Axial compression behavior of GFRP tube reactive powder concrete composite short columns with encased steel

25 full-scale GRS short columns were designed considering the diameter of GFRP tube,the thickness of GFRP tube,the number of fiber layers,the fiber winding angle,the slenderness ratio,RPC compressive strength,the area of I-shaped steel,the strength of encased steel.Based on the bilinear constitutive model of steel and the nonlinear constitutive model considering RPC constraint effect,the numerical simulation analysis of 25specimens was carried out by ABAQUS,the axial load-displacement curves and bearing capacity of specimens were obtained,the influence of different parameters on the bearing capacity and ultimate displacement was investigated.The expression of axial compression bearing capacity of GRS short columns was established by 1stOpt software.The results show that axial compression bearing capacity of GRS composite short columns increases significantly by increasing of the diameter of GFRP tube,the thickness of GFRP tube,the number of fiber layers,the fiber winding angle,the strength of encased steel,RPC compressive strength and the area of I-shaped steel.The ultimate displacement of GRS composite short columns increases clearly by increasing of the thickness of GFRP tube,the number of fiber layers,the fiber winding angle,the slenderness ratio and the area of I-shaped steel.As the diameter of GFRP tube increases,the ultimate displacement of GRS composite short columns gradually reduces.The full-scale GRS short columns specimens shows a good load-holding capacity and continuous local expansion failure mode.