Investigation of Microwave Towers Dynamic Response to Downburst Winds Using Cfd and Nonlinear Analysis

This study investigates the structural response of microwave towers under downburst wind loads intense, localized downdrafts caused by thunderstorms that often exceed standard design pressures, threatening the stability of telecommunication infrastructure. Using Computational Fluid Dynamics simulations, wind pressure profiles were analyzed. In Case 1, with the tower 95 meters from the downburst center, the average wind pressure was 1298 Pa, 28.5% lower than IS 875 standards, affecting primarily the lower sections (Zone I). In Case 2, at 35 meters from the center, pressure increased to 6425 Pa, exceeding IS 875 standards by 2.54 times and causing significant lateral stresses. Structural analysis revealed a base shear increase of 9.1%, from 1856.3 N in Case 1 to 2025.5 N in Case 2, with maximum deformation in Case 2 at 146.35 mm, below the IS 800 limit of 166 mm. Despite these extreme conditions, the structure remained within the elastic limit. Modal analysis confirmed that the first mode of vibration exceeded IS 1893 requirements, while the tower's spectral acceleration capacity of 3g allowed it to withstand accelerations up to three times gravity without permanent deformation. These findings emphasize the need for robust design strategies to enhance microwave tower resilience to extreme wind events.