内置高强钢管的圆钢管混凝土柱轴压性能试验研究

Experimental Investigation into Axially Compressive Behavior of Circular Concrete-Filled Steel Tubular Columns with Built-in High-Strength Steel Tube

开展了12根内置高强钢管的圆钢管混凝土柱的轴压试验,考察了内钢管屈服强度、内外钢管净距、内钢管取钢率、废旧混凝土块体取代率等因素对柱轴压性能的影响。研究表明:在总用钢量基本不变的情况下,通过适当减薄外钢管并在其内部设置高强内钢管,可使圆钢管混凝土柱的轴压承载力明显提高,同时柱的初始刚度也有所提高;适当增大内外钢管净距,可使柱的轴压承载力进一步增大;内钢管取钢率的改变以及废旧混凝土块体的采用,对该类柱的轴压行为影响不大;针对该类柱提出的改进的轴压承载力计算方法具有很好的预测精度。

Axially compressive behavior of 12 circular concrete-filled steel tubular columns with built-in high-strength steel tube was experimentally studied. The influences of yield strength of the inner tube, clearance between the outer and inner tubes, steel ratio of inner tube, and replacement ratio of demolished concrete lumps(DCLs) on the columns’ behavior were investigated. The test results show that, firstly, when the total steel usage keeps unchanged, the column’s axial load bearing capacity as well as initial stiffness can be greatly improved by thinning the outer steel tube and placing a high-strength steel tube inside;secondly, the axial load bearing capacity of such co-lumn can be further improved by appropriate increasing the clearance between the inner and outer steel tubes;thirdly, steel ratio change of inner tube and the reusing of DCLs have limited influence on the axial behavior of such column;finally, the proposed calculation method proves a high precision in measuring axial load bearing capacities of such columns.