The behaviour of square concrete-filled steel tube columns under concentrical loading was studied. More than one hundred specimens were tested to investigate the effects of thickness of steel tube on the load carrying...The behaviour of square concrete-filled steel tube columns under concentrical loading was studied. More than one hundred specimens were tested to investigate the effects of thickness of steel tube on the load carrying capacity of the concrete-filled tubular columns (CFTs). The effect of the grade of concrete and content of expansive agent were also investigated. The effect of these parameters on the confinement of the concrete core was studied as well. From the experimental study it was found that for both CFTs with different strength grade concrete core, the ultimate load carrying capacity increases with the increase in percentage of expansive agent up to 20% but it again decreases at 25% of expansive agent content. It was also shown that the failure mode of CFTs depends on the strength grade of concrete core.展开更多
The shrinkage characteristics tics of expansive concrete filled steel tube (CFST) are analyzed, Cold shrinkage, creep and autogenous shrinkage are considered as the main reasons of causing CFST contraction. In accorda...The shrinkage characteristics tics of expansive concrete filled steel tube (CFST) are analyzed, Cold shrinkage, creep and autogenous shrinkage are considered as the main reasons of causing CFST contraction. In accordance with the shrinkage characteristics of expansive CFST, a kind of energy-stored delayed expansive agent is exploited, which can not only compensate the shrinkage of the core concrete in every stages, but also make CFST expand according to the delayed expansion mechanism. As the result, the prestress loss weill be reduced and expansive energy will be utilized effectively.展开更多
基金Funded by the National Natural Science Foundation of China (50978162)the Key Laboratory of Advanced Civil Engineering Materials (Tongji University), Ministry of Education(K201002)
文摘The behaviour of square concrete-filled steel tube columns under concentrical loading was studied. More than one hundred specimens were tested to investigate the effects of thickness of steel tube on the load carrying capacity of the concrete-filled tubular columns (CFTs). The effect of the grade of concrete and content of expansive agent were also investigated. The effect of these parameters on the confinement of the concrete core was studied as well. From the experimental study it was found that for both CFTs with different strength grade concrete core, the ultimate load carrying capacity increases with the increase in percentage of expansive agent up to 20% but it again decreases at 25% of expansive agent content. It was also shown that the failure mode of CFTs depends on the strength grade of concrete core.
基金Funded by The Transportation Ministry,P. R. China.
文摘The shrinkage characteristics tics of expansive concrete filled steel tube (CFST) are analyzed, Cold shrinkage, creep and autogenous shrinkage are considered as the main reasons of causing CFST contraction. In accordance with the shrinkage characteristics of expansive CFST, a kind of energy-stored delayed expansive agent is exploited, which can not only compensate the shrinkage of the core concrete in every stages, but also make CFST expand according to the delayed expansion mechanism. As the result, the prestress loss weill be reduced and expansive energy will be utilized effectively.