Abstarct: Abstract Due to the ever-increasing development of the technology industry in the construction industry and the best possible utilization of the existing capacities, building construction has turned towards high-rise buildings day by day, and the technology used in this industry has also been developed. In this research, the behavior of BRB by cylindrical core with light weight concrete is investigated using finite element software. These types of capabilities are developed examples of common convergent and divergent capabilities that are used in high-rise buildings. In this thesis, after conducting the verification baxsed on the research conducted by Mr. Xiang Yi in 2016 and ensuring the process of conducting the research, we did the complete modeling of the proposed plan. In this research, two concrete cores and cores are used, and the specifications considered for the concrete core are made of light concrete with plastic particles, and for other steel components, ST-37 steel is used, and concrete is used Resistance grade C25 was used as the sheath filler. We have considered the geometric shape of the steel and concrete core as a cylinder and its sheath as a circle. In this research, the element was loaded from two sides so that the results are closer to the probability. After the analysis of the proposed design, in order to check the effect of the changes, it is compared with the conditions where there is no light concrete inside the steel core (steel core) and there is no outer shell. At the end of this research, it was concluded that the proposal using ST-37 steel has high energy absorption and load capacity compared to the ability of all steel, but according to the rules and controls in the National Building, 10th issue, 5th edition. The proposed braces are not considered BRB.