Two-step detection method of compressed member instability damage of transmission towers

Abstract

The transmission tower is prone to the strong wind and catastrophic wind, which may cause the collapse of the tower. The major members of lower body may begin to buckling under compressed force and finally collapse due to the compression induced instability. Therefore, the accurate and timely identification on instability damage of major members is essential for the structural strengthening and the prevention of tower collapse. The relationship among axial compressing force, bending moment, and axial stiffness of the major member is established based on numerical simulation with the aiding of commercial package ANSYS. Thus, a two-step detection method for the instability of major member of transmission tower is proposed: (I) The changing rate of three order wavelet packet energy curvature of nodal floor of the transmission tower is selected as a new index to detect the possible damage region; (2) Modal strain energy and interval estimation is utilized to determine the exact position of damaged major members. Finally, a real transmission tower constructed in China is taken as an example to examine the feasibility and possibility of the proposed approach. The made observations indicate that the detection quality of the two-step approach developed in this study is satisfactory.