0428

quantities may be usable for an hour or more, while larger quantities may only last for half an hour. Adhesive Joints Joints between two structural members may be designed to carry loads by stressing the joint in pure compression or tension, in compressive or tensile shear, in peel, or in some combination thereof. In pure compression or tension the joint is subjected to stresses only at right angles to the plane of the joint. Adhesive joints are strongest under these circumstances. In compressive or tensile shear the joint is subjected to stresses in a direction that is parallel to the plane of the joint. Adhesive joints are not as strong under these shear stresses, but they are quite adequate for most structural requirements. In peel, the joint is subjected to stresses at some angle that is intermediate between the two other cases, which results in a prying or peeling effect at one edge of the joint. Adhesive joints are weakest in peel and this type of stress should be avoided wherever possible. If peel stresses cannot be avoided, the adhesive joint must be supplemented with a mechanical fastener or should be taped. FRP tape or strips of FRP mat, together with polyester or epoxy resin, can improve the strength of the joint connection. The following steps should be taken to apply adhesives to joints: 1. Before bonding or gluing the polyester-fiberglass shapes, prepare the surface to ensure proper adhesion. Thoroughly clean the surface by wiping it with a clean cloth dampened with a solvent such as acetone, toluol, or Note: Read all SDS information and take appropriate precautions when working with adhesives or cleaning solutions. methyl alcohol. Do not, however, immerse or soak composite shapes in these solvents. When the surface has been cleaned, wipe it dry with a clean cloth. 2. Remove the surface veil left during manufacture by sanding both mating surfaces using 80-grit sandpaper (Figure 19.37). Sanding is adequate when the surfacing Figure 19.37 Sanding Composite Surface Unit 19 — Composites and Structural Erection 19.15 UNIT 19

veil has been removed. On large surfaces, power sanding can be used. 3. Remove any dust remaining on the surface to be bonded by wiping it with a clean, dry rag or brush (Figure 19.38). Figure 19.38 Removing Surface Dust Note: After sanding, do not wipe the surface with a rag dampened with solvent. Avoid recontamination of the surface by handling. If a surface becomes recontaminated, repeat steps 1 through 3 (including a light sanding to remove any film). 19.16 Structural Steel Erection 4. Mix adhesives (Figure 19.39) according to manufacturer recommendations. 5. Spread a thin film of adhesive on both surfaces that are to be joined, making sure to cover any glass fibers that have been exposed (Figure 19.40). 6. Use weights or clamps to appro- priately secure the assembly while the adhesive cures (Figure 19.41). Figure 19.39 Mixing Adhesives Figure 19.40 Spreading Adhesive Figure 19.41 Clamping Materials for Adhesive Curing UNIT 19

Joints bonded with epoxy adhesives generally can be handled with reasonable care after eight hours; however, it is desirable to leave the clamps in place (or maintain the bonding pressure on the joints) for 20–24 hours. If an oven is available, curing time can be lessened considerably by heating the assembly moderately (200°F for 11⁄2 hours). If heat curing is used, allow the assem- bly to cool to ambient temperature before unclamping. The structure should not be expected to carry its design load until the adhesive joints have cured a minimum of 48 hours at 70°F. Lower temperatures will require longer cure time. Caution! Do not permit the joints to move during the curing process. Always clean adhesive from tools before it hardens. Solvents such as acetate, acetone, or methyl ethyl ketone (MEK) are suitable (gasoline is not effective). Be certain to take appropriate precautions when using flammable solvents. Self-tapping screws, bolts, or rivets can also be used to hold freshly bonded joints in place. There are several advantages to using mechanical fasteners in this way: when they are used, there is no need to wait for the adhesive to cure, there is increased stress reliability at the joint, and correct alignment of parts can be maintained. Painting and Finishing Catalyzed resins, acrylic lacquers, and polyester, epoxy, polyurethane, or oil-based paints can all be used as sealants. All of these products will effectively seal a composite surface, but some resins provide better cor- rosion resistance. The composite manufacturer will specify the type of resin or paint to be used. Figure 19.42 shows an example of catalyzed resin being applied to a surface. Figure 19.42 Resin Application Warning! Always follow manufacturer’s instructions when using these products: during cure, they may generate toxic and harmful vapors. Unit 19 — Composites and Structural Erection 19.17 UNIT 19

▶▶OBJECTIVE 4: PROCEDURES FOR REPAIRING COMPOSITES Typical composite repair procedures Ironworkers may be asked to undertake include cleaning, resin sealing, splicing, resin filling, repairing burn damage, glass lay-up for small cracks, and hole filling. Cleaning Routine cleaning is recommended as a preventative maintenance measure; how- ever, prior to any repairs, it is necessary to remove foreign material which may contribute to poor adhesion in the repair and/or cause electrical problems. One method of cleaning composites is by wiping them with a solvent. This method is popular because it does not rely on the accessibility of a steam line (which is required for steam cleaning composite shapes). For many shapes already in service this is the only practical technique. To clean a shape with a solvent, simply wipe the shape with a non-abrasive cloth dampened in a solvent such as acetone. Note: Be aware that solvents evaporate quickly, so the cloth may require repeated soaking. Do not use gasoline or wipe surfaces to be adhesively bonded with a solvent, and do not immerse composite materials in solvents (pro- longed soaking may cause damage). Remember that solvents such as acetone are highly flammable and take appropriate precautions. Sometimes abrasive cloths may be required for a complete cleaning. If this is the case, surface repair of the composite piece may be required prior to returning it to service. Part of the cleaning procedure must be a thorough inspection of the shape. Ruptures to the surface can be caused by bolts, tools, or other items. Minor impacts normally have a minimal effect on the electrical and/or mechanical properties of the struc- tural shape, but they may cause cosmetic problems. If any questions regarding the performance (rather than only the appearance) of a composite material exist, contact the material manufacturer. 19.18 Structural Steel Erection UNIT 19

Resin Sealing Composite structural shapes are manu- factured with a resin-rich surface; this is accomplished by using a synthetic surfac- ing veil in most products, which improves both resistance to corrosion and resistance to ultraviolet light. This veil also prevents “fiber blooming,” the emergence of glass fibers on the surface of the part. Figure 19.43 shows a defect resulting in fiber blooming. If a composite surface has been drilled, cut, punched, sanded, or otherwise broken to expose the glass reinforcement, the surface must be resin-sealed to maintain optimum properties. To resin-seal a composite surface, follow these procedures: 1. Sand the damaged area as in Figure 19.44. Remove the dust and clean as required. Verify that the area to be repaired is free of moisture to ensure proper adhesion of the sealant. Allow to dry if cleaned with a solvent. 2. Use a manufacturer-recommended sealant to seal the surface. Figure 19.45 shows an example of resin being applied to a surface. 3. Cure the system and carefully remove excess sealant as in Figure 19.46. If possible, avoid sanding after curing has been done: sanding will reopen the sealed surface and require a repetition of the sealing procedure. Figure 19.43 Fiber Blooming Defect Figure 19.44 Sanding a Surface Defect Figure 19.45 Applying Resin Figure 19.46 Removing Excess Sealant Unit 19 — Composites and Structural Erection 19.19 UNIT 19

Splicing Most composites consist of layers of fiberglass. These layers have their strongest threads or strands running lengthwise through the material (the strands running in the transverse direction are approximately 1⁄4 of the strength of the lengthwise strands). As a policy, manufacturers do not ship fractured composite materials. However, during customer fabrication or in-plant operation these shapes, gen- erally referred to as profiles, may be damaged. The left flange in Figure 19.47 provides an example of such damage. Figure 19.47 Damaged Material When a profile is fractured, its function in the structural application must be care- fully reviewed from an engineering viewpoint. In general, if a profile has been struck by a blow severe enough to cause a fracture in excess of 4\", the best repair is to replace the entire section. If replacement is not feasible, then the damaged sec- tion must be repaired to maintain its structural integrity. Failing to do so may result in the fracture propagating down the entire length of the structure. To repair a fractured piece of material, follow the general splicing procedures given below. These procedures use a wide-flange beam as an example, but can be applied to other members (and to crosswise cracks) as well, although the splicing profile sections will vary: Choose the appropriate profile: care must be exercised in selecting profiles with sufficient physical properties for the application. In other words, make certain that the right shape is used for the job, and that it is strong enough to do the job. The splice will be made using angles on each side of the web/ flange interface (see 1 in Figure 19.48) and flat sheet on the back surface of the flange (see 2 in Figure 19.48). 1 19.20 Structural Steel Erection 2 Figure 19.48 Web/Flange Interface Cut the angles and plate to be used as a splice 6\" longer than the fracture. A good rule of thumb is to use the same thickness for the splicing profiles as was used for the damaged profile. Whenever possible, the same color should be used for the splicing profiles as was used for the damaged profile. UNIT 19

Trace the outline of the splicing profiles onto the damaged profiles and sand as shown in Figure 19.49. Since splicing uses an epoxy adhe- sive for the bond, tracing helps to avoid sand- ing where no bonding is to occur. Clamp all of the profiles into position as shown in Figure 19.50 and drill holes for the subse- quent insertion of bolts. Pre-drilling will ensure minimum movement of the profiles after the epoxy adhesive has been applied; movement of the epoxy joint can damage adhesive strength. Mix enough epoxy adhesive to cover all of the bonding surfaces. The epoxy repair kit typically requires that one part of hardener be added to one part of base until a uniform color appears. An example of this mixing is seen in Figure 19.51. Figure 19.49 Hand Sanding Figure 19.50 Clamping Materials for Splicing Spread the adhesive over the surfaces to be bonded as seen in Figure 19.52. This must include the splicing profiles in addition to the damaged section. Do not permit the profiles to stand after apply- ing the adhesive; proceed to the next step immediately, before the adhesive dries. Figure 19.51 Mixing Adhesive Figure 19.52 Spreading Adhesive After coating the surface with the adhesive, place the splicing profiles onto the damaged profile. Insert the bolts and tighten with a torque wrench as seen in Figure 19.53 (consult the manufacturer’s publications for the amount of torque that can be applied with the size of bolt used). The bolts will hold the splice together while the adhesive sets and serve as an additional bond. The mechanical clamp supplied by the bolts will also squeeze the epoxy into the damaged area. Figure 19.53 Tightening Bolts Unit 19 — Composites and Structural Erection 19.21 UNIT 19

Note: Always use the correct type of bolt when working with com- posite materials. Bolts used should be designed specifically for use with composites. The bolts should not be considered the primary bond. Remove excess adhesive from the repaired section before it cures. Wait 48 hours (or the time recommended by the manufacturer) for the adhesive to cure before using the damaged section that has been repaired. If needed to improve the repair’s appearance after the epoxy adhesive cures, chip away any of the epoxy that has squeezed from the joints (the repair will be functional whether or not the excess is chipped away). An example of epoxy squeeze out is shown in Figure 19.54. Resin Filling Resin filling is undertaken when a portion of the beam’s flange has received minor damage due to chipping. An example of this can be seen in Figure 19.55. In this situation, the repair is not severe enough to warrant splicing; however, some repair is required to prevent the absorption of contaminants (moisture, salt, chemicals, etc.). The following procedure to repair flanges through resin filling is less expensive than resin splicing and just as functional: Figure 19.54 Epoxy Squeeze Out Figure 19.55 Damaged Flange Figure 19.56 Sanding Damaged Area Note: If the adhesive is still soft after 24 hours at room temperature (70°F), the ratio mix of epoxy used may have been off. If it is still soft after 48 hours, a new repair may be required. 19.22 Structural Steel Erection 1. Sand the damaged area (Figure 19.56) to remove all loose material and to provide a good bonding surface. After sanding, clean and dry the damaged area. UNIT 19

2. Use a spatula or putty knife to fill the damaged area with either epoxy or catalyzed resin (see Figure 19.57), following all manufacturer instructions. If needed, add pigment to the epoxy or resin to match the color of the section being repaired. 3. Cover the repair with cellophane and press the flange and cellophane together, massaging the repaired area to remove entrapped air as seen in Figure 19.58. 4. Tape the cellophane securely into position to protect the repair while the resin cures (see Figure 19.59). Allow 24 hours for proper curing (or the time specified by the resin manufacturer). 5. After 24 hours (or the time specified by the resin manufacturer) has passed, remove the tape and cellophane and carefully sand the repaired area as seen in Figure 19.60. 6. Complete the repair by employing the resin sealing repair procedure. Figure 19.60 Sanding of the Repair Area Unit 19 — Composites and Structural Erection Figure 19.57 Fill the Damaged Area Note: If the resin/catalyst combination begins to smoke, the ratio of catalyst to resin is too high. Make a new mix of resin using less catalyst. Figure 19.58 Covering the Repair Area Figure 19.59 Tape the Repair Area 19.23 UNIT 19

Repairing Burn Damage Occasionally, composite shapes may be exposed to sparks or flames from cutting and/or welding. The resultant damage may range from cosmetic to structural. The extent of the damage can only be ascertained after removal of the charred area using sanding techniques. If parts of the shape are not discolored, they can be assumed to be undamaged. After the charred area has been removed through sanding, the size of the damaged area will dictate the nature of the repair. An engineering decision must be made as to what repair procedure should be used. At a minimum, the surface should be resealed; if the charred area is large and deep, the part should be replaced. Glass Lay-Up This technique is used for small fractures on a composite member when structural integrity is not threatened. It is similar to some procedures used in automotive body repair. Caution! Smoke released through burning, or from a charred area, may be hazardous if inhaled. The area around the charred part should be ventilated before any repair is made. 1. 2. 3. 4. 5. Sand the damaged area, tapering off as you move away from that area (taper both sides of the damaged area approximately 2\" to 3\" above and below the crack and 2\" to 3\" on either side of the crack). Remove all dust and clean the area to be repaired. Cut a piece of glass mat (the FRP material comes in a mat shape) to cover within 1⁄2\" at the edges of the sanded area. Cut a piece of 10 mil veil (in other words, a very thin amount) to cover all of the sanded area (multiple pieces may be used, as long as they are overlapped). Weigh the glass veil and mat to determine the amount of resin needed. Take an amount of resin 4 times that weight and add 1%–5% of the catalyst (based on manufacturer recommendations; start with 1%) to create a mixture. Stir thoroughly. Note: The time it will take for this mixture to harden depends on the amount of catalyst used and the environmental temperature. Always check and follow the manufacturer’s directions. Do not attempt to use catalyzed resin after it begins to gel. 19.24 Structural Steel Erection UNIT 19

6. Paint the sanded area with the resin/catalyst mixture. 7. Apply glass material (the mat) and thoroughly wet it with the resin/ catalyst mixture. 8. Add layers of glass and resin to obtain the desired repair thickness, being certain to press each layer as it is added to remove air. 9. Add the layer of veil and coat with the resin mixture. 10. Cover with cellophane until the repair is cured. 11. Sand to a smooth finish and coat with the resin mixture for corrosion protection. Hole Filling A relatively common problem in structural fabrication is hole mislocation. This can occur because of shop error, a drawing error, or a design change after the hole or holes have already been drilled. How a mislocated hole is filled depends on a number of factors including how the load on the structure will be applied, how important appearance is, and the proximity of other holes. One way to fill a hole is through bolting. To fill a hole this way, follow these steps: 1. Drill the mislocated hole to the nearest tap size. 2. Tap the hole to the smallest bolt size you have on hand. 3. Apply epoxy adhesive to both the bolt threads and the hole edges. 4. Screw the bolt into the hole. 5. Cut the bolt with a saw as close to the material being penetrated as possible. 6. Grind flush. 7. Reseal area with resin after epoxy has cured. Note: Always use a bolt designed specifically for use with composite materials. Unit 19 — Composites and Structural Erection 19.25 UNIT 19

19.26 Structural Steel Erection UNIT 19

▶▶GLOSSARY Abutment: Part of a bridge structure that supports the end of a span or accepts the thrust of an arch. An abutment often supports and retains the approach embankment. Adjustable locking pliers: Set of pliers that have straight or curved jaws that can be adjusted to clamp an object. Adjustable wrench: Wrench that has an adjustable lower jaw and is used to tighten or loosen hex-headed fasteners. Aerial lift: A type of elevated working platform. Alternating current (AC): Electrical current that cyclically varies in its magnitude and direction. American Institute of Steel Construction, Inc. (AISC): Non-profit institute and trade association that promotes steel use and serves the structural steel design community and construction industry. American standard beam: (Also called an I-beam.) Structural steel member that resembles the capital letter “I” in shape and is easily identified by the sharp slope on the inside face of the flange (162/3% slope). American standard channel: C-shaped structural steel member used in the fabrication of girts, purlins, and hangers, or as a substitute for light beams. All standard channels have a slope on the inside face of the flange. Amusement Industry Manufacturers and Suppliers (AIMS Int.): An association with the purpose of establishing communication and fostering professional working relationships with other amusement industry trade associations and with local, state, provincial, and federal government entities to promote and preserve the prosperity of the amusement industry. Most manufacturers of amusement park rides are members of AIMS International. Amusement park: Generic term for a collection of rides and other entertainment attractions assembled for the purpose of entertaining a large group of people. Anchor arm: Counterbalancing cantilever arm attached to a solid foundation. Anchor bolt: Bolt used to help position (and hold in place) the bottom steel columns of a structure with absolute accuracy. Glossary G.1 GloSSary

Angle: Structural steel shape that consists of two legs (of equal or unequal widths) set at right angles to each other. Antenna: Piece of equipment or device used to transmit and/or receive signals. Antenna array: A cluster of antennas. Approach: The portion of highway immediately adjacent to a bridge that affects the geometrics of the bridge (e.g., line, grade, width, and location). The approach includes the horizontal and vertical curves and grades that connect the highway alignment to the bridge alignment. Arch: A curved structure that supports a vertical load mainly by axial compression. Arch bridge: Bridge made with an arch. Architectural drawings: (Also called architectural blueprints.) Blueprints that depict the overall size and external appearance of a structure as well as the arrangement of the structure’s internal space. ASTM International: Originally known as the American Society for Testing and Materials, ASTM International is an international standards organization that develops and publishes technical standards for a wide range of materials, products, services, and systems. ASTM standards are determined as a result of the consensus of a large cohort of voluntary technical committees throughout the world. Atrium: An open area within a building that has no overhead structural members except a roof. Atriums are usually lighted by means of a skylight and often contain plants. Bar joist: A type of open web steel joist made of round bars, square bars, and/or other structural shapes. A bar joist is similar to a small truss made out of steel bars welded together. Bar steel: Structural steel shape that is like plate steel, but is usually 8\" or less in width. It can be round, square, hex, flat, or other shapes. Barrel-type drift pins: Type of pin with tapered ends used to align two or more plies of steel. Barreled: Tapered at the top and bottom. Base plate: A plate attached to the bottom of a column (usually in the fabrication shop) that sits on shims or leveling nuts at a pier, footing, or finished floor. Baylines: The column lines that make up the grid system in architectural drawings. Baylines are numbered 1, 2, 3, etc., in one direction, and A, B, C, etc. in the direction perpendicular to the numbered baylines. G.2 Structural Steel Erection GloSSary

Beam: Any horizontal member except a truss. Beams transfer the load of floors to columns and, at the same time, connect columns together to form a rigid frame. Beam bridge: Bridge that consists of a horizontal beam supported at each end by piers. Bearing: A device at the end of a beam that is placed on top of a pier or abutment. The ends of the beam rest on the bearing. Bearing-type connection: A connection where one member bears on top of another. Beater: (Also known as a sledgehammer.) Tool used to drive pins, align holes, move iron to its exact intended location, and for numerous other applications. Bent: A rigid frame commonly made of reinforced concrete or steel. Bents are used to support vertical loads and are placed transverse to the length of a structure. Bevel washer: Type of washer that provides a “square” seat for a bolt head or nut when a bolt passes through a beam or channel flange that has a sloping inner face. Bill of Material: (Also called a bill of lading.) A document issued by a carrier or shipper listing materials contained on a specific load. A bill of material also serves as a receipt of goods shipped. Biomass: A fuel source comprised of plants and animal waste. Birdseye level: Type of spirit level vial that is circular from an overhead view and that levels in all planes simultaneously. Block: A sheave enclosed with side plates through which a rope (wire or soft) is run to gain a mechanical advantage or to change the direction of pull. Bolt: Manufactured metal fastener with a round, rod-like body with a head on one end and threads to receive a nut on the other end. Bolt bag: A canvas or leather bag used to carry bolts, pins, and a small hammer. Bolt list: A list provided by the detailer to the fabricator that is then forwarded on to the steel erection contractor. This list identifies the entire quantity of bolts to be used for a job, and can be broken down in many different ways: by phase or sequence, tier, floor, area, etc. If broken down by connection, this list is called a point-to-point or connection bolt list. Bolting: (Also called “Bolting up.”) The primary means of connecting steel structures, which includes all of the activities surrounding the receiving of the bolts, nuts, and washers on the job site, as well as storing them, retrieving them for installation, and installing them in the iron. Bolting gang: The crew that conducts bolting up. Glossary G.3 GloSSary

Bottom chord shoe: Structural member that attaches the lower chord of a truss to a seat connection. Bracing: Pieces used to give rigidity or steadiness to a structure and to help hold parts in place. Bracing comes in three main types: adjustable, fixed, and temporary. Bridge: Structure that spans an obstacle to carry a pathway or roadway. Bridge deck: The top surface of a bridge that carries vehicle and/or pedestrian traffic. Bridge length: The length of a bridge measured between abutments. Buckling: State that occurs when the force of compression overcomes a member’s ability to handle it. Builders’ level: An instrument used to establish elevations and transfer straight lines. Builders’ levels are also useful in establishing the top of steel and finished floor elevations. Bull pin: Type of pin used to align two or more plies of steel. Bull pin holder: Leather tunnel loop that attaches to a belt and holds a driving pin. Bull tail: A piece, or several pieces that make up a collective piece, of rigging hardware that can be used in multiple-lift rigging procedures. Bullwheel: A large wheel on which a rope turns, as in a ski lift. Bundle tag: A tag attached to a deck bundle that indicates the bundle’s gauge, length, width, number of pieces, finish, and profile. The bundle tag determines where the bundle is located on the structural steel and shows the job area (usually one or two bays) where the bundle belongs. Burr: An imperfection in a surface or coating that can cause a snagging, cutting, or scrape hazard. Bus bar: A flat bar, usually copper, that is used to attach ground system end termination. Butt joint: The point at which the end of one decking sheet meets another and neither sheet laps over the other. Butt joints must occur over a supporting member (e.g., beam or bar joist). Button punching: The action of crimping the side laps of metal decking (usually on composite floor deck). A button punch is a tool an Ironworker uses to crimp the side laps of metal decking. Cable-stayed bridge: Type of bridge in which the cables that suspend the bridge deck are attached to towers so that the towers bear the load. G.4 Structural Steel Erection GloSSary

Calibrator: Tool or device that takes actual measurements of the tension in a fastener. Camber: To arch or bend upwards in the middle. Cantilever: Member supported at one end or in the middle (not at both ends). Cantilever bridge: Type of bridge that consists of one or more cantilever spans. Cantilever span: Bridge or bridge segment with a span supported not at the ends but toward the center of the bridge truss. Casing: Steel sleeve used to withstand the force of earth when drilling and setting caissons. Cast iron: An alloy of iron, carbon, and other elements. Depending on the mixture and methods of molding, this alloy can be soft, strong, hard, or brittle. Catch can: An inverted cone-shaped device with a handle used to catch hot rivets. Cellular deck: Composite or roof decking that has an additional flat bottom plate. The high areas of this deck type act as a chase to accommodate cables and electrical wiring. Centripetal force: Force that acts upon a body moving along a curved path. Centripetal force is directed toward the center of the curvature of the path and forces the body to remain on the path. Chamfered: Having a groove cut in. Channel: See American standard channel. Chase: Compartment with space for electrical and other cables. Chock block: Blocking used to prevent vehicles or equipment from accidentally rolling or moving. Choker: See sling. Chord: Main part of a truss, joist girder, or joist extending from end to end. Usually refers to the top and bottom of the members that run approximately parallel to one another and are usually more or less horizontal. Chords are connected to one another by an open web. Clear span: Any girder, beam, or other horizontal piece that is only supported at each end (for example, any structure that has columns at each end but no intermediate supporting columns in between). Clevis: A U-shaped fastening device with holes in each end though which a pin is placed. Clip Angle: An L-shaped piece of metal (typically with a 90° bend) used to make connections between two members. Glossary G.5 GloSSary

Clipped connection: A connection between two members in which one of the members uses clipped angles. Clipped round washer: Washer with a chord cut through the perimeter to allow fit. Cold shrink: A material used at coaxial cable connections to help prevent the cable from kinking during installation. Column: Vertical members that transfer load to the ground. Come-along: Small, portable winch that typically consists of a cable and a hand- operated ratchet. Commissioning: Term describing the final assessment of a mechanical system to eliminate any deficiencies through a run/test/evaluate sequence. When finished, the system should operate error-free. Communications tower: Tower with both transmission and reception capabilities. Composite floor deck: A type of decking that has rolled “ribs” with high and low areas. These ribs lock concrete and the deck together so that they work as a unit to carry subsequent floor loads. Composite foam panel sheeting: Type of sheeting that consists of a complete wall or roof unit ready for installation. Composite materials: (Also called composites or FRP.) Fiber or fiberglass reinforced polymer. Composites are increasingly used in construction today, and in some cases are used in place of structural steel members. Compression: Force that squeezes materials together. Connecting bar: (Also called a sleever bar.) A tool with one pointed end and one chisel end. It is used to align, pinch, or pry steel. Connection: Any point at which structural members are fastened to one another. Connector: An Ironworker who performs the task of installing and securing structural steel members. A connector is also a terminus to connect a tower transmission line to something else. Construction forklift: (Also called a telescoping forklift.) A forklift usually made for rough terrain that has a boom that telescopes in and out as well as up and down. Continuous span: Bridge or bridge segment with structural members that span continuously over one or more substructure units without a break. Contractor’s level: (Also called a dumpy or a builder’s level). A common optical level. G.6 Structural Steel Erection GloSSary

Controlled decking zone: Area of initial deck placement where only authorized workers may work. Controlling contractor: The prime or general contractor, construction manager, or any other legal entity on a project responsible for the coordination of all of the sub-contractors as well as the overall construction of the project (including its planning, quality, and completion). Coon: Walking astride a beam on the top of the bottom flange while holding the top flange with one’s hands. Cope: To remove a portion of a flange for fitting. Cornice hook: Large steel hook that fastens over the parapet of a wall. Coupler: An elongated nut. Cribbing: (Also called dunnage.) Pieces of wood set down so that steel structural members may be laid on top of them in order to keep the members off the ground (or off other pieces). Critical lift: A lift that exceeds 75% of the rated capacity of the crane or derrick, or that requires the use of more than one crane or derrick. Cross bridging: Bracing in which angle iron is fastened to the top chord of one joist and the bottom chord of an adjacent joist. Cutting plane line: Line drawn with attached arrows on a drawing to indicate the point from which a side or end elevation view or a section view is taken. Cutting shears: (Also called snips.) Tool that works like scissors to make small, intricate cuts in metal. Datum point: Reference point established using survey instruments. Deck bundle: Group of decking nested and banded together for shipping. Deck truss: Type of truss bridge in which the roadbed is on the top of the truss. Decking: Thin gauge steel sheets used in steel erection to act as a working floor and to stabilize a building frame. It acts as a form for floor slab or as a support for built-up roofing. Decking is also the process of laying down or installing metal deck. Deep long span steel joist: A long span joist with greater depth and span measurements than typical long span joists. Degree vernier system: Measurement system for radial angles in degrees that uses a vernier for fine adjustments and readings. Derrick: Mechanical lifting device with a pole or mast freely hinged at the bottom. Glossary G.7 GloSSary

Detail drawings: (Also called shop drawings.) Blueprints that give complete information concerning the field connections for various members. Detailing: Term used to describe the collective tasks of finishing off the erection of a building after the steel has been set and bolted. Diaphragm: A layer or membrane that separates or seals off a floor space. Direct current (DC): Electric current of constant voltage flowing only in one direction. Direct leveling: Leveling by means of placing a leveling tool directly on the structural member in need of being leveled. Direct-tension indicating washer (DTI): (Also called a load indicating washer, or LIW.) A hardened round washer that has a group of protrusions pressed out of the flat surface. Dissipate: (Referring to force) To spread force out over a greater area. Dolly bar: Tool used by a bucker-up (member of a riveting gang) to hold a rivet in place while a head is formed on the opposite end of a rivet. Double connection: Connection of two structural members on opposite sides of a column web or a beam web that involves the sharing of holes. Double-decked truss: Truss bridge with both upper and lower chords that support roadbeds. Down tower assembly (DTA): The control unit of a wind turbine. Draw up: To pull all of the plies in a connection closer together. Drawings: (Also called blueprints.) Plans drawn to scale and used by builders, plumbers, electricians, and other subcontractors. They include floor plans, elevations, site plans, construction details, foundation plans and wall sections, and plumbing, electrical, and mechanical plans. Dress out: Actions taken on the ground to make erection faster and easier once an Ironworker is in the air. Dressing out includes taking smaller pieces and attaching them to larger ones, adjusting or putting on lugs, straightening bent parts, slightly bending other parts, etc. The term is also sometimes used to refer to the act of repairing damaged pieces. Dunnage: See cribbing. Dynamic load: Live load. Dynamometer: Device used to give an accurate tension reading for tower guy wires. G.8 Structural Steel Erection GloSSary

Electrical braking: Slowing down or stopping a wind turbine rotor from turning by dumping energy from a generator into a resistor bank, converting the kinetic energy of the turbine rotation into heat. Electrode: (Also called a welding rod.) Consumable used in welding to conduct current through a workpiece and to fuse two base metal pieces together. Electrode bag: Bag used to hold extra welding rods. Elevation: A height measured either from the ground or from sea level to a reference point. Elevation may also refer to a type of view on drawings (looking from one side or end). End lap: The amount by which one sheet of decking overlaps the end of an adjacent sheet. End splice: A connection between two beams that occurs at the end of both pieces and does not compromise the strength of either piece. Engineer of record (EOR): An individual or company responsible for the structural engineering of a structure. Engineer or machinists’ level: A finely accurate direct leveling tool. Erection bolt: (Also known as a machine bolt or a soft bolt.) Bolt used to temporarily connect a structural member when it is being erected. Erection (“E”) drawings: Blueprints prepared by the steel fabricator to aid in systematically erecting the steelwork of a building. These plans show the location of the anchor bolts in the column footings and the location of each member in its proper place in the structure. Expanded metal: Sheet metal slotted and stretched to make a stiff network with openings of various patterns. Expansion dam: An assembly installed at a meeting point between two parts of a structure (bridge decks) designed to allow for movement of the parts to take into account thermal and moisture considerations. Expansion dams are commonly visible on a bridge deck as a hinged or movable connection. Fabricator: Company that fabricates pieces for steel erection projects. To fabricate is to take standard length steel shapes from a mill and cut, weld, drill and/or bend them following shop detail drawings to make pieces for a steel erection project. Face: One side of a tower. Fair up: To bring bolt holes into alignment. Fairlead sheave: A gate block used to change direction of pull for a hoist. Glossary G.9 GloSSary

Falsework: (Also called shoring.) Temporary structural supports used to hold components in place until construction is far enough along for the structure to support itself. Faying surface: The plane of contact between two plies of a joint. Feeler gauge: Thin metal strip or wire used to check if a bolt using a DTI has been tensioned correctly. Ferrule: Metal sleeve used to join one part to another. Fiber line: Generic term for ropes spun from synthetic materials or woven from natural fibers. Fit up: The process of assembling plate-steel components that are to be welded. Flare stack tower: Type of tower commonly found in refineries or other industrial plants. These towers elevate a flame or flare to burn by-products at a safe elevation above ground. Flashing: Gauged sheet metal used to close off small openings or gaps after decking has been installed. Flashing is most often used on composite floor decking to help seal off and prevent concrete leakage when the floor is poured. Flint lighter: (Also called a striker.) Tool used to light cutting torches. Folding ruler (or rule): Tool that has multiple sections of a ruler that fold up for easy storage. Footing: Part of a foundation bearing directly upon the earth. Forge: A special and portable hearth used to heat rivets on the job site. Form deck: Type of decking that uses extremely thin gauge deck material and very low profiles. It is used on short spans, and commonly in stair landings or working platforms where lightweight concrete is poured. Fossil fuels: A natural fuel such as coal, gas, or petroleum formed from the remains of living organisms. Foundation bolt: Bolt that ties the sill plate and frame of a structure to its foundation. Galling: Damage to fastener threads caused by torsion or friction. Galvanize: A process that coats iron or steel with a protective layer of zinc. Gate block: (Also called a snatch block.) Block that has one side plate that can be moved or removed easily without complete disassembly of the entire block for the insertion of a rope. G.10 Structural Steel Erection GloSSary

Gearbox: Generic term referring to a gear reduction drive contained in a casting or housing. Generator: Term for a mechanical producer of electricity. Gin pole: Device consisting of an upright spar guyed at the top to maintain a vertical or nearly vertical position used to raise loads of medium weight to heights of ten to fifty feet where only a vertical lift is required. Girder: Large beam, typically made of multiple plates. Girder bearing: The location where a joist girder bears on a column. Girder bridge: Bridge comprised of girders. Girt: Horizontal member to which sheets are normally attached in metal building construction. Global Wind Energy Council (GWEC): Global forum for wind energy. Gondola: Enclosed cabin suspended from an overhead cable used to transport passengers up and down a ski slope or over scenic or treacherous terrain. Grade: Degree of inclination or slope. Grating: A framework of parallel or crossed bars used as a partition, guard, cover, etc. Grillage: Network or frame of steel or timber serving as a foundation. Grip: The thickness of all plies of metal in a bolted joint. Grip strut: High strength-to-weight ratio type of serrated safety grating. Ground fault circuit interrupter (GFCI): Fast-acting circuit breaker that senses small imbalances in a circuit caused by current leakage to ground and, in a fraction of a second, shuts off the electricity. Ground halo: The perimeter of conductive material. Ground lead: A copper rod that is driven in the ground (usually 6 to 8 feet). Guy wire: (Also called a guy or guy cable.) A cable that supports some communications towers. Guyed tower: Tower constructed from a lattice-type framework that needs the support of guys to stand erect. Hanger: Structural steel piece used to support (or hang) other structural steel pieces and equipment. Hardened: The process by which steel is heated and quenched to give it qualities that will resist scratching and denting. Glossary G.11 GloSSary

Headache ball: Term given to the weight and hook assembly generally attached to the auxiliary line on a crane and used to hoist loads. Heat shrink: Material used to weatherproof transmission lines. Heat shrink constricts when heated. High-strength bolt: Any steel bolt with a tensile strength in excess of 100,000 lbs. per square inch (e.g., ASTM A325 and A490 bolts). “Hi-Lo” motorized climber: Small modular hoist designed to raise or lower a platform safely by climbing a length of 5/16\" diameter wire rope. Hook: Curved device used for hoisting. Hooker-on: Ironworker responsible for placing rigging hardware onto pieces for a crane to then hoist and swing to the connectors. Hooking on: To attach slings, cables, chokers, wire rope, and other equipment to structural steel shapes and other building components so that they can be lifted or hoisted to a specific point on a structure by means of a crane or some other rigging device. Horizontal axis wind turbine (HAWT): The most common type of wind turbine. A HAWT rotates around a horizontal axis. Hot: Term used to describe something that has electric current running through it. Hub: See turbine rotor. Hydraulic jack: Hydraulic tool used to raise or move iron a small distance or height. Hydraulic tools: Tools that use hydraulic fluid. Hydraulic wrench: Hydraulic tool used to install large-diameter bolts. Hydropower: Electricity produced through the power of water. Ice bridge: Structure that extends from the control building of a tower to the tower itself and protects transmission lines from ice build-up. Impact: Term used to describe the tensioning of a bolt with an impact wrench. Impact wrench: (Also called a calibrated wrench or a torque wrench.) Wrench with a dial or other indicator showing the amount of torque being applied. Inertia: The tendency for something currently at rest to remain at rest or for something moving in a straight line to continue moving in a straight line unless the object is acted upon by an outside force. In tandem: When two or more pieces are hoisted and erected together. Inverter: Device that converts direct current (DC) into alternating current (AC). G.12 Structural Steel Erection GloSSary

Isometric view: View used in drawings in which an object is revolved forward so that the top is viewed at about an angle of 30o. Circles appear as ellipses in isometric drawings. Job Hazard Analysis (JHA): A listing of all of the potentially unsafe conditions, actions, or hazards associated with a particular task, and the specific preventative or corrective actions that should be taken to eliminate or mitigate such hazards, actions, or conditions. Joist: A structural component consisting of a top and bottom chord and an open web. Joist girder: A main structural component used to support steel joists. Jumper line: Temporary line similar to an extension cord but without end connectors used to supply electricity temporarily. Jumping the pole: To move a gin pole vertically up a tower to the next working height. Kinetic energy: Energy associated with motion. Ladder-deck bridging: Girder bridge in which additional beams span across the main girders. Lateral bridging: Angle placed in a horizontal position as specified on drawings and welded to the top and bottom chord of a joist (or two joists). Lay down area: Portion of a construction site used to stage materials. Lay down yard: (Also known as a bone yard.) Site separate from the construction site used to stage materials. Layout: The act of preparing dimensional markings or placing items according to the blueprints. Layout instrument: Type of tool used in steel erection to establish working points, elevations, and benchmarks. Layout instruments include builders’ levels, lasers, transits, and theodolites. Leveling nuts: Nuts located on the anchor bolts on which the base plates of columns rest. Leveling plate: Plate used for precision leveling. Leveling stud: Bolt or all-thread with two nuts used specifically to level a piece of equipment or tower base. Lifting lug: Structural steel piece fabricated for the sole purpose of attaching rigging hardware to a structure. Glossary G.13 GloSSary

Lifting points: Places on a modular structure where Ironworkers must hook up hardware. Lightning rod: A conductive bar attached to a structure with a direct path to the ground lead. Line ladder: Support system used to attach transmission lines to towers. Lintel: Horizontal metal member spanning and carrying the load above an opening. Load: A piece (or pieces) being hoisted or suspended by a piece of hoisting equipment. Load is also the weight or stress applied to a building structure through its connections. Long span steel joist: Joist furnished with either underslung or square ends and with parallel chords or single- or double-pitched top chords to provide sufficient slope for roof drainage. Loran tower: A type of specialty guyed communications tower that transmits and receives naval or marine signals. Lug: Angle or plate with pre-punched/pre-drilled holes used to attach one beam to another or to a column. Lull: Name brand for a rough terrain extendable boom forklift. Measuring tape: Plastic or metal casing housing a rolled steel spring-loaded tape that measures distances. Mechanical braking: Slowing down or stopping a wind turbine rotor from turning by the use of a physical force. Mechanical energy: Energy (both potential and kinetic) present in a mechanical system. Member: (Also called a piece.) A piece of steel. Modular structure: A self-contained component of a system or unit that interfaces with other components. Modular structures are almost always assembled in a location other than the erection site. Moment connection: Special type of structural connection between a girder or beam and a column in which the flanges of the beam are welded to the flange(s) of the column(s). This tends to make the structure very rigid and stiff. Moment force: A twisting or torquing action; a force that tends to cause rotation around an axis. Momentary contact “on/off ” control switch: A switch on a tool that makes two actions necessary to start and/or operate the tool. This switch stops the tool from operating if the contact is released. G.14 Structural Steel Erection GloSSary

Monopole: A tower that tapers from the base to the top and is hollow in the center. Monopoles usually resemble large galvanized steel flagpoles or telephone poles. Movable live load: Dynamic load that moves. Multi-component field-assembled system: Sheeting assembled in the field that may consist of a variety of components, including sub-framing, vapor barriers, fiberglass or foam insulation, wallboard, sub-girts, liner panels, and exterior skin panels. Multiple-lift rigging: Rigging assembly manufactured by wire rope rigging suppliers that facilitates the attachment of up to five independent loads to the hoist rigging of a crane. Multiplier: Tool used to increase the amount of torque to tension a fastener. Nacelle: The shell or casing of a propeller-type wind turbine that covers the gearbox, generator, blade hub, and other parts. National Association of Amusement Ride Safety Officials (NAARSO): Non-profit organization that provides resources for amusement industry professionals. Nibbler: Small handheld tool that creates a metal cut in much the same way that a small jigsaw cuts through a piece of wood. Nominal: Approximate. Notation sequence: Pattern of letters and numbers presented in a specific order to convey information about the type, weight, and dimension of a structural member. Nuclear power: Electricity produced through nuclear energy. Nugget: The weld metal that joins the workpieces in spot, roll spot, seam, or projection welds. Oblique view: View in drawings wherein an object is illustrated with complete forward tilt so that circles in the front view appear as true circles, but circles in the side and top views appear as ellipses. Offshore wind turbine: Wind turbine placed in water rather than over land. Oiler: Individual usually employed as the helper of an operating engineer. Omni-directional: A transmission signal that travels in all directions (360°). Open web steel joist: Load-carrying member with parallel open web chords. Glossary G.15 GloSSary

Optical level: Remote leveling device that has a base and an eyepiece much like a telescope, allowing the person using it to gather information regarding the plumbing, aligning, or leveling of a structural member without actually having the instrument touch the member in question. Orthographic view: A view on drawings that only shows two dimensions: height and width. The third dimension can be shown by means of projection. Outrigger Beam: Beam that extends out from the roof of a building and is weighted down with counterweights. Overloading: A dangerous condition that occurs when a load suspended from a crane is above its rated capacity. Overspeed: A condition wherein an engine turns beyond its design limit. Panel point: Point at which bracing meets, usually referring to the top, not bottom, chord. Parapet clamp: Device that attaches to the top of a wall. Peeling: Stress that results in a prying or peeling effect. Personal Protective Equipment (PPE): Clothing or equipment used to protect an Ironworker from hazards. Perspective view: A view on drawings that shows an object as the eyes see it. Philadelphia rod: A graduated extendable stick or pole used to determine and transfer elevations with an optical instrument. Pick list: (Also called an erection list.) List that indicates the order in which pieces are hoisted or “picked” by a crane to be placed at their designated points on a structure. Piece mark: (Also called mark number or piece number.) A code normally painted or stamped on a member as a means of identifying that member. Pier: Vertical sub-structure for a column that supports the ends of a multi-span superstructure at a location between abutments. Pig iron: Cast iron that is poured into rough molds. Pinch point: Descriptive term for an area where a worker may become “pinched” between structure and machinery. Pinned connection: A connection that uses pins instead of bolts or welds. Plan view: A type of two-dimensional blueprint representation that gives the top or bottom view of an object. Planning: The act of developing a sequence of events to accomplish part or all of a construction project. G.16 Structural Steel Erection GloSSary

Plate: A structural steel shape consisting of a rolled sheet that is rectangular in cross section. Pleasure garden: Garden used for recreation and entertainment that typically charges a fee. Plumb: To manipulate a structure or individual members or pieces within a structure to bring the vertical members reasonably, if not perfectly, vertical. Plumb bob: An instrument used to check the plumbness of a column. Plumb line: A length of wire rope that incorporates and uses turnbuckles for tightening. Plumbing gang: A crew of Ironworkers responsible for plumbing a structure. Plumbing gangs are usually found on large projects. Pneumatic tool: A tool powered by compressed air. Pony truss: Truss bridge in which the sides are extended above the roadbed but are not connected. Powder-actuated tool: A type of tool powered and operated similar to a loaded gun. Power tool: Electrical, pneumatic, powder-actuated, and hydraulic tools. Pre-engineered falsework tower: A type of falsework that is most easily described as scaffolding. Preinstallation verification testing: Testing of fastener assemblies before they are installed to ensure that they will withstand their intended load. Preload: The clamping force between the connected plies and the tensile force in a bolt. Pre-stressed concrete: Concrete with reinforcing that has been tensioned prior to concrete pour/set/cure. Pretensioned connection (PT): A connection in which the plies have been compacted and the bolts have been tensioned by turn-of-nut tightening, calibrated wrench tightening, DTI use, or TC bolt tightening. Profile: A composite shape. Projection: The measured length that a bolt sticks out of the material into which it has been installed. Proof load: An amount equal to 70% of the ultimate tensile strength of a fastener, or its breaking strength. Puddle: A non-standard term for weld pool. Glossary G.17 GloSSary

Pulse method: A method of checking tower guy wire tension by striking a tower’s guy wire and recording the amount of time it takes for the vibration to return to the ground. Purlin: Longitudinal member in a roof frame, usually used for maintaining the spacing of rafters. Sheets are normally attached to purlins. Rail stops: Usually pieces of steel (blocks) anchored in such a way as to prevent a rail car from accidentally going past the end of a set of tracks. Raising gang: A crew of Ironworkers primarily responsible for the initial erection of structural steel. A raising gang usually consists of a foreman, a hooker-on, and at least two connectors. Ream: The action of enlarging a previously bored hole to a desired size by means of a reamer bit. Retaining wall: A wall built to hold back a slope of ground. A retaining wall must be designed to withstand enormous pressure and requires substantial footing to redistribute pressure to ground. Rigging configuration: The manner in which rigging hardware is arranged. Rivet: A metal pin that passes through holes in two or more pieces to hold them together. Rivets have a button or rounded head at one end, while the other end is hammered into a button head after insertion. Roof deck: A type of decking that has a smooth finish and is used to support the load of built-up roofing materials. It is usually designed to be part of a structure’s bracing. Rotor shaft: Driven shaft of a turbine assembly that connects the rotor to the generator. Saddle belt: A positioning belt that allows the wearer to sit, squat, or semi-stand comfortably. Safety Data Sheet (SDS): Form containing information regarding the chemical hazards of a substance. Sag method: Checking the tension of tower guy wires by sighting through a tube attached to a tower guy wire. Sag rod: Tie rod used to give lateral support to parallel members such as purlins. Scabbard: A multi-pocket holster used to hold and carry tools. Scaffold: Temporary platform on which workers sit or stand when performing tasks at heights above the ground. Scheduling: The process of attaching time periods and dates to the events identified during the planning process. G.18 Structural Steel Erection GloSSary

Scribe: Sharp-pointed tool used to create lines or markings on materials. Seat connection: The welding of a seat lug or angle of sufficient size in the web of a column or girder below a beam to be connected so that the bottom flange rests on the seat lug. This is usually done to eliminate the hazard of a double connection. Seat lug: Any structural shape bolted or welded to a column that will make a connection with the underside of the bottom flange of a beam or truss. Section view: (Also called a section, a cut, or a detail view.) View similar to an elevation view that presents details not visible in a plan view. Self-locking nut: Nut with either a mechanical mechanism or a slightly contracted thread pattern that will resist backing off a bolt once tightened. Self supporter: Tower built of lattice-type framework that requires no guy wires or cables to stand erect. Self-tapping screw: Type of screw with a tapered head and tapered cutting lips that simulates a drill bit. Self-tapping screws are used extensively when installing sheeting and roof decking. Servomotor: Small motor used for fine movement. Shackle: U-shaped metal rigging hardware with holes in each end through which a bolt-type pin is placed. A shackle is used as a fastening device. Shake out: To sort steel by checking inventory on a delivery, separating pieces into like groups, and placing pieces in their proper erection order. Shear: Stress that resists the tendency of two parallel forces acting in opposite directions to cause two adjoining planes of a body to slide onto each other. Shear plane: Cross section of a bolt that is subjected to shear forces in a connection. Shear stud: Manufactured connector that consists of a round, rod-like body of metal with a head on one end. Shear tab: Plate with pre-punched/pre-drilled holes used to connect one beam to another or to connect a beam to a column. Sheared plate: Plate that has been cut with hydraulic shears to specific widths. Sheaves: A pulley for hoisting or hauling that has a grooved rim for retaining a wire rope. Sheeting: Thin gauge metal used as a finished product or “skin” on the exterior walls and roofs of buildings. Glossary G.19 GloSSary

Shim: A thin slip of steel or plastic that is driven, stacked, or placed beneath base plates to level them or to plumb columns. Shim plates: Plates used to maintain beams’ centers. Shock loading: A dangerous condition that occurs when a load being raised or lowered is started or stopped suddenly. This condition can cause a crane to turn over or suffer structural damage, including collapse. Shunt meter: A device used to check the tension of tower guy wires by measuring the amount of force needed to deflect the wire. Side lap: The amount by which one sheet of decking overlaps an adjacent sheet along its side or edge. Side loading: A dangerous condition that occurs when a load is not suspended directly beneath the point of a boom of a crane. Side loading causes undue stress and has the potential to cause structural damage to a crane, including collapse. Signalperson: The individual responsible for signaling an operating engineer. Single skin sheeting: Type of sheeting installed directly onto the framing of a building. Ski lift tower: Tower used to support ski lift mechanism of pulleys and wire rope. Sledgehammer: See beater. Sling: (Also called choker.) Common method of anchoring equipment to a structure. Slings include a wide variety of configurations for fiber ropes, wire ropes, chains, and webs. Slip-critical connection (SC): A connection in which plies have been compacted and bolts tensioned by turn-of-nut tightening, calibrated wrench tightening, DTI use, or TC bolt tightening, but the steel surfaces being bolted together have been specially prepared by cleaning and painting. Slip-pin shackle: A rigging solution devised in the field that uses a pin inserted into a shackle and through a hole in the column. Small part: A piece or component used during the fabricating process to fabricate a structural steel member. Small parts are denoted on shop detail drawings with lower case letters that contrast with the capital letters used to designate other members or pieces. Snap loop: A leather tunnel loop that attaches to a tool belt and has a snap with which to connect a tool. Snapping: State that occurs when the force of tension overcomes a member’s ability to handle it. G.20 Structural Steel Erection GloSSary

Snatch block: See gate block. Snips: See cutting shears. Snug position: Bolts that have been drawn up to eliminate any gaps in the plies of steel, but have not been tensioned to any particular value. Snug tighten: Make so that all plies of steel in a connection have been drawn together. Snug-tightened connection (ST): A connection in which plies have been compacted, but the bolts have not been tensioned to any particular value. It is also described as the full effort of an Ironworker using a spud wrench to tighten a bolted connection. Soft rope: Rope in which the yarns are formed into the strands and the strands are laid into the rope loosely. Soft rope is limper but stronger than hard rope, and can be made of natural fibers such as cotton, hemp, and manila, and synthetic fibers such as nylon. Softener: Any material used to pad a sharp bearing point for a sling. Sorting hook: (Generally called a shakeout hook.) A hook with a tapered open end and no safety latch used to shake out structural steel. Span: Any distance of horizontal structural members that are supported between two verticals. Span length: The distance on a bridge between piers, towers, or abutments. Spandrel line: The perimeter of a building line. Specifically-engineered falsework tower: A falsework tower constructed of structural steel pieces that are designed, detailed, and fabricated for the sole purpose of being erected to temporarily support part of a larger structure until construction advances enough that the structure is able to support itself. Spirit level: A device used to determine whether something is plumb or level by direct leveling. Spirit levels include birdseye levels, torpedo/engineer’s levels, and engineer or machinist’s levels. The “spirit” refers to the liquid in the level vial, which is usually a type of alcohol or glycol that resists freezing. Splice: To mate any like members (for example, beams or columns) to make a continuous longer member. Splice plates: Plates used to make a splice connection. Spotting: To signal a truck, rail car, etc. where to set up, park, stop, or drop off. Spread footing: Concrete reinforced pad spread out over a large area to form the foundation for a wind turbine. Glossary G.21 GloSSary

Spreader bar: A beam, heavy duty pipe or square tubing, or fabricated truss or plate used to help prevent load tipping and/or sliding, or in hoisting loads excessive in length or not rigid enough to prevent undesirable bending or flexing. Spreader hook: Hooks with safety latches used to unload, sort, hoist, or otherwise handle structural steel. Spud wrench: Combination of a pin, lever, and wrench in which the wrench end is offset and the other end is gradually tapered to align bolt holes. Stabilizer plate: Piece of plate steel, usually shop welded to a column, of which the bottom chord extensions of joists or joist girders extend on either side. Stabilizer plates add stability to the joist/girder and help to prevent it from overturning during erection. Stacking: The act of erecting the sections or members that comprise a tower. Stage: The act of placing materials or pieces in a location, usually on the job site and close to the final position of the materials, where they will not be in the way of other crafts or Ironworker crews. Static load: Dead load. Steamboat ratchet: A load binder or tensioning device that uses internal screw threads at each end and screw sockets in the center. Steamboat ratchets have a composite reversible ratchet and handle. Steel: Purified form of iron that is one of the strongest metals used in construction. Stock material: (Also called plain material.) Steel that has not been welded, cut, blocked-out/coped, had holes drilled or punched into it, etc. Stress: A measure of force per unit area within a body. Stub: The base section of a guyed tower. Substructure unit: The foundation, piers, and abutments of a bridge. Sump pan: The point(s) on a roof or floor where the water will drain (i.e., a roof or floor drain). Surface veil: A protective covering on the outside of composite materials. Suspension bridge: Type of bridge that suspends its deck by means of large cables secured at each end and passed over the tops of high towers. Swing stage: Elevated working plank or platform, often made of aluminum. Tack welded: Fit-up assembled with welds of minimum size. G.22 Structural Steel Erection GloSSary

Tag line: A length of rope, sometimes with a hook attached, used for controlling a load. Tagging a load: The act of using a tag line to control a load, specifically to prevent the load from striking anything during the hoisting process and thereby damaging the load, structure, or hoisting equipment. Tandem lift: A hoisting procedure using more than one crane. Tapered reamer bit: Tool used for reaming holes. Tapping: Tool used to cut threads into the sides of holes. To tap is to cut threads into a hole. TC gun: Common name for the wrench used to tighten “torque control” (TC) type F1852 bolts. Tee: Structural member formed into the shape of the letter “T” and created by cutting a beam through the center of its web (thus forming two T-shapes). Telescoping forklift: See construction forklift. Tensile strength: The most tension a bolt can take without failing. Tension: A force that pulls materials apart. Tensioning sequence: Plan given on drawings or specifications indicating when various connections are to be tightened. Theme park: A more narrowly defined category of an amusement park. Theme parks are permanent facilities that use architecture, signage, and landscaping to help convey the feeling that people are in a different place or time. Theodolite: A device similar to a transit in appearance and function. Theodolites are, however, more accurate than standard transits. Thimble: A metal ring around which a wire rope is passed to prevent damage to the rope. Thread chase: (Also called a die nut.) Tool resembling a nut that is used mainly to clean and repair minor damage on anchor bolt threads. Thread run out: The portion of a bolt that has no threads. Threaded insert: A device with female threads that is “inserted” into another object. Through truss: Type of truss bridge in which the roadbed is on the bottom of the truss. Tie-joist: Bar joist that usually extends from one column to another column, but may extend from a column to a beam or girder. Tie-joists usually have bottom chord extensions that fit on either side of a stabilizer plate. Glossary G.23 GloSSary

G.24 Tier: The height of a building represented by one column (on a high rise structure, this is usually three floors). Tip speed ratio: The ratio between the speed of the wind and the speed of the tips of the blades of a wind turbine. Tongue-and-groove type joint: Interlocking male and opposing female pieces. Tool holder: Device used to carry or hold tools. Tool holders include scabbards, wrench holders, snap loops, and bull pin holders. Top hat: Term referring to the structural parts that make up a work platform/ antenna mounting area located at the top of some towers. Topping out: A party given at the erection of the uppermost member of structural steel to celebrate the completion of a project. Torpedo/engineer’s level: Rectangular level with spirit vials used for direct leveling, plumbing, and 45° aligning. Torque: Force applied in rotation. Torque can also refer to the turning effort when tightening a fastener. Torque stabilizer: (Also called a torque arm.) A structural assembly at guy points on a tower used to help prevent or eliminate twist. Torsion: Stress caused by twisting. Total station: Type of transit that can determine the distance along a site path to a target as well as the horizontal and vertical distances the make up the triangulation of the target. Total stations are usually only used for complex jobs. Tower: Any structure more vertical than linear. The three basic types of towers are guyed towers, self-supporters, and monopoles. Transfer: (Referring to force) To move force from a weaker to a stronger area. Transit: An instrument used to level, plumb, align, and lay out on a degree vernier system. Transmission lines: Thick coaxial cables made of copper or aluminum. Trip: To trip (or tripping) is to use one or more pieces of equipment to safely transfer something from horizontal to vertical or from vertical to horizontal. Truss: A horizontal structural member that acts like a beam, but is made up of many pieces with openings in between the pieces. Trusses are specially engineered to give maximum strength with minimum weight and are therefore often used to span large spaces such as lobbies and auditoriums. Truss bridge: Type of bridge that consists of a truss-like assembly of triangles. Structural Steel Erection GloSSary

Tubular steel rails: Type of roller coaster track that can be bent into shapes to allow coaster cars to make tight corners and go upside down. Tugger motor: Electric or pneumatic motor that powers a drum spooled with wire rope and used for miscellaneous hoisting. Turbine rotor: Fan-like component driven by steam in a turbine assembly. Turn-of-nut method: One acceptable method of tensioning bolts in which a bolt is snug-tightened, match marks are added to both the bolt and nut, and then the nut is turned an additional amount (1/3, 1/2, or 2/3 of a rotation depending on the length to diameter ratio of the bolt) while ensuring that the bolt head does not rotate. Turnbuckle: A link with an internal screw thread at each end and screw sockets in the center. Turnbuckles are used as a means of tightening, adjusting, or binding. Underslung: Condition in which the top chord of a joist, joist girder, or truss is longer than the bottom chord so that at each end the web runs diagonally between the chords instead of perpendicular as when the ends are square. Universal Mill Plate (UM): Plate rolled to a specific width. Vernier eyepiece: Secondary eyepiece on a theodolite that allows a magnified view of the vernier. Vertical axis wind turbines (VAWT): Type of wind turbine that rotates around a vertical axis. Weld washer: A washer that is placed on a deck where a weld will be made. The weld is then made through the hole in the washer, welding the washer, the decking and the support steel together. Well wheel: (Also called a well rope pulley.) A single sheave for use with a natural or synthetic rope to pull materials up to a higher working elevation (i.e., on a scaffold, by hand). Whooping: A series of shrill/loud high-pitched yells or “whoops” that indicate to the winch operator what action is needed at the top of a tower. Wide-flange beam: A structural steel shape that is used both as a beam and as a column, and is sometimes referred to as an H, HP, or W shape. Winch: Truck-mounted powered drum of wire rope used for pulling or hoisting. Wind farm: Site where multiple wind turbines are located together. Wind load: Wind pushing against a structure. Wind power: An environmentally clean, economically competitive, and publicly supported form of electricity generation. Glossary G.25 GloSSary

Wind sensor: Device that determines the speed of wind. Wind turbine: A machine that converts the kinetic energy in wind into mechanical energy, and ultimately into electricity. Wind vane: A moveable device attached to an elevated object and used to show the direction of the wind. Wind vanes are sometimes referred to as weather vanes. Windmill: A machine that converts the kinetic energy in wind into mechanical energy, which is then used directly by the machinery. Wrench holder: Device used to hold and carry wrenches. Wrought iron: A form of iron almost entirely free of carbon that has a fibrous structure with uniformly distributed slag content. Yard crew: A group of approximately three or four Ironworkers and a foreman who are responsible for receiving and unloading structural steel as it arrives on a job site. Zee: Structural member formed into the shape of the letter “Z.” Zero-emission technology: Term used to describe technology that results in a zero emission of carbon. G.26 Structural Steel Erection GloSSary



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