A.R Fachruddin B is a long-standing building, the building was built before the latest earthquake regulation, therefore the building needs to be studied about the feasibility of its structure with the proposed addition of reinforcement using bracing. This research was carried out with numerical analysis using finite element software to assist in calculating the lateral forces that occur due to dynamic seismic load spectrum response. The steps are carried out by evaluating the existing building conditions in advance to the base shear value, story shear, drift ratio, and cumulative deviation. The results of the existing evaluation showed that the building was not safe against the seismic load that occurred, so the bracing reinforcement was located on the inside of the building. The profile used for bracing reinforcement uses steel profile 2L 90.90.14 with a design ratio less than 0.74. The results of the analysis show that the base shear value due to dynamic seismic load has increased by 14.63% for the direction of X and 6.11% for the direction of Y. The story shear experienced the largest increase on the 5th floor X at 15.52%. Drift ratio values that occur in the structure before reinforcement with bracing do not meet the conditions permitted, therefore it is necessary to strengthen the drift ratio to meet the requirements so that a maximum decrease of 38% due to earthquake direction X and 35% Y direction. decrease so that it has fulfilled the allowable conditions, namely the deviation value is smaller than the limit of the cumulative deviation allowed. The use of bracing can add structural rigidity so that the structural frequency value has increased by 21.78% and the value of the structure period has decreased by 27.85%.