Altitudinal Distribution Pattern of Earthquake Load for Moment Resisting Frames Considering Nonlinear Behavior of Members

This study aims to investigate distribution of earthquake lateral load along the building’s height of moment resisting frames, considering the structure nonlinear effects. For this purpose several case study steel frames including 3, 7, and 15 story frame -which are common for urban areas- are considered. These frames are designed according to Iranian standard codes for steel buildings and Iranian seismic code of practice (Standard No 2800), using the standard equivalent static procedure, for a soil class of II. Thereafter considering seven earthquake ground-motion scaled records, a nonlinear dynamic analysis for each of frames was performed and distribution pattern of shear force was extracted in frame elevation. In order to take out a certain and reliable lateral load pattern, the incremental dynamic analysis is used and results are averaged. Eventually considering the effective factors in distribution of earthquake lateral load along the height, the extracted load pattern is simplified and formulated to be practicable. The presented equation shows 95% correspondence with the dynamic analysis results.