PSI - Issue 81

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 81 (2026) 372–376

© 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of DMDP 2025 organizers Keywords: natural frequencies; mode shapes; material variation; finite element modelling; frame building; dynamic characteristics; reinforced concrete; steel; timber. 1. Introduction The investigation of the dynamic behaviour of high-rise frame buildings with consideration of material variations across storeys represents an important task in contemporary engineering practice and requires the application of high-precision numerical modelling. In the study by Rigo et al. (2025), the importance of reducing residual deformations in lightweight timber shear walls (LFT) under dynamic loading is emphasised, as the inherent ductility of traditional connections facilitates energy dissipation but weakens the self-centring capacity of the structure. Experimental and numerical analyses of full-scale LFT walls combined with self-centring steel tendons demonstrate a significant enhancement in lateral seismic resistance and recovery capability of the system. Abstract The present paper sets forth the findings of a numerical study of the dynamic behaviour of a high-rise frame building with different materials. This study was conducted using the finite element method in the LIRA PC environment. The aim of this study was to evaluate how different combinations of reinforced concrete, steel and wood affect the natural frequencies and mode shapes of the nine-storey building frame. The computational model utilised three-dimensional finite elements with a 10 × 10 cm mesh. A total of nine material configurations for the lower (1 – 3) and upper (4 – 9) floors were analysed. The results demonstrated a clear dependence of the dynamic behaviour on the spatial stiffness of the structure. The configurations exhibiting higher stiffness, specifically option 3a (steel on the lower floors and reinforced concrete on the upper floors), demonstrated the highest natural frequencies, suggesting the highest overall stiffness. Conversely, configurations with wood on all or the majority of floors (group 2 and option 3b) exhibited the lowest frequencies, indicative of enhanced deformability. A comparison of the frequency spectra demonstrates a substantial impact of material heterogeneity on the modal parameters. Increases in the proportion of steel or reinforced concrete in the upper floors have been shown to result in higher mid- and high-frequency natural modes. Conversely, the use of wood has been demonstrated to reduce these frequencies, thereby affecting the overall stiffness of the structure. VIII International Conference “In - service Damage of Materials: Diagnostics and Prediction“ (DMDP 2025) Finite element simulation of the dynamic characteristics of a high-rise frame building considering variations in storey materials Mykhailo Hud*, Nataliya Chornomaz, Olga Meshcheryakova Ternopil Ivan Puluj National Technical University, Ternopil, 46000, Ukraine

* Corresponding author. Tel.: +38-098-061-97-16. E-mail address: mishagud77@gmail.com

2452-3216 © 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of DMDP 2025 organizers 10.1016/j.prostr.2026.03.064