Seismic energy dissipation under variable amplitude loading for rectangular RC members in flexure

Abstract

Summary The energy dissipation characteristics of reinforced concrete members that exhibit both strength and stiffness deterioration under imposed displacement reversals were investigated. To do this, 24 symmetrically reinforced concrete rectangular specimens were tested under stable variable and random variable amplitude inelastic displacement cycles. Stable variable amplitude tests were employed to determine the low‐cycle fatigue behavior of specimens where the loading sequence was the major variable. A 2‐parameter fatigue model was developed in order to express the variation of the dissipated energy in displacement cycles with the cumulative hysteretic energy. This model was then used to predict the energy dissipation of test specimens subjected to random variable amplitude displacement cycles simulating severe seismic excitations. It has been demonstrated that the remaining energy dissipation capacity for the next displacement cycle was dependent on the relative relationship between the maximal displacement cycle and the energy dissipated along the completed displacement path. The plastic energy dissipation capacity of reinforced concrete members is both displacement path dependent and cumulative hysteretic energy dependent.

Damage index of reinforced concrete members based on the energy dissipation capability degradation

“…The half cycle is defined as the path between two consecutive zero force crossings, that is, a cycle is divided into upper and lower two half cycles by the displacement axis in Figure . In previous research, 18 symmetrically reinforced concrete rectangular specimens were tested under variable amplitude displacement cycles to study the relationship between the energy dissipation capacity degradation of reinforced concrete members and the peak deformation, cumulative hysteretic energy dissipation and material parameters, and a method for predicting the half‐cycle energy dissipation capacity under variable amplitude displacement cycles was established.…”

“…The energy decay index of reinforced concrete members is defined as …”

“…The value of is zero at the first half cycle. The parameters A E, k and B E, k are calculated from …”

“…The research group obtained an estimation method for the energy dissipation capacity of reinforced concrete members under variable amplitude displacement cycles in previous research . Given the section size, reinforcement conditions, and variable amplitude displacement cycles of reinforced concrete members, the degradation process of energy dissipation capacity can be accurately predicted . That is, the energy dissipation capacity degradation of reinforced concrete members can establish a quantitative relationship with the structural design parameters.…”

“…Therefore, it is possible to guide the design by using the degradation index of the energy dissipation capability. On the basis of existing research, this paper proposes a damage index of reinforced concrete members based on energy dissipation capacity degradation and puts forward a performance classification criterion based on the damage index.…”