Abstarct: Effects of soil structure interaction may decreas or increas structure sresponce under earthquake loading. It’s depend on many factors as like as earthquake properties on earth surface, dynamic properties of soil, dynamic properties of structures and bedrock earthquake properties such as frequency content and duration. The aim of this thesis is assessment of frequency content and duration of earthquake on seismic response of structures including and not including soil structure interactin. Earthquakes cause complicated motions and loading in extended range of frequencies. Frequency content shows maner of ground surface motions. Affecting by frequency content may increas possibility of resonant phenomena in structures in addition soft soil under the structure especially when natural frequncy of soil profile and predominant frequency of earthquake are close to each other. Ground strong motion duration has sufficient effect on failure because of earthquakes. Most of physician phenomena such as stiffnes reduction and oure water presuure increasment in saturated sands depends on cyclic loading is made due to earthquakes. In this thesis two types of special moment frxame are modeld using Opensees finite element frxame work under loading because of bedrock earthquakes. Results show that by closing the natural frequency of structures and predominant frequency of earthquake responses are increased.