chapter 9 Flashcards

steel construction

1
Q

what have largely replaced wood beams and trusses

A

steal ones p. 239

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2
Q

2 primary metals alloyed in steel are

A

iron and carbon

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3
Q

common structural steel has less than what of carbon

A

3 tenths of 1 %

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4
Q

cast iron has a carbon content of

A

3-4 %

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5
Q

higher carbon content of cast iron makes things

A

more brittle

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6
Q

what has been completely displaced by steel in modern building

A

cast iron

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7
Q

how does cast iron tent to fail

A

by fracturing from impact loading rather than by yielding

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8
Q

basic properties of steel

A

strongest building material
non-rotting, resist to aging, dimensionally stable
consistent Quality
expensive

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9
Q

inherent disadvantages of steel is

A

tendency to rest when exposed to air and moisture

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10
Q

easy to protect from rust

A

`painting w/ rust inhibiting paint
coating the martial w/ zinc and aluminum
adding alloy element that resist rust

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11
Q

adding molybdenum to steel will

A

strengthen it

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12
Q

adding vanadium to steel will

A

strength and toughness

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13
Q

adding manganese to steel will

A

resistance of steel to abrasion p. 240

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14
Q

mixture of 2 or more metals fused to and dissolve into each other to enhance properties

A

alloy

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15
Q

lower carbon content of steel compared to cast iron results in a material that is

A

ductile

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16
Q

the ductility of steel is allows for it to be shaped by

A

rolling

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17
Q

what 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 below its recrystallization temp)

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18
Q

a measure of a metals ability to be drawn, hammered thin or rolled into shapes without breaking

A

ductility

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19
Q

common structural steel

A

astm a 36p. 241

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20
Q

expansion for slender members such as beams and colums can be determined through a property called

A

coefficient of thermal expansion

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21
Q

steel unable to push lateral constraints will

A

weaken, bow or buckle and fail

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22
Q

the speed of failure depends on several factors including

A

type of steel
mass of steel
load supported
type of connection used to join members
intensity of exposing fire

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23
Q

steel is a good conductor of heat b/c its a

A

hvy material

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24
Q

density of steel is around

A

490 per cubic ft

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25
Q

what members of steel can be expected to fail early when exposed to fire

A

bar joist or slender trusses p. 242

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26
Q

no matter its mass, steel is not inherently

A

fire resistive

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27
Q

usually way to protect steel from fire is

A

adding insulting material

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28
Q

steel colum incased in 3 inch of concrete will have a fire resist of

A

4 hours

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29
Q

coating used to increase fire resistance rating of struck components

A

spray applied fire resistive material p. 243

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30
Q

fireproofing can vary from ‘’ to produce fire resistants

A

7/8 to 1 7/8

31
Q

what has not be used in SRFMS since 70/s

A

asbestos

32
Q

cementitious materials are produced in various formulations ingredients include

A

portlan cememt , gypsum, perlite and vermiculite

33
Q

what can be used as an insulting material either in form of flat boards or plaster

A

gypsum

34
Q

process that heats a substance to a hight temp but below melting point

A

calcined

35
Q

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 )

A

calcination

36
Q

gypsum board is available in 2 types

A

regular and type x

37
Q

gypsum with no special additives is

A

regular

38
Q

gypsum with additive is ( to resist fire)

A

type x p. 244

39
Q

gypsum can be used to protect both

A

colums and beams

40
Q

what undergo a chemical reaction when exposed to heat of fire , will charm foam and expand when heated ( 15-30X )

A

intumescent material

41
Q

intumescent coatings are applied like paint with thickness of

A

.03-.04 inches

42
Q

when is similar to intumescent costing but based on more complex organic materials

A

mastic

43
Q

a common used method of protecting a steel floor or roof assembly is

A

membrane ceiling. 245

44
Q

what act as thermal barriers to protect the steel that support the floor or ceiling above

A

membrane ceiling s

45
Q

a ceiling are always rated as part of ‘’ its never rated independently

A

floor and ceiling

46
Q

what can be concealed above a ceiling membrane ( making them popular )

A

wiring, sprinklers, piping, ducts

47
Q

steel struck shapes can be used to construct a frame of

A

colums, beams and grinders

48
Q

rigid frames and arches can be constructed of

A

steel

49
Q

steel cables or rods can be use to support

A

roofs

50
Q

cold rolled steel studs are being used to construct

A

exterior walls p. 246

51
Q

steel is not used in forms of soild

A

slabs or panels more so in sheets( floor decking exterior curtian walls )

52
Q

beams and girder steel frames can be classified as

A

rigid , simple or semi rigid

53
Q

beams and colums in steel frame buildings are connected by

A

bolts or weldings ( riveting used 1st half od 20th century not used today )

54
Q

connections b’tw beams and colums in a ‘’ frame system are designed to resist bending forces from supporting loads and lateral forces

A

rigid (welds at tops of flanges , bolted at webs )

55
Q

a joint in a ‘’ frame are designed to support vertical forces primary

A

simple( bolted at web )

56
Q

connections in a ‘’ frame are not completely rigid but posses enough to provide diagonal support to the structure

A

semi rigid p. 247

57
Q

ideally a ‘’ wall continuous from foundation to highest story at which needed

A

shear

58
Q

what provide a structural member that can carry loads across greater spans more economically than beams can

A

steel trusses

59
Q

3 dimensional space frame are known as

A

delta trusses ( looks like greek letter delta )

60
Q

2 commonly known basic steel truss are the

A

joist girder and open web joist p.248

61
Q

hvy steel truss used to take place of steel beams as part of primary structural frame

A

joist grinder

62
Q

when round bars are used for diagonal members the open webs truss is known as

A

bar joist

63
Q

mass produced , found more commonly w/ depth less than 2ft and spans of 40 ft.

A

open web joist

64
Q

top od a rigid frame is known as ‘’ and points when the inclined members intersect there vertical are known as

A

crown / knees p. 249

65
Q

arch application roofs found in

A

sports complex, convention centers

66
Q

most common colum cross section are

A

hollow cylinder
rectangular tubes
wide flange shape similar ro the cross section of an i beam

67
Q

used to determine the load that can be supported by components , lower ratio = higher are more stable

A

slenderness ratio

68
Q

higher the slender ratio more likely it will

A

buckling will occur p. 250

69
Q

a common floor design in steel frame is ‘’ with a min thickness of

A

lightweight concrete 2 inch.p. 251

70
Q

fire resistance rating may be eliminated for roof construction located more than

A

20 ft above floor below for some occupancies

71
Q

what can easily fall during fire conditions regard trusses

A

steel trusses with slender components and simply supported on bearing ways or beams

72
Q

it makes much more heat to make what connections fail than what

A

rigid vs simple

73
Q

primary purpose of what plate is to strengthen the connection and increase the steel mass at the connections

A

gusset plates p. 252