冻融循环作用后钢管混凝土轴压短柱力学性能

Mechanical Properties of Concrete-filled Steel Tubular Stubs After Freezing and Thawing Cycles Under Axial Loading

为了给寒区钢管混凝土结构的设计与施工提供参考,针对拱桥拱肋或桥墩中普遍采用的钢管混凝土,考虑冻融循环次数、核心混凝土立方体抗压强度等因素的影响,进行了冻融循环作用后钢管混凝土轴压短柱的试验研究。基于试验结果分析,提出了冻融循环作用后核心混凝土的本构关系,同时利用该本构关系建立了冻融循环作用后钢管混凝土轴压短柱的有限元分析模型,并与试验结果进行对比。研究结果表明:冻融循环作用后钢管混凝土轴压短柱的破坏形态和荷载-应变曲线总体上与未遭受冻融循环作用试件类似,但试件的承载力和组合弹性模量随冻融循环次数的增加而减小;有限元理论模型的计算结果与试验结果总体吻合较好。

In order to provide reference for design and construction of concrete-filled steel tubular structures in cold regions, aimed at concrete-filled steel tube （CFST） which has been widely adopted in ribs of arch bridges or piers of bridges, considering the influence of number of freezing and thawing cycles and cube compressive strength of core concrete, test study on CFST stubs after freezing and thawing exposure under axial loading was carried out. Based on the analysis of the test results, a constitutive relationship of core concrete after freezing and thawing exposure was proposed. A finite element analysis model for CFST stubs after freezing and thawing exposure under axial loading was developed and in the model the new constitutive relationship of core concrete was adopted. Analysis results and test results were compared. The results show that the failure mode and load versus deformation curve of CFST stubs after freezing and thawing exposure are similar to those of the reference specimens without being subjected to freezing and thawing; however, the bearing capacity and composite elastic modulus of CFST stubs decrease with the increase of number of freezing and thawing cycles. The predicted results by finite element analysis model are generally agreed well with the measured results.