Seismic performance evaulation of 15 storey reinforced concrete building by non-linear time history analysis

The high level of damage and loss of life experienced during the last earthquake events indicate the importance of safe and realistic structural design. On the other hand, the recent developments in structural engineering, computer technology and material science enable engineers to predict the real behavior of structural systems under earthquake effects, more accurately. Both linear and non-linear methods are used to analyze the structural systems subjected to earthquake loads. The linear evaluation methods are based on strength and the non-linear evaluation methods are based on deformation and displacement. In the linear theory, it is assumed that the material is linear-elastic and displacements are small, so that the structural analysis can be performed by the conventional linear methods given in the codes. In the non-linear analysis however, the second-order effects and the strength and deformation characteristics of materials beyond linear-elastic limit are taken into account. Nowadays, forced-controlled methods have an important place for assessment of existing structures. In these methods, capacity calculation is done in sections, will be evaluated based on the structure components and system to obtain information of the performance. However, new generation of development studies and computer software may be more realistic and more accurate results for the methods used. Those methods are based of the strain represent the behavior of material facts (non-linear). The design of multi storey reinforced concrete buildings for earthquake action may be efficiently accomplished with the capacity design method. Briefly explained, this method focuses on the establishment of clearly defined plastic hinge zones, proper detailing of these, and the protection of the remaining elastic parts of the building against yielding. For the verification of the structural behavior during an earthquake, there exists however, a need for non-linear dynamic analysis method, as well as for design aid for eccentric and complicated building configurations. For the modeling of the plastic hinge zones, non-linear elements were developed, and implemented as user defined elements into an existing general code. These elements, treating as plastic hinge zones in structural walls, beams, and columns are presented and used in this study. The codes of earthquake are the most significant resource that can be used to build an earthquake-resistant building. According to their geographical location, their geological and sesimic characteristics that apply within the territory and local ground conditions, countries prepare regulations that include the rules, which must be followed during building design. For this purpose, a new Turkish Earthquake Code (TEC) is published in 2007 (Deprem Bölgelerinde Yapılacak Binalar Hakkkında Yönetmelik-DBYBHY) with recent earthquake resistant building design principles. This regulation of the seventh chapter, in earthquake zones available and will be strengthened all the buildings and building structures under seismic effects in assessing the performance will be applied accounting rules, the strengthening in the decisions will be based on principles and strengthening decided buildings strengthen the design principles are included. Developments in structural engineering, computer technology and the material science help engineers to be familiar to the earthquake motions and the effects of earthquake on buildings in a more realistic and accurate way. These developments with the observation of the non-linear behavior of structural systems in an earthquake enable engineers to accomplish designs that are more realistic. In this study, seismic performance of a 15 storey existing reinforced concrete structure is evaluated by the non-linear time history analysis method of Turkish Earthquake Code (TEC) 2007. The present master thesis is composed of seven chapters. The first chapter is designated for the brief explanation of the subject. The aim and the scope of the study is explained in this part. In the next four chapters of this study, non-linear behavior and the analysis are given as the main portion of the study. In this context, non-linear material models are expressed, the stress-strain relationships of various building materials have been analyzed, for the reinforced concrete section, moment-curvature curve properties and interaction surfaces were examined. In addition, quite small information is given about the plastic hinge hypothesis. The sixth chapter is devoted for the numerical investigations. A three dimensional structural model of a 15 storey building is analyzed by a structural analysis program in non-linear time history analysis method given by the TEC 2007. Then the performance level evaluation of the building structure with the non-linear performance approach method of TEC 2007. In this section, firstly an information was given about the existing reinforced structure features which used in analysis model. Loads, seismic zone, material properties, type of structure and a lot of other properties of the building was described. Then for the non-linear analysis, the plastic hinge properties of beams and columns were determined clearly. Shear walls were modeled with non-linear layered shell elements for more accurate results. In this part furthermore, selection and scaling for real earthquake ground motion records are explained briefly. Also in this chapter, important data entry information used for non-linear modeling of the structural components, load analysis and calculated plastic hinge properties and their assigns to the model for performance evaluation of the structural system are presented. The seventh chapter is the final chapter and is devoted to the results, conclusions and recommendations of the study. Main findings, the examination of the results of this study are explained in this chapter. The appendices are given the appendices chapter of this study. In this chapter, data information about the existing reinforced concrete building which used in study, cracked section properties which used in analysis model.