steel Construction Institute. Subsequently he commenced his doctoral studies on the nonlinear response of stainless steel structures at Imperial College London.

Upon obtaining his PhD in 2010, he worked as an adjunct lecturer and post-doctoral researcher at the Aristotle University of Thessaloniki and as freelance engineer for 2 years. In 2012 he returned to Imperial College London as a post-doctoral research associate working on an EU-funded project on the use of High Strength Steel for long span structural applications. He joined the School of Civil Engineering at the University of Birmingham as a lecturer in 2014.

Teaching

Teaching Programmes

  • Engineering Design
  • Structural Engineering 1
  • Civil Engineering Research Project
  • Individual Research Project

Postgraduate supervision

Marios is interested in supervising undergraduate and postgraduate students in the following research fields:

  • Structural fire engineering
  • Robustness of stainless steel and high strength steel structures
  • Deformation based design procedures for seismic applications
  • Ultimate response of hybrid steel and stainless steel cross-sections in compression and bending
  • Plastic design of stainless steel indeterminate structure
  • FRP strengthened steel structures
  • Perforated cold-formed steel members

Email for more information: m.theofanous@bham.ac.uk

Supervision and Co-supervision of PhD students

  • Jie Wang (at Imperial College London until August 2014). High Strength Steel Structures.
  • Michaela Gantou (since September 2014). Numerical modelling of High Strength Steel Structures.
  • Mohamed Elflah (since September 2014). Semi-rigid bolted connections of open beam sections to tubular columns.

PhD opportunities

Research

Current research activity

  1. High strength steel structures

Experimental and FE research of the structural response of high strength steel (S460 – S690) stub columns, beams, slender columns and beam-columns. Assessment of design rules in EN 1993-1-1 and EN 1993-1-12. Utilization of post-tensioning to mitigate excessive deflections. Optimization of post-tensioned high strength steel trusses

  1. Stainless steel structures

Effect of material nonlinear response on the ultimate response and ductility of stainless steel cross-sections, members and indeterminate structures. Assessment of novel laser welding fabrication on the structural response of welded stainless steel cross-sections members.

  1. Interfacial strength of concrete filled steel tubular columns

Composite action between concrete and still in concrete filled columns relies on the achievement of perfect bond between steel and concrete, therefore assessing the interfacial strength at the steel concrete interface is of paramount importance. To this end experimental and analytical research has been conducted in collaboration with Tianjin University in China to identify the various mechanisms and quantifying their contribution to the interfacial strength between concrete and steel.

  1. Deformation based design metallic structures

Stainless steel and structural steel structures exhibit significant strain-hardening in the post elastic material range, which is customarily not accounted for in design, thereby not harnessing the materials full structural potential. To this end the Continuous Strength Method has been developed by Prof. Leroy Gardner, which is in essence a deformation based design procedure that allows for strain hardening exhibited by stocky cross-sections. Current research in this area includes the derivation of design rules for non-doubly symmetric stainless steel sections in bending, the derivation of design rules to treat cross-sections under combined loading and extending the method to elevated temperatures, i.e. design cross-sections exposed to fire conditions.

  1. FRP-strengthened concrete beams

Most structural strengthening techniques for reinforced concrete beams in shear utilise FRP sheets which are connected to the concrete member by means of an adhesive layer. In most cases, failure occurs due to delamination/deboning of the sheet in the resin rich concrete face and is mainly defined by the tensile strength of the underlying concrete, thus not allowing the full potential of the FRP sheets to be exploited. To address this issue a novel anchoring scheme has been developed by the research team of Professor Manos at the Aristotle University of Thessaloniki and research is underway to optimize the scheme at local and structural level.

  1. Plastic design of stainless steel continuous beams

Eurocode design provisions specify a slenderness limit for plastic stainless steel sections but do not allow plastic design, mainly due to lack of available test data. Given the high material ductility of stainless steel and its high initial material cost, the extension of plastic design procedures to stainless steel indeterminate structures is warranted. To this end experimental and numerical research is being conducted and initial results are encouraging.

  1. Structural response of Elliptical Hollow Sections

Elliptical Hollow Sections (EHS) and Oval Hollow Sections (OHS) are a recent addition to the tubular section family and combine the structural efficiency associated with sections with different stiffness about the principal axes with the aesthetics of Circular Hollow Sections (CHS). Due to their unique geometry and in particular the fact that they are not comprised of plated elements nor have they a constant curvature, their treatment at cross-sectional level is challenging. The structural response of stainless steel OHS in compression and bending has been studied both experimentally and numerically. Suitable slenderness parameters have been identified and the suitability of the Eurocode 3 design rules to this form of sections has been verified, whilst a safe buckling curve, different form the ones specified in EN 1993-1-4 has been proposed. Further research concerns their structural response under combined loads at ambient and elevated temperatures.

  1. Stability of sandwich structures

Analytical and numerical research into the buckling and post-buckling response of sandwich compression members employing stiff face plates and flexible cores. Effect of assumed beam theory and pre-existing damage.

Other activities

  • Member of the Technical Chamber of Greece (chartered engineer)
  • Reviewer of the following journals:
    • Thin-Walled Structures
    • International Journal of Steel Structures
    • Journal of Engineering and Technology Research
    • The Open Journal of Civil Engineering

Publications

Journal Publications

  • Xiushu Qu, Zhihua Chen, David A. Nethercot, Leroy Gardner and Marios Theofanous. (under review). Push out tests and bond strength of rectangular CFST columns. Steel and Composite Structures.
  • Theofanous, M., Saliba, N. Zhao, O. and Gardner, L. (2014). Ultimate response of stainless steel continuous beams. Thin-Walled Structures 83, 115-157.
  • Manos, G.C., Theofanous, M. and Katakalos K. (2014). Numerical simulation of the shear behaviour of reinforced concrete rectangular beam specimens with or without FRP-strip shear reinforcement. Advances in Engineering Software 67, 47-56.
  • Xiushu Qu, Zhihua Chen, David A. Nethercot, Leroy Gardner and Marios Theofanous (2013). Load-reversed push-out tests on rectangular CFST columns. Journal of Constructional Steel Research 81(2), 35-43.
  • Theofanous, M. and Gardner, L. (2012). Effect of element interaction and material non linearity on the ultimate capacity of stainless steel cross-sections. Steel and Composite Structures 12(1), 73-92.
  • Theofanous, M. and Gardner, L. (2010). Experimental and numerical studies of lean duplex stainless steel beams. Journal of Constructional Steel Research 66 (6), 816-825.
  • M. Ahmer Wadee, Stylianos Yiatros and Marios Theofanous (2010). Comparative studies of localized buckling in sandwich struts with different core bending models. International Journal of Non-Linear Mechanics 45 (2), 111-120.
  • Theofanous, M. and Gardner, L. (2009). Testing and numerical modelling of lean duplex stainless steel hollow section columns. Engineering Structures. 31 (12), 3047-3058.
  • Theofanous, M., Chan, T.M. and Gardner, L. (2009). Flexural behaviour of stainless steel oval hollow sections. Thin-Walled Structures 47(6-7), 776-787.
  • Theofanous, M., Chan, T.M. and Gardner, L. (2009). Structural response of stainless steel oval hollow section compression members. Engineering Structures 31(4), 922-934.
  • Gardner, L. and Theofanous, M. (2008). Discrete and continuous treatment of local buckling in stainless steel elements. Journal of Constructional Steel Research 64(11), 1207-1216.

Conference Publications

  • Schillo, N., Theofanous, M., Gardner, L. and Feldmann, M. (2014). Material properties and local buckling behaviour of high strength steel hollow sections. In: Proceedings of the 7th European Conference on Steel and Composite Structrues, Eurosteel 2014, Naples, Italy, pp. 75-76.
  • Theofanous, M. and Gardner, L. (2014). Structural response of laser-welded stainless steel compression members. In: Proceedings of the 7th European Conference on Steel and Composite Structrues, Eurosteel 2014, Naples, Italy, pp. 81-82.
  • Theofanous, M., Gardner, L, and Koltsakis, E. (2013). Structural response of stainless steel cross-sections under combined compression and biaxial bending. In: Proceedings of the the 5th International Conference on Structural Engineering, Mechanics and Computation, pp. 1453-1458, Cape Town, South Africa.
  • Katakalos, K., Manos, G.C., Theofanous, M. and Kozikopoulos E. (2013). Experimental and numerical investigation of rectangular R/C beams retrofitted against shear utilising FRP strips. In: Proceedings of the 4th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, COMPDYN 2013, Kos, Greece.
  • Manos, G.C., Katakalos, K., Theofanous, M., Nalmpantidou, A., Tsakalidis, V. and Stathi, C. (2013). The earthquatke behaviour of low-rise houses made by either reinforced concrete, partially reinforced masonry or a novel steel composite system. In: Proceedings of the 4th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, COMPDYN, Kos, Greece.
  • Theofanous, M. and Gardner, L. (2012). The continuous strength method for stainless steel sections failing by distortional buckling. In: Proceedings of the 6th International conference on coupled instabilities in metal structures, pp. 539-546, Glasgow, UK.
  • Theofanous, M., Liew, A. and Gardner, L. (2012). Ultimate capacity of stainless steel RHS subjected to combined compression and bending. In: Proceedings of the 14th International Symposium on Tubular Structures, pp. 423-430, London, UK.
  • Theofanous, M., Preftitsi, F.G., Goulas, E. and Thomopoulos, K. (2011). The effect of the loading angle on the strength of carbon steel and stainless steel fillet welds. In: Proccedings of the 7th National Conference on Steel Structures, pp. 796-803, Volos, Greece.
  • Theofanous, Μ., Gardner L, The Influence of element interaction and material nonlinearity on the ultimate capacity of stainess steel cross-sections. In: Proccedings of the 7th National Conference on Steel Structures, pp. 812-819, Volos, Greece.
  • Theofanous, M. and Koltsakis, E. (2011). Numerical investigation of IPE beams strengthened against lateral-torsional buckling. In: Proccedings of the 7th National Conference on Steel Structures, pp. 529-536, Volos, Greece.
  • Theofanous, M. and Gardner, L. (2010). Plastic design of stainless steel structures. In: Proceedings of the International Colloquium on Stability and Ductility of Steel Structures, pp. 665-672., Rio de Janeiro, Brazil.
  • Theofanous, M. and Gardner, L. (2009). Structural behaviour of lean duplex stainless steel. In: Proceedings of the 9th International Conference on Steel Concrete Composite and Hybrid Structures (ASCCS 2009), pp. 759-766. Leeds, UK.
  • Wadee, M.A., Yiatros, S. and Theofanous, M. (2009). Effects of core models in the interactive buckling of sandwich struts. In: Puri, IK and Hajj, MR, editors: The joint ASCE-ASME-SES conference on mechanics and materials, pp. 123-124. Blacksburg, USA.
  • Gardner, L., Theofanous, M. and Chan, T.M. (2008). Buckling of tubular stainless steel columns. In: Proceedings of the 5th International Conference on Coupled Instabilities in Metal Structures, pp. 199-207. Sydney, Australia.
  • Theofanous, M. and Gardner, L. (2008). Slenderness limits for stainless steel cross-sections. In: Proceedings of the 5th International Conference on Thin-Walled Structures, vol. 2, pp. 899-906. Brisbane, Australia.

Technical Reports

  • Gardner, L. and Theofanous, M. (2013). Experimental studies of laterally restrained cold-formed stainless steel angle section beams subjected to geometric axis bending. Report to ANCON building products.
  • Theofanous, M., Gardner, L. and Wadee, M.A. (2013). WP2: Material and Section design. 1st annual report for the RFCS project: High strength long span structures (HILONG). RFSR CT 2012-00028.
  • Gardner, L. and Theofanous, M. (2009). Review of Osnaburgh Pavilion Design. Final Report to ARUP.