Revisiting Basic Wind Speed of Metro Cities of India

Abstract

An accurate prediction of design wind speed is critical to the estimation of wind loads on any earth-bound civil engineering structure. Concerns have been raised within the Indian design community concerning the precision of design wind speeds as well as the new formulation of the importance factor for cyclonic regions in the current Indian Wind Loading Standard. The current study investigates the extreme wind climate of India by carrying out an independent study of wind speeds at noncyclonic and cyclonic regions, respectively, using measured and simulated data. Further, the results were compared against the existing wealth of knowledge concerning other major international standard formulations, gust factors, and wind speeds of similar climate regions. This study demonstrates that the existing 50-year return period wind speeds in the IS for noncyclonic regions such as Mumbai and Delhi are overconservative resulting in uneconomical structures. Further, the study confirms that the existing 50-year return period wind speeds for cyclonic regions such as Chennai and Kolkata are conservative as well without the use of cyclonic factor (k4). The study recommends the removal of the cyclonic factor (k4) section from the standard and also recommends a basic wind speed of 39 and 44 m/s respectively for Mumbai and New Delhi.