Full-scale Test on the Performance of High-strength Recycled Concrete-filled Square Steel Tube Columns Under Axial Compression

To study the axial compression performance of high-strength recycled concrete-filled square steel tube( CFSST) columns,three high-strength CFSST full-scale specimens were designed with the same section size and different concrete type and internal structure. One of the three specimens was highstrength normal CFSST column; the second one was high-strength recycled CFSST column; and the last one was high-strength recycled CFSST column with a reinforcement cage. One-way repeated loading was adopted in the test. Through the experiment,the failure characteristic,load-bearing capacity,energy dissipation,ductility and stiffness of the specimens were analyzed. The ultimate bearing capacity of CFSST columns was calculated according to five relevant regulations at home and abroad. The test results show that the damage development and failure mode of recycled concrete-filled square steel tube column are similar to those of normal CFSST column. The load-bearing capacity,ductility and energy dissipation are improved significantly owing to the installment of the steel reinforcement cage inside the square steel tube. CECS 159—2004 can be used to predict the load-bearing capacity of CFSST columns,and the calculation results show well agreement with the test results.