Dynamic Response Of Multi-Degree Of Freedom Frames Subjected To Identical Support Excitation Due To Earthquake

ABSTRACT

  In structural dynamics, structures may be excited by two kinds of source, external loading acting directly on the super structure and secondly the ground motion acting on the sub structure (Seyoum, 2016). In the latter case ground motion may be expressed as acceleration, velocity or displacement. In the analysis of structures under ground motion, the ground acceleration, velocity, and displacement are presumed to be known since they can be obtained directly from instrument readings. When any two of these parameters are specified, analysis could be carried out effectively. Since earthquake engineering is based on the expectation that structures undergo serious deformation, and possibly collapse during intense ground vibration caused by earthquake, the Structural Engineer, is interested in predicting the expected structural responses (Hoskuldur, 2016). The most important factors influencing earthquake ground motions are earthquake magnitude, distance from the source of energy release, local soil conditions, variation in geology and propagation velocity along the travel path, and earthquake source conditions and mechanism (fault type, slip rate, stress conditions, stress drop, etc.). Past earthquake records have been used to study some of these influences (Chopra, 2006).