Thermo-mechanical simulation of the ConCrack Benchmark RL1 test with a filament beam model

•Participation in ConCrack: challenge for crack modelling of concrete structures.•Thermo-mechanical filament beam model able to describe the relevant phenomena.•Blind prediction and postdiction analysis after divulgation of experimental data.•Comparison with other teams involving great variety of numerical approaches.•One of the best blind stage predictions with a relative simple model. Cracking is an inherent characteristic of RC structural behaviour and its control is an important concern for durability and sustainability. The French national research program CEOS.fr – ‘Behaviour and assessment of special construction works concerning cracking and shrinkage’ – has carried out an experimental campaign focused on cracking behaviour. An international benchmark (ConCrack) was organized with the goal of achieving a state of the art on cracking modelling of concrete structures. In this paper, the blind prediction of the RL1 test – large RC beam specimen loaded in bending after free shrinkage – by means of a thermo-mechanical filament beam model is presented. Numerical and experimental results are compared in terms of temperatures, strains, displacements and cracking. Predictions of other participating teams involving distinct formulations are also contrasted. Beam elements presented one of the most successful performances at blind stage, with good predictions at both early age and loading stages. At the feed-back stage, a postdiction analysis was performed with updated parameters. Strain fields developed at early ages affected the mechanical response at mature ages by increasing general damage. Due to its conceptual simplicity and accuracy, the presented model can be a very interesting option for design and assessment stages of complex structural behaviours.