A pillar supports axial force; it generally supports axial compression but sometimes supports axial tension. For axial tension, pillars are very effective. For example, 40 cm2 sectional area of mild steel can support 1000 kN force (σ=250 MPa). Considering that the pillar sometimes supports tension, attention should be paid to the connection at both ends of the pillar. For axial compression, buckling phenomena are important. A slender pillar can buckle at a relatively low compressive stress. As the buckling happens in the weakest direction of the pillar, the section of the pillar should be designed so as to have homogeneous strength in all directions. From this view point square or circular pillars (solid or hollow) are desirable. The end connections of pillars have a significant effect on buckling strength. Brackets are fitted usually at the end connection of a built-up pillar but rarely for a circular pillar. The cross tie in a wing tank of a tanker is this kind of the pillar. Section of the cross ties are also studied in this chapter.