Mechanics Approaches for Advanced Concrete Materials

I am currently seeking graduate students. I have research funding so stipends are available. Please email me for more information at asturm@gs.ncku.edu.tw

Research Introduction

The goal of this research group is to develop design approaches for reinforced concrete (RC) structures using advanced materials such as fibre reinforced concrete (FRC) and ultra-high performance fibre reinforced concrete (UHPFRC) as well as fibre reinforced polymer (FRP) materials . These design approaches utilise fundamental mechanical principles to streamline the development and implementation of design approaches for these advanced materials. These mechanics principles include:

  • Partial interaction theory- This approach allows for the effects of bond on the cracking and tension stiffening behaviour of reinforced concrete structures

  • Shear friction theory- This approach allows for the effects of sliding along shear cracks. This phenomenon is not only important in shear but for concrete crushing as well

  • Segmental analysis- This is a modification of a conventional sectional analysis to allow for localised effects such as cracking in tension and crushing in compression. This is by considering the behaviour over a segment extending between two cracks

Currently this approach has been successfully applied to the flexure and shear behaviour of UHPFRC beams under conventional loading. The research group however seeks to extend this approach to other types of structures (eg columns, slabs, corbels), other types of loading (eg torsion , cyclic loading, fatigue, long-term loading) as well as other types of materials (eg anchored FRP).

Current Research Topics

The two main research areas that are currently being explored are:

  1. The effect of construction joints on the structural behavior of UHPC beams. The effect of vertical and horizontal construction joints with and without surface treatment on the flexural behaviour of UHPC is being explored. It is expected that this behaviour is different to that observed for conventional reinforced concrete beams as the construction joints will disrupt the influence of the fibres.

  2. The best approach to measure the tension properties of UHPC materials. Measuring the tension properties of UHPC is critical for design as the introduction of fibres allows tensile stresses to be transferred across cracks even after cracking. However in the literature as well as various design standards different tests have been suggested for characterising the tensile properties of UHPC. These have included:

    1. Flexural tests on prisms (US Standard Approach)

    2. Flexural tests on notched prisms (French Standard Approach)

    3. Tension tests on large dogbones (Sturm et al. 2018). Note these have been suggested for normal strength FRC specimens in the Australian Standard.

    4. Tension tests on small dogbones (Hong et al. 2020 and others)

Alexander Sturm

I am currently an Assistant Professor at National Cheng Kung University. Previously I was a PhD Candidate than Research Associate at the University of Adelaide from 2017 to July 2021. I was also a Visiting Research Scholar at North Carolina State University for a year in 2018.

Education

  • Ph.D in Engineering, University of Adelaide, 2020

Title: Mechanics-based approaches for the flexural and shear behaviour of ultra-high performance fibre reinforced concrete beams

  • B.E. (Honours) (Civil and Structural) with First Class Honours, University of Adelaide, 2016

  • B.Sc (Theoretical Physics), University of Adelaide, 2016

Academic Experience

  • Assistant Professor, Department of Civil Engineering, National Cheng Kung University (Since 2021/10-)

  • Research Associate, University of Adelaide (2021/1-2021/7)

  • Visiting Research Scholar, North Carolina State University (2018/2-2018/12)

  • Tutor, University of Adelaide (2015/2-2021/7)

Teaching

  • Advanced Prestressed Concrete (2021 Fall)

  • Steel Concrete Composite Structures (2022 Spring)

  • Strengthening and Retrofitting of Concrete Structures (2022 Spring)

  • Engineering Mathematics I (2022 Fall)

Academic Publications

  • Bashar, I. I., Sturm, A. B., Visintin, P., & Sheikh, A. H. (2022). "Analytical approach to quantify the pull-out behaviour of hooked end steel fibres." Australian Journal of Civil Engineering, 1-21.

  • Sturm, A.B. (2022). “AS3600:2018 The Australian Concrete Standard and Implications for Reinforced Concrete Design in Taiwan.” Chinese Society of Structural Engineering J. of Structural Engineering, 37(2).

  • Sturm, A. B., & Visintin, P. (2022). "Pre‐and post‐yield bond, tension‐stiffening, and cracking in ultra‐high performance fiber reinforced concrete." Structural Concrete.

  • Sturm, A. B., Visintin, P., & Bennett, B. (2022). "A hybrid deterministic-probabilistic approach for the characteristic crack widths and crack spacings in reinforced concrete tension and flexural members." Engineering Structures, 256, 114071.

  • Sturm, A. B., Visintin, P., and Oehlers, D. J. (2020) “Design oriented solutions for the shear capacity of reinforced concrete beams with and without fibres.” Journal of Structural Engineering, 147 (6), 04021066.

  • Sturm, A. B., Visintin, P., and Oehlers, D. J. (2020) “Mechanics of shear failure in fibre reinforced concrete beams.” Journal of Structural Engineering, 147 (3), 04020344.

  • Sturm, A.B., Visintin, P. and Oehlers. D.J. (2020) “Blending fibres to enhance the flexural properties of UHPFRC beams.” Construction and Building Materials, 244, 118328.

  • Sturm, A.B., Visintin, P. and Oehlers. D.J. (2020) “Closed form expressions for predicting moment redistribution in reinforced concrete beams with application to conventional concrete and UHPFRC.” Structural Concrete, 21 (4), 1577-1596.

  • Sturm, A.B., Visintin, P., Seracino, R., Lucier, G.W. and Oehlers, D.J. (2020) “Flexural performance of pretensioned ultra-high performance fibre reinforced concrete beams with CFRP tendons.” Composite Structures, 243, 112223.

  • Sturm, A.B. and Visintin, P. (2019) “Local bond slip behaviour of steel reinforcing bars embedded in UHPFRC.” Structural Concrete, 20(1), 108-122.

  • Sturm, A.B., Visintin, P., and Oehlers, D.J. (2019) “A rational design approach for the instantaneous and time dependent serviceability deflections and crack widths of FRC and UHPFRC continuous and simply supported beams.” ASCE Journal of Structural Engineering, 145(11), 04019138.

  • Sturm, A.B., Visintin, P., Vaculik, J., Oehlers, D.J., Seracino, R., and Smith, S.T. (2019) “Analytical approach for global load-slip behaviour of FRP plates externally bonded to brittle substrates with anchors.” Composites Part B: Engineering, 160(2019), 177-194.

  • Sturm, A.B., Visintin, P., Farries, K. and Oehlers, D.J. (2018) “A new testing approach for extracting the shear friction material properties of ultra-high performance fibre reinforced concrete.” ASCE Materials in Civil Engineering, 30(10), 04018235.

  • Sturm A.B., Visintin P. and Oehlers D.J. (2018) “Time-dependent serviceability behavior of reinforced concrete beams: Partial interaction tension stiffening mechanics.” Structural Concrete, 19(2), 508-523.

  • Sturm, A.B., Visintin, P., Oehlers, D.J. and Seracino, R. (2018) “Time dependent tension stiffening mechanics of fibre reinforced and ultra-high performance fibre reinforced concrete.” ASCE Journal of Structural Engineering, 144(8), 04018122.

  • Vaculik, J., Sturm, A.B., Visintin, P. and Griffith, M.C. (2018) “Modelling FRP-to- substrate joints using the bilinear τ-δ rule with allowance for friction—Full-range analytical solutions for long and short bonded lengths.” International Journal of Solids & Structures, 135, 245-260.

  • Visintin, P., Mohamed Ali, M.S., Xie, T. and Sturm, A.B. (2018) “Experimental investigation of moment redistribution in ultra-high performance fibre reinforced concrete beams.” Construction & Building Materials, 166(1), 433-444.

  • Visintin, P., Sturm, A.B., Mohamed Ali, M.S. and Oehlers, D.J. (2018) "Blending macro and micro fibres to enhance the serviceability behaviour of UHPFRC.” Australian Journal of Civil Engineering, 16(2), 106-121.

  • Visintin P, Sturm A.B. and Oehlers D.J. (2018) “Long- and short-term serviceability behavior of reinforced concrete beams: Mechanics models for deflections and crack widths.” Structural Concrete, 19(2), 489-507.

  • Visintin, P., Oehlers, D.J. and Sturm, A.B. (2016) “Mechanics solutions for deflection and cracking in concrete.” Proceedings of the Institution of Civil Engineers-Structures and Buildings, 169(12), 912-924.

Contact

Email: asturm@gs.ncku.edu.tw

Office: 47650, 5F, 卓裙大樓