吴涛, 魏慧, 刘喜, 刘全威. 箍筋约束高强轻骨料混凝土柱轴压性能试验研究[J]. 工程力学, 2018, 35(2): 203-213. DOI: 10.6052/j.issn.1000-4750.2016.10.0814
引用本文: 吴涛, 魏慧, 刘喜, 刘全威. 箍筋约束高强轻骨料混凝土柱轴压性能试验研究[J]. 工程力学, 2018, 35(2): 203-213. DOI: 10.6052/j.issn.1000-4750.2016.10.0814
WU Tao, WEI Hui, LIU Xi, LIU Quan-wei. EXPERIMENTAL STUDY ON AXIAL COMPRESSION BEHAVIOR OF CONFINED HIGH-STRENGTH LIGHTWEIGHT AGGREGATE CONCRETE UNDER CONCENTRIC LOADING[J]. Engineering Mechanics, 2018, 35(2): 203-213. DOI: 10.6052/j.issn.1000-4750.2016.10.0814
Citation: WU Tao, WEI Hui, LIU Xi, LIU Quan-wei. EXPERIMENTAL STUDY ON AXIAL COMPRESSION BEHAVIOR OF CONFINED HIGH-STRENGTH LIGHTWEIGHT AGGREGATE CONCRETE UNDER CONCENTRIC LOADING[J]. Engineering Mechanics, 2018, 35(2): 203-213. DOI: 10.6052/j.issn.1000-4750.2016.10.0814

箍筋约束高强轻骨料混凝土柱轴压性能试验研究

EXPERIMENTAL STUDY ON AXIAL COMPRESSION BEHAVIOR OF CONFINED HIGH-STRENGTH LIGHTWEIGHT AGGREGATE CONCRETE UNDER CONCENTRIC LOADING

  • 摘要: 完成了12根不同配箍形式和体积配箍率的箍筋约束高强轻骨料混凝土柱轴压性能试验,系统地研究了构件的破坏过程与破坏形态、应力-应变曲线及箍筋应变等;重点分析了不同配箍率和配箍形式对构件承载力和延性的影响;建立了适用于该类轴压柱峰值应力(f'cc)和相应峰值应变(εcc)的计算模型,并引入Richart、Mander、Razvi和Saatcioglu、Khaloo和El-Dash等经典模型对比分析建议模型的准确性。研究表明:峰值荷载过后,约束柱保护层整体被切掉后剥落,内部骨料和骨料与砂浆界面均出现少许裂缝,与普通混凝土构件存在显著差异,但应力-应变曲线发展规律与普通混凝土类似;最终破坏以箍筋屈服、相邻箍筋间核心区混凝土压碎破坏为标志,表面形成“H”形或45°斜向破坏面;同时,增大体积配箍率和改善箍筋形式分别能够提高核心区混凝土的侧向约束力和增大约束面积,“井”字形复合配箍可满足承载力和延性需求;结合配箍特征值(λt)和配箍形式影响参数(k)建立模型的计算结果与试验值吻合良好,能够准确、合理地预测该类构件的峰值应力和相应峰值应变。

     

    Abstract: In order to investigate the axial compression behavior of confined high-strength lightweight aggregate concrete (HSLAC), an experimental study of twelve HSLAC columns confined by reinforcement under concentric loading were carried out. The failure process, failure mode, stress-strain behavior and strain of lateral ties were studied in the research program. Expected general improvements in strength and ductility of specimens with respect to the effect of key variables such as the tie configuration and transverse reinforcement ratio were reported. And a calculation model of peak stress (f'cc) and the corresponding strain (εcc) suitable for confined HSLAC columns were proposed and compared with Richart model, Mander model, Razvi and Saatcioglu model, and Khaloo and El-Dash model to evaluate the accuracy. It is shown that, after the peak load point, the concrete cover were cut off and sudden spalling occurred as a whole, and a few cracks were found on the internal aggregates as well as the interface between aggregate and mortar, which present significant differences from normal concrete members. However, the development law of stress-strain curves is similar to the normal concrete. The plane of failure presents “H” shape or a diagonal failure at an angle of 45° with the horizontal surface. The results further indicate that the lateral restraint force and confined area of core concrete can be significantly increased by the reasonable selection of tie configuration and adding the amount of lateral ties. It is possible to obtain sufficient strength and ductility behavior in HSLAC columns through proper overlapping hoops with cross ties. The empirical model proposed by combining the stirrup characteristic values (λt) and coefficient (k), can accurately and reasonably estimate the peak stress and corresponding strain of confined HSLAC columns.

     

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