Behavior of the T-Shaped Concrete-Filled Steel Tubular Columns after Elevated Temperature

Table 5

Loading system.

Loading process	P1	P2	P3	P4
Loading method	Displacement	Force	Force	Displacement
Loading level	0.5 mm/min	1/10PU	1/20PU	0.5 mm/min

Note. (1) P1 is before the contact. P2 is the elastic stage. P3 is the elastic-plastic stage. P4 is the yielding or breaking stage. (2) , where is the ultimate bearing capacity, is the yield stress of steel tube, is the strength of concrete, is the cross-sectional area of steel tube, and is the cross-sectional area of concrete.