Steel structure global analysis methods representing nonlinear stress-strain material response

The project focuses on new metal (mainly steel) materials in structures which exhibits significantly non-linear stress-strain behaviour. This includes high-alloy steels such as stainless steel, where the degree of material non-linearity is highest among all common steels. Stainless steels are considered as the main and reference material in the project but the results of the projects will be also applicable and fitted for other materials such as even more common high strength steels (HSS), significantly cold-formed carbon steels or aluminium alloys. In the second stage, it may be used also for advanced design of steel structures at elevated temperature (fire).

The topic has been initiated by publication [1], based on numerical analyses and showing the limitations of commonly used elastic analyses for stainless steel members.

As there currently exists only very limited experimental data on HSS resp. stainless steel members the ongoing project contains a significant testing campaign.

2018-19 – SHS/RHS beam columns

20 members were tested in combined loading and significantly extended by a numerical study. A simple design rule has been developed.

The results are summarised in [2]. A defended PhD thesis describes the findings in detail [3].


Local buckling failure:

Flexural buckling failure:

2020-2021 – open I/H section beam columns

Behaviour of welded stainless steel I-sections members loaded by compression and major axis bending moment was tested. The test results were subsequently used for a validation of a finite element (FE) model, developed in ABAQUS software.

A possible modification of a simple design rule for SHS/RHS is planned for 2021. The test results were accepted for publication in [4].

The section resistance in bending and compression including also slender Class 4 sections, as well as the LTB resistance was studied in [5] based on the tests and numerical models. The proposed modification of design procedures was presented (and accepted) for prEN1993-1-4 design code.

2021 – frame tests

Tests of stainless steel frames are prepared for the second half of the year. A model is also prepared for validation.

Planned research for 2022 – 23

During these two years, following step and targets are expected:

  • modelling of beam-columns subjected/not subjected to latral torsional buckling (6/2022)
  • development of an elastic global analysis for steels exhibiting various degree of material-non-linearity, publication (12/2022)
  • modelling of structures (portal frames etc.) (4/2023)
  • development of elastic global analysis methods (of various sophistication level) for steel structures representing nonlinear stress-strain material response, publication (12/2023)


For more information, please, email:

[1] Jandera, M., Syamsuddin, D., Zidlicky, B., Stainless steel beam-columns behaviour, Open Civil Engineering Journal, 2017, 11(Suppl-1, M5), pp. 358–368.

[2] Židlický, B., Jandera, M., Stainless steel SHS and RHS beam-columns, Stability and Ductility of Steel Structures – Proceedings of the International Colloquia on Stability and Ductility of Steel Structures, 2019, 2019, pp. 1334–1341

[3] Židlický, B. Axial Compression and Bending Interaction of SHS and RHS Stainless Steel Members, PhD Thesis, 2020.

[4] Feber, N. , Jandera, M., Rossi, B., Kremen, T. Experimental study of welded austenitic stainless steel I-section beam-columns, Eurosteel 2021.

[5] Šorf, M., Jandera, M., Lateral-torsional buckling of slender cross-section stainless steel beams, Structures, 2020, 28, pp. 1466–1478.


Other relevant research fields:

  • Stainless steel
  • Residual stress
  • Cold-formed steel
  • Tubular structures
  • Stability of steel structures

Department of Steel and Timber Structures