H形钢部分包裹混凝土组合中长柱轴心受压承载力试验研究

Experimental Study on Axial Compression Capacity of H-shaped Steel Partially Encased Concrete Composite Middle Long Columns

为了研究H形钢部分包裹混凝土(PEC)组合中长柱的极限承载力,用Q235B和Q345两种钢材制作12个PEC中长柱,对其进行轴心受压承载力试验,试验主要考虑含钢率、混凝土强度等因素。研究分析了焊接H形钢部分包裹混凝土组合中长柱的轴心受压极限承载力、荷载-位移曲线,对试件的承载力和稳定系数进行了理论和试验结果的对比。结果表明:焊接H形钢部分包裹混凝土组合中长柱的破坏模式有混凝土被压碎、柱整体弯曲、柱翼缘局部屈曲;在试验长度范围内,PEC柱承载力的影响因素主要有含钢率和混凝土强度等级,含钢率越大承载力越高,高强度混凝土可以大幅提高PEC柱的承载力;按照叠加原理公式计算的PEC柱承载力基本都低于试验极限承载力,试验得到的整体稳定系数都高于按《钢结构设计标准》(GB 50017-2017)得到的稳定系数,偏于安全;高强度钢和低强度等级混凝土不能很好地发挥协同作用,低强度等级混凝土只起到填充作用,强度发挥很小。

In order to study the ultimate bearing capacity of welding H-shaped steel partially encased concrete(PEC) composite column. 12 PEC middle long columns,made of Q235B steel and Q345 steel,are tested under axial compression. The main parameters are steel ratio and concrete strength,etc. The ultimate bearing capacity and load-displacement curves of PEC middle long columns under axial compression are analyzed. Based on the theoretical analysis and experimental study,the bearing capacity and stability coefficient are compared. The following observations are obtained from the research. The typical failure modes of PEC middle long columns are crushing of concrete,overall bending of columns and local buckling. Within the column length of test. the main factors affecting bearing capacity of PEC middle long columns are steel ratio and concrete strength grade. Higher steel ratio provides higher bearing capacity. Using highstrength concrete can greatly improve the bearing capacity of PEC middle long columns. The theoretical results of PEC middle long columns' ultimate bearing capacity, which are based on superposition principle formula,are lower than test values,and for the overall stability coefficient,the test values are higher than the computing results based on Standard for Design of Steel Structures (GB 50017-2017),showing a tendency to safety. High-strength steel and low-strength concrete do not work together efficiently, and low-strength concrete only works as a filler and has little strength effect.