Assessment of End Tower Response to Downburst Wind Loads: Experimental and Numerical Studies

Natural hazards pose a significant threat to community resilience by disrupting power distribution systems, leading to widespread and frequent power outages. End towers are critical structures in a transmission line system that should contain the cascade failure of the towers from progressing along the line. Previous research has extensively investigated the behavior of tangent towers, which are the typical supporting towers along the line, under extreme wind loads. To the best of the authors’ knowledge, this study is the first to assess the effect of downburst loads on end towers numerically and experimentally. An aeroelastic test is carried out at the Wind Engineering, Energy and Environment (WindEEE) Research Institute on a 1:65 model of a transmission line that includes an end tower and two tangent towers. The transmission line is subjected to two simulated downbursts having different jet velocities, while considering different locations of the downburst relative to the end tower. The critical downburst configurations that cause the maximum transverse and longitudinal base shear force for the end tower are identified. Furthermore, the experimental data are used to investigate the dynamic amplification factor of the end tower under downburst loads. Finite element analysis of the tested line is conducted under the simulated downburst loads to assess the adequacy of the ASCE-74 provisions in calculating the downburst loads for end towers.