The investigation on power transmission tower failures during the Vardah cyclone has forced the need for assessing the most vulnerable parts of the towers and their failure mechanisms. In India, Vardah cyclone brought a huge devastating effect that includes the failure of more than 500 power transmission lines and the collapse of 54 high tension transmission towers which lead to huge power disruption. In this research, one such similar transmission tower is considered and initially checked for its capacity followed by static linear buckling analysis to evaluate its critical members of failure. The parameters such as critical stress, joint forces, maximum displacement and failure modes are assessed considering the strong wind force of Vardah having a speed of about 155 Km/hr. The linear buckling analysis has been carried out by SAP2000 commercial software, which illuminated the critical stress and the panel failures for both leg and the diagonal members. The study focuses on the spotting of the most vulnerable member by assessing the parameters like critical stress, maximum panel drift ratio and joint forces by which the integral stability of the tower panel can be identified. The numerical research findings are validated with the actual real-time post failure patterns of the transmission towers. The members with high critical stress, joint force and maximum panel drift are considered to be the most vulnerable members and they act as the failure initiators leading to a progressive collapse condition. These vulnerable members need more attention during the design and implementation phases. Suggestions are highlighted to strengthen these vulnerable members where the emphasis can be given to avoid such similar failure scenarios.
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