Chpt 9

Question 1

The basic properties of steel are as follows

Answer 1

Strongest of building materials
Non rotting, resistant to aging, and dimensionally stable
Consistent quality due to controlled industrial process used in its manual facture
Relatively inexpensive, but strength and variety of forms enable it to be used in smaller quantities than other materials

Question 2

The lower carbon content of steel compared to that of cast iron results in a material that is ___ rather than brittle

Answer 2

Ductile

Question 3

A very commonly used steel for structural purposes is designated

Answer 3

ASTM 36

Question 4

The ductility of this steel is illustrated by comparing the stress exerted on the steel with the resulting deformation known as the

Answer 4

Strain

Question 5

To the fire service, the ____ of steel at elevated temperatures is its most significant characteristic

Answer 5

Deterioration of the strength

Question 6

That at a temperature of around 1000f the yield point of the steel has dropped from 36000 psi to approximately

Answer 6

18000 psi

Question 7

At 1200f the yield point has dropped to approximately

Answer 7

10,000 psi

Question 8

Because temperatures in excess of ____ are regularly encountered in fires, failure of unprotected steel to a greater or lesser degree can be anticipated

Answer 8

1200F

Question 9

The speed with which unprotected steel fails when it is exposed to a fire depends on several factors, including the following

Answer 9

Mass of steel members 
Intensity of the exposing fire 
Load supported by the steel 
Type of connections used to join the steel members 
Type of steel

Question 10

The amount of expansion for slender members, such as beams and columns, can be determined through a property known as the

Answer 10

Linear coefficient of thermal expansion

Question 11

If an unrestrained steel beam 20 feet long were heated from 70f to a uniform temperature of 1000f it would expand

Answer 11

1.4 inches

Question 12

Both yielding and thermal expansion take place simultaneously; however the tendency for steel to ____ and, therefore, to bend and buckle is the more significant concern in most fire situations

Answer 12

Yield

Question 13

Beams and columns in steel frame buildings are connected by one of two methods

Answer 13

Bolting or welding

Question 14

When a framing system is classified as a ______, the connections between the beams and the columns are designed to resist the bending forces resulting from the supported loads and lateral forces

Answer 14

Rigid frame

Question 15

In the case of a ____, the joints are designed primarily to support a vertical force

Answer 15

Simple frame

Question 16

In a ____, the connections are not completely rigid but possess enough rigidity to provide some diagonal support to the structure

Answer 16

Semi rigid frame

Question 17

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

Answer 17

Steel trusses

Question 18

They are frequently used in three dimensional space frames, in which case they are known as _______ because the cross section resembles the Greek letter delta

Answer 18

Delta trusses

Question 19

When round bars are used for the diagonal members, the open web truss is known as a

Answer 19

Bar joist

Question 20

Are frequently used in closely spaced configurations for the support of floors or roof decks

Answer 20

Bar joists

Question 21

Are frequently supported on a masonry wall to support a roof

Answer 21

Bar joists

Question 22

Are heavy steel trusses used to take the place of steel beams as part of the primary structural frame

Answer 22

Joist girders

Question 23

The top of the rigid frame is known as the

Answer 23

Crown

Question 24

And the points where the inclined members intersect the vertical members are known as the

Answer 24

Knees

Question 25

A ____ is constructed as a solid arch that may be built up from angles and webs with a cross section similar to that of a beam

Answer 25

Girder arch

Question 26

A _____ is built using truss shapes

Answer 26

Trusses arch

Question 27

It is, possible to produce wire for use in bridge cables with strengths as high as

Answer 27

300,000 psi

Question 28

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

Answer 28

Slenderness ratio

Question 29

In general, columns used for structural support in buildings should not have a slenderness ration greater than

Answer 29

120

Question 30

There are three methods by which steel structural members can be used to support floors in multistory buildings. These include

Answer 30

Open web joists
Steel beams
Light gauge steel joists

Question 31

A very common floor design in steel frame buildings uses a _______ supported by corrugated steel decking

Answer 31

Light weight concrete with a minimum thickness of 2 inches

Question 32

The corrugated steel is, in turn, supported by

Answer 32

Open web joists

Question 33

Where floor loads or spans dictate, _____ are used to support flooring instead of the lighter open web joists

Answer 33

Steel beams

Question 34

The factors that affect the possible failure of steel were also discussed. Two of these factors the mass of the steel members and the type of structural connection result from the

Answer 34

Structural design used

Question 35

The rigid connections used in the beam and girder type of frame have a greater _____ at the point of connection than do simple connections

Answer 35

Mass of steel

Question 36

Steel connections, both in the case of rigid connections used with beam and girder frames and heavy trusses, frequently make use of a steel web known as a

Answer 36

Gusset plate

Question 37

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 fall

Answer 37

Knee joints

Question 38

In a structure with a large beam and girder frame made of repeating sections, the____ of the frame tend to be mutually supporting

Answer 38

Adjacent sections

Question 39

A steel column encased in 3 inches of concrete with a siliceous aggregate would have a fire resistance of

Answer 39

Four hours

Question 40

Can be used as an insulating material either in the form of flat boards or a plaster

Answer 40

Gypsum

Question 41

Has no social additives to enhance fire resistance, although it will provide some degree of fire protection

Answer 41

Regular gypsum

Question 42

Contains additives to increase its fire resistance and is usually required where a specified fire resistance is desired

Answer 42

Type X gypsum

Question 43

The most commonly used SFRM are

Answer 43

Mineral fiber or expanded aggregate coatings such as vermiculite and perlite

Question 44

A very commonly used method of protecting a steel floor or roof assembly is the

Answer 44

Membrane ceiling

Question 45

A _____ consists of a ceiling material suspended from the supports for the floor or ceiling above

Answer 45

Membrane ceiling

Question 46

The most common method is to use _____ in a steel framework suspended by wires

Answer 46

Mineral tiles membrane ceilings

Question 47

Because the membrane ceiling forms an integral part of a fire rated assembly, it follows that any removal or penetration of the ceiling material reduces or even eliminates the _____ of the total assembly

Answer 47

Fire resistance