矩形钢管混凝土柱往复拉压荷载下工作性能试验研究

超高层建筑巨型框架结构的巨型柱在大震作用下有时会出现往复拉压受力情形,为提高巨型柱的抗震能力,目前有的超高层建筑巨型框架结构采用了多腔体钢管混凝土巨型柱。为深入研究这种巨型柱的腔体在往复拉压荷载下的性能退化问题,取这种巨型柱中有代表性的矩形腔体,进行了3个配钢率为7.53%和1个配钢率为3.77%的相同截面矩形柱在往复拉压荷载下的工作性能试验研究。4个试件均沿杆长对中分成左右不同构造的两段,左杆段为有栓钉区段,右杆段为无栓钉区段。通过试验,比较分析了各试件的承载力、刚度及其退化过程、栓钉的作用和破坏特征。给出了抗拉、抗压承载力计算公式,计算结果与试验符合较好。研究表明:在矩形钢管腔体内设置栓钉可明显提高构件的抗拉、抗压工作性能;增加矩形钢管的钢板厚度可明显提高钢板对栓钉的约束能力,从而提高栓钉与混凝土共同工作的性能。

Experimental study on mechanical performance of rectangular concrete filled steel tube columns under reciprocating tension and compression load

The reciprocating tension and compressive stress may occur sometimes in the giant columns of super high-rise buildings with mega frame structure during strong earthquakes.At present,concrete filled steel tube mega columns with several cavities are adopted towards some tall buildings with mega frame structures in order to improve the seismic performance of giant columns.In order to study the performance deterioration of this kind of columns under reciprocating tension and compression load,the representative rectangular cavity in this kind of columns,including three columns with steel ratio 7.53% and one column with steel ratio 3.77% and all with the same cross section,were tested under reciprocating tension and compression loading.Each specimen were divided mediad into two half parts.One half was welded with studs and the other half without studs.Based on the experiment,load bearing capacity,stiffness and its deterioration process,the stud effect and failure characters were comparatively analyzed.The simplified calculating formulas of the column under tension and compression were established,and the calculated results agree well with those from the test.The results show that setting studs in rectangular concrete filled steel tube columns can obviously improve working performance under tension and compression load.Increasing the thickness of the steel plate in rectangular steel tubes can obviously improve their constraint capacity on the studs,so as to improve the collaboration performance between studs and concrete.