Numerical and full-scale test case studies on post-elastic performance of transmission towers

Abstract

Post-elastic capacity of transmission tower is critical for the realistic assessment of tower vulnerability under the extreme loading conditions. This paper first presented a series of numerical simulations of a lattice transmission tower section under torsional (longitudinal) or bending (transverse) loading in both static and dynamic scenarios. From the results of the numerical simulations, four prototypes of lattice transmission towers were constructed and tested for the investigation of the post-elastic performances of the towers under different loading conditions. The tests results showed that there existed significant post-elastic strength reserve of the tower under investigation. For the towers tested in this research, the post-elastic strength reserve was 1.22 for flexure-torsion (i.e. tower under longitudinal loading) governed by diagonals, and 1.37 for bending (i.e. tower in transverse loading) governed by inelastic buckling of the main legs. Diagonal members affected the failure modes of transmission towers and their connection design may be a weak link in the development of their post-elastic capacity.