chapter 9 Flashcards
steel construction
1
Q
what have largely replaced wood beams and trusses
A
steal ones p. 239
2
Q
2 primary metals alloyed in steel are
A
iron and carbon
3
Q
common structural steel has less than what of carbon
A
3 tenths of 1 %
4
Q
cast iron has a carbon content of
A
3-4 %
5
Q
higher carbon content of cast iron makes things
A
more brittle
6
Q
what has been completely displaced by steel in modern building since the 19th century
A
cast iron
7
Q
how does cast iron tent to fail
A
by fracturing from impact loading rather than by yielding
8
Q
strongest building material
non-rotting, resist to aging, dimensionally stable
consistent Quality
expensive
ARE basic properties of ?
A
STEEL
9
Q
inherent disadvantages of steel is
A
tendency to rest when exposed to air and moisture
10
Q
ways to ‘’’ from rust `painting w/ rust inhibiting paint
coating the martial w/ zinc and aluminum
adding alloy element that resist rust
A
protect
11
Q
adding molybdenum to steel will
A
strengthen it
12
Q
adding vanadium to steel will x2
A
strength and toughness
13
Q
adding manganese to steel will resistance of
A
resistance of steel to abrasion p. 240
14
Q
mixture of 2 or more metals fused to and dissolve into each other to enhance properties Or usefulness of the base metal is called ‘’’
A
alloy
15
Q
lower carbon content of steel compared to cast iron results in a material that is
A
ductile
16
Q
the ductility of steel is allows for it to be shaped by
A
rolling
17
Q
what steel can be used for members that have thin cross sections, such as floors and roof decks and wall studs
A
cold rolled steel ( shaped after its cools ABOVE its recrystallization temp)
18
Q
a measure of a metals ability to be drawn, hammered thin or rolled into shapes without breaking
A
ductility
19
Q
common structural steel ‘’’ which includes magnesium, carbon, and silicone
A
astm A36p. 241
20
Q
expansion for slender members such as beams and colums can be determined through a property called
A
coefficient of thermal expansion
21
Q
steel unable to push lateral constraints will
A
weaken, bow or buckle and fail
22
Q
the speed of ‘’ depends on several factors including:
type of steel
mass of steel
load supported
type of connection used to join members
intensity of exposing fire
A
failure
23
Q
steel is a good conductor of heat b/c its a
A
hvy material
24
Q
density of steel is around ‘’ PER CUBIC FT
A
490 per cubic ft
25
what members of steel can be expected to fail early when exposed to fire X2
bar joist or slender trusses p. 242
26
no matter its mass, steel is not inherently
fire resistive
27
usually way to protect steel from fire is
adding insulting material
28
steel colum incased in 3 inch of concrete will have a fire resist of
4 hours
29
coating used to increase fire resistance rating of Structural components... Most common are mineral, fiber, or expanded aggregate coding such as vermiculite and perlite
spray applied fire resistive material p. 243
30
fireproofing can vary from '' in thickness to produce fire resistants
7/8 to 1 7/8
31
what has not be used in SRFMS since 70/s
asbestos
32
cementitious materials have Dentines ranging from 15-50 LB/FT AND are produced in various formulations ingredients include:
pc
g
p
v
portlan cememt , gypsum, perlite and vermiculite
33
what can be used as an insulting material either in form of flat boards or plaster
gypsum
34
The process that HEATS a SUBSTANCE to a high temperature but below the melting or fusing point causing loss of moisture, reduction or oxidation and decomposition of carbonates and other components is called -
calcined
35
process of DRIVING FREE and chemically bounded water out of gypsum( water turns to steam upon exposure to fire and in doing so absorbs the heat )
calcination
36
gypsum board is available in 2 types
regular and type x
37
gypsum with no special additives is
regular
38
gypsum with additive is ( to resist fire)
type x p. 244
39
gypsum can be used to protect both ''' providing a fire resistant reading from ''-''
colums and beams
1-4 hours
40
what undergo a chemical reaction when exposed to heat of fire , will charm foam and expand when heated ( 15-30X )
intumescent material
41
intumescent coatings are applied like paint with thickness of
.03-.04 inches
42
when is similar to intumescent costing but based on more complex organic materials
mastic
43
a common used method of protecting a steel floor or roof assembly is
membrane ceiling. 245
44
what act as thermal barriers to protect the steel that support the floor or ceiling above
membrane ceiling s
45
a ceiling are always rated as part of '' its never rated independently
floor and ceiling
46
what can be concealed above a ceiling membrane ( making them popular )
wiring, sprinklers, piping, ducts
47
steel Structural shapes can be used to construct a frame of:
C
B
G
colums, beams and grinders
48
rigid frames and arches can be constructed of
steel
49
steel cables or rods can be use to support
roofs
50
cold rolled steel studs are being used to construct
exterior walls p. 246
51
steel is not used in forms of soild '' or '' more so in sheets .
slabs or panels more so in sheets( floor decking exterior curtian walls )
52
beams and girder steel frames can be classified as
rigid , simple or semi rigid
53
beams and colums in steel frame buildings are connected by X2 WHAT IS NOT USED TODAY '''
bolts or weldings ( riveting used 1st half od 20th century not used today )
54
connections b'tw beams and colums in a '' frame system are designed to resist bending forces from supporting loads and lateral forces
rigid (welds at tops of flanges , bolted at webs )
55
a joint in a '' frame are designed to support vertical forces primary
simple( bolted at web )
56
connections in a '' frame are not completely rigid but posses enough to provide diagonal support to the structure
semi rigid p. 247
57
ideally a '' wall continuous from foundation to highest story at which needed.... Reinforced walls located between columns and beams to brace them laterally
shear
58
what provide a structural member that can carry loads across greater spans more economically than beams can
steel trusses
59
3 dimensional space frame are known as
delta trusses ( looks like greek letter delta )
60
2 commonly known basic steel truss are the
joist girder and open web joist p.248
61
HEAVY steel truss used to take place of steel beams as part of primary structural frame
joist grinder
62
when round bars are used for diagonal members the open webs truss is known as
bar joist
63
mass produced , found more commonly w/ depth less than 2ft and spans of 40 ft.
open web joist
64
top of a rigid frame is known as '' and points when the inclined members intersect there vertical are known as
crown / knees p. 249
65
arch application roofs found in
sports complex, convention centers
66
most common colum ''' are:
hollow cylinder
rectangular tubes
wide flange shape similar ro the cross section of an i beam
cross section
67
used to determine the load that can be supported by components , lower ratio = higher are more stable
slenderness ratio
68
higher the slender ratio more likely '' to occur
buckling will occur p. 250
69
a common floor design in steel frame is '' with a min thickness of
lightweight concrete 2 inch.p. 251
70
fire resistance rating may be eliminated for roof construction located more than
20 ft above the floor below for some occupancies
71
what can easily fail during fire conditions regard steel trusses:
'' components
''' supported
steel trusses with slender components
simply supported bearing walls or beams
72
it takes much more heat to make '' connections fail than '' ?
rigid vs simple
73
primary purpose of what plate is to strengthen the connection and increase the steel mass at the connections
gusset plates p. 252
74
Steel alloy with higher yield points have less
Ductility page 241
75
What can steal be coded with to protect against formation of rust? X 3
Painting the surface with rust in inhibiting paint
Coding the material with zinc and aluminum
Adding alloy elements that resist rust
76
The ductility of ASTM 836 steel can be illustrated by comparing the stress exerted on a steel against the resulting deformation known as
Strain
77
What stress is reached when steel undergos a deformation?
Yield point stress
78
Steel brEAKS at what stress
Ultimate stress
79
What take place simultaneously regarding expansion?
Yielding and thermal expansion
80
The tendency for steel to “”, and therefore bend or buckle is more significant concern in most firefights
Yield
81
Steal has a tendency to “” vs break during fires
Bend or buckle, as the temperature increases, steal loses its strength gradually bending 243
82
What is the most commonly used SFRM
Foam board
83
Amount of water, trapped in gypsum
20%
84
Max fire rating regarding time in gypsum board ?
Four hours
85
''' are never rated Independently they are rated as one part of the floor or ceiling system
Ceiling membranes
86
Joist's in simple frames are designed to support which type of forces
Vertical forces
87
The connection between a beam and the column in a rigid frame system are designed to resist what forces
Bending
88
Steel beam and trusses are frequently supported by(type of material)”” walls
Masonry
89
Connection in a semi rated frame are not completely rigid a possession of rigidity to provide some “” support to the structure
Diagonal
90
Shear panels are reinforced walls, located between columns and beams to brace them how ?''''
Laterally
91
What are frequently used in closely space configurations for supports of roofs or roof decks?
Bar joists
92
How SHOULD gable roof ridge frame structures be braced?
Horizontally
93
As the slenderness ratio goes up for a structural component, a material becomes less likely to
Buckle
94
In a gable Ridge frame steel structure what is the strongest part of the frame hence the last part to fail
Rigid connections
95
The comparison of the height or length of a structural component and the width or thickness of it is known as '''' ratio ..
Structural ratio
96
Steel rigid frame buildings with inclined ''''' roofs are widely used for construction of one story, industrial buildings, farm buildings and a variety of other applications
Must be braced diagonally for structural rigidity
Gabled rigid frame
97
'' arches are used to support floors on buildings where large unobstructed floors are needed such as gymnasium and convention halls,,,, can be constructed to distances in excess of 300 feet....
Designed as either grinder arches or trusted arches
Steel arches
98
''' arch is constructed as a solid arch that may be built up from the angles webs with a cross-section similar to that of a beam
Grinder arch
99
'''ARCH is built using ''' shapes. The pin connects allows for slight movement between the 2/2 due to settlement or temperature change.
Trusted arch
TRUSTED
100
''' suspension system can be used in slender components, such as rods and cables, drawing steel bars through a die to produce wire greatly increases the strength of the steel wire for use in bridge cables can have strands as high as'''' such slender supports easily buckle under compression force, and therefore are limited to the support of '' forces
Steel suspension system
300,000 PSI
Tension
101
Steel joists are spaced ____ INCHES apart.
16 to 48 inches.
102
building materials would not be effective to use in the form of solid slabs or panels?
steel
103
Steel joists are produced in DEPTHS of – INCHES
6-12 inches
104
'''' are mass produced in our available with DEPTH up to 6 feet and spans up to 144 feet however they are more frequently found with depth less than 2 feet and spans of 40 feet
Open web joists
105
When the yield point stress of a steel member is reached, which is approximately ____ psi the steel undergoes a pronounced deformation.
36000 PSI
106
Ceiling materials are rated -
As part of the floor and ceiling assembly.
107
Steel alloys with higher yield points have LESS
LESS ductility
108
Steel arches used in the construction of gymnasiums in convention halls can span distances in excess of –
300 FT
109
In the production of steel, elements are combined to produce an end result that can be used for a specific purpose. Which of the following elements added to steel will add the resistance of steel to abrasion?
Magnesium
110
substance or mixture composed of two or more metals fused to and dissolved into each other to enhance the properties or usefulness of the base metal is called a(an) -
alloy
111
In the production of steel, elements are combined to produce an end result that can be used for a specific purpose. Which of the following elements added to steel will produce strength alone
Molybdenum.
112
The load and/or temperature threshold at which a steel alloy will begin to deform.
yield point stress" of steel?
113
What happens to the quality of steel as the carbon content increases?
The steel becomes harder and more brittle.
114
Cementitious materials have densities ranging for ___ lb/ft^3.
15-50
115
Steel rigid frames usually are used for spans from ___ and are fabricated by welding or bolting together steel shapes and plates.
40-200 ft
116
Cold rolling occurs at temperatures -
Above recrystallization temperatures.
