BIM-driven optimization of life cycle cost in seismic design of urban buildings

The predominant strategy in structural design is based on reducing the initial weight of the structure, while potential future costs due to, for instance, earthquake damage might be overlooked. This strategy means that no life cycle cost (LCC) assessment is performed over the design process. Yet, while many studies have addressed the LCC-based design of regular structures under earthquake loads, rare studies have applied it to irregular structures. Furthermore, the lack of utilization of Building Information Modeling (BIM) capabilities in previous LCC-based design is evident. This study aims to highlight the impact of irregularity on optimizing the LCC of high-rise steel structures by providing an optimization framework for seismic design of regular and irregular structures integrating the capabilities of LCC and BIM. Using BIM, it is possible to significantly reduce the limitations of LCC analysis, such as time spent in data collection and exchange, and to increase the accuracy and speed of calculations. The framework here first combines results of different architectural and structural software through programming within MATLAB environment and then uses NSGA-II algorithm for establishing a trade-off between initial cost and LCC. To check the workability of the framework, six 3D tall steel structures, with 10-, 13-, and 20-floors, in two categories of regular and setback irregular are first designed for gravity and seismic loads and their performance using non-linear analyses are then analyzed. The results showed that the indirect costs of irregular structures were relatively higher than regular ones while higher initial cost needed to reduce LCC. For example, for both the 20-story regular and irregular structures, a 15% increase in initial costs resulted in a 24 and 17% reduction in their LCCs, respectively. Given that irregular structures are more susceptible to sustaining earthquake damage than regular ones, the proposed framework here can further provide the economic viability of irregular structures from an LCC-based perspective.