内置带孔灌浆管的预填骨料钢管混凝土短柱轴压性能试验研究

Experimental study on axial compression properties of preplaced aggregate concrete-filled steel tube stub columns

针对传统钢管混凝土(CFST)脱空脱黏这一突出问题,结合CFST的高承载力和预填骨料混凝土(PAC)低收缩的优点,提出一种内置带孔灌浆管的预填集料钢管混凝土(PACFST)柱,并详细阐述了其制作方法。同时,为了研究其轴压承载性能,设计了8根内置带孔灌浆管的PACFST短柱,试验的主要参数为外管宽厚比、柱的空心率、PAC强度和灌浆料强度。研究结果表明:峰值荷载后,柱外钢管出现鼓曲破坏,破坏模式均为剪切型破坏;此外,承载力随外管宽厚比、空心率的增加而降低,随PAC强度和灌浆料强度的增加而提高。最后,通过比较本文试验结果、已有文献和规范中关于钢管混凝土柱承载力的计算结果,分析适用于内置带孔灌浆管的PACFST柱的承载力计算方法,结果表明,内置带孔灌浆管的PACFST短柱轴压承载力试验结果与欧洲规范中空夹层钢管混凝土柱计算结果最为接近。

In response to the prominent problem of delamination and debonding in traditional steel tube concrete(CFST),this paper proposes a preplaced aggregate concrete filled steel tube(PACFST)column with built-in perforated grouting pipes,combining the high bearing capacity of CFST and the low shrinkage advantages of preplaced aggregate concrete(PAC),and elaborates on its manufacturing method in detail.At the same time,in order to study its axial compressive bearing capacity performance,8 PACFST short columns were designed.The main parameters of the experiment are the width to thickness ratio of the outer pipe,the hollow ratio of PACFST columns,PAC strength,and the strength of the grouting material.The research results indicate that upon reaching the PACFST column reaches its ultimate bearing capacity,the outer steel tube undergoes bulging failure,and the failure mode of the specimens is shear type failure;In addition,the ultimate bearing capacity decreases with the increase of outer pipe width to thickness ratio and hollow ratio,and increases with the increase of PAC strength and grouting material strength.Finally,by comparing the experimental results with the calculation results of the ultimate bearing capacity of steel tube concrete columns in existing literature and specifications,the applicable calculation method to the new PACFST column proposed in this article was analyzed.The results show that the ultimate bearing capacity results of PACFST short columns under axial compression are closest to the calculation results of Eurocode 4 for concrete-filled double skin steel tube columns.