PSI - Issue 81

Mykhailo Hud et al. / Procedia Structural Integrity 81 (2026) 372–376

376

4. Conclusions The modal analysis demonstrated that the selection of materials for individual storeys of a high-rise frame building exerts a substantial influence on its dynamic behaviour. The overall stiffness of a structure is contingent not only on the mechanical properties of the primary framing material, but also on the manner in which these materials are distributed along the building's height. Configurations involving timber across multiple storeys, such as group 2 and variant 3b, exhibit the lowest natural frequencies. Conversely, combinations of steel and reinforced concrete, specifically variants 1a, 2a, and 3a, result in increased stiffness, accompanied by consistently higher modal frequencies. Variant 3a, in particular, demonstrates the highest medium-range frequencies, thus forming the stiffest model of all scenarios considered. The utilisation of timber in the upper levels of a structure has been demonstrated to result in a reduction of stiffness. Conversely, the incorporation of steel or reinforced concrete has been shown to yield higher frequencies and enhanced modal performance. The findings of this study underscore the necessity of incorporating material heterogeneity considerations into the design of high-rise buildings. Local changes in the upper storeys can significantly influence global dynamic behaviour. References Hud, M., Ihnatieva, V., Baran, D., 2024. Influence of mass distribution on natural vibrations of a reinforced concrete building frame. Procedia Structural Integrity 59, 692 - 696 https://doi.org/10.1016/j.prostr.2024.04.098. Iasnii, V., Yasniy, O., Homon, S., Budz, V., Yasniy, P., 2023. Capabilities of self - centering damping device based on pseudoelastic NiTi wires. Engineering Structures, 278, 11555 https://doi.org/10.1016/j.engstruct.2022.115556. Rigo, P., Polastri, A., Mazelli, A., Bedon, C., Casagrande, D., 2025. Experimental and numerical analysis on Light-Frame Timber shear-walls coupled with self centering steel cables, Construction and Building Materials 504, 144393 https://doi.org/10.1016/j.conbuildmat.2025.144393. Solgi, M., Rajabi, E., Amiri, G.G., Dehkordi, M.R., 2025. Seismic resilience evaluation of a 3D steel moment frame building with triple friction pendulum isolators, Structures 72, 108075 https://doi.org/10.1016/j.istruc.2024.108075 Yi, J., Zhao, B., Yuan, X., Lin, G., Lu, X., 2024. Experimental investigation on seismic performance of a super high-rise mega frame-double core tube composite structure,Journal of Building Engineering 97,110680 https://doi.org/10.1016/j.jobe.2024.110680. Yang, M., Wu, J., Zhang, O., 2025. Inclination and acceleration data fusion for two - dimensional dynamic displacements and mode shapes identification of super high - rise buildings considering time delay, Mechanical Systems and Signal Processing 223,111938 https://doi.org/10.1016/j.ymssp.2024.111938. Yasniy, P., Pyndus, Yu., Glad’o , V., Okipnyi, I., Shul’gan , I., 2011. Scientific and technical section FEM prediction of the influence of warm prestressing on fracture toughness of heat-resistant steel. Strength of Materials 43(2), 113-121 doi:10.1007/s11223-011-9277-x