0428

TROLLEY TRAVEL. With palm up, fingers closed and thumb pointing in direction of motion, hand is jerked horizontally in direction trolley is to travel. EXTEND BOOM. (Telescoping Boom). One Hand Signal. One fist in front of chest with thumb tapping chest. RETRACT BOOM. (Telescoping Boom). One Hand Signal. One fist in front of chest, thumb pointing outward and heel of fist tapping chest. Figure 3.30 (cont.) Crane Signals These two signals (Figure 3.31) are commonly used, but are not among those listed Figure 3.31 Additional Crane Hand Signals as standard signals by Subpart CC. They do, however, appear in ASME B30.5. Verbal Signals According to ASME B30.5-3.3.5, in order to ensure the safety of all personnel, the load being hoisted and the hoisting equipment when using voice/verbal crane signals, the voice/verbal signals shall be identified and agreed upon by the person directing the hoisting operations, the crane/hoisting equipment operator and the designated signalperson. The signalperson shall give direction signals from the point of view of the operator of the crane/hoisting equipment (e.g., swing left is “the operator’s left”). The voice/ verbal signals shall consist of three parts in the following order; function and direc- tion, distance and/or speed, and function stop. For example: hoist down slow, 10 ft, 8 ft, 4 ft, 2 ft, 1 ft, hoist stop. Note: Whenever there is a concern as to safety, the operator must have the authority to stop and refuse to handle loads until a quali- fied person has determined that safety has been assured. Unit 3 — Tools and Equipment for Structural Steel Erection 3.29 UNIT 3

3.30 Structural Steel Erection UNIT 3

▶ UNLOADING, HANDLING, AND STORING STRUCTURAL STEEL MATERIALS UNIT 4 ▶ OBJECTIVES After completion of this unit, you should be able to describe the procedures for unloading, handling, and storing structural steel materials. This knowledge will be evidenced by correctly completing the assignment sheet, performing the skills in the performance exercise assessment, and by scoring a minimum of 70% on the unit test. Specifically, you should be able to: 1. Describe the basic procedures of unloading, sorting, dressing out, and storing structural steel 2. Describe how to unload structural steel safely and appropriately Each of these objectives is covered in the pages that follow. Note: This unit will provide the apprentice or inexperienced jour- neyman with the basic knowledge required to perform the tasks described. This knowledge is not a substitute for the practical experience gained by actually performing these tasks. These tasks should be performed only under the supervision of an experienced journeyman or foreman until you are competent enough to perform them without supervision. Unit 4 — Unloading, Handling, and Storing Structural Steel Materials 4.1 UNIT 4

▶▶OBJECTIVE 1: UNLOADING, SORTING, DRESSING OUT, AND STORING STRUCTURAL STEEL Before any steel structure can be erected efficiently and economically, all of its members or pieces must be unloaded, shaken out, dressed out, and stored. Unloading Structural Steel Various factors determine who will unload the pieces of a structure when they arrive on a construction site and where they are unloaded. These include, but are not limited to, the following: • The project’s schedule and personnel resources • Site layout • The type of structure to be erected For example, a small project with ample stor- age room and easy-to-meet deadlines may need to use only one crew of Ironworkers to unload, sort, and erect all of the pieces of a structure. A large job (e.g., a high-rise build- ing) with insufficient vacant space to store floor after floor of steel within reach of a crane or derrick (Figure 4.1) and a deadline for com- pletion nearly impossible to meet, however, may require several crews. Each crew may be in charge of one specific task (i.e., just unload- ing, just sorting, just raising, etc.). On many job sites, the yard crew is respon- sible for receiving and unloading the steel as it arrives. This crew typically consists of three or four Ironworkers and a foreman. They unload the steel as it comes in (usually by truck) using a crane or derrick. Figure 4.1 Derrick On most high-rise building projects, however, the raising gang unloads and sorts the steel, and hoists it directly to a decked floor on the building itself. 4.2 Structural Steel Erection UNIT 4

Caution! Only employees essential to the operation are permitted in the load fall zone. Workers are prohibited from working under suspended loads except while connecting steel, and hooking or unhooking a load. In general, there are four basic locations for unloading steel on a job site: 1. Within reach of an erection crane (see Figure 4.2) 2. Close enough to an erection crane to enable the use of a telescoping forklift (Figure 4.3) or small crane (Figure 4.4) to carry the steel to the erection crane when needed Figure 4.2 Steel Shaken Out Within Reach of an Erection Crane Figure 4.3 Telescoping Forklift Figure 4.4 Small Crane Unit 4 — Unloading, Handling, and Storing Structural Steel Materials 4.3 Note: Certain conditions, such as lack of space or equipment limita- tions, may warrant using an unloading and shake-out sequence. See Figure 1.37 on page 1.19 for a diagram of such a sequence. UNIT 4

3. At a lay down yard (or bone yard), with the steel transported to the job site later as needed 4. On the structure itself, using the last completed floor of the structure as the “yard” When steel is unloaded onto the floor of a building (Figure 4.5), it must be set on dunnage or cribbing that has been placed per- pendicular to other dun- nage or cribbing set in the metal decking’s “low” cor- rugations. This prevents the unloaded steel from crushing the metal deck- ing’s “high” corrugations. The dunnage must also be placed over the top of the supporting steel as decking will not otherwise withstand the concentrated weight of a load of steel. Weights and load factors must always be considered before any concentrated load is placed on a floor. In some cases, if the pieces are large and/or the area is not large enough to accom- modate the pieces being unloaded, they will be erected immediately after being raised from the truck (Figure 4.6). Figure 4.5 Steel Being Unloaded onto the Floor of a Building 4.4 Figure 4.6 Piece Being Erected After Being Raised From the Truck Structural Steel Erection UNIT 4

Note: Tips for safely and appropriately unloading structural steel are given in Objective 2. Shaking Out Structural Steel Shaking out is a term applied to the process of sorting steel. This sorting is under- taken by a shake-out crew of three or four workers and a foreman; depending on the project, this crew may be the same as the unloading or raising gang. Depending on the job, too, steel may be shaken out more than once. A load may be shaken out in a storage yard, inventoried, dressed out, loaded on a truck, sent to the job site, and then shaken out again for erection. During this second shaking out, members should be sorted as closely together as is safe to expedite hook-on time. Shakeout crews use spreader hooks and at least one set of sorting hooks (generally called shakeout hooks) to sort steel. When using sorting hooks, make sure that the hooks are hooked into the web, turned opposite to one another, and placed under the flange. It is important to attach sorting hooks opposite to each other as illustrated in Figure 4.7. Figure 4.7 Sorting Hooks Positioned Opposite Each Other Unit 4 — Unloading, Handling, and Storing Structural Steel Materials 4.5 UNIT 4

To help remember the correct – and safe – way to position sorting hooks, Ironworkers often use this phrase: “hook right, be right.” When each worker positions his or her hook on the side of the end of the beam that is on the right to him or her, the hooks will be properly and safely positioned opposite each other. Placing the hooks opposite to each other allows the piece to be moved level. It also prevents the piece from rolling over – as it would if each worker attached the beam on the same side – and thereby toppling over other pieces and potentially causing injury. If a piece to be shaken out has angle lugs with attachment holes either welded or bolted to each end, ensure that each sorting hook is barreled into its hole (Figure 4.8). Sorting hooks are the only hooks that can be barreled into a hole; if there are no holes, seat the sorting hook under the top flange (Figure 4.9). An inventory is completed as part of the shaking out process. While this inventory is being taken, if the mark that is placed on each piece by the fabricator is small, it should be re-written in larger, more eas- ily visible numbers and/or letters on the same end as the fabricator’s mark. The piece should then be placed with its marked end facing up so that it can be quickly and easily identified (see Figure 4.10). Figure 4.8 Sorting Hook Barreled into Hole Figure 4.9 Sorting Hook Placed Under Flange Caution! As with any rigging hardware, sorting hooks should be inspected thoroughly before each shift to make certain that they are in good condition and rated for the heaviest intended load. 4.6 Figure 4.10 Numbers Marked on Beams Structural Steel Erection UNIT 4

Note: In the rare event that a piece is not marked, its length, cross- sectional dimensions, hole patterns, coping, and lug placements should be measured and compared to the measurements and details provided on the project’s blueprints. Once the piece has been identi- fied through the blueprints comparison, it should be marked with its appropriate number. Each piece’s centerline or balance point should be marked on it during shak- ing out as well. These sorts of markings can be seen in Figure 4.11. The shaking out process is also the best time to iden- tify and repair damaged pieces. Before any repairs are made to damaged or misfabricated pieces, however, the foreman should be informed. Any piece that cannot be repaired, or that would take too long to repair, must also be reported to the foreman. Figure 4.11 Centerlines Marked on Beams Dressing Out Structural Steel Dressing out steel is conducted by mem- bers of the yard or shake out crews, or by the raising gang. Dressing out steel is the process of doing whatever can be done on the ground to make tasks easier, faster, and just generally more efficient “in the air.” This includes assembling small pieces that bolt underneath and are difficult and time-consuming to assemble in the air, but are often quickly and easily assembled on the ground. It also includes attaching smaller pieces to larger ones, adjusting or putting on lugs, straightening bent parts or slightly bending parts, etc. Figure 4.12 provides an example of dressed-out steel. Figure 4.12 Dressed-Out Steel Unit 4 — Unloading, Handling, and Storing Structural Steel Materials 4.7 UNIT 4

Storing Structural Steel Steel should be stored in a logical order, so that all of the pieces to be used for the first phase of a project are stored together in one area and all the pieces for the sec- ond phase are stored together in another area, etc. Within each area, pieces should be stored in sets, with like pieces grouped together as demonstrated in Figure 4.13. Each set should denote a change in section or length and be placed so that all markings are visible from the lanes between the rows or sections of material. There should be ample room between stacks, sections, and sets, and pieces should never be stacked more than four feet high. This allows workers to walk between and place chokers on pieces safely. On a small job, the part of the job site designated to store materials and keep them together is known as the lay down area. This area is typically within reach of an erection crane. On large projects, or for projects where there is not enough room at the job site for material storage, a lay down yard is used. This area is typically not within reach of an erection crane, and may be located several blocks away (or even further) from the job site. Sometimes, and particularly for high-rise buildings, as has already been observed, steel is unloaded and stored directly on the decked floor of a structure. Caution! Safety must be considered at all times, no matter what the task. Keep working areas clean and orderly with necessary equip- ment and materials neatly arranged. Do not allow any loose articles to lie around. Figure 4.13 Storage of Steel Pieces Regardless of where storage occurs, however, all materials and pieces should be stored on dunnage to keep them off the ground. This makes it easier to place a choker on a piece, reduces the accumulation of mud, and prevents steel pieces from freezing to the ground. 4.8 Structural Steel Erection UNIT 4

▶▶OBJECTIVE 2: SAFELY AND APPROPRIATELY UNLOADING STRUCTURAL STEEL Only qualified riggers should unload steel. Before unloading, be certain to under- take the following: 1. Determine the chart and capacity of the crane or equipment (this should be done before a project has even started). 2. Ensure that the area where the steel will be unloaded is firm, level, and dry, with good drainage. 3. Use adequate dunnage to prevent pieces from accidentally falling over. 4. Check the shipping list to see which pieces of steel are on the truck (i.e., with which phase, level, tier, section, or area the load corresponds). This inventory may also be conducted during shaking out. If there are any overages, shortages, or other discrepancies from the load ticket or bill of lading, notify the foreman immediately. 5. Ensure, when spotting the crane, that the crane will be within its rated capacities for the entire unloading process (from when steel is hoisted from the truck to when it is swung and then placed on the ground). 6. Ensure that the rigging to be used is adequate and in good working order. Destroy or remove from service any damaged rigging components. While unloading, be certain to adhere to the following: 1. Use softeners whenever possible around sharp corners or when extreme loads are placed on rigging. 2. Only use hooks with safety latches. 3. Always allow for deflection when unloading with a lattice boom or hydraulic crane. 4. Never allow a load of steel to “nest” or shift after being lifted from a truck. Such a shift can create a tremendous shock load to a crane or lift, causing it to collapse and/or the rigging to fail. Before allowing a load of steel to be hoisted, ensure that the pieces are safely contained and that nothing will fall out. Warning! Do not use sorting hooks because they do not have safety latches. Only use sorting hooks for their intended purpose: sorting iron. Never hook chokers into sorting hooks. Unit 4 — Unloading, Handling, and Storing Structural Steel Materials 4.9 UNIT 4

5. Unload large, heavy beams and girders that need to be “rolled up” (i.e., turned over) onto the ground first, and then roll them up. Attempting to roll them up on the truck can result in the truck’s leaning or flipping. If it is not possible to unload the piece onto the ground first, try to roll the piece to the center of the trailer to minimize the risk of the truck’s leaning or flipping. 6. Ensure that neither you nor your partner are in a pinch point when lifting steel from a truck. The load can shift as the crane boom deflects under the weight. 7. Ensure that you do not accidentally knock pieces off the truck. If a piece is knocked off, it may cause injuries to persons or damage the truck. 8. Unload steel in whole truckloads, or several pieces at a time, whenever possible. Leave enough room between bundles to shake out the steel as needed. 9. Turn the base plates of columns and the numbers on members (beams, angles, channels, etc.) so they face in the same direction. Safety Tips for Unloading Rail Cars Although loads will usually be shipped by truck, steel may arrive by train for large jobs where there is railroad access to the job site. Keep these tips in mind when unloading rail cars: 1. 2. 3. 4. 5. 6. 7. 8. 9. Hand brakes should be in working order before moving a rail car. The track must be clear of workers and materials before moving a rail car. A signalperson must be used when the engineer’s view of the track is obscured. When spotting rail cars, do not block crossings or roadways. Place appropriate flags on the track and keep them in place during loading and unloading operations. Always remove the flags when the track is clear. Rail stops should be fastened at the open end of the tracks. Rail cars standing on an incline must have their brakes tightly set, and a chock block must be placed on the track in case the brakes fail. Be careful when unloading; make sure that nothing is accidentally knocked off the train. Shore or block pieces and the rail car so that they will not tip over. 4.10 Structural Steel Erection UNIT 4

▶ STRUCTURAL CONNECTIONS UNIT 5 ▶ OBJECTIVES After completion of this unit, you should be able to identify the types and charac- teristics of structural connections. This knowledge will be evidenced by correctly completing the assignment sheet and by scoring a minimum of 70% on the unit test. Specifically, you should be able to: 1. Identify different structural connection types and fastening methods This objective is covered in the pages that follow. Unit 5 — Structural Connections 5.1 UNIT 5

▶▶OBJECTIVE 1: STRUCTURAL CONNECTION TYPES AND FASTENING METHODS A connection is a junction between two members. These members are connected through pieces fabricated from plates, angles, or other rolled structural shapes. There are an almost infinite number of structural connection design possibilities, but strength, budget, and constructability dictate which connections are typically used in a structure. Two basic design types and four fastening methods are the most commonly used. These two basic design types are shear connections (includ- ing combination shear connections) and moment connections. The four fastening methods commonly used are bolting, welding, pinning, and a combination of bolt- ing and welding. Note: Shear, compression, torsion, load, axial, seismic, and moment forces can all affect the structural integrity of a connection, and therefore influence its design. Most common structural failures occur because of shortcomings within connections or forces which exceed those taken into consideration in the original design. It is a common misconception that the fabricator – or the structural steel detailer who is contracted by the fabricator – has a share in the design responsibility for a structure. This is not the case. Structural steel connections are very sensitive to even slight errors in design calculation, so the responsibility for their design (and of the integrity of the structure) rests with the EOR. Shear Connections Shear connections are used to connect a beam between a column flange or web surfaces, or from girder web to girder web, or any combination thereof. They allow for some rotation within a connection, use clips made from rolled angles or plates, and are usually shop-welded or bolted to the web of the beam and bolted to the column or girder in the field. Shear connections tend to be the most simple and least time consuming connection designs both for the fabricator and the erector, and are therefore the most com- monly used connections. They are used whenever possible. 5.2 Structural Steel Erection UNIT 5

As Table 5.1 illustrates, shear connections are fastened by bolting, welding, or a combination of bolting and welding. Combination shear connections are made with both bolts and welds to allow for forces such as twist, torsion, and compression. Table 5.1 Shear Connection Fastening Methods Moment Connections Moment connections are designed to transfer moment forces, as well as all other forces, between members involved in a connection. Moment connections are most commonly located between girders and columns, but they can exist between beams and girders and as an end splice between two beams. Shear Connection Fastening Methods Bolted Shear Connections Welded Shear Connections Bolted Angle Cleat Welded Angle Cleat Bolted Angle Seat Welded Angle Seat Combination Shear Connections Flexible End Plate Combination Angle Seat Web Side Plate or Shear Tab (Commonly Called a Knife Lug) Combination Angle Cleat Unit 5 — Structural Connections 5.3 UNIT 5

Moment connections give a structure additional strength and rigidity, and assist in resisting damage from extreme forces. Steel moment framed connections in par- ticular are popular for steel structures in high seismic areas. Shared or combination moment connections (those which use bolts and welds within the same moment connection), however, are prohibited in high seismic areas. Similar to shear connections, moment connections may be fastened by bolting, welding, or a combination of bolting and welding. These different fastening meth- ods are illustrated in Table 5.2. Table 5.2 Moment Connection Fastening Methods Moment Connection Fastening Methods Bolted Moment Connections Welded Moment Connections Bolted Girder to Column with Flange and Web Plates Welded Girder to Column Bolted End Plate Welded Flange and Web Plates Combination Moment Connection Welded Flange and Bolted Web 5.4 Structural Steel Erection UNIT 5

Pinned Connections Simply put, a pinned connection is a connection that uses pins in place of bolts or welds. Since pins are usually expensive, and it is virtually impossible to make a modifica- tion to pinned connections in the field, these connections are limited in application and are more rarely used than other types of structural connections. As a result, although pins can be used for making connections between structural shapes, built-up sections, eye bars, and/or rods, they are usually limited to bracing connections where small pins are adequate and to adjustable members composed of rods containing turnbuckles (adjustable members are used because they incorpo- rate tolerances for potential inaccuracies in pin hole fabrication). Figure 5.1 shows various pins and their accessories. Pins used for structures have diameters of 11⁄4\" to 24\" (or more). The entering ends of small pins are chamfered for ease in inserting, while the threaded ends of larger pins like bridge pins are fitted temporarily with pilot nuts to guide them through the holes and driving nuts for insertion. After a large pin has been driven, these nuts are removed and replaced with the appropriate permanent nuts. Figure 5.1 Pins and Accessories Unit 5 — Structural Connections 5.5 UNIT 5

Figure 5.2 illustrates the insertion of small pins using hand tools. When driving a small pin with a sledgehammer, use a soft- faced hammer or a block of hard wood as a pad between the end of the pin and the sledgehammer. Large pins are driven by the use of a block of steel or a timber suspended from the boom of a crane or from cable slings operated from scaffolding. Hydraulic jacks may also be used to force large pins into position. Double Connections Beams that use bolted angle cleat connections and share bolt holes between the webs of columns and girders over more than one bay in a struc- ture are called double con- nections. Figure 5.3 shows a double connection. Double connections are fre- quently hazardous. In order to connect the second mem- ber using the shared holes, the bolts in the first mem- ber must be loosened and the nuts removed. Because of the danger of a column falling away under this scenario, or of a worker falling if the loosened member she or he is sitting on gives way, a double connection is not allowed into a column web unless a seat lug or staggered clipped connection (see Figure 5.4) is used. Figure 5.2 Inserting a Pin Figure 5.3 Double Connection 5.6 Structural Steel Erection Figure 5.4 Clipped Double Connection UNIT 5

A clipped connection uses clips with extra holes on beams; each end connection has an extra hole on the bottom of the clip. When making a connection, this extra hole should be on the opposite side of the connection of the incoming beam. The first beam is then connected by bolting the extra hole in the longer clip and by bolting a second hole to stabilize the connection. When the next beam is erected, the bolt in the extra hole is left alone, while the other bolt is removed. The second beam is then bolted at its extra hole and another hole is bolted with a bolt that fas- tens both clips on either side of the shared girder or column. This allows for at least one bolt to remain in the connection at all times. If a seat lug (welded, bolted, or a combination) is used, it is connected so that the bottom flange of the member to be double connected rests on the seat lug. In other words, the first beam is bolted or welded to the seat lug, thus eliminating the need to remove bolts or nuts before attaching the second beam in the double connec- tion. Seat lugs are most commonly made of angles and are likely shop-attached to a column, girder, or beam so that a member (beam or girder) can be bolted or welded to it in the field. Unit 5 — Structural Connections 5.7 UNIT 5

5.8 Structural Steel Erection UNIT 5

▶ SECTION 2 ERECTING STRUCTURAL STEEL UNITS 6-13



▶ ERECTING COLUMNS AND BEAMS UNIT 6 ▶ OBJECTIVES After completion of this unit, you should be able to describe the processes involved in preparing and erecting columns and beams. This knowledge will be evidenced by correctly completing the assignment sheet, performing the skills in the perfor- mance exercise assessments, and by scoring a minimum of 70% on the unit test. Specifically, you should be able to: 1. Describe anchor bolt inspection and column base plate preparation procedures 2. Describe the three primary means of rigging columns 3. Explain the process of erecting columns 4. Explain the process of erecting beams, including beam-to-column and beam-to-beam connections 5. Identify column and beam splices 6. Describe adjustable, temporary, and fixed bracing 7. Describe the topping out ceremony Each of these objectives is covered in the pages that follow. Caution! Only employees essential to the operation are permitted in the load fall zone. Workers are prohibited from working under suspended loads except while connecting steel, and hooking or unhooking a load. Unit 6 — Erecting Columns and Beams 6.1 UNIT 6

▶▶OBJECTIVE 1: ANCHOR BOLTS AND COLUMN BASE PLATES Before a column can be erected, the shims, leveling nuts, or leveling plates in place should be checked to ensure that they are set at the proper elevation. Once they have been checked, the location, spacing, orientation, and projection of each set of anchor bolts should also be checked. They should be reviewed against the project’s blueprints both individually and as they relate to each other. If the orientation of the anchor bolts or the location of a set of bolts is incorrect, the problem should be brought to the attention of the controlling contractor as soon as possible. The controlling contractor can then arrange for the problem to be fixed before any delays in the steel erection occur. Caution! Prior to the erection of the column, the controlling con- tractor must provide written notification to the steel erector if there has been any repair, replacement, or modification of the anchor bolts. Do not begin erecting without ensuring that the required notification has been given. Anchor Bolt Location and Spacing Where there is excessive error in an anchor pattern placement in relation to grid- lines provided in a structure’s anchor setting plan, structural connections will not line up, making it so that when bolts are tightened in these connections, the col- umns will end up severely out of plumb. Anchor bolt locations and spacing should be checked for accuracy before a structure is erected to prevent this problem. The generally accepted tolerance from one anchor setting center to another along a grid line is +/- 1⁄4\". This is not an additive (or accumulative) tolerance. In other words, the +/- 1⁄4\" tolerance cannot be compounded across several sets of anchor bolts. If a first set is 1⁄4\" wider than it should be, the next set cannot be 1⁄4\" wider than it should be from the first set (if it is, the second set would actually be misaligned or improperly spaced by 1⁄2\"). Along a building line, the maximum tolerance is +/- 1\" over the entire length. Anchor bolt placement tolerances are given in Figure 6.1. 6.2 Structural Steel Erection UNIT 6

Figure 6.1 Anchor Bolt Placement Tolerances The location of each anchor bolt in relation to other anchor bolts in the same pat- tern should not deviate more than +/- 1/8\". In other words, the distance between anchor bolts on 10\" centers of a base plate at the concrete finish level should vary no more than 97⁄8\" to 101/8\". To account for these tolerances, base plate holes are standardly oversized at 5/16\" (1/16\" is typical for other holes in structural steel). Never make holes in base plates larger with a torch to make the base plate fit the anchor bolts, and never heat anchor bolts with a torch or straighten them without the approval of the Engineer of Record (EOR). Unit 6 — Erecting Columns and Beams 6.3 UNIT 6

Anchor Bolt Orientation Where there are anchor bolts that have one center-to-center dimension different from another, the anchor bolt pattern must be checked to ensure that it is properly oriented to prevent erection difficulties. If, for example, an anchor bolt pattern is 10\" by 14\" center-to-center, and the 14\" is supposed to be split by the numbered gridline but is actually split by the lettered gridline, there are bound to be problems during erection. Such problems may not be immediately apparent as long as the individual anchor bolts within a pattern are right on their centers because the column base plate will still fit. However, the problem will become obvious and serious once beams, tie- joists, or girts are being erected and it is discovered that the needed clips and holes are on the opposite side of the column! Anchor Bolt Projection Anchor bolt projection is the measured length that an anchor bolt sticks out of fin- ished concrete, and it is calculated to allow for proper shimming and securing of a base plate to concrete. Anchor bolt projection allowances are generally provided on ground floor anchor bolt plans and sections; however, normal tolerance is +/- 1/8\". If projection is too low, the shims provided for the base plate of the column to raise it to its proper elevation may make it difficult or impossible for a nut to fully engage the anchor bolt. Plug welding the anchor bolt and nut assembly together and then welding the nut to the base plate may remedy this problem; however, it will not allow for removal of the column without significant damage to the anchor bolt or the base plate. Another way to remedy the problem is to extend the anchor bolt by means of a cou- pler (an elongated nut). This allows the column to be removed or adjusted without damaging the anchor bolt or the base plate. If projection is too high, the nut cannot be tightened down on the base plate because the anchor bolt shank sticks out too far. This problem is commonly overcome by stacking structural washers on top of the base plate or by using a thread-cutting die to cut (make) more threads along the shank of the anchor bolt. Note: Do not make ANY alterations to anchor bolts or column base plates without the approval of the EOR. 6.4 Structural Steel Erection UNIT 6

Repairing Anchor Bolts While checking the layout of the anchor bolts, use a thread chase (also called a die nut) to repair any damaged threads. This will help to ensure that the nuts will run on the bolts and that valuable time is not wasted later (such as when a crane is holding a load). Anchor bolts that are severely bent or broken (see Figure 6.2) must be repaired according to specifications established by the EOR. If only minor discrepancies are found in the spacing of anchor bolts within one pattern, they may be repaired by using a pipe fitted over the bolt (the pipe should have a slightly larger inner diameter than the diameter of the anchor bolt). When fixing minor discrepancies, be careful not to cause thread damage. Anchor bolts may also be adjusted by placing a nut on them to protect the threads and then by striking the nut with a hammer to adjust the spacing of the bolts. If there has been any flattening of the threads, they must be cleaned, lubricated, and set straight with a thread chase. Column Base Plates After the anchor bolts have been inspected, each anchor bolt pattern on the footing or pier should be marked with the number of the corresponding column and/or base plate. Columns are usually fabricated with the base plates attached. However, for extremely large columns or when job specifications dictate, the base plate is set separately and the column is then field welded to it before or after grouting (again, this depends on what is outlined in the specifications). Each base plate should have a centerline scribed in both directions on it by the fabricator. If this centerline is missing, it should be marked by an Ironworker. Centerline marks should be aligned with the corresponding grid lines when the column/base plate is erected. When installing column base plates, note the elevation of the top of concrete through- out the job site. Where the concrete elevation exceeds the underside elevation of the base plate, the concrete will have to be chipped down to accommodate the column and to ensure that the steel is erected so that connections are at the proper elevation. Figure 6.2 Damaged Anchor Bolts Note: Always be conscious of instances where the base of a column extends below grade: holes for columns can fill with snow, water, ice, or trash and impede the timely erection of a structure. Unit 6 — Erecting Columns and Beams 6.5 UNIT 6

▶▶OBJECTIVE 2: RIGGING COLUMNS There are three basic means of rigging columns: rigging them with a wire rope choker and shackle, rigging them with two wire rope chokers or a bull tail, and rig- ging them with a slip-pin shackle system. Note: Only wire rope chokers (not synthetic slings or chokers) should be used to set columns. If a wire rope choker is choked around a column, the choker should be placed approximately 3 to 4 feet below the top of the column so that the column hangs as vertically as possible; this makes the column easier to erect. Place the eye of the choker, or shackle if one is used in choking directly to the column, between the flanges of the column. Rigging Columns with a Wire Rope Choker and Shackle To rig a column with a wire rope choker and shackle, first select the proper diam- eter and length of choker. A shackle – of proper size – should be used to make the choker easier and faster to remove after the column is in place and the anchor nuts are run down tight. The shackle is attached to the eye of the choker (the shackle is shack- led to the eye of the choker and the choker is choked through the shackle). The shackle should be placed so that the pin is towards the eye; this allows the choker to move on the body of the shackle when tightened. A rope can then be attached to the shackle (Figure 6.3) so that the shackle and the choker can be pulled down with the rope. Figure 6.3 Choker with Shackle and Rope Used for Column Rigging 6.6 Structural Steel Erection UNIT 6

Since the rope allows the choker to be pulled down the column while the operator simultaneously lowers the load, an Ironworker can pull it down to the point where she or he can reach it to unhook it, thereby eliminating the need for the headache ball safety latch to be deactivated. Rigging Columns with Two Wire Rope Chokers or a Bull Tail This method of rigging columns uses the same choker and shackle assembly described above in rigging columns with a wire rope choker, but it also uses a bull tail (or a choker that is longer than the choker choked around the column) shackled to the line above the headache ball, as is shown in Figure 6.4. When this method is used, an Ironworker does not need to play an active part in unhooking the choker (it is connected to the load line so that the operator can unhook it). The bull tail is hooked to the shackle, which is rigged directly to the column, while the safety latch on the headache ball is tied open and the choker on the column is hooked to the ball as usual, which allows the load to be released extremely easily. Figure 6.4 Using a Bull Tail or Chokers to Rig Columns Note: Tying back the safety latch is against regulations, but is allowed in some instances. When used, it may require other special precautions, procedures, documentation, and/or training. Unit 6 — Erecting Columns and Beams 6.7 UNIT 6

Rigging Columns with a Slip-Pin Shackle System For most multi-story buildings, for structures where the weight of columns is so great that choking a choker around a column is not practical, or when other conditions dic- tate (such as needing to release a column without exposing Ironworkers to unneces- sary fall hazards), columns may be rigged using a slip-pin shackle (Figures 6.5–6.7). Figure 6.5 Slip-Pin Shackle, Close-Up Figure 6.6 Slip-Pin Shackles Attached to Column With a slip-pin shackle, an Ironworker can stand on a decked or poured floor, or on the ground, pull the shackle’s rope and disconnect the choker, preventing the Ironworker from having to climb the column to release it. Slip-pin shackles are not manufactured by commercial rigging hardware manufacturers; they are devised in the field and make use of items such as rope (shown in Figures 6.5–6.7), eye bolts (as shown in Figure 6.6), and a spud wrench (as shown in Figure 6.7). Since columns are rigged from the top and not around (which may cause skewing), using a slip-pin shackle to set columns tends to ensure that the columns hang almost perfectly plumb. Figure 6.7 Slip-Pin Shackle Setup Being Used to Hoist a Column When using a slip-pin shackle, make sure that holes of the proper size (appropriate to receive the pin) have been drilled in the columns. 6.8 Structural Steel Erection UNIT 6

▶▶OBJECTIVE 3: ERECTING COLUMNS Ironworkers should only erect in a day as many columns as can be tied together with beams on that day. Before being hoisted into place, each column should be checked for bent lugs or other damage. If any damage is found, it should be repaired on the ground, where it is easily accessible. There are six basic steps in erecting columns: 1. Locate the correct column and hook up the rigging on the piece so that it hangs as close to plumb as possible. 2. Trip the column. 3. Hoist the column and position it over anchor bolts or splice plates. 4. Check to make sure the bottom of the column base plate is free of mud or other debris. 5. Lower the column into place (making sure that the piece is turned in the proper direction), then tighten the anchor nuts or insert and tighten all of the necessary bolts. 6. Signal the operator to release the load, remove the rigging hardware, and then flag the operator back to the hooker-on. Typically, the hooker-on (the Ironworker responsible for hooking on) uses whatever rigging system is being used to hook up the column, and then signals the crane oper- ator to hoist the load. While the operator is lifting the column, the hooker-on watches closely to make sure that the column does not catch on any other piece of steel. Once the column is vertical, the hooker-on signals the operator to swing the col- umn to the connectors (the Ironworkers who do the connecting), who are in posi- tion to set the column. At this point, one of the connectors takes over the signaling of the crane. Note: Foreman approval is required for any repairs. Unit 6 — Erecting Columns and Beams 6.9 UNIT 6

Next, the column is lowered onto the anchor bolts and, when the column sets down on the shim (Figure 6.8), leveling nuts, or leveling plates, the anchor nuts are tightened to secure the column (Figure 6.9). If a column is out of plumb enough to be a hazard, it should be taken care of while the crane is still hooked on to it, as Figure 6.10 demonstrates. An experienced journeyman or a foreman will make that decision. After the base plates or columns are set in place, minor adjustments may have to be made to the shims or leveling nuts to level the base plate or plumb the column. Once the column is plumb enough, the column rigging is removed from the column and placed back onto the headache ball. The flagman then flags the operator to swing back to the hooker-on and the process continues until all the needed columns are set. Figure 6.9 Nuts on Anchor Bolts Tightened to Secure the Column Figure 6.8 Ironworkers Guide a Column to Be Set on Shims Figure 6.10 Column Being Brought Closer to Plumb Before the Crane is Cut Loose Caution! Follow these safety tips when erecting columns: • Never position yourself directly under a suspended load. • Pay close attention to pinch points. • Do not release the load before the column has been secured. 6.10 Structural Steel Erection UNIT 6

▶▶OBJECTIVE 4: ERECTING BEAMS Generally, after the connectors finish erecting a structure’s columns, they fill their bolt bags with bolts and move to position themselves to hang steel beams. The fore- man or hooker-on helps direct the connectors to the location where the first beam will be erected, as well as to the locations of where subsequent beams will be erected. To get into position, the connectors climb up a column, stand a ladder up against a column (one connector works from the ladder while the other holds the lad- der securely), or use a lift as in Figure 6.11. Aerial lifts – either ele- vated working platforms or boom lifts – are used whenever applicable. They help eliminate Ironworker expo- sure to unnecessary fall hazards. Once on lift or ladder, the connectors are ready to erect beams. In building construction, “beam” is a generic term that can refer to any wide-flange or American Standard beam, no matter what its designed function is, while beams erected between or on the tops of columns are technically called girders. The term girder is most frequently used in bridge construction, and girders that are fabri- cated for bridges are generally larger than those used in building construction. However, like other types of beams, a girder performs the same function whether it weighs 700 pounds or 130 tons: it transfers loads from other, smaller, load-bearing pieces to the columns to which it is connected. The process of erecting girders and other beams, and the tools that are used, are therefore basically the same no matter the structure. There are two ways in which beams may be connected to a structure: beam-to- column connections and beam-to-beam connections. Figure 6.11 Connectors Using Aerial Boom Lift Unit 6 — Erecting Columns and Beams 6.11 UNIT 6

Beam-to-Column Connections A beam-to-column connection involves hanging a beam between or on top of two columns. This may require some- one on the ground to slightly loosen the nuts on the anchor bolts so that the columns can move enough to fasten the beam to the bearing plates or to allow the beam to slide between the columns (see Figure 6.12). Slightly loosening the nuts on the anchor bolts works for the first eleva- tion of steel attached to the columns only; there will be a minimal amount of give in the steel after this point, so later beam installations will require more effort on the part of the connectors. Figure 6.12 Ironworker on the Ground Loosens the Anchor Nuts Slightly Warning! Always re-tighten any anchor bolts that were loosened immediately after the piece is erected. When making beam-to-column connections, beams should be set in a box pattern rather than in one column line. When beams are erected in one column line, they are more prone to fall over if the columns are not shimmed properly, if wind speed increases, or if other unforeseen things occur. Beam-to-Beam Connections Beams can also be connected to other beams. Before any intermediate beams can be connected between other beams, all equipment such as boilers, generators, and/or motors should be in place inside the structure. When hanging intermediate beams, the connectors are able to work from the beams or girders already erected (see Figure 6.13). Figure 6.13 Connector Works from a Previously Erected Girder 6.12 Structural Steel Erection UNIT 6

Note: Unless otherwise dictated by rules, regulations, or safety poli- cies, the choice of whether to walk on the top of or coon a beam is left to the judgment of each Ironworker. This decision should be based on conditions such as wind velocity and size of the beam as well as personal preference; however, whenever possible, connectors should coon a beam instead of walking along the top flange. When erecting an intermediate beam, the connectors should skew the beam (i.e., make it not perpendicular) and flag the operator to lower the load enough to clear the top flanges of the two beams already installed. Once the load is properly lowered, one end of the beam that is being erected should be moved to the shear tab or bolt holes (depending on the design). A spud wrench or sleever bar is then inserted fully into a hole and the other end of the beam is brought to the lug or holes on that end. It may be necessary to use a beater or a sleever bar to move this end of the beam into position. Procedures for Erecting Beams Regardless of whether a beam fastens to the web or flange of a column, the web of another beam, or a splice plate (see Objective 5), the same basic steps are used to connect the pieces: 1. Place chokers on the correct beam as close to the center of the load as possible so that it will lift level and without a “roll” (refer to Figure 6.14). 2. Lift the beam into position and use a spud wrench or sleever bar to align the bolt holes (insert the spud wrench or sleever bar as far as possible into each hole). 3. Insert at least two bolts in each end and tighten them wrench tight. 4. After the beam is secured, one of the connectors signals the operator to release the load. At this time, the connector removes the choker, places the choker back on the hook, and signals the operator to swing back to the hooker-on. 5. The connectors then move to the next connection point. Figure 6.14 Beam “Rolled” During a Lift Unit 6 — Erecting Columns and Beams 6.13 UNIT 6

What this means is that, while the connectors are moving to their needed positions, the Ironworker doing the hooking on follows the foreman’s pick list (if one exists) and places a choker on the next appropriate beam as close to the center of the load as possible. Beams being lifted with a properly placed choker are shown in Figure 6.15. Figure 6.16 depicts a hooker-on sending beams to a connector. 6.14 Structural Steel Erection Figure 6.15 Beams with Choker Properly Placed Figure 6.16 Hooker-On Sending Pieces to the Connectors Note: Some companies require two chokers to be placed on each beam (see Figure 6.17) for safety. Always pay attention to and follow safety rules and job- and company-specific policies and procedures. Figure 6.17 Beam Rigged with Two Chokers and Safety Stanchions with Cable for Fall Arrest Anchorage UNIT 6

Just as with column erection, once a beam is in the air and is clear of obstructions, the connector who is in the best view of the operator takes over the signaling. The connector who can grab the beam first does so; if this connector is the signalperson, he or she continues to signal the operator until the beam is close to the position where it goes. The connectors then make the connection. As Figure 6.18 illustrates, experienced connectors work together as a team to make the job of beam erection easier. Being a connector requires patience and a lot of communication. The foreman will monitor the erection progress by referring to the blueprints to ensure that the correct beam is being hung at the proper eleva- tion, right side up, and turned in the right direction, but experience helps connec- tors recognize when a beam is hung at the wrong location or elevation, positioned upside down, turned in the wrong direction, or otherwise hung incorrectly. Tag Lines When used, a tag line should be placed on the end of the beam that will face the con- nectors (see Figure 6.19). For example, if a crew is working in a northern direction, and the connectors are both on the southern ends of the pieces being erected, the tag line should be placed on the southern ends of the pieces. In addition, when “filling in” intermediate beams between girders, it is likely that all of the piece mark numbers will face one direction. In these instances, the foreman or the hooker-on may choose to place the tag lines on all of the numbered ends of the girders to help indicate which end is the numbered end. Figure 6.18 Connectors Working Together as a Team Figure 6.19 Tag Line on End of Beam Unit 6 — Erecting Columns and Beams 6.15 UNIT 6

Caution! Follow these safety tips when erecting beams: • If you are a connector, work with your partner(s) as a team and communicate with each other at all times. • Never release a load until it has been properly bolted at both ends (with at least two bolts in each end drawn up wrench tight). • Keep your hands and fingers away from pinch points. • Do not sit or stand on a wrench or bar that has been inserted in a bolt hole unless you are properly tied off. • When possible, coon beams to reduce the risk of falling. • When working off of the ground, do not drop materials or tools. If you do drop something, yell “headache” as a warn- ing to anyone working below you. • To ensure that the proper size of rigging hardware is used when erecting beams and making connections, know the weights of the different beams being used. A great deal of variation may exist in the sizes and weights of different beams, even on the same elevation or floor. Multiple-Lift Rigging or “Christmas Treeing” A potentially dangerous rigging practice is the use of multiple-lift rigging, often referred to as “Christmas treeing.” Christmas treeing is performed by rigging up to five beams together with chok- ers and shackles (or, preferably, with chokers and a bull tail) to allow lower pieces to be set first. This is shown in Figure 6.20. Different designs of bull tails may be used for Christmas treeing, but whatever bull tail is used, it must be of a size that is sufficient to support the entire load, not just the weight of one of the beams. Figure 6.20 “Christmas Treeing” Using a Bull Tail and Three Beams 6.16 Structural Steel Erection UNIT 6

The most obvious danger in multiple-lift rigging is that the beams higher in the rig- ging assembly are over the heads of the connectors and may slip out of the chokers, be wind blown, or tip and swing onto the connectors while the lower pieces are being erected. Because of its dangers, multiple-lift rigging requires specific training and has specific regulations that govern its use. Do not to attempt multiple-lift rigging unless you have had specific training in it. Remember, however, that Christmas treeing is a common, legal, and accepted prac- tice. When all appropriate safety precautions are taken, and employees are trained in the method, it can be a safe practice as well. Unit 6 — Erecting Columns and Beams 6.17 UNIT 6

▶▶OBJECTIVE 5: COLUMN AND BEAM SPLICING Some columns are not placed on anchor bolts; they are placed on top of columns that have been erected previously. This is called a column splice. Beams can also be placed onto beams: these beam splices are connected by bolting one beam to the end of a previously erected beam. Depending on design factors, column splices use different methods to fasten one column to another, including bolting using splice plates, bolting using a cap and base plate, and welding. Beam splicing usually involves using splice plates. Bolted Column Splices Using Splice Plates Splice plates are one common method of bolting two columns together. These plates are usually attached – either in the fabrication shop or in the field – to the top of a column, as is shown in Figure 6.21. Because they are placed on the top instead of on the bottom of the column, these plates do not bend when the column is lifted from the ground. Before the column is erected, the bolts should be loosened just enough so that the column that will share plates can slide between the plates without binding. Once the column has been slid into place, the connectors use their tools to align the holes, and insert and tighten enough bolts to hold the column securely until the bolt up crew inserts all of the bolts at the connection. Figure 6.22 shows connectors aligning holes and inserting bolts into a column splice. Figure 6.21 Column Splice Plates Bolted to the Top of a Column 6.18 Structural Steel Erection Figure 6.22 Connectors Use Their Tools to Align Holes and Insert Bolts into a Column Splice UNIT 6

Bolted Column Splices Using Bearing Plate/Base Plate Design These column splices are the most simple and economical to erect in the field. A cap and base plate is welded to the column in the fabrication shop. In the field, the upper col- umn in the splice is simply lowered onto the lower column, the holes are faired up, and the bolts are inserted in the same manner as described for other splice plates. Figure 6.23 portrays a column splice with a bearing plate design (also called a base plate design). Welded Column Splices Column splices are not always bolted; some- times they are designed as welded connec- tions. As with other splice connections, in welded column splices the bottom of one column rests on the top of the column below. This type of splice usually has temporary connecting lugs on both the upper and lower columns, which are used to align and tem- porarily secure the column until it is welded (Figure 6.24). The temporary connection lugs should have all of the bolts inserted into them and be drawn up wrench tight before the load is released and the rigging hardware removed. A welded column splice may also use splice plates that are welded to each column, as shown in Figure 6.25. When this is the case, holes are typically located in the columns and in the plates for the connectors to use to align and secure the columns until they are welded. Beam Splicing Using Splice Plates As with the plates used in column splices, when using splice plates for beam splicing, connectors fair up the holes and insert bolts in the plates. Figure 6.23 Column Splice with Bearing Plate/Base Plate Design Figure 6.24 Welded Column Splice Figure 6.25 Welded Column Splice with Splice Plates Unit 6 — Erecting Columns and Beams 6.19 UNIT 6

In beam splicing (Figure 6.26), the flanges and webs of both beams must be even; if the beams are of different sizes, shim plates must be used between the flanges and/or webs to keep the centers in line. In some instances, a beam that was previ- ously erected will have one of the splice plates welded or bolted to the bottom of the flange to act as a rest for the beam currently being connected. This helps align both beams, making the connector’s job easier. Figure 6.26 Beam-to-Beam Connection Using Splice Plates 6.20 Structural Steel Erection UNIT 6

▶▶OBJECTIVE 6: BRACING Some structures have bracing that must be erected in conjunction with the rest of the structure. Bracing is used to temporarily or permanently stiffen, make firm, or brace elements of a structure. Bracing pieces are erected generally using the same tools and practices as beams. However, if the structure is not plumb, or if it is too rigid or too large for bolt holes to be aligned using a sleever bar, a steamboat ratchet, turnbuckle, or a come-along can be used to draw the bracing into position. Temporary Bracing All structural frameworks must be thoroughly cross-braced as bays or panels are erected to prevent their collapse under wind forces or erection loads. Temporary bracing can be used for this. Temporary braces are usually lengths of wire rope (called plumb lines) containing turnbuckles for tightening. Temporary bracing is typically removed after all pieces are bolted and/or welded in place. It is often, however, left in place until decking and/or sheeting installation is complete. Adjustable Bracing Adjustable bracing can be either temporary or permanent. It takes two primary forms: plumb lines (the temporary bracing described above) and adjustable rod diagonal bracing. Adjustable rod diagonal bracing is similar to plumb line bracing in that it is adjusted and tightened with turnbuckles. This type of bracing uses heavy rods (round bar threaded on the end to accept a turnbuckle) instead of wire rope. After all the parts of the structure are in place and all connections have been made, the turnbuckles are wired or blocked so they will not be loosened by vibration. The intersecting diagonals in any panel of adjustable bracing should be equally tight and under a slight initial tension. Because it would add stress rather than support to a structure, no slack in these diagonals is permitted. They must also not be brought so tight that they are under heavy stress. Unit 6 — Erecting Columns and Beams 6.21 UNIT 6

Fixed Bracing Some buildings have “X” or “cross” bracing that must be erected at the same time as the rest of the steel. The task of erecting this fixed bracing, which is the most common type of bracing and is nearly always permanent, follows the sequence of individual floor framing (i.e., it is completed as each floor is erected). Fixed bracing is usually lightweight (making a light choker sufficient for hoisting), and is adjusted when the structure is plumbed. When rigging fixed diagonal brace beams for erection, the choker should be placed closer to the end that will be higher in eleva- tion (off center), so that it hangs in a manner similar to that of the installed position (see Figure 6.27). This will make it easier for the connectors to make the connection. Figures 6.28-6.31 show different examples of fixed bracing. Figure 6.27 Beam Rigged for Diagonal Brace Figure 6.28 Bracing for 150' Trusses Figure 6.30 Fixed Bracing on Aluminum Truss Figure 6.29 Fixed Bracing Figure 6.31 Ironworker Connecting Bracing 6.22 Structural Steel Erection UNIT 6

▶▶OBJECTIVE 7: TOPPING OUT The topping out ceremony is a celebration cherished by Ironworkers. Whenever the skeleton of a bridge or building is completed, “topping out” is a signal that the uppermost steel member is going into place and that the structure has reached its height. The loca- tion of the structure being topped out does not matter. It could be a bridge across a canyon or river in an isolated area that is miles away from human habitation, or it could be a building in the heart of a busi- ness district in a large city. In any case, Ironworkers attach a national flag or an evergreen tree to the top- most member of a structure being erected either before it is raised to its position or, in some cases, after the member is placed (Figure 6.32). Figure 6.32 Topping Out Ceremony If a structure is in an isolated area, the celebration may amount to nothing more than three cheers and the waving of hard hats. However, in a big city where the building may cost millions of dollars to complete, the topping out celebration is sometimes attended by city officials, dignitaries, and other persons of prominence. Historical Background of the Topping Out Ceremony Although no one knows exactly how it started, the topping out ceremony has roots stretching back more than a thousand years. The symbol is tied to an old Scandinavian custom in which Norsemen venerated the evergreen. The trees were plentiful throughout Northern Europe and were used as building material and firewood. Viking chieftains often constructed high homes called mead halls in cel- ebration of a successful raid. After constructing the halls, the chieftains hoisted an evergreen tree to the ridgepole. The Germans and the Swiss also lay claim to the custom of using an evergreen to signal the completion of a new building. As iron and steel replaced timber as primary building materials, the custom of top- ping out evolved as well. When the last strands of cable were laid for the Brooklyn Bridge over a hundred years ago, the Ironworkers celebrated by placing American Unit 6 — Erecting Columns and Beams 6.23 UNIT 6

flags on the wheel used to help lay the cables. By 1920, U.S. Ironworkers were drap- ing their work with American flags. Why an American flag? This was probably because of the so-called “American Plan,” which was launched in 1919 during the post-war Red (i.e. Communism) Scare. The American Plan promised starvation wages, deadly hours, hopeless safety conditions, the dreaded “yellow-dog contract,” which forced workers to swear never to join a union, and ultimately, the destruction of unions. The American Plan suggested that unions were somehow un-American, so the presence of the American flag at topping out ceremonies made a strong state- ment confirming Ironworkers’ patriotism. The same topping out tradition is followed in Canada (with the Canadian flag sub- stituted for the American one). The final beam is usually painted white and signed by all of the Ironworkers on the site. One of the more notable topping out ceremo- nies in Canada was the final lift for the CN tower in 1976. The inside of the last section was signed by over 10,000 schoolchildren prior to being set by “Olga,” the Sikorsky helicopter that placed the member at its final height of 1,816 feet. The CN tower was the tallest free-standing structure in the world for 31 years and continues to be the tallest structure in the Americas. The use of both flag and evergreen may have arisen to balance the final beam. Still, some topping out ceremonies involve only the evergreen tree as a signal for celebration. Contemporary Topping Out Ceremonies No two contemporary topping out ceremonies are carried out in exactly the same way, and no ceremony has exactly the same meaning for every Ironworker. For some, the evergreen symbolizes that the job was completed without loss of life, while for others it is a good luck charm for future occupants. For some, the flag signals a structure built with federal funds, but for others it suggests patriotism and the American dream. The topping out ceremony, like all traditions, does not seem to consist of rules or a strict ritual. Nonetheless, tradition runs deep, and when Ironworkers raise the topping out beam aloft with its customary symbols, the flag and the tree, it offers a link with history. The ceremony is a proud connection between heroic people of a heroic past and today’s similarly hardy people who know what it is to face a chal- lenge and overcome it. 6.24 Structural Steel Erection UNIT 6

▶ INSTALLING JOISTS, JOIST GIRDERS, AND TRUSSES UNIT 7 ▶ OBJECTIVES After completion of this unit, you should be able to describe the historical back- ground of joists, joist girders, and bridging. You should also be able to identify joists and joist girders and explain the installation of joists, joist girders, and trusses. This knowledge will be evidenced by correctly completing the assignment sheet, performing the skills in the performance exercise assessment, and by scoring a minimum of 70% on the unit test. Specifically, you should be able to: 1. Identify open-web, long-span, and non-standard steel joists 2. Describe bar joist connections 3. Describe joist girders and joist girder connections 4. Describe the process of erecting joists and joist girders 5. Describe bridging 6. Describe trusses Each of these objectives is covered in the pages that follow. Unit 7 — Installing Joists, Joist Girders, and Trusses 7.1 UNIT 7

▶▶OBJECTIVE 1: STEEL JOISTS The first joist was created in 1923 as a Warren truss type joist (Figure 7.1) with top and bottom chords of round bars and a web formed from a single continuous bent bar. Figure 7.1 Warren Truss Configuration It was soon joined by many other types of joists, but these joists, all developed to various manufacturer’s designs and fabrication standards, caused problems by mak- ing it difficult for architects, engineers, and builders to compare rated capacities. To solve this problem, the Steel Joint Institute was created in 1928, and it has since strived for standardization and sound engineering practices in joist construction. Through its efforts, a standard load table covering spans of up to 96 feet and depths of up to 48 inches has been jointly approved by the Steel Joist Institute and the American Institute of Steel Construction (AISC). Other specifications have been similarly approved, and joists are currently governed by the Steel Joist Institute, AISC, and the Canadian Institute of Steel Construction (CISC). Joists in use today typically fall into two categories: open web steel joists and long span steel joists (which also include deep long span steel joists). Open Web Steel Joists The term “open web steel joist” refers to load-carrying members with parallel open web chords. These members are suitable for the direct support of floors and roof decks. Open web steel joists are also called short span joists or bar joists. They are 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, and is often used instead of a junior I-beam in an effort to reduce material costs without sacrificing strength. Bar joists typically span from one bayline (column or grid line) to another. 7.2 Structural Steel Erection UNIT 7

Figure 7.2 illustrates how bay lengths are measured to determine intended design strength. Figure 7.2 Bay Length Measurements Used to Determine Intended Design Strength Because bar joists have open webs, it is possible to run pipes or other fittings between the openings. Bar joists are placed so that they rest on top of the flanges of supporting beams, girders, or masonry walls. It is often best to hoist them in bundles with a rig. These bundles should be set at convenient points throughout a structure, and, if possible, individual joists should be properly placed by hand. Long Span Steel Joists Long span steel joists can be 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. Figure 7.3 illustrates various chord possibilities for joists. Except for offset, double-pitch joists, where depth should be given at the ridge, long span joist designa- tions are determined by a joist’s nominal depth at the center of the span. Part of the designation for these joists should be given as section number or total design load (TL) over design live load (LL): TL/LL. Deep long span steel joists share the same specifica- tions (nominal depth configurations and measure- ment criteria) as long span joists, but their depth and span measurements are greater than those of long span joists. Unit 7 — Installing Joists, Joist Girders, and Trusses 7.3 Figure 7.3 Chord Configurations for Long Span Steel Joists UNIT 7

Non-Standard Types of Steel Joists When the design of a structure may dictate (due to strength, durability, or cost), non-standard steel joists, such as those indicated in Figure 7.4, are also sometimes used. Whenever a non-standard steel joist is to be used, make certain you know of any limitations it may present in depth or length, and see your foreman if you have any questions or concerns. Camber Camber is the upward curvature of a joist or joist girder (see Objective 3) intended to compensate for antici- pated deflection to prevent sag under load. All pitched joists (refer back to Figure 7.3 for examples) are cambered in addi- tion to having a pitch, unless specified otherwise. When non-standard steel joists are used, the amount of camber desired should be provided on the structural drawings. Table 7.1 lists approximate cambers for standard joists based on chord lengths. Figure 7.4 Examples of Non-Standard Joists Top Chord Length Approximate Camber 20'0\" (6096 mm) 1⁄4\" (6 mm) 30'0\" (9144 mm) 3/8\" (10 mm) 40'0\" (12192 mm) 5/8\" (16 mm) 50'0\" (15240 mm) 1\" (25 mm) 60'0\" (18288 mm) 11⁄2\" (38 mm) 70'0\" (21336 mm) 2\" (51 mm) 80'0\" (24384 mm) 23⁄4\" (70 mm) 90'0\" (27432 mm) 31⁄2\" (89 mm) 100'0\" (30480 mm) 41⁄4\" (108 mm) 110'0\" (33528 mm) 5\" (127 mm) 120'0\" (36576 mm) 6\" (152 mm) 130'0\" (39621 mm) 7\" (178 mm) 140'0\" (42672 mm) 8\" (203 mm) 144'0\" (43890 mm) 81⁄2\" (216 mm) Table 7.1 Camber for Standard Types of Joists 7.4 Structural Steel Erection UNIT 7