Nonlinear Analysis of Irregular Building Due to Intensive Earthquakes

Abstract

Abstract In the twenty-first century, the seismic design of buildings seems to have become a fully recognised topic. There are guidelines and standards which should be taken into account by designers in seismic areas. Designers using modern international guidelines have ascertained that the behaviour of structures is not as expected. New challenges in the construction industry result in the construction of structures with new, unusual shapes. These are structures that do not meet the assumptions of safe construction in seismic areas. Contemporary buildings are also characterized by their irregular distribution of structural elements. Such solutions are not beneficial from the point of view of seismic engineering and can lead to reduced dynamic resistance and damage in such structures. In this paper, a five-storey, irregular-shaped RC building model was subjected to different earthquakes with varying magnitudes, PGA and PGV values, and duration of the intense shock phase. Once the model was verified using previous in-situ measurements, the building model was subjected to five earthquakes. Numerical nonlinear analysis of the building was performed using a verified FEA model in the time domain through non-linear time history analysis with the Broyden-Fletcher-Goldfarb-Shanno (BFGS) method. The building's dynamic properties were measured using various methods of excitation. The model was influenced, among others, by two far-field representative events caused by the last earthquake in Turkey, which resulted in strong ground motion. The analysis results identified the locations of structural damages and allowed for the assessment of the structure's dynamic resistance. The results of the calculations prove that the duration of the intensive phase of extortion is one of the reasons for the building damage in earthquake-prone. Building collapses occur with earthquakes which are characterized by a long duration of the intensive phase of excitation and high values of velocity of earthquake components. The article highlights inadequate dynamic resistance of the building, leading to excessive drift and unfavourable structural solutions.