Steel Frame Construction Advantages and Disadvantages History of

History of Iron and Steel Making n n Prior to the mid 19 th

Iron and Steel Making n n n A refining process 1 st , iron

Foundry Production n n (small percent) Adding scrape metal reduces carbon content White cast

Steel Making n n n (a further refinement) Steel making process (lower the carbon

Mild Structural Steel n n ASTM A 36 (predominant for decades) ASTM A 572

High Alloy-Stainless Steel n n n 18/8 Stainless 18% chrome 8% nickel

Steel Finishes n n n Texture Galvanizing (zinc) Aluminizing Cladding Vitreous Coatings (porcelain enamels)

Open-Web Steel Joist n n K Series (span to 60 feet, depths 8 to

Joining Steel Members n n n Rivets Bolts Welds

Joining with Bolts n n n n Carbon steel bolts (ASTM A 307) High-strength

Joining with Welds n n n Types of welds The size of welds Welding

Steel Connections n n n Gusset plates and angles in use with rivets, bolts

Stabilizing the Frame n Diagonal Bracing n Eccentric Bracing n Moment Connections n Shear

Steel Construction Process n Fabricators

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Steel Frame Construction Advantages and Disadvantages

History of Iron and Steel Making n n Prior to the mid 19 th century steel a very rare and valuable commodity Development of the Bessemer Process Discovery of iron ore Today, more than 20% of all steel production is used in building construction

Iron and Steel Making n n n A refining process 1 st , iron extracted from iron ore 2 nd , carbon rich iron production 3 rd , reduce carbon content in steelmaking Add alloying elements

Foundry Production n n (small percent) Adding scrape metal reduces carbon content White cast iron Gray cast iron (graphite flakes) Malleable cast iron (annealing) Ornamental wrought iron (97% pure)

Steel Making n n n (a further refinement) Steel making process (lower the carbon content) Control impurities (residual elements) Add allowing elements Electric furnaces Open hearth furnaces Basic oxygen furnaces

Mild Structural Steel n n ASTM A 36 (predominant for decades) ASTM A 572 and A 992 (less expensive and stronger)

High Strength Low Alloy Steels

High Alloy-Stainless Steel n n n 18/8 Stainless 18% chrome 8% nickel

Steel Finishes n n n Texture Galvanizing (zinc) Aluminizing Cladding Vitreous Coatings (porcelain enamels)

Structural Steel Shapes

Open-Web Steel Joist n n K Series (span to 60 feet, depths 8 to 30 inches) LH Series (span to 96 feet, depths 18 to 48 inches) DLH Series (span 144 feet, depths 52 to 72 inches) Joist Girders

Joining Steel Members n n n Rivets Bolts Welds

Joining with Rivets

Joining with Bolts n n n n Carbon steel bolts (ASTM A 307) High-strength bolts (ASTM A 325 & A 490) Bearing connections Friction or slip-critical connections Impact wrenches Turn of the nut method Load indicator washer (visual inspection Tension control bolts