Life-cycle cost-oriented multiobjective optimization of composite frames considering the slab effect

The life-cycle cost-oriented design philosophy is a promising tool for building resilient cities as it helps in gaining insights into the impact of hazard-induced damage and repair of civil and infrastructure systems. In this study, a socioeconomic parameter-independent practical formulation was introduced for life-cycle cost analysis by combining the economic loss rate associated with different damage limit states and cloud analysis-based probabilistic seismic demand model. A framework for life-cycle cost analysis-based seismic design optimization was proposed using an emerging nature-inspired algorithm, namely, the multiobjective cuckoo search. By considering an eight-story prototype composite frame, the framework was used to determine the trade-off design alternatives between competing optimization objectives. Conventional and improved fiber models were developed to comparatively evaluate the influence of the slab spatial composite effect on Pareto optimal designs. The key drivers of change in three cost indicators were identified using generalized linear models. The result indicates that the overstrength factor is the critical design parameter affecting the initial construction, seismic damage, and life-cycle costs, with statistical significance at the 0.001 level.