摘要
为完善混凝土强度理论和塑性-损伤模型,通过参考岩石损伤比强度理论,根据现有普通混凝土、再生混凝土、轻骨料混凝土和纤维混凝土等多类混凝土多轴强度试验数据,推荐损伤比变量中的五经验系数取值,完善多类混凝土损伤比强度理论并揭示约束混凝土工作原理。分析表明,随着静水压力的增加,混凝土压损伤比将由单轴受压时为1左右线性递减至小于0.5,八面体剪应力先增大后减小,轴向峰值应力提升为某一定值,压损伤比取值减小引发非弹性体积膨胀减小至不变,因而导致混凝土由单轴受压脆性破坏向多轴受压塑性破坏转变,该理论为钢管混凝土柱中发挥混凝土耗能潜力提供理论依据。依据混凝土损伤比强度理论,确定多类混凝土塑性-损伤模型中的三轴强度参数,包括膨胀角、拉压子午线强度比值和二轴等压与单轴抗压强度比值,并建议常温静力荷载下多类混凝土的单轴受压、受拉应力-应变曲线方程及其参数表达式,常温地震荷载下普通混凝土的单轴受压、受拉应力-应变曲线方程及其参数表达式,以及火灾升温环境下普通混凝土的单轴受压、受拉应力-应变曲线方程及其参数表达式,建立约束混凝土三轴塑性-损伤模型。介绍多类混凝土塑性-损伤模型在钢-混凝土组合结构有限元模型中的应用,模型中混凝土采用实体单元而钢管与钢梁采用壳单元,可模拟钢管与混凝土之间的界面滑移与约束作用,当采取增强约束拉筋强柱构造方法时可提升钢管混凝土柱及其结构的承载力、抗震与抗火性能。
To enhance the concrete strength theory and plastic-damage model,a series of work was performed in this paper.Referring to the rock damage ratio strength theory,based on multiaxial strength test data of various types of concretes such as plain concrete,recycled aggregate concrete,lightweight aggregate concrete,and fiber concrete,the five empirical coefficients in the damage ratio variable were recommended.This improves the damage ratio strength theory for various types of concretes and elucidates the working principles of confined concretes.The analysis indicates that with the increase in hydrostatic pressure,the compressive damage ratio of concrete decreases linearly from around 1 under uniaxial compression to less than 0.5.The octahedral shear stress initially increases and then decreases,while the axial peak stress increases to a certain value.The inelastic volume expansion decreases to be constant when the pressure damage ratio decreases,leading to the transition of concrete from brittle failure under uniaxial compression to plastic failure under multi-axial compression.This strength theory provides a theoretical basis for exploiting the energy consumption potential of concrete in concrete-filled steel tubular columns.Based on the concrete damage ratio strength theory,the triaxial strength parameters for various types of concrete in the plastic-damage model were determined.These parameters included the dilation angle,the ratio of tensile meridian to compressive meridian,and the ratio of biaxial isobaric strength to uniaxial compressive strength.Additionally,equations of uniaxial stress-strain curves and corresponding parameter expressions for various types of concretes under static loading at room temperature,under seismic loading at room temperature,and under fire heating conditions were proposed,respectively.On these bases,a triaxial plastic-damage model of confined concrete was established.The plastic-damage model for various types of concretes was applied in finite element models of steel-concrete composite structures.In the model,the concrete was represented using solid elements,while steel tubes and steel beams were represented using shell elements.This setup allows for the simulation of interface slip and restraint between the steel tube and concrete.When employing the reinforcement strong column construction method,the bearing capacity,seismic resistance,and fire resistance of the steel tube concrete column and its structure can be enhanced.
作者
丁发兴
吴霞
吕飞
王文君
孙浩
SADAT Said Ikram
许云龙
王恩
王莉萍
余志武
DING Faxing;WU Xia;LÜFei;WANG Wenjun;SUN Hao;SADAT Said Ikram;XU Yunlong;WANG En;WANG Liping;YU Zhiwu(School of Civil Engineering,Central South University,Changsha 410075,China)
出处
《铁道科学与工程学报》
北大核心
2025年第2期690-711,共22页
Journal of Railway Science and Engineering
基金
国家自然科学基金面上项目(51978664)
中南大学中央高校基本科研业务费专项资金资助项目(2022ZZTS0603)
中南大学高性能计算平台资助项目。
