Abstract
This paper is concerned with the approximate analysis of simple rigid space frames. A space frame may be projected on a plane with the equivalent stiffness which is derived from the generalized slope deflection equations provided that the deformation of a frame due to load exists mostly about a certain axis. Analizing the projected plane frame with the ordinary method, the moment distribution is expressed with the components about the axis which is normal to the projected plane. The final distribution of stresses can be obtained with respects to the equilibrium condition of the original frame and the direction and stiffness of the members. The results are fairly correspond to the exact solutions which are obtained from the generalized slope deflection equation method. If the behaviour or deformations on a structucture can be appreciably considered with respects to the stiffness of members, the procedure of this analysis is applicable to the more intricate structures.
