Promotion Josiane Giese

On 02.09.2024, Dipl.-Ing. Josiane Giese successfully defended her scientific work as part of the doctoral procedure with the topic "Stability sensitivity of thin-walled structures made of carbon concrete". In addition to the chair of the doctoral committee, Prof. Dr. Katharina Kleinschrot (TU Dresden), Prof. Dr.-Ing. Dr.-Ing. E.h. Manfred Curbach (TU Dresden) was present as an assessor. Prof. Dr. Birgit Beckmann (TU Dresden) was also present as a member of the doctoral committee.

Abstract:

The use of the innovative composite material carbon concrete enables the construction of slender and material-saving load-bearing structures, which can contribute to improving resource efficiency and reducing CO₂ emissions in the construction industry. Due to the low component thicknesses, however, the consideration of stability-relevant aspects comes to the fore, which are generally of secondary importance in conventional reinforced concrete construction and are more associated with thin-walled steel construction. In order to expand the state of knowledge on this still relatively unexplored topic of carbon concrete, the research of the present work dealt with the load-bearing and deformation behavior of normal force-loaded, bar-shaped structures made of carbon concrete of different slendernesses. In particular, it was investigated how the sensitivity to stability failure is to be assessed and which parameters influence the structural behavior and to what extent. Based on the material behaviour under uniaxial compressive loading, which was characterized by previous tests on compressed, disc-shaped test specimens, three relevant slendernesses were first derived for the stability tests. They were selected with λ = 62, 85 and 125 to cover a wide range of applications. For the experimental investigation of the stability behavior, a test rig was developed with which numerous tests were carried out on hinged test specimens of different lengths with and without imperfections applied as planned. They were used to quantify the influence of the slenderness itself as well as imperfections such as inhomogeneities in the cross-sectional structure and deviations in the external cross-sectional shape, but also eccentricities in the load application. In addition to the stress-deflection behavior of the specimens, the stress-strain curves and the moment-normal force curves were also used to evaluate the tests and the results were checked for agreement with different approaches to predicting the load-bearing capacity.

In view of the fact that stability problems involve failure without prior notice and that the load-bearing capacity is usually significantly reduced compared to the cross-sectional load-bearing capacity, this topic is of considerable importance for the filigree carbon concrete construction method. The knowledge gained in the course of this work makes an important contribution to the fundamental understanding of the stability behavior of slender, compression-stressed structures made of carbon concrete and thus also to their safety and efficiency.

We would like to congratulate Ms. Josiane Giese on completing her doctorate and wish her all the best and every success for the future.