Capacity Requreiment of Steel Moment Frames in Compliance with Seismic Demand

点击翻译按钮获取中文摘要

The results obtained from this project are summarized as follows :1. Damage-causing earthquake input energy used in energy-based seismic design is defined as the maximum response of the sum of elastic strain energy and plastic dissipated energy. The input energy can be predicted by using a pseudo-velocity response spectrum corresponding to the apparent natural period of a frame, which is determined based on the mean of the plastic dissipated energy per half-cycle in the whole vibration.2. Maximum half-cycle energy input ratio is defined as the ratio of the maximum increment of the sum of elastic strain energy and plastic dissipated energy during a half-cycle of vibration to the damage-causing earthquake input energy. The maximum half-cycle energy input ratio is evaluated by extensive numerical response analysis. A method is proposed to predict the maximum seismic response and residual deformation of bilinear systems based on the balance between input energy and absorbed energy during a … More half-cycle of vibration.3. An equivalent single-degree-of-freedom system is proposed that can simulate the seismic response of a multistory frame. A method for predicting the collapse mechanism under earthquake excitations is devised, taking into consideration the correlation between dynamic horizontal forces acting on each story. In addition, load-deformation relationships of equivalent single-degree-of-freedom systems are determined based on the predicted collapse mechanism.4. A seismic design procedure is proposed to estimate the ductility demanded of beams in strong-column/weak-beam steel frames. Critical parameters that control the earthquake response of steel frames are characterized and incorporated into the equivalent single-degree-of-freedom representation. Maximum and cumulative plastic rotations induced into beam-ends are derived in explicit forms as functions of these parameters, and the accuracy of the estimated rotations is demonstrated through comparison with numerical results. Less