COSC 254 3RD TEST
What are types of metal decking?
*Roof decking *Form deck *Cellular decking *Vented Metal Decking
What is a lockpin and collar fastener or swedge bolt?
*Same concept as a tension control bolt, except it has annular rings around it and is secured with a collar fastener instead of a nut
What are self-drilling screws?
*Screws that drill their own holes and form helical threads in the holes as they are installed. *They are plated with cadmium or zinc to resist corrosion
What are two instances where welding would be used in a shear connection?
*Single tab shear connection *Simple frame connections
In regards to mixing wood and light gauge framing in the same building, how are the two components typically used in regards to each other?
*Some builders find it economical to use wood to frame exterior walls, floors, and roofs, with steel framing for interior partitions. *Sometimes all walls, interior and exterior, are framed with steel, and floors are framed with wood.
What is done to brace light gauge steel construction?
*Steel straps screwed to the faces of the studs *1 1/2 inch channels passed through the punched openings in the studs and welded or screwed to an angle clip at each stud
Light gauge steel construction can be used in buildings normally framed with what size of wood members?
2 inch
At what intervals are holes punched in the factory in light gauge steel to allow for wiring, piping, and bracing to pass through?
2 foot
On average, how many junk cars does on mini-mill consume?
300,000
Steel with yield strengths of what two PSI's are used?
33000 and 50000 psi
Smelting is done in what?
A blast furnance
What is zinc?
A blue white metal that is low in strength, relatively brittle, and moderately hard
What is done to produce cylindrical shapes in metal?
A piece of metal is rotated against a stationary cutting tool in a lathe
What change is required by the IBC in regards to fireproofing as a result of the twin towers falling?
A higher bond of strength for spray applied fireproofing with occupied floors greater than 75 feet above the level of firefighter access
What are junction boxes supported on between studs?
A metal bracket
What is brass?
A metal formulated of copper and zinc plus small amounts of other metals. It is resistant to corrosion.
Roller Straightener
Corrects any residual crookedness in structural steel
Most metals _________ by oxidation.
Corrode
What is one of the longest single span roof structures in the world?
Cowboy Stadium
Hot Saw
Cuts continuous lengths of finished structural steel into shorter segments
What is plasma cutting?
Cutting with a tiny supersonic jet of superheated gas that blows away the metal. It can give more precise cuts than flame cutting at thicknesses of up to 2 inches
What creates structural tentlike roofs?
Fabrics and cables made of cold drawn, hig tensile strength steel wire
What are some things that are usually done to metals to protect them and enhance their appearance?
Finishing them with nonmetallic coatings such as paints, lacquers, organic coatings, porcelain enamel, and thermosetting powders.
When corrugated steel sheets are used for siding, what are they supported on?
Girts, which are horizontal Z-shapes or channels that span between the outside columns of the building
When would the other vertical flange of a joist hanger be used?
If the web of the joist were oriented to the left rather than the right.
What is magnesium?
It is a strong remarkably lightweight metal that is much used in aircraft but remains too costly for general use in buildings.
Light gauge steel compared with masonry walls, which can be constructed during wet or cold weather conditions?
Light gauge steel
Which can span longer distances? Light gauge steel construction or wood members?
Light gauge steel
Which is more prone to twisting or buckling? Light gauge steel members or wood?
Light gauge steel members
What two things can be combined together to produce thin, but relatively stiff, wall panel systems?
Light gauge steel studs and concrete
Prior to the beginning of the 19th century, metals had (great/little) structural role in buildings except in connecting devices.
Little
Threaded steel fasteners and other small parts can be galvanized through what process in which zinc is fused to the steel at room temperature in a tumbler that contains zinc dust, impact media, and other materials?
Mechanically galvanizing
What are the two ways to join metal components?
Mechanically or by fusion
Between ferrous and nonferrous metals, which tend to be more expensive?
Nonferrous
Light gauge steel members used for framing interior partitions and other nonloadbearing applications are specified as what?
Nonstructural metal framing (distinct from cold-formed metal framing)
Structural members that serve only to resist lateral forces are ___ required to be fireproofed.
Not
What are Partially-REstrained (PR) moment connections? (semi-rigid connections) moment resisting
Not as rigid as FR connections, but possess a dependable and predictable moment-resisting capacity that can be used to stabilize a building frame
For angles and HSS members, what is the shape designation followed by?
Numerals indicating depth, width, and thickness, in that order.
The bolts through the flange of the column are added as the beam is erected where?
On the construction site
What is the preferred location for continuous insulation in a metal framed wall or roof?
On the exterior (cold) side of the metal components, as shown in Figure 7.17.
What is an iron worker that temporarily assembles the beams and girders with enough bolts to keep them up
Raising gang
Loadbearing and nonloadbearing panels can be made that are suitable for use in what types of buildings?
Residential and light commercial
What types of doors are usually used for access in air supported structures?
Revolving doors
What types of insulation that can span across the stud cavities must be placed on one side or the other of light gauge framing members?
Rigid foam, semirigid mineral fiber, or other types of insulation.
What 3 ways can steel be joined together?
Rivets, bolts, or welds
Single corrugated sheets are commonly used for _____ ______.
Roof decking
What is zinc commonly used for?
Roofing and flashing
What are the two basic geometries used in anticlastic curvature?
Saddle and radial tent
What is usually made of hardened type 410 stainless steel?
Self-drilling and self tapping fasteners
What are light gauge steel members usually joined with?
Self-drilling screws
What type of connections are used where small changes in alignment could be detrimental to the performan of a structure?
Slip-critical
What are some ways to inspect welds?
Sophisticated magnetic particles, dye penetrants, ultrasonic, or radiographic testing procedures that search for hidden voids and flaws within each weld.
Weathering steel:
Steel without any protective finish that will remain exposed to exterior conditions in the completed construction
___________ members tend to be straighter and more uniform than ______ members and are much more stable dimensionally because because they are unaffected by changing humidity.
Steel; Wood
What is the rope the iron worker holds to guide the steel in its final place?
A tagline
What is steel?
A very small, closely controlled amount of carbon mixed with iron
What is the ASTM standard for wide-flange structural shapes?
ASTM 1992
What is the ASTM standard for manufacturing light gauge members?
ASTM A1003
What is the ASTM designatio nof mild structural steel?
ASTM A36
What is the designation of high-strength, low alloy steels?
ASTM A992 or ASTM A572 for high strength
What is the Bessemer Process
Air was blown into a vessel of molten iron to burn out the impurities
What are today's steel framing fireproofing look like?
Beam and column enclosures made of boards or slabs of gypsum or other fire-resistive materials (can also serve as the finished interior surface)
What is annealing steel?
Bringing steel to a high temperature and then cooling it very slowly. This makes it softer, easier to work with, and less brittle.
Copper is the primary constituent of which to versatile alloys?
Bronze and brass
How are trusses held in alignment during assembly?
By a simple jig made of plywood and blocks of framing lumber
How is air kept away from the electric arc?
By a thick coating on the electrode that melts to create a liquid and gaseous shield around the arc or by a core of vaporizing flux in a tubular steel electrode.
How is stainless made?
By alloying steel with other metals, primarily chromium and nickel, forming a self-protecting oxide coating that makes it highly resistant to corrosion
What are some ways copper can be formed?
By casting, drawing, extruding, and hot or cold rolling
How is steel often galvanized?
By coating it with zinc to protect against corrosion
How was fireproofing of steel framing originally done?
By encasing steel beams and columns in brick masonry or poured concrete
What metals are often used for electroplating?:
Chromium and cadmium
Cooling bed
Cools the structural shapes
What is an alloying element in certain corrosion-resistant steels?
Copper
What material has the highest thermal and electrical conductivity of any metal used in construction?
Copper
What are some common things that require soldering?
Copper plumbing and sheet metal roofing
What are expensive metals but often the most economical materials for applications that require their unique combination of functional and visual properties?
Copper, brass, and bronze
What does anticlastic curvature mean?
The fabric is curved simultaneously in two opposite directions.
Air supported structures are pressurized by what?
The fans that are used to heat, cool, and ventilate the building
What is done to steel wires and cables to make them so strong?
The metal is drawn through smaller and smaller orifices to produce the wire, a process that subjects the metal to a high degree of cold working.
Does thickness of the metallic coating vary depending on the severity of the environment in which the members will be placed?
Yes
Has steel taken over the need for ornamental metals?
Yes
Is it possible to frame any building with light gauge steel members that can be framed with nominal 2 inch wood members?
Yes
What is galling?
Tearing to the surfaces of joined members when referring to bolt connections.
Fabric structures are either ______ or _____.
Tensile; pneumatic
Roughly 40 percent of North American steel is made using what process?
The Basic Oxygen Process
What invention made steel so readily available?
The Bessemer Process
In a fully noncombustible light gauge steel frame building, what should floors be constructed of?
corrugated steel decking with concrete topping or precast concrete
The process of converting iron ore to steel beings with ______ of the ore into cast iron.
smelting
If the building is not too tall, the _____ crane will do the lifting for the entire building.
mobile
What are C-sections?
stud or joist sections
What are potential advantages of composite columns in tall buildings?
*Reduced steel usage *Greater rigidity of the building against wind forces *Simplified beam--column connections
What are some different ways bolts can be installed?
*Bearing-type connection *Slip-critical connection
How are large buildings made stable against the lateral forces of wind and earthquakes?
*Braced frames *Shear walls *Moment-resisting frames
How can concrete decks be erected?
*By pouring them in place over removable plywood forms *In the form of precast concrete planks lifted into place mcuh like the metallic elements of the building
What is light gauge steel sheet formed into? (Cold Formed)
*C-shaped sections to make short span framing members *Corrugated configurations utilized as floor and roof decking
What are some ways to deck a roof
*Corrugated metal with or without concrete fill *Rigid insulation boards as permanent formwork with a lightweight concrete fill *Corrugated water-resistive decks
What is a rigid perimeter? (tube structures)
*Diagonal bracing, shear walls, or beam to column moment connections are incorporated into the outer walls of the building frame and the entire interior structure is assembled with simpler shear connections
What are the three AISC beam-to-column connections?
*Fully Restrainted (FR) moment connections *Partially-Restrained (PR) moment connections *Simple connections
What is composite metal decking?
*It is designed to work together with the concrete floor topping to make a stiff, lightweight, economical deck. The decking serves as tensile reinforcement.
How is the header made?
*It is made of two joists placed with their open sides together *The top plate of the wall continues over the top of the header
What are some of the advantages of light gauge steel framing?
*It is versatile and flexible; requires only simple, inexpensive tools; furnishes internal cavities for utilities and thermal insulation; and accepts an extremely wide range of exterior and interior finish materials. *It may be used in buildings for which noncombustible construction is required by the building code
What are the two most successful and economical industrialized prefabrication systems in the US?
*Manufactured (mobile) home *Package industrial building
What are some ways to increase the strength of a member?
*Pass a stud through steel rollers so that a dense array of dimples are produced *Angles *Straps *Plates *Channels *Etc.
What are the 3 types of composite columns?
*Surrounding a steel wide-flange column with sitecast reinforced concrete *steel pipe filled with concrete *Wide-flange column inserted within steel pipe before concrete is added to create a higher loadbearing capacity
What is one thing structural drawings do not show that need to be determined by the fabricator?
*The length of each member *Routine connections of the frame
What are some ways to verify the necessary tension has been reached in tightening bolts?
*Turn of nut method *Direct tension indicator (DTI) *Tension control bolt *Lockpin and collar fastener or swedge bolt
Wide-flange shapes
*Used for most beams and columns *Depths from 4 to 44 inches *9 to 730 pounds per foot
The greater share of structural steel is made form virtually what percentage of scrap steel in mini mills?
100
What is the actual depth of a wide flange beam?
12.22 inches
When did steel become plentiful and inexpensive?
1850s
When was the Eiffel Tower built and out of what?
1868. Wrought Iron
Columns are generally fabricated in _____ story lengths
2
Light gauge members correspond closely to the dimensions of the standard sizes of nominal ______ inch framing lumber.
2
Steel framing is erected every _____ stories.
2
Using, the Bessemer Process, how long would it take to transfer a piece of iron into steel?
20 minutes
Nominal gauge of loadbearing members:
20-10 gauge (10 is thicker) in factors of 2
What is the spacing of light gauge steel framing compared to wood?
24 inches o.c. rather than 16 inches o.c.
Nominal gauge of nonloadbearing members:
25-14 gauge (14 is thicker) in factors of 2
Studs in tall walls are generally braced at how many feet?
4
In a slip critical connection, what percent of their ultimate tensile strength must they be tightened to?
70 percent
What does 600S162-54 mean?
6 inch deep (600), stud or joist section (S), 1.625 in wide (162), made from 54 mil thick sheet metal (54)
What is the width of a wide flange?
6.49 inches
What is a topping-out party?
A ceremony for the placing of the last beam.
When steel is shipped to a fabricator, what accompanies it?
A certificate that gives the chemical analysis of that particular batch
What is cut from the top of the beam web to permit the backup bar to pass through?
A clearance hole
Flutter and perimeter uplift forces has restricted spans of air supported structures to what?
A few hundred meters
What is the basic oxygen process?
A hollow, water cooled lance is lowered into a container of molten iron produced from ore along with recycled steel scrap. A stream of pure oxygen at very high pressure is blown from the lance into the metal to burn off the excess carbon and impurities. A flux of lime and fluorspar is added to the metal to react with other impurities, particularly phosphorus, and forms a slag that is discarded.
What are open web steel joists/
A mass produced truss used in closely spaced arrays to support floor and roof decks
What is machining?
A process of cutting unwanted material from a piece of metal to produce the desired shape
What makes a mobile home possible?
A rigid undercarriage (chassis) welded together from rolled steel shapes
What is the top plate of a wall made of?
A runner channel
In typical window or door heads, what is used to frame the top of the opening?
A runner channel that is cut and folded at each end
What is tin?
A soft, ductile, silvery metal that forms a self-protecting oxide layer.
What is a rivet?
A steel fastener consisting of a cylindrical body and a formed head. It is brought ot a white heat in a forger, inserted while hot through holes in the members, and hot worked with a pneumatic hammer to produce a second head opposite the first.
What is a package industrial building based on?
A structure of welded steel rigid frames supporting an enclosure of corrugated metal sheets.
What is a steel space truss? (space frame)
A truss made 3 dimensional carrying its load by bending along both of its axes, much like a two-way concrete slab
What are light gauge members nested into to form a strong enough configuration for a ridge board or header?
A tubular configuration
What are web stiffeners?
A two-piece assembly that is inserted inside a joist and screwed to its vertical web to help transmit wall loads vertically through the joist.
What is anodizing?
Adding a thin oxide layer of controlled color and consistency to the surface of a metal
What is an alternative to soldering in non-structural applications?
Adhesives
What is an example of a pneumatic structure?
Air supported structures
Nonferrous metals
All other metals that are not ferrous
What are metals mixed with other metals called?
Alloys
What is the nonferrous metal most often used in construction?
Aluminum
With a mirror finish in foil or sheet form, reflects more heat and light than any other architectural material?
Aluminum
What is terne metal?
An alloy of 80 percent lead and 20 percent tin
What is bronze?
An alloy that combines copper with a small amount of tin
The effects of cold working are easily reversed by what?
Annealing
How are exposed structural steel members specified as where a high standard of appearance quality is desired?
Architecturally exposed structural steel (AESS)
What is aluminum oxide used for?
As an abrasive in sandpaper and grinding wheels
What are channel sections used for?
As truss members and bracing, and for short beams, lintels, and stringers in steel stairs
What are copper salts used for?
As wood preservatives
Small rectangular ______ ______ are welded beneath the end of each beam flange to prevent the welding arc from burning through.
Backup bars
For deep welds, what is put beneath the groove before welding begins to prevent the molten metal from flowing out the bottom of the groove?
Backup bars or backing bars
What tend to be more structurally efficient than moment frames?
Braced frames and shear walls
What has riveting been replaced by in the present day?
Bolting and welding
Slip-critical connection?
Bolts are preloaded (tightened during installation) to such an extent that friction between the adjoining faces of the steel members (the faying surfaces) resists movement between the members.
What is a bearing type connection?
Bolts need only be installed to a snug tight condition. Movement between the joined members is resisted by the bolts themselves as the sides of the bolt holes in the connected members bear against the bodies of the bolts.
What is a tension control bolt and what are some of its advantages?
Bolts that have protruding splined ends that twist of under adequate tension. *An advantage of using them is that they can be installed by a single worker, unlike conventional bolts, which require a second worker with a wrench to prevent the other end of the bolt assembly from turning during tightening.
What is done to light gauge members to prevent twisting and buckling?
Bracing and bridging
How would screw threads in metal be produced in a hole?
By the use of a helical cutting tool called a tap
How are high temperature fusion connections made?
By welding
How are rigid steel frames efficiently produced?
By welding together steel wide-flange sections or plate girders
What is sometimes done to beams and girders so that they will deflect into a straight line under load
Cambering (curved slightly in an upward direction)
What are simple connections? (shear connections)
Capable of unrestrained rotation under normal loading and have negligible moment-resisting capacity
What was the first all metal structure made from?
Cast Iron and it was a bridge
What are some examples of ferrous metals?
Cast iron, wrought iron, steel, and stainless steel
What process of forming steel tends to produce somewhat weaker metal than most other processes, but it is useful for making elaborate shapes that could not be manufactured economically in any other way?
Casting
What are alloys of zinc commonly used for?
Casting small hardware parts such as doorknobs, cabinet pulls and hinges, bathroom accessories, and components of electrical fixtures
"U"
Channel
What two things are used for lighter bracing and framing tasks?
Channel sections and furring channels
MC10x8.4
Channel shape (MC) Nominally 10 inches deep (10) Weighing 8.4 pounds per foot (8.4)
Stuff still need to read:
Chapter 11 and 96-140 in the course packet
What is coke?
Coal whose volatile constituents have been distilled out, leaving only carbon.
What can be done to change the appearance of metal or to protect it from oxidation?
Coating it with a thin layer of another metal
What process of forming steel will harden and strengthen many metals?
Cold drawing and cold rolling
What types of steel shapes with substantially higher strengths than hot-rolled structural steel are used as reinforcing and as components of open web joists?
Cold rolled steel shapes
What term is used for light gauge steel members used in structural applications and exterior wall cladding systems?
Cold-formed metal framing
Shear studs are welded every few inches to the top of each beam in what type of decking?
Composite metal decking
A strip of the slab in composite metal decking can be assumed to act together with the top flange of the steel to resist ______ forces
Compressive
How do you make a moment connection?
Connect the beam flanges strongly across the joint by means of full penetration groove welds
What is another way of adding energy absorbing capacity into a building frame?
Damping devices such as buckling restrained bracing
What does lateral bracing for walls consist of?
Diagonal steel straps screwed to the studs
What 2 things are around openings in steel light gauge construction?
Double members and headers
Headers and trimmers for floor openings are ______ and _________ to create a strong, stable box member.
Doubled, Nested
What produces holes in metal?
Drilling
What are the differences between welding in a shop and in the field?
Economies and Structural continuity
What is the less durable form of galvanizing?
Electrogalvanizing
What refining process produces aluminum?
Electrolysis
What are some standard accessories for light gauge steel framing?
End clips, web stiffeners, foundation clips, v-bracing, joist hangers, flat strap bracing, and 1 1/2" cold rolled channels
What is the group that puts together steel framing?
Erectors
What are some examples of ways stainless steel is used?
Fasteners, roofing and flashing sheet, hardware, railings, and other ornamental metal items.
What would be mechanically fastening?
Fasting with drilled or punched holes for the insertion of screws, bolts or rivets.
What are the two classifications of metals in building construction?
Ferrous and nonferrous
Which category of metals is the strongest but most have a tendency to rust?
Ferrous metals
What are nonferrous metals typically used for because of their attractiveness, being easy to work with, and their resistance to corrosion?
For finish components of buildings
What is the most use of zinc in construction?
For galvanizing
What process of forming steel will impart a grain orientation to the metal that closely follows the shape of the piece for improved structural performance?
Forging
What is one way to increase the span of a standard beam?
Form a castellated beam by cutting the member in a zigzag and welding point to point
What is the design process in tensile structures referred as?
Form finding
What was cast iron used for in the first half of the 19th century? And why was its usefulness limited?
Framing. It was limited by the unpredictable brittleness of cast iron and its relatively high cost.
"F"
Furring
The thermal conductivity of light gauge steel framing members is greater or less than wood and any other primary structural material?
Greater
The _________ and ________ used hidden cramps of bronze to join blocks of strone, and architects of the ___________ countered the thrust of masonry vaults with wrought iron chains and rods.
Greeks; Romans; Renaissance
Exterior walls are sheathed with what?
Gypsum sheathing panels
Light gauge steel construction may be classified as either Type I or Type II construction if protected with what materials?
Gypsum sheathing, gypsum wallboard, or plaster
What are some lesser known fastening techniques?
Hand-held clinching devices and pneumatically driven pins that penetrate the members and hold by friction.
What are high strength bolts?
Heat treated during manufacturing to develop their greater strength used for structural steel connections
Properties of many metals can be changed by what?
Heat treatment
What is forging metal?
Heating a piece of metal until it become soft, then beating it into shape. It was originally done by hand with a blacksmith's forge, hammer, and anvil. Now most forging is done with powerful hydraulic machinery that forces the metal into shaped dies.
What is tempering steel?
Heating it to a moderate degree and cooling it more slowly, making it both hard and strong.
What is quenching steel?
Heating steel until it is red-hot and then plunging it into cold water.
What are one of the longest-span structural forms available to the building designer?
Heavy arches
What type of iron ore that is used to make steel has been depleted in many areas of the earth?
High grade iron ore
What type of bolts are used in steel frame construction?
High strength and carbon steel bolts
what types of steels are produced in mini-mills?
High-strength, low-alloy steels
Where is weathering steel most used?
Highway and bridge construction
What self-annealing process does not increase the strength of metal?
Hot rolling
The manner in which a bolted structural steel connection derives its strength depends on what?
How the bolts are installed
What is a major problem in the assembly of slip-critical connection?
How to verify that the necessary tension has been achieved in each bolt
Where is tin usually found?
In buildings primarily as a constituent of terne metal
What are some common uses of brass?
In doorknobs, weather stripping, ornamental metal work, screws, bolts, nuts, and plumbing faucets
Where is Type 316 typically used?
In marine environments
How are bearing type connections stressed?
In shear
How are slip-critical connections stressed?
In tension
Angles are usually bolted to the web of the beam where?
In the fabricator's shop
What is magnesium usually used for?
In various lightweight tools and as an alloying element that increases the strength and corrosion resistance of aluminum.
What is an abundant mineral found in ferrous metals and is relatively easy to refine?
Iron ore
What is the erectors labor force?
Ironworkers
ASTM A913 Steel
Is subjected to a process of quenching (rapid cooling) and then tempering (partial reheating) to give the steel an optimized balance of strength, toughness, and weldability
What does an end clearance do?
It allows for slight inaccuracies in connections and makes it easier to lower the beam into place during erection
What is electroplating?
It coats metals such as chromium and cadmium onto steel to improve the appearance of the steel and protect it from oxidation
How does a flame cutting torch cut steel?
It combines a slender high-temperature gas flame with a jet of pure oxygen to burn away the metal
What is laser cutting?
It cuts thin metal plates with high quality precision
How does zinc prevent corrosion? And what is this process called?
It forms a self protecting gray oxide coating, and even if the zinc is accidentally scratched through to the steel beneath, the zinc interacts electrochemically with the exposed steel to continue to protect the steel from corrosion. It is called galvanic protection
What is Type 316 stainless steel?
It has a higher nickel content than 304 and the addition of small amounts of molybdenum. It is more corrosion resistant than Type 304
What is Type 410 stainless steel?
It has a lower chromium content and is less corrosion resistant than the 300 series alloys. It allows it to be hardened through heat treatment
What is chromium?
It is a very hard metal that can be polished to a brilliant mirror finish. It does not corrode in air. It is often electroplated onto other metals for use in ornamental metalwork, bathroom and kitchen accessories; door hardware, and plumbing and lighting fixtures
What is steel?
It is any range of alloys or iron that contain less than roughly 2 percent carbon
What is titanium?
It is low in density, about half the weight of steel, and very strong. It is one of the most corrosion resistant metals. It is a constituent in many alloys, and its oxide has replaced lead oxide in paint pigments. It is sometimes used in architectural sheet metal for siding and roofing
What is mild steel?
It is ordinary structural steel that contains less than 3 tenths of 1 percent carbon, plus traces of beneficial elements such as manganese and silicon and of detrimental impurities such as phosphorus, sulfur, oxygen, and nitrogen
What is wrought iron?
It is produced by hammering semi-molten iron to produce a metal with long fibers of iron interleaved with long fibers of slag. It is much less brittle than cast iron
What are some advantages to bolting?
It is quick and easy for field connections that need only resist shearing forces, and it can be accomplished under conditions of adverse weather or difficult physical access that would make welding impossible.
What are characteristics of copper?
It is slightly more dense than steel and is bright orange-red in color. When it oxidizes it forms a self protecting coating that ranges in color from blue green to black, depending on the contaminants in the local atmosphere. It is moderately strong and can be made stronger by alloying or cold working, but it is NOT amenable to heat treatment.
What is typical of an alloy?
It is stronger and harder than the elemental metal that is its primary ingredient
In cold regions, what must be done to light gauge steel framing in order to minimize thermal bridging?
It must be detailed and insulated
What is the staggered truss system?
It relies on story high steel trusses, staggered on alternating floors of a building structure, and spanning between perimeter columns, to support the floors and roof.
Steel's Weaknesses
It tends to corrode in certain environments and is loses strength during severe building fires
What is a braced frame?
It uses diagonal bracing to create stable triangular configurations within the otherwise naturally unstable rectilinear geometry of the frame *This is a shear connection *This connection is capable of the small rotations necessary for it to behave essentially as if it were hinged
A metal is seldomly used in what state?
Its chemically pure state
What are some great qualities of aluminum that make it better in some situations than steel?
Its density is about one-third of steel and it has moderate to high strength and stiffness, depending on which of a multitude of alloys is selected. It can be hardened by cold working, and some alloys can be heat treated for increased strength. It can be hot or cold rolled, cast, forged, drawn, and stamped, and is particularly well adapted to extrusion
What is the largest issue concerning the sustainability of light gauge steel construction?
Its high thermal conductivity of framing members. Meaning, it conducts hot and cold very well. Therefore, proper insulation surrounding the entire member is needed.
What are used to bridge floor joists in light gauge steel construction?
Joist blocking between the joists or steel straps screwed to their top and bottom edges
What two things are used to join members around openings?
Joist hangers and right angle clips of sheet steel
What are CJ composite joists?
Joists rated for composite floor construction
Most buildings that use open web joists utilize which series?
K
What are the three series open-web joists are produced in?
K series (spans up to 60 ft [depth 8 to 30 in]), LH series (longspan 96 ft [depth 18 to 48 in]), DLH Deep Longspan (52 to 72 in deep [span up to 144 ft]),
Shear connections are not on their own adequate for providing _____ resistance.
Lateral
What types of buildings would require noncombustible steel construction?
Larger buildings and those whose uses require a higher degree of resistance to fire.
What are carbon steel bolts?
Lower strength bolts used to fasten minor framing elements or temporary connections.
What are brazing and soldering?
Lower-temperature processes in which the parent metal is not melted. Instead, a different metal with a lower melting point is melted into the joint and bonds to the pieces that it joins.
What is rolling steel?
May be done either hot or col, it forms the metal by squeezing it between a series of shaped rollers.
What is cellular decking?
Manufactured by welding together two sheets, one corrugated and one flat. It can be made sufficiently stiff to support structural loads *It provides spaces for electrical and communications wiring
What is vented metal decking?
Manufactured with small, slotted openings comprising roughly 1 percent of the overall decking area. *Sometimes is used where impermeable roofing membranes are installed over lightweight insulating concrete fills to allow excess moisture in the concrete to escape downward through the decking, rather than become trapped under the roofing membrane.
Which is stiffer and more resistant to the passage of sound? Masonry walls or steel framed walls?
Masonry
What is often used between the subfloor and the steel framing to provide cushioning between the joints?
Mastic adhesive
In situations where noncombustibility is not a requirement, what two materials can be mixed in the same building?
Metal and wood light framing
What is aluminum powder used for?
Metallic paints
What are the strongest building materials presently in common use?
Metals
What are die castings?
Metals that are electroplated with another metal such as chromium for appearance, are not especially strong, but they are economical and they can be very finely detailed
What are members coated with to protect against corrosion?
Mettalic coated with zinc or aluminum-zinc alloy
Mini-mills produce stronger, less expensive steel than what?
Mild structural steel
What is the most common machining operation?
Milling
Are ornamental metals in present day produced with the same processes like the past?
No
How many vertical flanges of teh joist hanger are attached to the joist?
Only one
What is the most common structural steel product fabricated from hot and cold rolled shapes?
Open web steel joists (OWSJ)
What are metals normally mixed with to modify its properties fora particular purpose?
Other metals
Metals are usually found in nature in the form of what?
Oxide ores
What increases the risk of condensation within the framing cavity of a light gauge steel wall?
Placing continuous insulation on the interior, warm side of the framing
What is a fabricated way to make beams span longer distances?
Plate girders
Framing of light-gauge steel construction proceeds in a ___________ fashion.
Platform
What are used to cut light gauge steel?
Power saws, special electric shears, or hand shears
What are joist girders?
Prefabricated steel trusses designed to carry heavy loads, particularly bays of steel joists.
What are often screwed or welded together to frame ceilings and roofs?
Prefabricated trusses of light gauge steel members
What allows builders to design and construct light gauge steel framed houses without having to employ an engineer or architect?
Prescriptive requirements in the International Residential Code for One- and Two-Family Dwellings
How is roofing sheet and ductwork metal joined?
Primarily with interlocking, folded connections
How is metal decking usually welded?
Puddle welding
What is drawing metal?
Pulling a metal rod through a series of progressively smaller orifices in hardened steel plates until the desired diameter is reached to produce wires
What can be done to steal to make it harder than heat treatment but very brittle?
Quenching
What are some typical uses of aluminum
Roofing and flashing sheet, ductwork, curtain wall components, window and door frames, grills, ornamental railings, siding, hardware, electrical wiring, and protective coatings for other metals, chiefly steel.
What is zinc-tin alloy coated steel and stainless steel sheets usually used for?
Roofing metals that are close in appearance and durability to traditional terne metal.
What are the primary uses of copper?
Roofing, flashing sheet, piping, tubing, wiring for electricity, and communicaitons
How much recycled material does steel made by the basic oxygen process contain?
Roughly 25 to 35 percent
In some cases, what are required at the ends of a groove weld (deep weld) to facilitate the formation of a full thickness of weld metal at the edges of the member?
Runoff bars
What used to be used for floor and roof decking?
Shallow arches of brick or tile were often built between the beams, tied with steel tension rods, and filled over with concrete to produce level surfaces.
How is structural steel labeled?
Shape designation and number fo the batch of steel from which it was produced.
Strength and stiffness of members depend on what factors?
Shape, size, and strength and thickness of sheet metal used when manufacturing it.
What are the two types of connections?
Shear and moment connections
In loadbearing applications, concrete panels provide _______ resistance while the steel studs provide most of the resistance to ________ and ______ loads acting perpendicular to the face of the panel.
Shear; gravity; wind
What is used to cut metal sheets?
Shears
How is light gauge steel frame construction manufactured?
Sheet steel is fed from continuous coils through machines at room temperature that cold work the metal and fold it into efficient structural shapes.
___________ ________ brace the last joist at the end of the building and help transmit stud forces through to the wall below.
Short crosspieces
What are placed between the runner channel that frames the top of the opening and the header above?
Short studs that maintain the rhythm of the studs in the wall
Wood trim in light gauge steel construction is attached with what?
Special finish screws, which are analogous to finish nails, which have very small heads
Where steel frame fireproofing material does not need to serve as a finished surface, what is used?
Spray-applied fire-resistive materials (SFRM) "Spray-applied fireproofing". These are most prevalent
What is the least expensive form of steel fireproofing?
Spray-applied fireproofing
What is the most common type of fireproofing in steel structural frames?
Spray-applied fireproofing
Light gauge steel shapes are furnished in ______ lengths and are cut to length where?
Standard. They are cut to length on the construction site.
What is the densest structural material?
Steel
Which is lighter? Steel or wood framing members?
Steel
What is rigid insulation board usually supported on when being used as permanent formwork?
Steel subpurlins
What are fabricated roof trusses for lighter loads typically made of?
Steel tee or paired-angle top and bottom chords with paired angle internal members
What are put in locations where large vertical forces must pass through floor joists to prevent them from buckling?
Steel web stiffeners are screwed to the thin webs of the joists
What are the highest-strength metals used in construction?
Steel wires and cables used to prestress concrete
What would you do if the column flanges were insufficiently strong to accept the forces transmitted form the beam flanges? What would this be called?
Stiffener plates would be installed inside the flanges of the column to better distribute these forces in to the body of the column.
Welded connections, properly designed and executed, are (stronger/weaker) than the members they join?
Stronger
What is HSS?
Structural tubing that is often used for columns and for members of welded steel trusses and space trusses. Their hollow shape makes them especially suitable for members that are subjected to torsional stresses or buckling associated with compressive loads.
Concrete on light gauge steel can be connected to the face using what types of fasteners?
Stud anchors,sheet metal shear strips, welded wire reinforcing, or expanded metal that is welded or screwed to teh studs adn tehn becomes embedded in teh concrete.
"S"
Stud or joist
What additional materials contribute significantly to resistance to buckling, twisting, and lateral wind and earthquake loads?
Subflooring, wall sheathing, roof sheathing, and interior finish materials
What are Fully Restrained (FR) moment connections? (rigid connections) moment resisting
Sufficiently rigid that the geometric angles between members will remain virutally unchanged under normal loading
What is the rigid core?
The central area containing elevators, stairs, mechanical chases, and washrooms, is structured as a stiff tower, using diagonal bracing or shear walls *Moment connections are generally not efficient enough to stiffen a rigid core *The rest of the building can be connected with shear or moment connections and rely on the core for its lateral stability
What is an eccentrically braced frame?
The ends of diagonal braces are offset some distance from each other where they connect to horizontal members *These connections introduce greater energy-absorbing capacity or resilience into the building frame, important for resistance to severe earthquake stresses *Shear connection
What is another economical way to make steel that was developed in Europe in 1868?
The open-hearthed method
What does 18-8 refer to?
The percentages of chromium and nickel, respectively
What is casting?
The process of pouring molten metal into a shaped mold while it cools
What is extruding metal?
The process of squeezing heated but not molten metal through a shaped die to produce a long metal piece with a shaped profile matching the cutout in the die.
What is stamping metal?
The process of squeezing sheet metal between two matching dies to give it a desired shape or texture.
What is the most common arrangement in stabilizing a building frame?
The rigid core
What is significant about MC 10x8.4?
The same form is used for wide-flange American Standard, and tee shapes
What must be done to steel members that extend from inside to outside of a building enclosure?
The steel members must be broken, insulating spacers must be inserted between inside and outside steel, or some other method must be used to prevent thermal bridging at such locations.
What are some problems that occur whenever light gauge steel members are not insulated?
The thermal performance of the wall or roof is greatly reduced, energy losses increase substantially, and moisture condensation within the framing cavity or on interior building surfaces may occur, with attendant damage to materials, growth of mold and mildew, and discoloration of surface finishes.
What are gypsum sheathing panels?
They are similar to gypsum wallboard but made more resistant to moisture and weather with glass mat faces and specially formulated water-resistant gypsum cores.
What are end clips?
They are used to join members that meet at right angles.
What are foundation clips?
They attach to the ground-floor platform to anchor bolts embedded in the foundation.
What are joist hangers?
They connect joists to headers and trimmers around openings.
What do nonferrous metals do naturally that protect them from further corrosion?
They form thin, tenacious oxide layers
What do bolts do in moment connections?
They hold the beam in place for welding and also provide shear resistance
What is a structural problem with steel when it comes to heat and fire?
They lose their structural strength and stiffness rapidly
What do short masts do in tensile structures?
They minimize buckling problems
What are moment-resisting frames? (rigid frames)
They rely on stronger and stiffer moment connections between beams and columns to provide lateral stability. *Not all of the connections in the frame must be moment connections *They are more difficult to make, therefore, they are used only to the extent required, with the reaminder of the frame relying on simpler, less costly shear connections
What are intumsecent mastics an intumescent paints?
Thin coatings that allow steel structural elements to remain exposed to view in situations of low to moderate fire risk *They expand where exposed to fire to form a thick, stable char that insulates the steel from the heat of the fire for varying lengths of time, depending on the thickness of the coating
How does cold working cuase the steel to gain considerable strength?
Through a realignment of its crystalline structure
Why are column splices made at waist height?
To avoid interference with beam to column connections and as a matter of convenience
Why would a beam be cut into a dog-bone configuration?
To create zone of the beam that is slightly weaker in bending than the welded connection itself. During a violent earthquake, the beam will deform permanently in this zone while protecting the welded connection against a more severe failure.
Where light gauge steel construction is mixed with wood, special care must be taken in the details to ensure what?
To ensure that wood shrinkage will not create unforeseen stresses or damage to finish materials.
What is a very specialized way to fireproof the building applicable to only steel box or tube columns exposed on the exterior of building?
To fill the columns with water antifreeze
Why must air be kept away from the electric arc?
To prevent rapid oxidation fo the liquid steel
Why is cold rolled steel utilized?
To produce small section steel rods and steel components for open web joists where the higher strength can be utilized to good advantage. *It also can be drawn through dies to produce the very high strength weirs used in wire ropes, bridge cables, and concrete prestressing strands
What was wrong with the first fireproofing of steel framing?
Too heavy and not economical
"T"
Track
What is another way of referring to Type 304?
Type 18-8
What is the most common type of stainless steel?
Type 304
What is form deck?
Used as permanent formwork for concrete floor decks, with the reinforced concrete slab supported by the steel decking until the slab can support itself and its live loads.
What are two ways someone can drill?
Using a dril lpress or a lathe
What is used to fold sheet metal?
Using a large machine called a brake
How are bolts usually tightened?
Using a pneumatic or electric impact wrench
What accessories are used for bracing?
V-bracing, flat strap bracing, and 1 1/2" cold rolled channels
What is a slag
Various impurities that floats on top of the molten metal
What can steel angles be used for?
Very short beams supporting small loads (lintels), connecting wide -flange beams, girders, and columns in steel frame buildings, and as diagonal braces and members of steel trusses, where they are paired back to back to connect conveniently to flat gusset plates at the joints of the truss
What are shear walls?
Very stiff walls made of steel, concrete, or reinforced concrete masonry. They permit shear connections
What are beam blanks or blooms?
Very thick approximations of the desired final shape, which are then rolled into final form
What are selected to achieve the right heat and penetration for the weld?
Voltage, amperage, and polarity of the electric current
What is the accepted nomenclature for wide flange shapes?
W, nominal depth of the shape in inches, a multiplication sign, and the weight of the shape in pounds per foot (W12x26)
What is used to connect prefabricated panels and creates stronger connections?
Welding
Which is stronger? Welding or soldering?
Welding
What are demand-critical welds?
Welds that may be subjected to very high stresses during a seismic event and are critical to maintaining the stability of the building structure. *They are subject to their own special design, materials, installation, and inspection requirements.
What is cold working steel?
When steel is beaten or rolled thinner at room temperature, its crystalline structure is altered in a way that makes it much stronger, though also somewhat more brittle.
What is welding?
Where a gas flame or electric arc melts the metal on both sides of the joint and allows it to flow together with additional molten metal from a welding rod or consumable electrode.
What is milling?
Where a rotating cutting wheel is used to cut metal from a workpiece
What is a shear connection? (Also called a framed connection)
Where the connection only joins the web of the beam, but not the flanges, to the column *It is capable of transmitting vertical forces (shear) from a beam to a column *Because it does not connect the beam flanges to the column it is of no value in transmitting bending forces (bending moment)
What scenario would it be more economical in the long run to use light gauge steel construction?
Where the risk of damage from termites is high.
What is hot dip galvanizing?
Where the steel parts are submerged in a molten zinc bath to produce a thick coating. It is the most durable form of galvanizing.
How are external threads on a steel rod cut?
With a die
What is an economical method of cutting steel of almost any thickness?
With a flame cutting torch
Steel trusses made of light gauge members may be applied over what type of walls?
Wood framed
Light gauge steel construction is the noncombustible equivalent of what?
Wood light frame construction
Where a light gauge steel frame building is constructed to be fully noncombustible, what cannot be used for subfloors or wall sheathing?
Wood structural panels
Are wider joist spacings frequently more economical?
Yes
Does steel offer designer possibilities that exist with no other material?
Yes
Are track sections larger in actual size than the studs? And why?
Yes. Because the studs will sit inside of the track.
Does the necessary R value of insulation needed in light gauge steel construction vary?
Yes. Higher R values are required for colder climates.
Are members ever delivered precut to required lengths?
Yes. On large job sites
What is a moment connection?
a connection capable of transmitting bending forces between a beam and column
The scrap structural steel is made from comes mostly from defunct what?
automobiles
What materials stronger than metals are beginning to appear more frequently in building construction applications?
carbon or aramid fibers
Ferrous metals
consist primarily of iron
Light gauge steel accepts insulation more readily than what?
masonry walls
Building codes generally limit the use of exposed steel framing to buildings of ____ to _____ stories, where escape in case of fire is rapid
one; five
Only _____ may be used to attach exterior or interior finish materials in light gauge steel frame construction?
screws
What is plate stock formed into? (Cold Formed)
square, rectangular, round, and elliptical hollow shapes that are then welded along the longitudinal seam to form hollow structural sections (HSS)
Until the 19th century, ____ had been a rare and expensive material.
steel
What 2 basic proportions are wide flanges manufactured in?
tall and narrow for beams and squarish for columns and foundation piles
For a very tall building _____ cranes are used.
tower
