Indeterminate Frame

Publisher Summary A frame is made of straight or linear members. An indeterminate frame is obtained by adding extra restraints at the supports of a determinate frame, or by increasing the number of frame members. This chapter introduces flame analysis by IFM and the stiffness method. The treatment includes mechanical load, thermal load, and support settling. A frame member carries three internal forces: an axial force (F), a shear force (V), and a bending moment (M); and a node of a flame has three displacements: a translation, a transverse displacement, and a rotation. A flame member can be formulated by combining the action of the bar and the beam members. The analysis of frame structures is considerably more difficult than that of beam or truss. The complexity is greater because more algebraic equations are required even though the same four types of equations are used—the equilibrium equation, compatibility condition, deformation displacement relation, and force deformation relations. Further, this chapter illustrates the analysis for support settling for IFM and the stiffness method by considering the portal frame as an example. In IFM, support settling is handled by calculating an initial deformation vector and then the deformation vector.