Modal Evaluation of Reinforced Cement Concrete Tall Buildings Using ETABS

Abstract

The planning and construction of tall buildings are regulated by lateral forces such as seismic and wind loads. It is imperative to perform a modal analysis of the framework before performing the dynamic evaluation of the building when subjected to lateral forces. Consequently, building professionals focus on calculating the inherent frequency and associated natural period in tall structures to assess the vibrational behaviour of the building's frame. The current research aims to investigate and evaluate the performance of various tall building frameworks with differing shear wall configurations under free vibration, as the arrangement of shear walls significantly influences the stability of the structure against lateral forces. This investigation employs the eigenvalue estimation method for examining rectangular buildings with various shear wall configurations using the FEM program ETABS. The outcomes of this research include predictions of the natural frequency and mode shape for numerous tall rectangular building simulations with numerous configurations of shear wall components by modal simulation. The natural frequency range, time period, mode shapes, and mass participation factors were extracted from the data.
As the model’s stiffness increases due to the incorporation of shear wall, the natural time period diminishes across each configuration It is imperative to perform. The model incorporating centrally positioned shear walls in a core configuration demonstrated a 35% reduction in the fundamental time period compared to rectangular structures without shear walls. The investigation is restricted to the modal evaluation of tall rectangular building frameworks and does not include uncertainty quantification (UQ).