Fachwerkmodellbildung mit topologischen Optimierungsverfahren

Strut-and-tie modelling with topological optimisation

Design and detailing of discontinuous or shear critical regions in reinforced concrete structures are usually based on strut-and-tie modelling. Typical examples of such structures are corbels, frame corners, block-outs or spatial concrete structures. Strut-and-tie models that are developed from the inner distribution of forces, and therefore evoke only minor redistributions or crack formations, have proven especially suitable for such design purposes. In general, the stress trajectories used to develop such models are derived from linear-elastic calculations. Alternatively, similar models can be derived from topological optimisation results. The strut and node locations are indicated directly by calculated material densities. These results can then be easily transferred into strut-and-tie models and generated for arbitrary complex structures.
This contribution shows the basic principles of topology optimisation, favourable parameter adjustments to derive appropriate models, simplifications for strut-and-tie models and finally its implementation in reinforcement design. Truss frames, corbels and shear-coupling mechanisms w.r.t concrete lining segments with various reinforcement concepts, e.g. conventional rebars, steel fibres or mesh-like micro reinforcement, are presented as examples.