information regarding the PEB, you should refer to thecurrent Steelworker TRAMAN.STRUCTURAL STEEL CONNECTORSThere are four basic connectors used in makingstructural steel connections. They are bolts, welds, pins,and rivets. Bolts and welds are the most commonconnectors used in military construction. Pins are usedfor connections at the ends of bracing rods and varioussupport members that require freedom of rotation.Commercial prefabricated steel assemblies may bereceived in the field with riveted conectors. Types anduses of the four basic connectors are discussed in thefollowing text.BoltsBolts are used more than any other type ofconnectors. They are easy to use and, in contrast to allother types of connectors, require little specialequipment. The development of higher strength steelsand improved manufacturing processes have resulted inthe production of bolts that will produce strongstructural steel connections.Specifications for most bolted structural joints callfor the use of high-strength steel bolts tightened to a hightension. The bolts are used in holes slightly larger thanthe nominal bolt size. Joints that are required to resistshear between connected parts are designated as eitherfriction-type or bearing-type connectors.Bolted parts should fit solidly together when theyare assembled and should NOT be separated by gasketsor any other type of compressible material. Holes shouldbe a nominal diameter, not more that 1/16 inch in excessof the nominal bolt diameter. When the bolted parts areassembled, all joint surfaces should be free of scale,burrs, dirt, and other foreign material. Contact surfaceswith friction-type joints must be free of oil, paint, orother coatings.WeldsWelding is a highly specialized skill, and weldingof load-bearing parts of a structure should be performedonly by properly qualified personnel. As an EA, you willnot be expected to perform welding operations.However, you should have a general knowledge of theprincipal welding processes and the different types ofwelds and their applications, and you should know howwelding symbols are used to identify weldedconnections shown in working drawings.The two principal welding processes used instructural work are electric arc welding and oxy-MAPPgas welding. In the electric arc welding process, weldingheat, sufficient to fuse the metal together, is developedby an electric arc formed between a suitable electrode(welding rod) and the base metal (the metal of the partsbeing welded). In the oxy-MAPP gas welding process,heat is obtained by burning a mixture of MAPP gas andoxygen as it is discharged from a torch designed for thispurpose. While electric arc welding is normally used formetals that are 1/8 inch or larger in thickness,oxy-MAPP gas welding is usually restricted to thinnermetals.The principal types of welds and welded joints thatare suitable for structural work are shown in figures 1-48and 1-49.On drawings, special symbols are used to show thekinds of welds to be used for welded connections. Thesesymbols have been standardized by the AmericanWelding Society (AWS). You should become familiarwith the basic welding symbols and with the standardlocation of all elements of a welding symbol.The distinction between a weld symbol and awelding symbol should be noted. A weld symbol is abasic symbol used to indicate the type of weld. Basicweld symbols are shown at the top of figure 1-50. Thesupplementary symbols shown in the figure are usedwhen necessary in connection with the basic weldsymbols.A welding symbol consists of the following eightelements, or as many of these elements as are required:(1) reference line, (2) arrow, (3) basic weld symbol,(4) dimensions and other data, (5) supplementarysymbols, (6) finish symbols, (7) tail, and (8) specifica-tion, process, or other reference. These elements of thewelding symbol have specific standard locations withrespect to each other, as shown in figure 1-50. When afinish symbol is used in a welding symbol, it indicatesthe method of finish, not the degree of finish. Forexample, a C is used to indicate finish by chipping, anM indicates machining, and a G indicates grinding.1-24
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