Performance-based Design of Steel Moment Frames Sustaining Beam-Hinging Mechanism

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The results from this project are summarized as follows:1. Energy input can be predicted by using a pseudo-velocity response spectrum. However, this method of prediction cannot be applied to extremely long ground motions. The critical duration of a ground motion is determined in order to limit the range in which the method of prediction is applicable.2. A method is proposed to predict the maximum seismic response of single-degree-of-freedom systems with polylinear load-displacement relationships. Based on the balance between earthquake input energy and absorbed energy during a half-cycle of a vibration, the maximum seismic response is derived as a function of the damage-causing earthquake input energy and the maximum half-cycle energy input ratio. The applicability of the proposed method is confirmed through comparisons with numerical results of various single-degree-freedom systems.3. A procedure for seismic design has been proposed to estimate the ductility demanded of beams in steel … More moment frames that sustain overall collapse mechanisms. In this study, a method is presented to predict a collapse mechanism that will most likely form in a frame structure under severe earthquake excitations, and the amplification factor of the ductility demand is determined based on the predicted collapse mechanism. The seismic responses of steel frames that sustain various collapse mechanisms are examined numerically. The results of the proposed method favor the overestimation of ductility demand for frames that sustain partial collapse mechanisms in a few stories but the approximation of the upper limit of numerical results.4. Critical parameters that control the earthquake response of steel frames with hysteretic dampers are characterized and incorporated into the equivalent single-degree-of-freedom representation. Maximum and cumulative plastic deformations induced in hysteretic dampers are derived in explicit forms as functions of these parameters, and the accuracy of the estimations of plastic deformations is demonstrated through a comparison with numerical results. Less