The Effect of Nonlinear Behavior of Bolted Connections on Dynamic Analysis of Steel Transmission Towers

Transmission towers are kinds of complex lattice structures which affects their accurate modeling and analysis and brings about some problems in the prediction of their actual behavior. For this reason, full-scale experiments are usually applied for transmission towers to examine their resistance and control their behavior. In this paper, the displacements of a transmission tower in the full-scale test, including effective parameters such as geometric and material nonlinearity and joint slip effect are attained applying the developed nonlinear analysis software. These displacements for four cases of analysis: linear, geometric nonlinear, geometric and material nonlinear and lastly, geometric and material nonlinear along with joint slip effect are obtained and compared with the results of the full-scale test. In this comparison, the results of geometric and material nonlinear analysis along with joint slip effect coincide well with the results of the full-scale experiment which demonstrates the joint slip effect importance and the capability of developed software. Finally, the tower natural frequencies are obtained and it is obvious that taking the joint slip effect into account of the analysis reduces the natural frequencies of the tower as a significant parameter in the dynamic analysis of these kind of structures either individually or as coupled system along with conductors.