Determination of the inelastic displacement demand and response control of steel frame type structures by seismic energy equations

based design methodologies. Firstly it takes into account frequency content and duration of the earthquake record. Moreover hysteretic behavior of the structural members can be considered in the analyses rather than envelope curves. Additionally, energy is a scaler value whereas force and displacement are vector terms. Hence using energy for evaluating the structures is a more rational approach. Since energy procedures have effective features, an energy-based procedure to compute inelastic top displacement of the MDOF systems under the effect of a given earthquake record is developed in the content of the thesis. At the outset existing equations to predict seismic input energy are evaluated through elastic SDOF specimen tests and their correlation with the experimental results was found to be weak. Therefore, a new formulation is developed, which considers the duration, frequency content and intensity of the earthquake, spectral acceleration and velocity, damping ratio of the structure and soil type. The product of the proposed relation satisfactorily matched with the experimental and numerical results. Correlation of the proposed equation with the experimental results are found to be strong (0.75). The proposed spectral input energy equation considers the damping ratio, whereas the damping effect on the input energy has been considered insignificant in the current literature. However, the performed experimental and numerical works showed that the damping ratio may have a significant effect around the dominant frequncies of the earthquake record. Therefore it should be considered in a precise design equation. Even though the proposed spectral equation satisfactorily envelopes the experimental results, a more precise calculation of the relative seismic input energy is required to obtain more accurate top displacement predictions. Therefore, a piece-wise exact method is developed in close form. Results of the piece-wise method are compared with the experimental and numerical results. The predictions of the piece-wise method were significant. Since the relative seismic input energy is predicted and computed satisfactorily, an energy-based intensity measure is also proposed in the thesis. The efficiency, sufficiency and the predictability of the proposed intensity measure is evaluated through several shake table tests and compared with almost all of the avaliable intensity measures. The proposed intensity measure suitably predicts the severity order of the earthquake records. The correlation of the proposed intensity measure with the experimental results was found to be very strong for all of the dynamic tests. Finally a hybrid spectrum that consists of spectral input energy and displacement is proposed to predict top displacement of a MDOF system. The proposed procedure is applied to two frame type structures which have 9- and 20-storeys. Average of the relative error in the prediction of top displacement occurred was around 20%.