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Three stiffness reduction functions are used. The formation of plastic hinge is considered in limit load. These functions cause the yielded cross section to be subtracted from the member stiffness. In the limit load, in which plastic hinges may fom1 at both ends of a beam-column element, the entries of stiffness matrix reduce to zero. To consider the secondary effects, like P-8 and P-i1, exact stabi.1ity functions are used. A computer program is prepared for structure analysis. An automatic incremental-iterative procedure and Newton-Raphson iterations are used for
nonlinear analysis. Also, redistribution of
the forces in structure is predicted by computer program. The numerical results are compared with plastic-zone methods and actual structural loading tests. This comparison proved that proposed functions are better than similar methods.