Damage Assessment of an SRC Frame-Core Tube Structure under the Action of a Main Aftershock Sequence

Table 6

Limit states and its corresponding description of the performance state.

Limit states	Performance level	Description of performance state
LS1	Complete workability	The structure is intact, the stressed members are almost undamaged, and the building can still work safely.
LS2	Basic workability	The structure is basically intact, and the main load-carrying members are slightly damaged. Slight vertical cracks begin to occur in the coupling beam, and small oblique cracks may appear in walls. The whole structure is in an elastic state with no yielding and can continue to be used after simple repair.
LS3	Workability after repair	The structure is greatly damaged, both structural and nonstructural members are damaged, and vertical cracks in the coupling beam and oblique cracks in the wall are developed. The structural members have large residual deformation and need to be repaired.
LS4	Life safety	Structures and members are severely damaged, cracks in beams and walls extend to a large extent, and the yielding status of the coupling beam and walls is obtained. The lateral deformation of the lateral load resistance components is observed obviously, and the structure is in a plastic working status.