Performance assessment and calculation of robustness of high-rise diagrid tube structures with various configurations

Resilience is an appropriate criterion for evaluating the ability of a structural system to reduce the probability of damage caused by an event. To date, the seismic resilience of novel structural systems such as diagrid structures has not been studied. In the present research, the effect of various perimeter geometric patterns on the robustness index of diagrid structures is evaluated. For this purpose, six diagrid structures of 24 and 48 stories with perimeter configuration angles of 49 degrees, 67 degrees, and 74 degrees are designed. The seismic capacity of the structures is calculated using the incremental dynamic analysis (IDA) based on the maximum story drift parameter and under near-field earthquakes. Next, the fragility function of these structures in limit states are determined based on lognormal statistical distribution. Seismic performance levels for diagrid structures are also developed. The proposed formulation in the MCEER report is used to calculate the loss function of structures. In addition to the structural damage, non-structural damage is also considered in estimating the seismic resilience of the structures, according to the HAZUS guideline. Furthermore, an additional factor is defined in the loss function as an assurance of the quality of construction. Finally, the resilience of high-rise buildings with diagrid structures is determined for a specific hazard level. The results show that diagrid structures have relatively high robustness and using perimeter triangular elements can reduce the degradation of structures after the earthquake. As observed in the results, considering damage to non-structural elements causes a decrease in the quality function of the studied structures. It is demonstrated that increasing the perimeter configuration angles decreases the robustness index of diagrid structures. Based on this analysis results, insufficient knowledge of the quality of construction can decline the seismic performance of diagrid structures by up to 6%.