If a 1-D structural member is symmetrical about its axis and the loading is also symmetric, then it can be idealized as a 1-D column, simulated by an equivalent line. If such a symmetrical structure is subjected to a lateral load, it can also be idealized by using an equivalent 1-D line (Figure 2.1). For axial and lateral loads, the beamcolumn idealization is shown in Figure 2.1b. It should be noted that such a beamcolumn idealization represents a linear superposition of effects of the column and the beam, and it does not take into account nonlinearity, which may lead to effects such as buckling.