Wind Design of Slender Tall Buildings in Sri Lankan Context

Abstract

Lateral forces due to wind and earthquake loading are two important phenomenon in design of tall buildings. In the recent decades due to the development of various technologies, tall buildings are becoming more slender, flexible, light weight and irregular in shape. Though flexible and lightweight structures are preferred to minimize the effect of earthquake loading, they becoming more susceptible under wind loading. Wind tunnel testing is adopted as most precise tool to determine the performance of such slender structures under wind loading. Determining the performance of the proposed structural system quite precisely during the preliminary design stage is essential to obtain an efficient, safe and economical design. Due to the associated cost and time performing a wind tunnel test in the preliminary design stages may not be always viable. In such instances preliminary design is carried-out extrapolating the design provisions available. In Sri Lanka BS 6399-2:1997, BS EN 1991-1-4:2005, AS/NZS1170.2:2011 standards are generally adopted in wind design of structures. After withdrawal of British standards, European standards are being adopted as primary design standards internationally including Sri Lanka. Due to the complex nature of the wind and its interaction with the dynamically sensitive slender structures scope of wind design codes to predict the wind effects on slender tall buildings are limited. This study intends to present the importance of selecting suitable wind design approaches to predict dynamic wind effects on tall buildings during the preliminary design stages overcoming the limitations of existing design provisions. A case study authors involved were presented with the validation of wind tunnel testing to elaborate the wind design of slender tall buildings in Sri Lankan context.