The analysis of the thin-walled structural problem is still a topic of interest and research by many scientists with many different solutions and theories. This paper presents the occurrence of stress components on the thin-walled bars with open sections. Vlasov's theory has been applied to analyze the stress state on thin rods. At the same time, using the Midas civil structure calculation program based on finite element principle for structural analysis with taking into account sectional warping. From the results obtained by the finite element method, it is necessary to select and design carefully for thin-walled bars.