箍筋约束方形混凝土柱轴压强度尺寸效应律  

Size Effect Law of Nominal Compressive Strength for Squared Concrete Columns Confined by Stirrups

作　　者：金浏[1] 李平[1] 杜修力[1] JIN Liu;LI Ping;DU Xiuli(The key laboratory of Urban Security and Disaster Engineering,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学,城市减灾与防灾防护教育部重点实验室,北京100124

出　　处：《应用基础与工程科学学报》2021年第4期986-998,共13页Journal of Basic Science and Engineering

基　　金：国家重点研发计划项目(2018YFC1504302);国家自然科学基金项目(51822801,51421005)。

摘　　要：箍筋约束混凝土柱轴压破坏名义强度存在尺寸效应,为了提高大尺寸箍筋约束方形混凝土名义轴压强度设计计算的合理性,研究了考虑尺寸效应的方形箍筋约束混凝土柱名义轴压强度的计算方法.考虑混凝土的非均质性,建立方形箍筋约束混凝土柱的三维细观数值模型,对其轴压作用下的破坏机制、失效模式和尺寸效应行为进行了分析.进而,凝练出了影响其轴压破坏尺寸效应的主导因素—箍筋的约束作用,即随箍筋约束作用增强,试件的名义轴压强度尺寸效应减弱.在经典的Ba6ant材料层次尺寸效应律的基础上,考虑箍筋约束作用的影响机制与规律,建立箍筋约束混凝土方柱构件层次的尺寸效应半理论-半经验公式.通过与模拟结果及已有试验数据的对比得知,所提出的尺寸效应公式能够很好地预测箍筋约束混凝土方柱的名义轴压强度.The nominal compressive strength of concrete column confined by stirrups under axial compression exists size effect.To improve the design rationality of the nominal axial compressive strength of large-sized squared concrete column confined by stirrups, the calculation method of nominal compressive strength considering size effect was studied.Considering the heterogeneity of concrete, the three-dimensional meso-scale models of concrete column confined by stirrups were established.The failure mechanism and size effect behavior of the models under axial compression were studied comprehensively.Moreover, the main parameter(stirrups ratio) that affects the size effect of nominal compressive strength of concrete column confined by stirrups was revealed.In addition, based on the classic Ba■ant’s size effect law, considering the influence mechanism of confinement effect of stirrups, a semi-theoretical and semi-empirical size effect formula of the nominal compressive strength for stirrup-confined squared concrete column was established.Compared with the numerical and existing experimental data, the proposed size effect formula was demonstrated to well predict the nominal compressive strength of squared concrete column confined by stirrups.

关 键 词：约束混凝土柱 箍筋约束 轴压强度 细观模拟 尺寸效应 半理论-半经验公式 

分 类 号：TU528[建筑科学—建筑技术科学]