Behaviour of steel-to-concrete connections under combined axial force and cyclic bending

Abstract Experimental study is completed on the behaviour of end-plate-type steel-to-concrete mixed connections under combined compressive normal force and cyclic bending. The main focus of the research in on the rotational stiffness of the mixed connection and its cyclic deterioration. The initial elastic stiffness is analyzed under different values of constant compressive axial forces. Interpretation and definition of rotational stiffness are introduced. The compressive axial force significantly increases the rotational stiffness, depending on the structural solution. Characteristics of the ultimate behaviour are determined under increasing cyclic bending moment and constant axial force. The tested mixed connections are classified according to strength and rigidity using the moment-rotation envelope curves. The cyclic characteristics of the moment-rotation response of the joints are analyzed. Early deterioration of the rotational stiffness is observed.