Structural failure analysis of 345 kV transmission line

An ice storm in Central Iowa on March 7, 1990, caused the domino failure of 69 H frame steel pole structures that were part of a 345 kV transmission line covering a distance of approximately 30.6 km (19 miles). This paper briefly documents the damage, and presents the nonlinear structural analyses performed on a portion of the above transmission line using the ETADS software, which is a structural finite element submodule of TL Workstation software. The analysis included a characterization of the likely storm loads and their application to the transmission systems. The methodology used in trying to simulate the sequence of events leading to the failure is also presented.<>