Why did residential block in Croatian national revival street in Sisak damaged in earthquake had to be demolished

Residential block located in Croatian national revival street in Sisak is the largest building demolished after being damaged by Petrinja earthquakes in 2020. After the earthquake building was declared unsuitable for housing because of damage. All residents had to move out and since then the building is not in use. Classification of damage to building was determined according to The European Macroseismic Scale (EMS-98) and Technical Regulations for Structures (NN 7/22, article 24). In this paper is explained why is it neccessary to determine the level of actual earthquake resistance for buildings of this type, period of construction and initial seismic flaws. Earthquake resistance level of existing building can be determined only by seismic design calculations. Except for standard methods of calculations, such as linear-elastic calculation using response spectrum, it is necessary to calculate structures using nonlinear methods, such as pushover analysis. Reconstruction level and concept are defined by buildings damage level and determined earthquake resistance of the building. Course of procedures, such as evaluation of damage, study of state of existing structure and finally building design, which led to decision to demolish the building will be shown in this paper.