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ECU CMGT 2210 - Lecture 11- Metal

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Slide 1Slide 2HistorySlide 4HistoryHistorySlide 7Slide 8Structure and CompositionSlide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Slide 59Reinforcing SteelFerrous Metal PipeUnit 11: MetalKamalesh Panthi, Ph.D.Department of Construction ManagementEast Carolina UniversityCMGT 2210 - Construction & Civil Materials1In this Unit…Introduction Structure and Composition- different typesSteel Erection SequenceStructural Steel- Different ShapesConnectionsSteel Protection2History1750 +•Growth in use of cast iron for framing in industrial buildings and other structures•Coalbrookdale Bridge, 1779 (top right)•First all-metal structure•Cast iron•Right: Crystal Palace, 1851 (bottom right)•cast iron and glass•Eiffel Tower, 1889•wrought iron34History51850 +•Steel becomes increasingly plentiful with the development of large scale steel making methods such as the Bessemer process.•After the U.S. Civil War, excess steel making capacity sets the stage for the first use of steel in buildings.• Home Insurance Company Building, 1885, (right)–First tall building supported entirely by a fire-protected metal frame (cast iron and steel)History6Modern•Steel is one of three commonly used noncombustible structural materials. (Concrete and masonry are the others.)•Suitable for construction of buildings of all sizes, from single family residences to the tallest skyscrapers.•Commercial steel - 36 ksi to over 270 ksi (kips per square inch).•Steel is sold in hundred pound units (cwt), and priced including labor (for example, $ 120 cwt).Advantages- Light in proportion to its strength;- Strong and stiff;- Quick to erect;- Precise and predictable material;- Recyclable.Disadvantages- Corrodes, and- Weakens quickly under hightemperatures with a quick drop ofstrength and large deformations.7Iron and Steel Production8Making Cast Iron•Iron ore, oxides of iron extracted from the ground, is combined with coke (carbon derived from coal) and limestone in a large blast furnace.•Hot air forced through the furnace burns the coke. Chemical reactions with the combustion products remove oxygen from the ore, leaving elemental iron, but with a relatively high carbon content.•The limestone combines with impurities and is drawn off as waste slag.Structure and Composition9•Cast iron•Typically 2% – 4% carbon•Strong in compression, but less so in tension•Brittle (prone to sudden failure)•Wrought iron•Little or no carbon•Strong in tension, but weaker in compression•Malleable (easily shaped) and relatively soft •Steel•Less than 2% carbon•Strong in both tension and compression•Ductile (not prone to sudden failure)10Mild steel (low carbon steel)•The commonly used alloy for structural steel members•Not more than 0.3% carbon•Small amounts of other alloys, such as nickel, chromium, molybdenum, manganese, vanadium, and silicon improve strength, toughness, and other qualities•Reasonably strong, highly ductile, and easily welded•Equally strong in tension and compressionMild Steel111213The Fabricator•The steel fabricator is responsible for providing each needed piece of structural steel to the construction site. •Traditionally, the fabricator prepares shop drawings showing the dimensions of each piece of steel required for the job.The Construction Process14•The shop drawings are reviewed by the architect and structural engineer before the fabricator begins work.•The fabricator frequently is also responsible for determining the details of the steel connections themselves, based on more general connection load requirements provided by the structural engineer. The Construction Process15The Fabricator•More recently, with building information modeling (BIM) systems, steel fabrication information and details may be developed by the structural engineer in the building model as an alternative to relying on fabricator shop drawings.The Construction Process16The Fabricator•Fabricated steel members are stacked in the fabricator's yard using an overhead crane, awaiting transportation to the construction site.•Note the identifying labels on each piece of steel.The Construction Process17The Fabricator•Steel members are individually labeled to correspond to information on the erection drawings so that each piece can be assembled in the proper location once delivered to the construction site.The Construction Process18The Erector•The erector is responsible for erection of steel once delivered to the construction site. •The erector may or may not be the same entity as the fabricator.•The erector's workers are called ironworkers.The Construction Process19The Erector•As the frame is erected, temporary cables with turnbuckles are used to plumb up (make vertical) the frame.The Construction Process1 ) Erect the first level columns (positioned, elevation checked and plumbed);2) Install the girders and then the beams;3) Check the entire level for plumbness;4) Weld or tighten all connections, including diagonal bracings;5) Grout the column base plates;6) Install the edge angles and the decking;7) Start next level.Steel Erection Sequence.20212223Install the girder and the beams2425262728Production of Structural Shapes29•Structural shapes are produced in a rolling mill. Prior to rolling, the beam blanks are reheated to the necessary temperature.•Blanks then pass through a series of rollers in which they are progressively deformed into the desired final shape.30•Wide-Flange (W-Shape) : The most commonly used shape for beams and columns; Not an "I-beam"!•Channels, angles, tees: For trusses, lighter weight framing, and other miscellaneous uses•American Standard: Traditional I-beam with a shape that is less structurally efficient than a contemporary wide-flange of the same weightProduction of Structural Shapes31•Example designation: W10 x 30•W: Wide-flange shape•10: Nominally 10 inches deep•30: 30 pounds per lineal footThe unshaded portions of the diagrams illustrate how a variety of weights of beams can be rolled from the same set of rollers by opening up the space between the rollers.Wide-Flange


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