In his recent video, Jürgen Bellmann, SOFiSTiK AG, explains the Triple Crack Model for brick elements (three cracks perpendicular to each other).
By incorporating smeared reinforcement, engineers can accurately account for the tension-stiffening effect.
In his presentation, Jürgen showcases the model’s features and presents analysis results. Starting with a single-span example of a brick concrete structure, he compares linear and non-linear cracked deflection, revealing the superior accuracy achieved through the Triple Crack Model. Wingraf helps visualise volume and beam elements, offering comprehensive insights into stress distribution.
Smeared reinforcement takes centre stage as Jürgen explores its application using quad elements. By demonstrating the well-known distribution of reinforcement in cracked quads, he emphasises the concept of smeared reinforcement. This technique enables accurate representation without needing individual beam elements. The model is then applied to 3D brick elements in a two-span girder example, further exemplifying the versatility of smeared reinforcement.
Using Wingraf, Jürgen showcases the model’s extensive analysis capabilities. Engineers gain a comprehensive understanding of structural performance by directly visualising stress in reinforcement, concrete stresses (including compression and tensile stress), and crack directions. The video illustrates crack patterns in mid-span and over the intermediate support, providing valuable insights into crack development.
Jürgen introduces the LADE material law and explains its significance. With a compression stress state of zero in the z-direction, the model accurately represents stress behaviour. Notably, the model eliminates the need to consider Poisson’s ratio after the crack occurrence, simplifying analysis and enhancing accuracy.
Jürgen presents an example of a wind turbine foundation to demonstrate real-world applications. By employing smeared reinforcement, stress distribution in volume elements is visualised, with reinforcement one representing radial reinforcement and three describing vertical reinforcement.
The model’s maximum crack strain parameter provides a valuable tool for identifying cracked elements. By referring to the FCTK curve, engineers can assess strains above the peak, enabling precise crack detection. Additionally, the model supports surface visualisation, aiding engineers in analysing yielding behaviour.
In conclusion, the Triple Crack Model signifies a groundbreaking advancement in non-linear concrete analysis. By simulating three cracks per element and incorporating smeared reinforcement, the model offers engineers unprecedented accuracy and insight into structural behaviour. With its extensive analysis capabilities and practical applications, the Triple Crack Model is set to revolutionise the field of concrete engineering.