Research on the Estimation Method of the Stiffness Degeneration Index of Reinforced Concrete Members

Table 1

The properties and imposed displacement patterns of 24 specimens [17].

Specimen		Vy (kN)	uy (mm)	ρw (%)	ρ (%)	Displacement pattern	Displacement amplitude of CC stage
Group	No.
1	R1	67.60	12.97	0.226	0.766	SV1	20 mm, 40 mm and 60 mm
	R2	67.60	12.97			SV2	40 mm, 20 mm and 60 mm
	R3	67.60	12.97			SV3	60 mm, 40 mm and 20 mm
2	R4	67.60	12.97	0.402	0.766	SV1	20 mm, 40 mm and 60 mm
	R5	67.60	12.97			SV2	40 mm, 20 mm and 60 mm
	R6	67.60	12.97			SV3	60 mm, 40 mm and 20 mm
3	R7	67.60	12.97	0.804	0.766	SV1	20 mm, 40 mm and 60 mm
	R8	67.60	12.97			SV2	40 mm, 20 mm and 60 mm
	R9	67.60	12.97			SV3	60 mm, 40 mm and 20 mm
4	R10	51.50	11.70	0.402	0.587	SV4	20 mm, 40 mm, 60 mm and 40 mm
	R11	51.50	11.70			SV5	40 mm, 20 mm, 60 mm and 40 mm
	R12	51.50	11.70			SV6	60 mm, 40 mm, 20 mm and 40 mm
5	R13	80.11	14.39	0.402	0.971	SV4	20 mm, 40 mm, 60 mm and 40 mm
	R14	80.11	14.39			SV5	40 mm, 20 mm, 60 mm and 40 mm
	R15	80.11	14.39			SV6	60 mm, 40 mm, 20 mm and 40 mm
6	R16	89.02	16.66	0.402	1.198	SV4	20 mm, 40 mm, 60 mm and 40 mm
	R17	89.02	16.66			SV5	40 mm, 20 mm, 60 mm and 40 mm
	R18	89.02	16.66			SV6	60 mm, 40 mm, 20 mm and 40 mm
7	R19	67.60	12.97	0.226	0.766	RV1	—
	R20	67.60	12.97	0.402	0.766	RV1	—
	R21	89.02	16.66	0.402	1.198	RV1	—
8	R22	89.02	16.66	0.804	1.198	RV2	—
	R23	89.02	16.66	0.226	1.198	RV2	—
	R24	51.50	11.70	0.226	0.587	RV2	—

Note. V_y is the yield load, u_y is the yield displacement, ρ_w is the transverse reinforcement ratio at the plastic hinge region, and ρ is the longitudinal reinforcement ratio in the test section.