Structural particularities of RC frame structures with wide rectangular columns highlighted through nonlinear analysis

High-rise residential buildings (22 m < buildings’ height < 36 m) represent an architectural-engineering performance model that optimizes the ratio between the percentage of occupied land and the utility of the space built. Designing residential buildings with a structural system composed of reinforced concrete (RC) frames with wide rectangular columns (WRC) is a challenge accepted and met by engineers. This type of structures can allow a prefabrication percentage of the structural elements up to 70% (only the columns and the slabs are cast in place). Another advantage is represented from the architectural point of view by the absence of the inner corners, which cannot be avoided in case of classical columns. Such buildings were designed and erected in Iași, Romania in the 1980s, in accordance with the calculation models and regulations of that period. The paper presents the analysis of an existing high-rise residential building with WRC by response spectrum (RS) and Time-history analysis (THA). A set of artificial accelerograms was generated based on earthquakes recorded at the site. The numerical model was chosen to match the input data used for the initial calculation of the structure. The results show that these types of buildings are stiffer than traditional framed structural systems and that under the action of major earthquakes the possibility of failure is high. The results have been compared with the current requirements of the standards highlighting the performance and weaknesses of these structural systems. The aim of the research is to identify vulnerabilities for rapid and targeted response in the event of a major earthquake.