Research Article
Deflection-stiffness Relationship and Practical Implications for Seismic and Wind Imposed Design of Tall Steel Buildings
Vijay Kumar Khanna*
Issue:
Volume 14, Issue 1, February 2026
Pages:
1-10
Received:
23 November 2025
Accepted:
20 December 2025
Published:
16 January 2026
DOI:
10.11648/j.ajce.20261401.11
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Abstract: Tall steel buildings are increasingly governed by serviceability considerations arising from seismic and wind actions, where control of lateral deflection and inter-storey drift becomes as critical as strength-based design. This paper investigates the fundamental relationship between lateral stiffness and deflection response in tall steel structures, with the objective of clarifying the role of stiffness in satisfying codal requirements for safety, serviceability, and occupant comfort. A common misconception in design practice is that increased structural flexibility invariably leads to reduced seismic demand. While period elongation associated with reduced stiffness may lower seismic base shear, it can result in excessive lateral deflections, inter-storey drifts, and wind-induced accelerations that govern serviceability performance. Using a shear-building idealisation, closed-form analytical relationships are developed to link effective lateral stiffness, fundamental natural period, inter-storey drift, and seismic base shear. Three representative lateral load-resisting systems-a steel moment-resisting frame (SMRF), a braced frame (BRBF), and a core-outrigger system-are evaluated for a 20-storey steel building to illustrate the influence of stiffness on global and local response parameters. The comparative results demonstrate that increased stiffness leads to improved drift control and wind-serviceability performance, even where seismic base shear increases modestly. A worked example is presented to demonstrate drift verification against Eurocode seismic serviceability limits and wind habitability criteria, showing that serviceability requirements often govern system selection in tall buildings. The study provides practical guidance on balancing stiffness, damping, and structural configuration during preliminary design. The proposed analytical framework supports rational comparison of alternative lateral systems and offers useful insights for engineers prior to undertaking detailed numerical analysis.
Abstract: Tall steel buildings are increasingly governed by serviceability considerations arising from seismic and wind actions, where control of lateral deflection and inter-storey drift becomes as critical as strength-based design. This paper investigates the fundamental relationship between lateral stiffness and deflection response in tall steel structure...
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