输电塔装配式钢桁架承台抗震性能试验

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

关键词:  装配式钢桁架承台  山区输电线路  低周往复荷载试验  有限元分析  抗震性能

Key words:  assembled steel truss cap  mountainous transmission line  low cyclic loading test  finite element analysis  seismic performance

摘要:

为研究装配式钢桁架承台的抗震性能,设计、加工了1个足尺装配式钢桁架承台,并对其进行低周往复荷载试验,分析其破坏机制、滞回曲线、骨架曲线、刚度退化、延性、能量耗散能力和应变等。基于试验结果,采用ANSYS软件建立试件的有限元模型并进行参数分析,得到在不同参数下模型骨架曲线的变化趋势,并提出破坏前骨架曲线的经验公式。结果表明:试件以主材中部屈曲变形为主要破坏模式,当主材中部发生局部集中破坏时,试件达到极限承载力；试件能够承受较大的水平力,水平极限荷载约为水平荷载设计值的12倍,延性系数约为15,试件具有一定的延性和变形能力；试件的抗震性能主要随承台高度、主材径厚比、下压力的减小而提高,其破坏前骨架曲线的经验公式与有限元数据吻合较好。

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.