预制拼接槽型UHPC柱偏心受压性能试验研究

Experimental Study on Performance of Precast Spliced Slotted UHPC Columns under Eccentric Compression

为研究预制拼接槽型UHPC柱在受压条件下的力学性能及其影响因素,开展2根整浇UHPC柱及14根预制拼接槽型UHPC柱在不同拼接形式、不同偏心受压方向及不同偏心距下的轴心或偏心受压试验研究.通过考察试件的极限承载力、破坏形态、轴向及侧向变形性能,研究了拼接方式、偏压方向和偏心距对其静力性能的影响.试验结果表明:钢纤维延缓了UHPC的开裂,增强了试件的变形能力,但预制拼接槽型UHPC柱在轴压和小偏压荷载下仍表现出明显脆性破坏特征;在该试验中,偏压柱的破坏形态主要为小偏心受压破坏及大偏心受拉破坏;在相同偏心距下,不同拼接形式、不同偏心受压方向的柱体破坏形态及承载能力表现趋于一致;在相同尺寸与配筋下,预制拼接槽型UHPC柱承载力随偏心距的增加而减小.最后,通过对比试件承载力试验值和我国现行规范理论计算值,定性地指出了现行规范的局限性.本文试验数据可为预制拼接槽型UHPC柱设计提供参考.

To investigate the factors influencing the mechanical performance of precast spliced slotted ultra-high performance concrete(UHPC)columns under eccentric compression,two fully cast UHPC columns and four⁃teen precast spliced slotted UHPC columns were tested under axial or eccentric compression loading with different splicing forms,different eccentric compression directions,and different eccentricities.The influence of splicing forms,eccentric compression directions,and eccentricities on the static performance of the specimens is analyzed by investigating the ultimate carrying strength,failure modes,and axial and lateral deformation capacity.The results indicate that steel fibers can prevent premature cracks of UHPC and enhance the deformation capacity of the speci⁃mens,but the precast spliced slotted UHPC columns exhibit significant brittle failure characteristics under axial and eccentric compression load.In this experiment,the failure modes mainly divide into the compression failure mode for small eccentricity and tension failure for large eccentricity.The columns with different splicing forms and eccen⁃tric compression directions have similar behavior under the same eccentricity.The ultimate carrying strength of pre⁃cast spliced slotted UHPC columns decreases with the increase of eccentricity under the same section dimension and reinforcement ratio.Finally,the limitations of the current Chinese codes are pointed out qualitatively by comparing the experimental ultimate carrying strength with the theoretical values by referring to the current Chinese codes.The test date in this paper can provide a reference for precast spliced slotted UHPC column design.