轴向受力下钢管混凝土K型节点应力集中系数影响分析

Stress Concentration Factors Impact Analysis of Concrete-filled Steel Tubular K-joints Under Axial Force

钢管混凝土K型节点广泛应用于钢管混凝土桁式拱桥,但该类型节点的疲劳破坏已在现有的桥梁中发现。以实际工程建立钢管混凝土K型节点有限元模型,进行了主管径厚比2γ,主支管的壁厚比τ、管径比β、夹角θ和偏心率ρ五个参数分析,揭示其在轴向受力下几何参数对应力集中系数的影响。研究结果表明:钢管混凝土K型节点最大SCF远小于空钢管K型节点,尤其在受压支管周边;各影响参数中,主支管的管径比参数β对SCF的影响是最显著的,主管的径厚比参数2γ对SCF的影响是最小的。

Concrete-filled steel tubular(CFST)K-joints have been widely used in CFST trussed arch bridges,but fatigue damage of the joint has been observed in existing bridges.Based on a practical engineering,the finite element model of K-joint of CFST was established.Five parameters(main diameter-thickness ratio 2γ,wall thickness ratioτof main branch pipe,diameter ratioβ,angleθand eccentricityρ)were provided for the parametric analysis under axial force to reveal the influence of the parameters on SCFs.The results show that the maximum SCF of K-joints of CFST is much smaller than that of hollow tubular K-joints,especially around the compression branch pipe.Among the influence parameters,the diameter ratioβof the main branch pipe has the most significant effect on SCF,and the diameter to thickness ratio 2γof the main pipe has the least effect on SCF.