Joint device with controllable displacement limit value for reinforced concrete structure

The joint device comprises an SMA core material, an outer sleeve, a steel encircling sleeve support, a steel pin anchoring support, a steel pin and a fastening nut, the outer sleeve is of a cylindrical structure with a hollow shaft cavity, and connecting holes are formed in the side walls of the two ends of the outer sleeve in the length direction; and each group of connecting holes are elliptical connecting holes which are symmetrical relative to the axis of the outer sleeve. The oval connecting holes in the two ends of the outer sleeve can limit the deformation displacement value of the shape memory alloy bar and the soft steel spring, namely, the controllable effect is achieved, restoring force can be provided through combination of the shape memory alloy bar, the soft steel spring and the outer sleeve, so that the joint has the self-resetting capacity in the earthquake process, and the earthquake resistance is improved. And meanwhile, after the joint returns to the normal state, the outer sleeve serves as