冻融循环对十字形型钢混凝土柱轴压性能影响分析

Impact Analysis of Freeze-Thaw Cycles on Axial Compression Performance of Cruciform SRC Columns

为探究十字形型钢混凝土(SRC)柱经冻融作用后力学性能的演变,考虑混凝土强度、配筋率及长细比三个影响因素,采用ABAQUS软件对十字形SRC柱进行冻融和压缩模拟研究,对比分析冻融循环对十字形SRC柱荷载-应变曲线及承载力退化规律的影响,并归纳总结其承载力退化系数表达式.结果表明:SRC试件极限承载力与冻融循环次数呈负相关趋势,冻融循环导致混凝土劣化,使构件轴压承载能力降低,100次冻融循环后,SRC柱的极限承载力最大下降8.48%;而构件轴压承载能力与配筋率呈正相关趋势,因此适当提高混凝土强度及配筋率可有效抵御构件的冻融损伤;此外,极限承载力与长细比成反比,长细比过大,构件易发生弯曲失稳破坏;所提出轴压承载力退化系数计算值与模拟值吻合度较好.

To explore the mechanical property evolution of cruciform steel-reinforced concrete(SRC)after freeze-thaw cycles,considering the three influencing factors of concrete strength,steel ratio,and slenderness ratio,freeze-thaw and compression simulations on cruciform SRC columns were conducted using ABAQUS.Furthermore,this study comparatively analyzes the impact of freeze-thaw cycles on the load-strain curves and load degradation patterns of cruciform SRC columns,summarizing the formulas for load degradation coefficients.Results indicated that the SRC specimen bearing capacity negatively correlates with the number of freeze-thaw cycles.Freeze-thaw action deteriorates the concrete,decreasing the SRC bearing capacity.After 100 freeze-thaw cycles,SRC bearing capacity decreased by a maximum of 8.48%.The yield of SRC columns is positively correlated with the steel ratio,indicating that increasing concrete strength and steel ratio can effectively mitigate freeze-thaw damage.Additionally,bearing capacity inversely correlates with the slenderness ratio;excessively high slenderness ratios can predispose SRC columns to bending instability.The calculated values of the proposed bearing capacity degradation factor align well with the simulated values.