STRUCTURAL FAILURE ANALYSIS OF 345 KV TRANSMISSION-LINE

An ice storm in Central Iowa on March 7, 1990, caused the domino failu re of 69 H frame steel pole structures that were part of a 345 KV tran smission line covering a distance of approximately 30.6 km (19 mi). Th is paper briefly documents the damage, and presents the nonlinear stru ctural analyses performed on a portion of the above transmission line using the ETADS software, which is a structural finite element submodu le of TL Workstation software [1]. The analysis included a characteriz ation of the likely storm loads and their application to the transmiss ion systems. The methodology used in trying to simulate the sequence o f events leading to the failure is also presented.