钢管自应力自密实高强混凝土柱偏心受压性能试验研究

为提高钢管内混凝土的密实度，减小混凝土的收缩，以保证钢管与混凝土更好地共同工作，满足实际工程需要，该文提出采用钢管自应力自密实高强混凝土柱，考虑偏心距、长径比和初始自应力等参数的影响，设计制作21根钢管自应力自密实高强混凝土柱和3根钢管自密实高强混凝土柱试件，通过偏心受压试验，考察试件的破坏形态，实测试件的荷载-挠度曲线和荷载-应变曲线，分析各参数对偏心受压试件受力性能的影响。研究表明：偏心受压试件主要发生弯曲失稳破坏；试件极限承载力随偏心距或长径比增大而减小，当初始自应力为3 MPa~5 MPa时，钢管自应力自密实混凝土偏心受压柱的极限承载力提高9.2%~11.7%。参考国内相关规范，通过试验数据回归分析，提出钢管自应力自密实高强混凝土柱偏心受压承载力计算公式，可供工程设计参考。

EXPERIMENTAL STUDY ON SELF-STRESSING SELF-COMPACTING AND HIGH-STRENGTH CONCRETE FILLED STEEL TUBULAR COLUMNS UNDER ECCENTRIC COMPRESSION

In order to improve the compactness of core concrete fills in steel tubes and reduce shrinkage which can ensure better composite action and meet project needs, twenty-one self-stressing self-compacting and high-strength concrete filled steel tubular columns and three self-compacting and high-strength concrete filled steel tubular columns were designed and tested under eccentric compression. The factors influencing the failure mode of specimens, namely slenderness ratio, eccentricity ratio and initial self-stressing, were investigated. The load-strain curves and load-column deflection curves were analyzed. The results showed that the eccentrically compressed specimens mainly demonstrate flexible buckling failure; the ultimate bearing capacity of the specimen decreases with the increase in load eccentricity ratio and slenderness ratio. The ultimate bearing capacity of the self-stressing and self-compacting concrete filled steel tubular columns can be improved by 9.2%~11.7% with initial self-stressing ranging between 3 to 5 MPa. Based on the relevant domestic design codes, a predictive equation for the ultimate bearing capacity of self-stressing self-compacting and high-strength concrete filled steel tubular columns was derived through regression analysis, and can serve as a reference for practical engineering design.