RESEARCH ON NATURAL VIBRATION CHARACTERISTICS AND SEISMIC RESPONSE OF LONG-SPAN PRESTRESSED TRUSS STRING STRUCTURE

摘要

The previous studies on dynamic performance of truss string structures are reviewed and the analysis of natural vibration characteristics and seismic response for truss string structure was conducted based on the project of Harbin Meeting Exhibition & Sports Center.The subspace iteration method was adopted to analyze the natural vibration characteristics in both single-span and the whole-structure level.With geometric nonlinear effect in consideration,comparison of seismic responses in single-span and the whole-structure level was conducted while the effect of regulation of each design parameter on natural vibration frequency and seismic response was also discussed.The research in this paper indicated that the outer-plane vibration of bottom cable and inner-plane vertical vibration of whole structure were the primary parts of structural natural character of vibration.Lateral overturning was the weakest part of single truss string structure,leading to the importance of longitudinal connective members.The structural natural frequencies would increase as the growth of load and prestress as well as the decline of the bottom cable area and cable sag.Considered the large variation of seismic response in single-span and the whole-structure level,finite element analysis of the whole structure was necessary.The response like internal force and deformation varied greatly under different seismic stimulation and the weakest part in the structure fell on the truss in the span direction under Tafa wave.The peak displacement along the seismic stimulation direction was decreased by increasing the cable prestress.