Nonlinear Analysis of Towers and Stacks

Beam-column finite elements in conjunction with transfer matrices and an incremental loading procedure are used to directly generate the total moments, and axial and transverse displacements of a stack or tower structure having a stepped or tapered cross section. The structure may be subjected to any number of concentrated shears, axial forces, and moments, as well as any number of piece-wise constant distributed transverse and longitudinal forces. By additional use of a standard Southwell plot, the transverse deflections generated by compressive axial loads may be plotted to yield the critical buckling load. Solution of the internal forces and deflections proceeds serially from the free end of the stack or tower structure, without the necessity of computing global elastic and geometric stiffness matrices. Computer storage therefore varies linearly rather than to the square of the number of finite elements used to model the stack or tower configuration.