CHAPTER 3 STRUCTURAL STEEL TERMS/LAYOUT AND FABRICATION OF STEEL AND PIPE

Structural steel is one of the basic materials used in the construction of frames for most industrial buildings, bridges, and advanced base structures. Therefore, you, as a Seabee Steelworker, must have a thorough knowledge of various steel structural members. Additionally, it is necessary before any structural steel is fabricated or erected, a plan of action and sequence of events be set up. The plans, sequences, and required materials are predetermined by the engineering section of a unit and are then drawn up as a set of blueprints. This chapter describes the terminology applied to structural steel members, the use of these members, the methods by which they are connected, and the basic sequence of events which occurs during erection.

STRUCTURAL STEEL MEMBERS

Your work will require the use of various structural members made up of standard structural shapes manufactured in a wide variety of shapes of cross sections and sizes. Figure 3-1 shows many of these various shapes. The three most common types of structural members are the W-shape (wide flange), the S-shape (American Standard I-beam), and the C-shape (American Standard channel). These three types are identified by the nominal depth, in inches, along the web and the weight per foot of length, in pounds. As an example, a W 12 x 27 indicates a W-shape (wide flange) with a web 12 inches deep and a weight of 27 pounds per linear foot. Figure 3-2 shows the cross-sectional views of the W-, S-, and C-shapes. The difference between the W-shape and

Figure 3-1. - Structural shapes and designations.