Chapter 9 - Steel Construction Flashcards
Steel is a _______ and ________________ building material.
strong and non combustible
p 257
The basic properties of steel are as follows:
- ____________ of the building materials
- Non-_________, resistant to _________ and dimensionally stable
- Consistent ___________ due to controlled industrial process used in its manufacture
- Relatively ___________, but strength and variety of forms enable it to be used in __________ quantities than other materials.
- Strongest
- rotting / aging
- quality
- expensive / smaller
p 258
Steel is basically an alloy of _______ and _________.
iron / carbon
p 258
Common structural steel has less than _______ _______ of one percent carbon.
three tenths
p 258
Cast iron has a carbon content of _________ to ______ percent.
three to four
p 258
The higher carbon content of cast iron produces a material that is _______ but _________.
hard / brittle
p 258
The composition of steel can be altered by adding other materials. ______________, for example, can be added to increase strength. ____________ increases strength and toughness. ____________ increases the resistance of steel to abrasion.
Molybdenum / vanadium / manganese
p 258
The lower carbon content of steel compared to that of cast iron results in a material that is _________ rather than brittle.
ductile
p 258
- Capable of being shaped, bent, or drawn out.
Ductile
p 258
The rolling process consists of repeatedly passing ingots of steel heated to ________*F between large rollers until the desired shape is achieved.
2,200
p 258
The ductility of steel allows it to be rolled in a ______ _______.
cold state
p 258
A very commonly used steel for structural purposes is designated _______ ______.
ASTM A36
p 259
Because excessive deformation of steel is undesirable, the maximum stress that develops within steel members under conditions of loading must be kept below the ________ ________.
yield point
p 259
Steels for special application, such as those used in bridge strands, have strengths as high as __________ psi but very little __________.
300,000 / ductility
p 259
Steel possesses two inherent disadvantages:
- Tendency to _______ when exposed to air and moisture
- Loss of __________ when exposed to the heat of a fire
- rust
- strength
p 259
Steel can be protected in several ways from the formation of ______. Methods include painting the surface with a _______-inhibiting paint and coating the materials with ______ and ___________.
rust / rust / zinc and aluminum
p 259
Steel can also be produced using ingredients that resist rust, as in the case of ___________ steel.
stainless
p 259
The fires typically encountered by firefighters do not create temperatures hot enough to _______ steel. However, they do create enough heat to greatly ________ steal, resulting in structural failure.
melt / weaken
p 259
Note that at a temperature of around 1000*F the yield point of the steel has dropped from ________ psi to approximately _______ psi.
36,000 / 18,000
p 259
At 1200 *F the yield point has dropped to approximately ________ psi - a loss in strength of approximately _____ percent.
10,000 / 72
p 259
The loss of strength because of increased temperature is not a _________ occurrence, rather, the steel loses its strength _________ as its temperature increases.
sudden / gradually
p 260
The speed with which unprotected steel fails when it is exposed to a fire depends on several factors, including the following:
- _______ of the steel members
- __________ of the exposing fire
- ______ supported by the steel
- Types of ______________ used to join the steel members
- Type of _______
- Mass
- Intensity
- Load
- connections
- steel
p 260
Although steel is a good conductor of heat, it is also a very heavy material, having a density of around ______ pounds per cubic feet.
490
p 260
A wide flange steel beam 14 inches in depth with a 10 inch wide flange would have a weight of ____ pounds per foot of length. A beam 20 feet long would weigh _______ pounds.
74 / 1480
p 260
When lower _________ exist in the steel, it must be heated to a higher temperature for the yield point to be reached.
stresses
p 260
When individual steel members are rigidly ________ and _______ into a large structural system, they are better able to resist failure than if they are simply supported.
welded or bolted
p 260
The amount of expansion for slender members, such as beams and columns, can be determined through a property known as the linear coefficient of __________ __________.
thermal expansion
p 260
If an unrestrained steel beam 20 feet long were heated from 70F to a uniform temperature of 1000F, it would expand _____ inches.
1.4
p 260-261
The basic method by which steel is used in the design of buildings is the construction of a structural framework that supports the _______, _______, and exterior _______.
floors, roof, and exterior walls
p 262
- Large, horizontal structural member used to support joist and beams at isolated points along their length.
Girder
p 262
Beams and columns in steel frame buildings are connected by one of two methods: __________ or _________.
bolting or welding
p 262
The connections of a beam to a column not only transfers the _______ between members but also determines the _________ of the basic structure.
loads / rigidity
p 263
Beam and girder steel frames can be classified as _______, ________, or _____-_______.
rigid, simple or semi-rigid
p 263
When a framing system is classified as a ________ frame, the connection between the beams and the columns are designed to resist the bending forces resulting from the supported loads and lateral forces.
rigid
p 264
In a rigid frame connection, sufficient rigidity exists between the beam and the column so that ____ ________ occurs in the angle between the beam and the column as the loads are applied.
no change
p 264
In the case of a simple frame, the joints are designed primarily to support a __________ force.
vertical
p 264
Simple frame:
A degree of __________ change between beams and columns can occur if some form of diagonal bracing is not provided.
angular
p 264
In a semi-rigid frame, the connections are not completely rigid but provide some ____________ support to the structure.
diagonal
p 264
When rigid connections are not used, lateral stability for a frame must be provided through the use of __________ bracing or ________ _________.
diagonal / shear panels
p 264
________ ________ are reinforced walls located between columns and beams to brace them laterally.
Shear panels
p 264
________ _________ provide a structural member that can carry loads across greater spans more economically than beams can.
Steel trusses
p 264
Steel trusses:
They are frequently used in three-dimensional space frames, in which case they are known as _______ trusses because the cross-section resembles the Greek letter _______.
delta / Delta
p 264-265
Two commonly encountered applications of the basic steel truss are the ______ _____ joist and the joist ________.
open web / girder
p 265
Open web joist are mass produced and are available with depths of up to ____ feet and span up to ______ feet. However, they are more frequently found with depths less than ____ feet and spans of ____ feet.
6 / 144 / 2 / 40
p 265
- Open web truss constructed entirely of steel, with steel bars used as the web members.
Bar joist
p 265
When round bars are used for the diagonal members, the open web truss is known as a ______ _______.
bar joist
p 266
________ _________ are heavy steel trusses used to take the place of steel beams as part of the primary structural frame.
Joist girders
p 266
Gabled rigid frames:
Steel rigid frames usually are used for spans from _____ to ______ feet and are fabricated by welding or bolting together steel shapes and plates.
40 to 200
p 267
Gabled rigid frames:
The top of the rigid frame is known as the ________ and the points where inclined members intersect the vertical members are known as the ________.
crown / knees
p 267
Steel arches are used to support roofs on buildings where large unobstructed ________ are needed. These include occupancies such as _____________ and ____________ _______.
floors / gymnasiums / convention halls
p 267
Steel arches can be constructed to span distances in excess of ______ feet.
300
p 267
A ________ arch is constructed as a solid arch that may be built up from angles and webs with cross section similar to that of a beam.
girder
p 267
A ________ arch is built using truss shapes with pin connections. The pin connections allow for slight movement between two halves due to ____________ or _____________ change.
trussed / settling / temperature
p 267
The strength of steel is such that it can be used in very slender forms such as ______ and ________.
rods / cables
p 268
Drawing steel bars through a ______ to produce wire greatly increases the strength of the steel.
die
p 268
It is possible to produce wire for use in bridge cables with strengths as high as ___________ psi.
300,000 psi
p 268
Because of the high compressive strength of steel, the cross section of steel columns can be very small compared to their to ________. Because of this slenderness, the possibility of ___________ is greater with steel columns than with columns made of other materials.
length / buckling
p 268
The most common column cross-sections are the hollow _________, the rectangular _______ and the wide ________ shape similar to the cross sections of an I-beam.
cylinder / tube / flange
p 268
Steel columns
A property of a given column, known as its “______________ _______” is used in combination with the condition of the column end to determine the load that can be safely supported without buckling.
“slenderness ratio”
p 269
The ___________ the numerical value of the slenderness ratio, the more likely it is that buckling will occur. In general, columns used for structural support in buildings should not have a slenderness ratio greater than ______.
higher / 120
p 269
Columns that are erected so they cannot _________ at their ends have less tendency to buckle than columns that are free to _________ at their ends.
rotate / rotate
p 269
A very common floor design in steel frame buildings uses a lightweight concrete with a minimum thickness of ____ inches supported by __________ steel decking.
2 / corrugated
p 270
Light gauge steel joist:
The steel joist are produced with depths of ____ to ____ inches and can be spaced _____ to ____ inches apart depending on the span and the load to be supported.
6 to 12 / 16 to 48
p 270
The rigid connections used in the beam and girder type of frame have a greater _______ of _________ at the point of connection than do simple connections. Therefore, it takes much more heat to produce failure in _______ connections than it does in the less massive simple connections.
mass of steel / rigid
p 270
Although the primary purpose of a gusset plate is to strengthen the connection, the gusset plate also increases the _______ _______ at the connection, thereby decreasing it possibility of failure.
steel mass
p 271
In gabled rigid frame structures the ______ _______ between the roof and the wall will be the strongest part of the frame and the last part to fail.
knee joint
p 271
In a structure with a large beam and girder frame made of repeating sections, the adjacent sections of the frame tend to be mutually ___________. These adjacent sections provide a degree of _____________ to the overall system that reinforces the structures strength.
supporting / redundancy
p 271
If steel trusses are constructed with ________ chords and ___________ members and are simply supported on a bearing wall or beam, they can easily fail and collapse under fire conditions.
slender / diagonal
p 272
A steel column encased in 3 inches of concrete with a siliceous aggregate would have a fire resistance of ______ hours.
four
p 272
__________ can be used as an insulating material either in the form of flat boards or a plaster.
Gypsum
p 272
Gypsum board is available as _________ or _________.
regular or type X
p 272
Gypsum consists of approximately _____ percent entrapped water.
21
p 272
Gypsum
The water turn to steam upon exposure to fire and, in doing so, absorbs the heat. This process is known as ___________.
calcination
p 272
The most commonly used spray-applied fire resistive materials (SFRMs) are _________ fiber or expanded aggregate coatings such as ___________ and _________.
mineral / vermiculite / perlite
p 273
The applied fireproofing can vary from ____ to ____ inches to produce a fire resistive rating of ___ to ___ hours.
7/8 - 1 7/8 / 1 to 4
p 273
______-_________ mineral fibers are relatively soft and can be easily dislodged from the steel.
Low-density
p 273
High density SFRMs that use magnesium oxychloride have densities ranging from _____ to _____ lb/cu ft.
40 to 80
p 273
- Containing or composed of cement. Has cement like characteristics.
Cementitious
p 273
The cementitious materials have densities varying from _____ to _____ lb/cu ft.
15 to 50
p 273
- Coating or paint like product that expands when exposed to the heat of a fire to create an insulating barrier that protects the material underneath.
Intumescent coating
p 274
Intumescent coating
The coating material will expand to _____ to ____ times its original volume. The expanded coating then acts as an ___________ material to protect the steel.
15 to 30 / insulating
p 274
_________ coatings function in a manner similar to intumescent coatings except they are based on more complex organic materials and their reaction to heat is more complex.
Mastic
p 274
- Usually refers to a suspended, insulating ceiling tile system.
Membrane ceiling
p 274
