People have always needed house. But increasing in human population in these last decades, make it unavoidable to build accelerated and economical residential structures. So, using precast concrete large panel is one of the best choice, because of better quality and reducing of construction time. Composing large panel with floor and roof section, forms a system that offers high resistance to fire and sound. There is not sufficient information about seismic behaviour of precast concrete large panel buildings. Because of that, many research based on experimental and theoretical models have been developed to investigate seismic behaviour. Nowadays, the most important part of seismic design of structures is carried out based on equivalent static method and calculation of seismic forces from linear spectrum of an earthquake, with application of a structural reduction factor, which contains the design philosophy. The reduction factor is a coefficient that contains inelastic behaviour and shows hidden resistance and ductility of structures in the inelastic zone. With attention of behavior factor signification in structural seismic design seems the determination of this factor is necessary. In this research many kind of precast structures consist of large panels in 4, 8 and 12 stories and 1, 3 and 5 bays considered. Affect of tow kind of horizontal connection in use, uniform and triangular loading with different compression resistance of concrete were investigated. The seismic behaviour of such structures is strongly dependent upon the characteristic of both horizontal and vertical connections between panels. Because of that, sufficient assumptions based on experimental research were used. To receive this goal, the static pushover analysis has been used.
