Large Capacity Multistory Frame Analysis Programs

In order to analyze large multistory building frames efficiently by digital computer, it is necessary to use special computation techniques that take advantage of the sparse nature of their stiffness matrices. Two different methods are described and compared in this paper. Both solution techniques are based on the displacement method of structural analysis. The first employs a special form of Gauss-Seidel iteration of the equilibrium equations. The second arranges the stiffness matrix in the form of a tri-diagonal system of submatrices, and then obtains the solution by using a recursion equation. Comparisons of the two methods, based on the computer time required, indicate that either may be preferred in appropriate conditions. In general, the iterative solution is faster if only a single loading condition is to be considered, and if the structure has a relatively large number of bays. The recursion solution is faster if the structure is tall and slender, and if many loading conditions are involved.