部分包覆亚型钢-混凝土组合柱抗震性能研究

Research on Seismic Performance of Partially-Encased Composite Ya-Shaped Steel-Concrete Columns

目前PEC柱在实际工程中的应用越来越广泛,亚型钢PEC柱相比H型钢PEC柱承载力提高的同时结合了钢管混凝土柱的优点。为了研究亚型钢PEC柱的抗震性能,通过ABAQUS软件以剪跨比、轴压比、水平往复荷载加载方向、亚型钢腹板及翼缘厚度为参数对42个试件进行了低周反复荷载作用下的数值模拟。模拟结果表明:亚型钢PEC柱滞回性能良好,强轴和剪跨比为1.875及以上的弱轴方向加载的柱的最终破坏形态为柱底两侧开口处混凝土被压碎、亚型钢屈曲的弯曲破坏,但强轴柱底中间未开口处混凝土也严重损伤,弱轴柱没有明显损伤;剪跨比在1.875以下的弱轴柱开口处混凝土压溃、未开口处混凝土产生交叉裂缝,柱顶混凝土也有部分损伤,型钢未屈曲,为剪切破坏。通过参数的影响分析,剪跨比、翼缘和腹板厚度的增加能提高试件的延性、耗能能力以及降低刚度退化的速率,但峰值荷载随着剪跨比的增加而降低;强轴柱的峰值荷载随轴压比增大而减小,而弱轴柱的峰值荷载在轴压比小于0.3时随轴压比的增大而增大。最后提出了在一定条件下适用的亚型钢PEC柱抗震承载力计算式并根据影响参数进行修正,验证了修正后算式的可靠性,为亚型钢PEC柱在工程中的应用提供了参考。

At present,the application of PEC columns in practical engineering is becoming more and more widespread.Compared with H-shaped steel PEC columns,the bearing capacity of Ya-shaped steel PEC col-umns is improved while combining the advantages of steel tube concrete columns.In order to study the seis-mic performance of Ya-shaped steel PEC columns,numerical simulations were conducted on 42 specimens under quasi-static loading by using ABAQUS software,with shear-span ratio,axial compression ratio,hori-zontal reciprocating loading direction,thicknesses of Ya-shaped steel web plates and flanges as parameters.The simulation results showed that the hysteretic performance of the Ya-shaped steel PEC column was good.The final failure mode of the column loaded in the weak axis direction with a strong axis and shear-span ratio of 1.875 or above was the crushing of concrete at the openings on both sides of the column bottom and the bending failure of the Ya-shaped steel buckling.However,the concrete at the middle of the strong axis col-umn bottom without an opening was also severely damaged,and the weak axis column was not significantly damaged;The concrete at the opening of the weak axis column with a shear span ratio below 1.875 was crushed,and there were cross cracks in the concrete at the unopened position.The concrete at the top of the column was also partially damaged,and the steel section was not buckled,indicating shear failure.Through the analysis of the influence of parameters,it was found that increasing the shear span ratio,thicknesses of flanges and webs could improve the ductility,energy dissipation capacity,and reduce the rate of stiffness degradation of the component,but the peak load decreased with the increase of shear-span ratio;the peak load of strong axis columns decreased with increasing axial compression ratio,while the peak load of weak ax-is columns increased with increasing axial compression ratio when the axial compression ratio was less than 0.3.Finally,a formula for calculating the seismic bearing capacity of Ya-shaped PEC columns under certain conditions was proposed and modified based on the influencing parameters,verifying the reliability of the re-vised formula and providing a reference for the application of Ya-shaped steel PEC columns in engineering.