EFFECT OF PHASE OF INPUT EARTHQUAKE WAVE ON DYNAMIC RESPONSE OF BUILDINGS WITH SPINDLE-SHAPED RESPONSE CURVE

Present paper deals with the way of searching for the input external earthquake waves that realize both maximum and minimum responses on the target structures, where an example is adopted from steel frames whose response curve reveals spindle-shape. The effect of the phase of external earthquake on the dynamic response of the structures is also investigated, where the external input waves are taken from the results obtained through the proposed method. Consequently, the phase characteristics of the earthquake waves are found to have an important role on the dynamic response of the structures, which is, up to three to five times as large as those resulted from those waves obtained upon the ordinary acceleration response spectrum given by Japanese Building Code. Additionally, degree of the correlation between the input energy from external earthquake and the maximum response of structures is shown to be unexpectedly a little and, on the other hand, the total magnitude of the input energy as well as the duration of the input of the earthquake have a relatively large effect on the response of the structures, where the duration of the external excitation has less impact on the maximum displacement of structures.