Damage Deformation of Flexure-Yielding Steel-Reinforced Concrete Coupling Beams: Experimental and Numerical Investigation

Table 8

Method of defining performance levels for SRC coupling beams.

Performance level	Damage description	Performance criterion
		Rebar or steel strain	Concrete strain	Load carrying capacity
Being basically intact	There are fine cracks in concrete, while steel or rebar is not yielding	εy	0.002	—
Slight damage	Concrete cover is not crushing, and residual crack width is less than 1 mm	0.015	0.005	—
Moderate damage	Concrete cover is not spalling, and residual crack width is less than 2 mm	0.03	0.0075	95% Pmax
Severe damage	Concrete core is not crushing, and rebar or steel is not fracturing	εsu	εcu	85% Pmax

Note: ε_y is the yielding strain of steel or rebar, ε_su is the tensile strain of steel or rebar, ε_cu is the ultimate strain of the concrete, P_max is the lateral load carrying capacity of specimens.