Cost and Damage Comparison of RC Frame Buildings Designed Using IS Code and the Unified Performance-Based Design Method

The seismic design code of India follows the traditional force-based approach for designing buildings to resist a lateral force representing earthquake excitations. Owing to various limitations of this approach, there is a growing interest toward performance-based design (PBD) when designing buildings for seismic events. The unified performance-based design (UPBD) is a new and advanced PBD approach capable of effectively designing buildings for specific performance levels and drift. Despite its potential benefits, the widespread adoption of PBD remains limited, especially in India. To address this gap, a comprehensive study was conducted to evaluate the effectiveness of two distinct design methodologies: the conventional force-based Indian standard (IS) code method; and the innovative UPBD approach. The study focused on analyzing the cost implications and seismic damage outcomes of each method. Nine reinforced concrete frame buildings were initially designed using the IS code method, followed by detailed nonlinear analyses to assess their performance. Subsequently, the buildings are redesigned using UPBD to achieve equivalent performance levels and drift, setting a standardized benchmark for comparison. Cost is assessed based on the weight of concrete and steel, while a modified Park and Ang damage index is used to quantify damage. The research findings unveiled that buildings designed using the UPBD method exhibited lower overall costs and showcased reduced vulnerability to structural damage compared with those designed using the traditional IS code approach. The UPBD-designed buildings demonstrate superior performance metrics and potential cost savings, emphasizing the economic and structural benefits of adopting the UPBD method for seismic design.