螺旋箍筋约束UHPC加固混凝土柱大偏心受压性能试验研究

Experimental study on performance of concrete large eccentric compressed columns strengthened by UHPC constrained by spiral stirrups

设计了4根近似1/2足尺UHPC(超高性能混凝土)加固普通混凝土柱和1根未加固普通混凝土对比柱,进行大偏心受压试验研究,旨在研究方形螺旋箍筋约束UHPC加固方法的有效性,主要研究不同螺旋箍筋间距和加固层是否配置螺旋箍筋对普通钢筋混凝土大偏心受压柱受力性能和变形情况的影响。对试验柱的破坏现象、承载力、侧向挠度、钢筋应变以及混凝土压应变等进行分析。试验结果表明,方形螺旋箍筋约束UHPC加固效果显著,该加固法对构件承载力提高幅度较大,并且能有效提高构件延性;提出螺旋箍筋约束UHPC加固法计算基本假定,推导出螺旋箍筋约束UHPC加固柱的大偏心受压正截面承载力计算公式,承载力计算值与试验值误差较小,研究结果可为此类加固方法工程设计计算提供参考。

Four approximately 1/2 full⁃foot UHPC(ultra⁃high performance concrete)reinforced ordinary concrete columns and one unreinforced ordinary concrete comparative column were designed for large eccentric compression test research,aiming to study the effectiveness of the UHPC reinforcement method constrained by square spiral stirrups,mainly to study the influence of different spiral stirrup spacing and whether the reinforcement layer is equipped with spiral stirrups on the mechanical performance and deformation of ordinary concrete large eccentric compressed columns.The failure phenomenon,bearing capacity,lateral deflection,steel bar strain and concrete compressive strain of the test column were analyzed.The experimental results show that the reinforcement effect of UHPC constrained by square spiral stirrups is remarkable.This reinforcement method can greatly improve the bearing capacity of components and can effectively improve the ductility of components.The basic calculation assumptions for were proposed,and the UHPC reinforcement of eccentric columns constrained by spiral stirrups was derived.The bearing capacity calculation formula of the large eccentric compressed normal section of columns strengthened by UHPC constrained by spiral stirrups and was derived,and the error between the calculated value and the experimental value of bearing capacity is small,and the research results can provide a reference for the engineering design calculation of this kind of reinforcement method.