Investigation of seismic performance and strengthening of an existing reinforced concrete building according to TBEC-2018

In this day and age, improvement of the earthquake performance levels of the existing structures has been the subject of different studies in terms of earthquake engineering. It is aimed that these structures that are investigated in several researches shall be able to provide adequate performance against earthquake forces by using various strengthening methods. In the scope of this thesis study, seismic performances of three, five and eight storey existing and strengthened reinforced concrete buildings having the common floor plan, material and section properties of the structural members are investigated according to Turkish Building Earthquake Code-2018. To obtain the earthquake performance results of reinforced concrete structures, displacement demands of the buildings have been obtained and utilized in nonlinear analyses. SAP2000 structural analysis program is used in the non-linear analyses. Constant single mode pushover method which is one of the pushover analysis methods in the earthquake code is used for the related buildings. In this method, the earthquake load increments effecting on the floors at each of the pushover step in the considered earthquake direction are defined in proportion to the constant mode shape determined in the first step after the non-earthquake loadings and never changed during the pushover calculation. Since the column and beam members of the buildings are modelled with the frame system, the behavior model of the non-linear analysis method that is applied to the structure is chosen as lumped plastic behavior model for the earthquake performance of the reinforced concrete buildings. By this model, it is assumed that the plastic deformations uniformly occur along the regions in finite length where the internal forces reach their plastic capacities. The determined strengthening techniques are provided by adding concentric steel bracing members to existing reinforced concrete buildings and jacketing of the determined columns. As a result of non-linear pushover analyses applied to the existing and strengthened buildings, damage situations of the structural members are determined, seismic performances of the buildings are evaluated and suggestions are proposed.