Head of the project: Ing. Čavajdová Kristína

Research team: prof. Ing. Vičan Josef, CSc., doc. Ing. Odrobiňák Jaroslav, PhD.

Duration: September 2022 – August 2023

The optimisation of the design method for verification of slender steel beam – columns is still current issue not only from the scientific point of view, but also for design practice field. The actual behaviour of slender steel elements subjected to a combination of axial compressive force and bending moments which arises due to the eccentricity of compressive force, is included in the calculations relatively complex and not sufficiently accurate. Therefore, the project objective is comparison of suitability of established design approaches, according to the European standards, on the basis of parametric numerical analyses result. By verifying beam-column resistance using the geometrically and materially nonlinear analysis with imperfections included (GMNIA) and comparing results to the values obtained from the experiments of the beam-column resistances, it is possible to accurate recommendations for the use of different types of design procedures under currently applicable European standards.

Head of the project: Ing. Bartuš Jakub

Research team: doc. Ing. Odrobiňák Jaroslav, PhD.

Duration: September 2022 – August 2023

Within the scope of my dissertation, a series of laboratory measurements will be carried out. The main objective is to investigate the behaviour of longitudinal shear forces in composite steel and concrete beams with openings in the web. Four specimens will be tested as part of the laboratory measurements. Each specimen consists of a concrete slab and a steel beam with an asymmetric welded cross-section. The concrete part of the beam will be connected to the steel part employing shear connectors. The load will be applied to the beams by a hydraulic press in the form of a four-point bend. Strain gauges will be used to record the measured quantities. A finite element numerical model will be developed to validate the results. Results obtained from experimental tests will be compared with numerical ones. The experiment output will be processed in the form of a scientific article in an impacted journal.               

Head of the project: Ing. Kraľovanec Jakub, PhD.

Research team: doc. Ing. Odrobiňák Jaroslav, PhD.

Duration: September 2022 – August 2023

The most important and especially the most useful output from the project will be the real application of knowledge on real bridges in practice, because only applicable knowledge can be considered truly beneficial in this area. The obtained outputs of the project will be the basis for scientific publications - min. one publication in an impactful scientific journal with a quartile of at least Q2 (according to the Web of Science database) and publications and participation in scientific conferences, the proceedings of which will be indexed in the Scopus or Web of Science databases. The grant project will enable research in the area of indirect determination of the value of the residual prestressing force, which is very relevant in view of the recent accidents of post-tensioned bridges of the first generation. These bridges were built in the middle of the 20th century in the former Czechoslovakia, so they are nearing the end of their useful life. For these reasons, the proposed project is focused on an area that ultimately affects our entire society. As part of the research, several types of prestressed concrete samples will be examined. Specifically, it will be post-tensioned prefabricated beams, concrete beams and pre-tensioned railway sleepers. All these samples are chosen as suitable examples of rod (beam) constructions. The performed experiments will be aimed at verifying several indirect methods for determining the residual prestress, the knowledge of which is a key knowledge in the static assessment of existing prestressed concrete bridges and structures. Numerical simulations and experimental measurements will be part of the verification, while the synergy of these two analyzes is essential in any research in this area.          

Head of the project: Ing. Zahuranec Michal

Research team: doc. Ing. Odrobiňák Jaroslav, PhD.

Duration: September 2022 – August 2023

Damage to structures due to corrosion of reinforcement is one of the significant impacts that affect the reliability and also the residual life of structures and bridges, which can lead to failure and consequently loss of life. Almost all materials used in construction are subject to degradation. Material corrosion is one of the most well-known degradation modes. In the construction industry, the most commonly used materials are concrete, concrete reinforcement and prestressing reinforcement. As part of a grant project, my aim is to investigate corrosion on prestressing bars in an accelerated manner using direct current - accelerated testing. For this purpose, I plan to prepare steel frames that will serve as a cage for the possibility of prestressing the bars. The bars will be prestressed to 80% and 40% of the ultimate capacity (ultimate limit state). The tension in the prestressing bars will be measured using resistive bonded strain gauges. A force transducer will be placed on the outside of the frame at the bar to record the prestressing force value. A drain pipe shall be placed in the frame and soaked with 5 % brine. The DC current will be induced from a laboratory power supply where the anode will be connected at two points namely at both ends of the rod. The cathode will be connected to a copper plate which will be immersed in the salt solution. Tests will be carried out at different time lengths where it will also be observed whether the corrosion and voltage waveform is linear or non-linear. All specimens will be ground, cleaned and compared to a zero weight measurement of the prestressing bar after the test is completed.