Experimental and numerical researches on a new type of tower for steep mountainous areas

摘要

An unequal-leg transmission tower with a transition section is a new type of tower that can be used to construct transmission lines in steep mountainous areas, and it has the advantages of less earth excavation, small construction workload and less environmental damage. To study this type of tower, a full-scale tower test was performed and a finite element model considering joint-slippage effects was constructed to predict the tower's structural responses. The predicted deformation, ultimate bearing capacity and failure mode agreed well with experimental results, indicating the validity of the numerical model. The model was used to simulate the mechanical properties of the unequal-leg tower. Furthermore, the effect of test trusses on the structural response of the test tower was determined by comparing numerical and experimental results. Finally, five finite element models with different transition section lengths (0-12 m; grade difference: 3 m) were constructed to study the effect of the transition section length on the mechanical properties of entire tower. Nonlinear analysis results indicated that the ultimate bearing capacity of the entire tower changed only slightly with an increase in the transition section length, with the maximum variation being about 0.8%. Thus, the transition section had little effect on the ultimate bearing capacity of the entire tower. The results of this study indicate that the structural behaviour of the new type of tower meets engineering requirements.