Investigating life cycle cost in optimized bracing frames based on performance

The purpose of this research is to evaluate the life cycle cost of performance-based optimally designed concentrically braced frames. Today, the effect of earthquake on the design of a structure is considered with the aim of optimizing the weight and reducing the initial construction cost of the structure. Although such a structure will have the lowest construction cost, it is not possible to estimate the cost due to an earthquake during its operation. Life cycle cost analysis is a suitable method to examine the cost and performance of structures that should be in service for a long time. In the first step of this study, two three-span ten-story frames with a concentrically bracing system with the position of the bracing in the middle span and the side spans, using the center of mass meta-heuristic algorithm in the framework of the performance-based design method, and considering the weight of the structure as the objective function and the external penalty function method have been optimized. In this study, OpenSees software was used to perform nonlinear modeling and analysis, and MATLAB software was used to implement the optimization problem. In the second step, the life cycle of the frames resulting from the optimization process has been investigated using the Wen and Kang relationship. According to the obtained results, placing the brace in the side spans reduces the structural component life cycle by almost 10% compared to the brace frames with the placement of the brace in the middle span.