Investigation of nonlinear behaviour of structures under static and dynamic loads

Linear static methods existed in the current seismic codes are used by civil engineers for analyses and design of buildings. However, it is expected that buildings, designed according to decreasing earthquake load which decreased using earthquake load reduction coefficient, show post elastic behaviour. To provide collapse of a building during a destructive earthquake, it is desired that the building has adequate strength and ductility. Earthquake safety of a building which designed current seismic code could be determined by appropriate nonlinear analysis methods. Generally lumped and distributed plastic hinge models are used while nonlinear modelling of a building. In this thesis, behaviour of reinforced concrete buildings under static and dynamic loads is investigated by using distributed plastic hinge model (fiber element model). In the first chapter of the thesis; properties of reinforced concrete material, parameters which effect to earthquake behaviour of the buildings, object of the study and scope are expressed. In the second chapter of the thesis, the studies including distributed and lumped plastic hinge models in the literature are presented. In the third chapter of the study, it is informed that about nonlinear behaviour of structural systems and causes of them. In the fourth chapter of the study, numerical applications are performed by using distributed and lumped plastic hinge models. Therefore, various reinforced concrete structures are designed and nonlinear dynamic and static pushover analyses are performed. Selected earthquake acceleration records are used for dynamic analyses. In first numerical study of this thesis, static pushover analyses of a reinforced concrete frame are performed according to various lateral load shape by using lumped plastic hinge and distributed plastic hinge and results are compared for these hinge models. For second numerical study, damages which occurred by soil effect, for selected plane system are investigated by using distributed plastic hinge model. For this, selected earthquake acceleration records are scaled according to design spectrum which defined for local soil classes in Turkish Seismic Code and nonlinear dynamic analyses are performed. Damages occurred in the selected structure model are evaluated after analyses. Also, static pushover analysis of the structure model is performed and compared with results of nonlinear dynamic analysis. In third numerical application, behaviour of reinforced concrete structure systems which subjected to increasing lateral static loads by considering whether or appropriate confined reinforcement and various concrete compressive strength is investigated by using distributed plastic hinge model. For this, reinforced concrete structure systems are designed which have 11 stories and 4 spans and C20, C25, C30 ve C35 concrete strength respectively. Confinement reinforcement spacing of columns and beams of selected structural systems is designed as appropriate and inappropriate to Turkish Seismic Code and after the analyses obtained results are compared. In fourth numerical study, a comparison is made by using design spectrums of Turkish Seismic Code and Eurocode-8. Therefore, selected earthquakes acceleration records are scaled according to response spectrum which defined each codes and nonlinear dynamic analyses are performed by using distributed plastic hinge model. Structural damages are evaluated according to obtained results. In this thesis study, it is aimed to show applicability of distributed plastic hinge model for nonlinear static and dynamic analyses of reinforced concrete structures and to be source for future studies.