Seismic behavior of prestressed concrete filled steel tubular lattice tower subjected to combined compression-bending-torsion
Yu-Sen Liu, Xu-Hong Zhou, Yu-Hang Wang, Yang Zhou, Yong-Sen Lan, Qiang� Li
Abstract
Prestressed concrete filled steel tubular (CFST) lattice tower is an innovative application to combine prestress and CFST composite structure to onshore tall wind turbines . In order to explore the seismic behavior of prestressed CFST lattice tower under a complex load state, there was pseudo-static testing carried out for prestressed four-chord CFST lattice columns under compression-bending-torsion combined load. The hysteretic performance of the specimens was analyzed by obtaining the failure mode, load-displacement hysteretic curve, energy dissipation , stiffness degradation , variation of strands stress and steel strain. The influence of prestress on seismic behavior of CFST lattice chords was investigated from prestress loss rate. Results showed that: the inclined battens of CFST lattice columns were seriously damaged with or without strands, while the inclined battens of non-prestressed specimen were damaged first and then the CFST chords. The existence of inclined battens had a great influence on the structural stiffness , while the application of strands significantly affected the initial stiffness and structural ductility of the prestressed specimen, but did not have any significant effect on ultimate bearing capacity. Post-tensioned strands could protect the main bearing chords and reduced the cracking of concrete in the tension area under the coupling action of compression, bending, and torsion.