Metamodel-assisted design optimization of robust-to-progressive-collapse RC frame buildings considering the impact of floor slabs, infill walls, and SSI implementation

Although mathematical optimization can be a handy tool for structural design, neglecting to consider criteria such as safety can result in designs vulnerable to specific scenarios. One aspect of structural safety that has been gaining interest is buildings' progressive collapse (PC) resistance. Many experimental and numerical studies have been developed on this subject, although few investigations have related it to structural optimization. This paper presents a procedure called Optimization-based Robust Design to Progressive Collapse (ObRDPC) that integrates both topics. This framework incorporates typically overlooked factors, such as including floor slabs and infill walls as part of the superstructure or accounting for soil-structure interaction. The methodology is applied to five case studies of three-dimensional reinforced concrete frame building structures. The results demonstrate the significant influence of slabs and walls on the PC resistance of buildings. Beams are the elements that benefit the most from the presence of both to bridge over the failure of a load-bearing element. On the other hand, increasing the structure levels improves its robustness, contrasting with increasing the span length. The impact of PC-resistant design on beams, columns, and foundations is also evaluated compared to the traditional approach.