Forensic investigation of unexpected failure in a full-scale transmission tower test

초록

This study investigated the primary cause of unexpected failure of a transmission tower during a full-scale load test designed to validate a newly proposed code in Korea based on the load and resistance factor design (LRFD). The experiment involved 10 load cases with specified load factors. Based on the initial plan, the structure was expected to withstand the first nine load cases, followed by the final load case, to determine its ultimate load-carrying capacity and collapse mode. However, the 70.3 m tall structure failed during the fourth load case, exhibiting buckling of the main post between the third and fourth arms. A forensic investigation, including structural analysis and stress measurements, revealed that the failure primarily resulted from the repeated application of ultimate load levels. Accordingly, this study proposes a rational proof load test sequence for transmission towers based on the LRFD method.

키워드