Analysis of a rigid space frame by leading matrix method

Although the finite element method has become a predominant structural analysis and design tool, in another way of the structural analysis method this research tried to analyse the rigid space frame by the modified moment distribution method. The moment distribution method is a numerical solution technique employed to obtain solutions for certain classes of rigid frames and continuous beams. This method has been used widely because of its simplicity in calculation. But this method is limited by the infinite cyclic distribution of the unbalanced joint actions, complication in handling side sways and some difficulties in some rigid space frame analysis. A new method by adapting geometric series and leading matrix is applied to solve a rigid space frame. This proposed method divides the structure into two parts, the main and connecting frame. The main frame is useful for making the leading matrix that consists of the coefficients of influence of unit load acting on any joint to other joints. The connecting frame distributes the unbalanced node actions between two nodes on the main frame at a time by the geometric series An application of this new method is illustrated with a rigid space frame. The results obtained by this method have been compared with the results from a FEM software and a good agreement has been found.