The Seismic Design Process of RC Column Components in SDOF System considering the Earthquake Duration Effect

Table 1

The performance classification criteria based on the stiffness decay index [24].

Nos.	Stiffness decay index DK,k	Damage phenomenon	Damage stage	Performance criteria
1	D K,k < 0	No visible cracks	No damage	Intact
2	0 < DK,k ≤ 0.4	Multiple horizontal cracks	Mild damage	Repairable
3	0.4 < DK,k ≤ 0.6	Horizontal cracks connecting end to end	Moderate damage
4	0.6 < DK,k ≤ 0.8	Unidirectional oblique cracks, intersecting cracks	Severe damage	No collapse
5	0.8 < DK,k ≤ 1	Concrete crushed	Destruction	Collapse