Axial tension and compression testing apparatus under restraining action and testing method thereof

The invention relates to an axial tension and compression testing apparatus under a restraining action and a testing method thereof. The axial tension and compression testing apparatus comprises a reaction wall, a portal frame, an axial tension and compression device and a horizontal restraining device, wherein the axial tension and compression device comprises a vertical actuator, an upper connecting plate, a lower connecting plate, an upper connecting head, a lower connecting head and a fixing compression beam; the horizontal restraining device comprises a horizontal actuator, a horizontal loading head, a horizontal fixing head, a triangular support frame and a support frame compression beam. The apparatus and the method can be applied to a loading test on an axial tension and compression test piece needing a horizontal restraining action and to an axial tension and compression performance test of the test piece by simulating the restraining action of a steel pipe or a densified spiral stirrup; the apparatu