Investigation of the structural response of five lateral load-resisting systems for a mid-rise structure in Uganda

Abstract

The design of efficient and cost-effective tall buildings necessitates a comprehensive understanding of key factors influencing the selection of the structural system, as well as knowledge of how the chosen system will interact with architectural, mechanical, and other aspects. This study aimed to compare the seismic response of five different lateral load resisting systems (Moment resisting frame, frame tube, shear wall – frame, core shear wall and energy dissipation using Fluid viscous dampers) for both symmetric and asymmetric hypothetical models subjected to earthquake conditions in Uganda. The five LLRS were modelled using Extended Three-dimensional Analysis of Building Systems software (ETABS) software for a symmetric and asymmetric plan. Thereafter, a design optimization process was carried out for all the LLRS, which involved constructing finite element models and iteratively refining the design to meet minimum capacity requirements for structural elements while minimizing lateral displacements at the top floor. The Seismic response of the optimized models was obtained using a code-based spectrum with a peak ground acceleration (PGA) value of 0.162g and the lateral displacements of the models were evaluated and compared graphically using MS Excel. The findings highlight the seismic response of each LLRS and provide valuable insights into their performance. The study demonstrates the structural effectiveness of the Moment Resisting Frame (MRF) for symmetric midrise models. However, its use in asymmetric models can result in significant displacements that may exceed acceptable limits. The Frame Tube system indicates that effective lateral resistance can be achieved even with small section sizes. While Fluid Viscous Dampers (FVD) can offer significant structural efficiency especially for the symmetric model. Ultimately, the study reveals the Core Shear Wall placed around the center of mass as the most structurally efficient and cost-effective system for midrise structures in Uganda