Structural design of high-rise buildings

High-rise buildings are exposed to both static and dynamic loads. Depending on the method used and how the structure is modelled in finite element software the results can vary.

Some of the issues and modelling techniques, introduced below, are investigated in this Master’s thesis. Dynamic effects such as resonance frequencies and accelerations are considered. The variation in static results from reaction forces, overturning moments, deflections, critical buckling loads, forces between prefabricated elements and force distributions between concrete cores are investigated with different models. The models are evaluated by different elements and methods, such as construction stage analysis, to study the impact these have on the results.

Simplified calculations by hand according to different standards, regulations and codes such as SS-ISO, EKS and Eurocode have been compared with finite element analyses. The 3D-finite element software used for the analyses is Midas Gen.

From the results it can be observed, when modelling a high-rise building in a finite element software, that one model is often not sufficient to cover all different aspects. To see the global behaviour, one model can be used, and when studying the detailed results another model with a fine mesh, that have converged, is often needed. The same principle applies when evaluating horizontal and vertical loads, different models or methods are usually needed.