investigation of using various force distribution methods at seismic behavior of steel mr frames designed by ddbd method

When a structure is subjected to a strong earthquake, seismic forces are distributed on the structure’s floors. this is not the exact case when a designer designs a building by utilizing the forced-based design method. however, it is so clearly that distribution of the base shear obtained from code’s formula along the height of the building, significantly affects building’s design elements. this results in different seismic behaviour during occurrence of strong earthquakes.because this significant impacts on the structural performance, distribution of determined base shear along the height of the building are investigated via utilizing various current codes. regarding this, one can expect that a building which has passed all design criteria, during a strong earthquake presents unpredictable behaviour. in fact, as soon asthe building crosses its elastic limit, the idea of using inertia-based distribution of lateral forces may be useless. previous experiences confirm this so by this view cannot be expected to lead to optimal distribution of forces in the members of the building.