Confidence level for Iranian Existing Moment Resisting RC Structures Based on Demand and Capacity Factored Design Method

The Demand and Capacity Factored Design (DCFD) method is a performance-based analytic approach used in structural engineering to assess analysis and design factors. This method involves calculating factored demand and capacity to ensure structural safety and reliability. By considering uncertainties in structural modelling and design parameters, the DCFD method provides a probabilistic framework for evaluating the performance of structures under various conditions. In recent decades, Iran has made significant advancements in the design and construction of structures following building codes. As a result, a considerable portion of residential buildings in the country now adhere to the latest building code editions. The Iranian Standard No. 2800, focusing on seismic-resistant building design, stands out as a crucial and impactful code among the various building regulations in Iran. Therefore, the question that emerges is how these regulations will impact the performance of intermediate-moment resisting reinforced concrete structures in upcoming events. In this research, the effectiveness of buildings designed according to the various versions of standard No. 2800 is assessed across operational (OP), immediate occupancy (IO), life safety (LS), and collapse prevention (CP) performance levels through the DCFD method. Structural non-linear analysis is conducted using incremental dynamic analysis. The results show that the confidence level of CP performance level, decreases with increasing height of structures, and the reliability of 8-storey structures is less than 90%. Therefore, it seems necessary to consider CP performance levels in seismic evaluations.