Abstract：
Combined with the engineering project of Tianyang North Garden sales center in Beijing, by building PMSAP model and comparing results of the performance index of the whole structure and the internal forces of components, this paper analyses that the sloping roof defined as "elastic plate 6" can share with beams and columns, and lead to a corresponding decrease in internal forces of beams and columns, because of considering in and out of plane stiffness at the same time. To increase the safety of beam reinforcement in the project, can only consider stiffness out of plane, which is defined as "elastic mode". This paper further disserts the effect of changing slope to internal force of sloping roof structure. In sloping roof structures, the axial pressure of horizontal side beams decreases with increasing slope, while shear force and moment increases with it; axial pressure of oblique beams increases with increasing slope, while shear force of beams’ end decreases with it; axial force of the middle column decreases with increasing slope, while corner column increases with it, that means increasing the slope of the structure can reduce the difference between middle column and corner column.
