عنوان مقاله [English]
In this paper, the conceptualization of the structural resilience has been assessed for three studied diagrid structural systems. Moreover, there is a basic studied model comprising a full bundled tube skeleton which has been used for performing all numerical comparisons among the seismic response parameters. The effect of the geometrical configuration of the perimeter diagonal beam-column elements on the seismic resilience lemma has been evaluated through numerical explanations due to the released fragility curves. The three studied 24-story diagrid structures are considered with uniform geometric configurations and internal bundled flexural cellules which form a hybrid resistant skeleton. The uniform diagonal angles for diagrid models are considered 49°, 67° and 74° respectively. Several nonlinear time history (NTHA) and incremental dynamic analyses (IDA) were performed on the four studied 24-story structural models under near-field ground motions with various directivity effects. The probability of the exceeding performance limit states for the studied structures has been calculated based on the FEMA provisions. The assumed performance levels in preparing of fragility curves are including the immediate occupancy (IO), the life safety (LS), the collapse prevention (CP) and the probabilistic global instability (GI) indices. Also, the robustness of seismic resilience for the studied structures has been determined according to the proposed formulation of the damage function as reported by MCEER.
Moreover, the obtained results indicate that the assumed geometric pattern for the perimeter inclined elements would relatively reduce the maximum inter-story drift and increases the collapse capacity of the diagrid structures. In addition, the definition of large angles for diagonal elements can cause an increase in the probability of occurring the seismic performance levels higher than the L.S. criterion.
Moreover, the evaluation of the related seismic resilience for all studied structures proved that the diagrid systems have a high ability to withstand against a specific limit of damage. It is demonstrated that implementing triangular patterns in the external framed panels of the seismic resistant skeleton would decrease the estimated amount for the qualified deterioration effects in structures after a strong earthquake. In this regard, with increasing the skeletal angles of inclined elements, the effect of diagonal configuration on controlling the probability of occurring higher performance limit states would be effectively decreased. This research results, indicate that the geometric pattern of diagrid elements is able to rise the value of the skeletal hard resilience component and relatively exceed the capability of structural stability against near-field ground motions.