压弯扭复合荷载作用下钢管约束钢筋混凝土柱的承载力及弯扭相关关系研究

以4个钢管约束钢筋混凝土柱(STRC)在弯扭和压弯扭复合荷载作用下的试验研究为基础,采用有限元软件ABAQUS建立了钢管约束钢筋混凝土柱的有限元模型,分别模拟试件在弯扭以及压弯扭复合荷载作用下的破坏模式和承载能力,与试验结果进行对比,验证了有限元模型的正确性。通过有限元模型参数化分析,研究钢管强度、钢管厚度、截面尺寸、混凝土强度、纵筋直径与屈服强度、箍筋直径与屈服强度以及轴力等因素对复合荷载作用下承载力的影响。研究结果表明,钢管厚度、截面尺寸、纵筋的直径与屈服强度以及轴压力是影响复合荷载作用下承载力的主要因素。当圆形截面STRC柱的轴压力达到0.3N_u(N_u为柱轴压承载力)或方形截面STRC柱的轴压力达到0.5N_u时,柱的承载力达到最大。在不同因素的影响下,相同荷载作用下钢管约束钢筋混凝土柱的受弯承载力和受扭承载力之间的相关关系基本一致。

Ultimate capacity and bending-torsion correlation of steeltube confined RC columns under combinedcompression-bending-torsion load

Based on tests of four steel tube confined RC columns under combined bending-torsion and compression-bending-torsion loading, the FE software ABAQUS was adopted to establish finite element model and simulate the failure modes and bearing capacity of specimens under combined bending-torsion and compression-bending-torsion loading. Compared with tests results, the accuracy of the finite element models was validated. The influence of steel tube strength, steel tube thickness, section size, concrete strength, the diameter and yield strength of longitudinal bar and stirrup bar, and axial force on capacity under combined load was studied by parametric analysis of finite element model. The results show that the thickness of steel tube, the size of section, the diameter and yield strength of longitudinal bar and the axial fore are the main factors affecting the torsional capacity under combined load. When the axial pressure of the circular steel tube confined RC column reaches 0.3 Nu （Nu is axial bearing capacity）or the axial pressure of the square steel tube confined RC column reaches 0.5Nu, the bearing capacity of the column reaches the peak. Under the influence of different factors, the relationship between bending and torsion of steel tube confined RC column under the same load is basically the same.