This paper investigates the effect of bending torsion which is the cross-sectional warping of thin-walled rods at plane frame joints in the framework of the “semi-shear” theory of V.I. Slivker. Studied are the shell finite element models of rigid and “warping hinge” joints in thin-walled bar structures, designed and calculated in the software package Ansys Workbench. The correlation of the geometric characteristics of thin-walled profiles and the connecting plate is considered towards the change in the value of normal stresses and bimoments when the cross-sectional axis is rotated. The obtained ratios of the bimoment stresses before and after the rotation of the cross-sectional axis of the joints are presented. The study concentrates the distribution of the bimoments and warpings in the plane frame with rigid joints with and without the consideration of the coefficient of the cross-sectional axis rotation. The comparison of the obtained results for both cases is shown.