Experimental study of seismic performance of assembled steel truss cap for transmission tower

Abstract:

To study the seismic performance of assembled steel truss cap, a full-scale specimen was designed and manufactured. Subsequently, low cyclic loading tests were conducted to analyze its failure mechanisms, hysteretic and skeleton curves, stiffness degradation, ductility, energy dissipation capacity and strain, etc. Based on the experimental results, a finite element model of the specimen was established using ANSYS for parametric analysis. The variation trends on skeleton curves of the model under different parameters were obtained, and an empirical formula of skeleton curve before destruction was proposed. The test results indicate that the specimen is mainly damaged by local buckling deformation at the mid-section of main material. When localized damage occurs at this central region, the specimen reaches its ultimate bearing capacity. The specimen can bear significant horizontal forces, with the horizontal ultimate load approximately 12 times the design value. The ductility coefficient is about 15, indicating that the specimen has considerable ductility and deformation ability. The seismic performance of the specimen improves mainly with the decrease of the height of the cap, the ratio of diameter to thickness of the main material and the downforce. Furthermore, the empirical formula of the skeleton curve before destruction aligns well with the finite element data.