A truss is a structure composed of straight, slender members connected at their ends by frictionless pins or hinges. A truss can be categorized as simple, compound, or complex. A simple truss is one constructed by first arranging three slender members to form a base triangular cell. Additional joints can be formed in the truss by subsequently adding two members at a time to the base cell, as shown in Figure 5.1a. A compound truss consists of two or more simple trusses joined together, as shown in Figure 5.1b. A complex truss is neither simple nor compound, as shown in Figure 5.1c; its analysis is more rigorous than those of the previously stated trusses.