Abstarct: Concrete shear walls would improve the stiffness and ductility of moment frxame systems in tall buildings, but the weight of the aforementioned structural system would cause foundation engineering problems especially in loos sandy soils. An appropriate choice for solving this problem is substituting this shear walls with buckling restrained braces (BRB), having less weight and provide appropriate ductility and stiffness, In seismic design of structures. In this study, 3 models of 15, 25 and 35 floor buildings with two systems of special reinforced concrete moment frxame and also special reinforced concrete moment frxame equipped with buckling restrained brace, designed In accordance with the Iranian design codes. After the structural element sections are finalized, 3d models are modeled in OpenSees And by choosing a number of appropriate earthquake records compatible with the target spectrum, Incremental Nonlinear Dynamic Analysis (IDA) are performed. The maximum story drift are considered as demand parameter. By selecting the HAZUS relative displacement capacity for seismic performance damage levels (Slight, Moderate, Extensive and Complete) seismic fragility curves are produced. In taller building models more seismic Fragility is observed. For example in complete damage state for 15, 25, 35 floor models having special RC frxames the median fragility are 1/01g, 0/76g and 0/61g respectively. Moreover, the median seismic fragility for Complete damage state for 15, 25, 35 models equipped with BRBs are 1/14g, 0/82g and 0/65g, respectively.