Summary The escalating growth of the tall buildings as well as the increasing number of extreme wind events in the Indian coastal region have certainly arisen the question of the safety and stability of these buildings situated in the metropolitan cities along the coastline. In such a scenario where there have been a constant focus on more researches for a unified wind code, however a comprehensive comparative study is required not only to assess and analyze the dynamic peak factors of the tall building models due to wind load, but also to enlighten the differences in the obtained results as well as their patterns respectively. The aspect ratio of buildings essentially governs the stability as well as contributes to a great extent on the dynamic responses in terms of base shear, base moment and torsional effects at the base. However, a framework based on the Indian wind database could ease the complexity of such parametric survivability studies of such structures. Distinguished variations in the dynamic responses for a series of models of tall buildings with varying aspect ratios along the height are analyzed as well as discussed in the present study, and the pattern of the deviation of the results with a parallel framework is also addressed to propose a mechanism for assessing the behaviors of tall buildings under specific wind speed predominant in the Indian coastal region that would help to ensure the safety and stability of structures subjected to wind hazards in Indian context in future.

Site specific assessment of wind speed becomes essential to analyze the susceptibility of any slender structure. With the increasing number of occurrences of extreme wind events in the Indian subcontinent, a quantitative measure of wind hazard based on recent developments becomes the need of the hour for India. The Indian standard (IS-875-part III) is a national code for reference to the basic wind speed in India essentially for infrastructural planning and design of midrise to tall structures and the specified basic wind speeds in the code are computed based on 50 years return period by Gumbel probability distribution. However, recent cyclones reported extreme wind events already exceeded the specified value in the code. The Gumbel distribution (Type I ) is applied in the present study by method of moments (MOM) on the long term wind data (yearly maxima) considering the last few decades (40 years) available for forecasting wind speed at different return periods. The AD (Anderson darling) test results are also accommodated to establish the accuracy of the tail behavior of the statistical distribution used, where the p-value is found to be less than 0.05. Further, in the present study, site specific basic wind speed map is also proposed considering latest event data. Indeed, based on the present study, 100 years return period for basic wind speed is recommended instead of 50 years to ensure enhanced structural safety and serviceability during its design life.

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