Dbd-Test 2- History/vocab/formulas

Front 1

Which of the following would be most important in selecting a structural system for a proposed restaurant and warming house at the mid-slope of a ski resort?
A. cost, resistance to loads, and construction limitations
B. style, integration with building systems, and fire resistance
C. building occupancy, construction limitations, and style
D. fire resistance, resistance to loads, and cost

Back 1

C. building occupancy, construction limitations, and style

Front 2

Which of the following is not correct concerning live load calculations?
A. Live loads can be reduced when a structural member supports more than 150 square feet in the occupnacy is not public assembly and if the live load is less than 80 psf.
B. Live loads include snow, people, and furniture.
C. Any live load reduction cannot exceed 40 percent for structural members supporting load form one story.
D. Snow load reduction is calculated according to the formula Rs= S/40 - 0.5  if the roof pitch is more than 20 degrees

Back 2

A. Live loads can be reduced when a structural member supports more than 150 square feet in the occupnacy is not public assembly and if the live load is less than 80 psf.

Front 3

he elastic limit of a material is:
A. the point at which a material continues to deform without any increase in load
B. the maximum unit stress that determines the engineering working stress to design a member
C. the point beyond which unit stress increases faster than unit strain.
D. the unit stress below which deformation is directly proportional to stress..

Back 3

D. the unit stress below which deformation is directly proportional to stress..

Front 4

The reaction for which of the following types of beams cannot be found using the principles of equilibrium?
A. continuous beams
B. cantilevered beams
C. simply supported beams
D. overhanging beams

Back 4

A. continuous beams

Front 5

Select the incorrect statement
A. Trusses are usually required to have lower cord bridging
B. Spacing of trusses depends entirely on the spaning capabilities of purlins and the type of truss used.
C. Parallel chord trusses usually have greater stresses toward the center of the span.
D. The method of joints is often used to find all the forces in a truss.

Back 5

B. Spacing of trusses depends entirely on the spaning capabilities of purlins and the type of truss used.

Front 6

Which of the following techniques would be most appropriate to prepare the soil for a building site that tests have shown to be rpimarily composed of silt and organix silt?
A. compaction
B. surcharging
C. densification
D. fill

Back 6

D. fill

Front 7

Which of the following types of bolts should be used in a joint with long slotted holes where the load perpendicular to the length of the hole is repeatedly reversed?
A. A325 slip-critical
B. A490 bearing-type
C. A307 bearing-type
D. none of the above

Back 7

A. A325 slip-critical

Front 8

If the allowable stress on a wood beam is 1450 psi, what is the required section modulus if the beam must resist a moment of 4518 ft-lbs cause by snow loading?
A. 27.8 in3 (inch cubed)
B. 28.1 in3
C. 29.9 in3
D. 32.5 in3

Back 8

D. 32.5 in3

Front 9

The maximum bending moment on a 20-foot long beam is 8200 ft-lbs. If the beam is Douglas fir-larch dense no. 1, and lateral support is provided, what is the most economical size that should be used? (Neglect effects of deflection.)
A. 4x10
B. 4x12
C. 6x8
D. 6x10

Back 9

B. 4x12

Front 10

A uniformly loaded W 12x45 beam spans 13 feet. If is is A36 steel, laterally supported, and carries a total load of 65,000 pounds, how much will it deflect?
A. 0.29 inches
B. 0.32 inches
C. 0.35 inches
D. 0.38 inches

Back 10

B. 0.32 inches

Front 11

Pantheon

Back 11

Romans,
Year 123 AD


Concrete Dome = Compression on top, Tension on bottom.

Hint 11

Its architects understood intuitively the nature of the stresses in a concrete dome, which the lower part tends to crack because of circumferential tensile stresses. Since they had no material that were strong in tension, their solution was to make the dome walls about 20 feet thick at the bottom, in order to keep the unit tensile stresses low enough to be resisted by the concrete. To reduce the weight of the dome, its underside was coffered.

Front 12

Hagia Sophia,

Back 12

Anthemius & Isidorus,
537 AD

Shallow dome supported on pillars, reconstructed after several earthquakes, iron tie around base added in 1847 (tension)

Hint 12

Its main dome was shallow and supported by four pillars, through pendentives and arches that rose from the pillars. The arches resisted both vertical forces and outward thrust from the dome; unfortunately, however, the arches did not provide sufficient buttressing, and a portion of the dome collapse in 558 AD. In 1847 an iron tie was placed around base of the dome to resist in tension the outward thrust.

Front 13

Dome of the Florence Cathedral

Back 13

Filippo Brunelleschi,
1436


Two masonry domes, thicker inside shell, thinner outside shell, tension rings on bottom. Some was constructed without any centering.

Hint 13

There are actually two masonry domes: a thick inner shell and a thinner outer shell. Brunelleschi understood that a dome tends to spread a part, and build in a series of circumferential iron chains to act as tension rings and hold the dome in equilibrium.

Front 14

Crystal Palace

Back 14

Joseph Paxton,
1851

Steel Frame Construction.

Hint 14

Prefabricated Glass and cast iron structure. Fabricated and erected in 6 months.

Front 15

Fallingwater, PA

Back 15

Frank Lloyd Wright,
1936

3 story masonry structure. 6 concrete cantilevers over water.

Hint 15

3 story masonry structure. 6 concrete cantilevers over water.

Front 16

Airplane Hangars Italy

Back 16

Pier Luigi Nervi,
1936-1939


Lamella roofs, short concrete pieces connected.

Hint 16

His airplane hangars built for the Italian Air Force, between 1936-1939, had lamella roofs formed by short prefabricated reinforced concrete members connected at their joints.

Front 17

Johnson Wax Building, WI

Back 17

Frank Lloyd Wright,
1939


Slender mushroom-like columns flare at top to support roof.

Hint 17

Perhaps the most interesting element of this building is a great work space with slender mushroom-shaped concrete columns that flare out at the top to support the roof. The structural columns, ceilings, and lighting form an integral design and provide space with virtually no sense of enclosure.

Front 18

Yale University Skating Rink, CT

Back 18

Eero Saarinen,
1958

Steel cables hung from a central reinforced arch, wood roof partially stabilized by cables.

Hint 18

Steel cables in tension are the essential structural element. Steel cables are hung from central reinforced concrete arch. The outer ends of the cables are anchored to heavy curved perimeter walls. The roof is wood, the weight of which partially stabilizes the cables.

Front 19

Palazzeto Dello Sport, Rome

Back 19

Pier Luigi Nervi,
1960


Ribbed concrete shell dome, supported on 36 Y-shaped buttresses

Hint 19

Its roof, a ribbed concrete shell dome, is supported on 36 Y-shaped concrete buttresses which resist the forces at the edge of the shell.

Front 20

Dulles Int. Airport, Washington

Back 20

Eero Saarinen,
1962

Concrete roofs supported on steel cables, which are suspended from concrete columns, that lean outwards to balance inward pull of cables.

Hint 20

The concrete roof is supported by steel cables that are suspended between huge concrete columns, that lean outwards to balance the inward pull of the cables.

Front 21

CBS Building, NY

Back 21

Eero Saarinen,
1964


42 story structure, resist loads inner core and perimeter walls, piers are granite clad

Hint 21

This 42 story structure, resist lateral forces by both inner core and perimeter walls, which consist of concrete piers five feet long apart.

Front 22

Toronto City Hall

Back 22

Viljo Revell
1965


Two curved office slabs surround a low circular city council chamber. Each wall is a curve that inherently resists overturning.

Hint 22

Each office tower is a huge curved shell that provides strength and rigidity against overturning forces caused by wind or earthquake.

Front 23

Houston Astrodome

Back 23

1965


9.5 acre steel lattice dome, 710’ diameter weight is only 30 PSF.

Hint 23

First of such structure: domes enclosing stadiums. It weights less than 30 PSF, one twentieth of the weight of Brunelleschi’s inner dome in Florence.

Front 24

First National Bank, Chicago, IL

Back 24

Perkings & Will,
1966

Superframe (rigid frame) stiff horizontal trusses connected to massive exterior column, slender profile tapers gracefully to wider column at ground.

Hint 24

This building has a slender profile that tapers gracefully to a wider base in order to resist wind overturning forces more effectively. It utilizes a special type of rigid frame called super-frame or mega-frame. This consists of a very deep, stiff horizontal truss or girder wherever a mechanical floor occurs, about 15 to 20 stories apart, connected at each end to a large exterior column. The interior column and horizontal girders at the other levels form a secondary rigid frame.

Front 25

John Hancock Building, Chicago

Back 25

SOM Skifmore,Owings and Merrill,
1968

100 story, tapered form, large exterior X bracing trussed tube system.

Hint 25

“Big John” is a gigantic trussed tube, which is very efficient in resisting wind forces. The overall dimension of the building is utilized to resist overturning forces, while the truss members resist shear by direct stress, rather than bending.

Front 26

Knights of Columbus Building

Back 26

Roche & Dinkeloo,
1969

26 story, 4 corner concrete towers that supports 80’ steel girders that support steel floor structure. Corner towers resist lateral forces as circular cantilevers from the foundation.

Hint 26

ts four corner tower constructed of concrete with dark brick … support the main 80 foot long horizontal st… girders, which in turn support the steel fl… structure. The towers also resists horizontal …. Or earthquake forces by acting as huge circular tubes which cantilever from the foundation.

Front 27

US Pavillion at Expo 70, Japan

Back 27

David Geiger,
1970

Inflatable roof, vinyl membrane, w/stiffening steel cables anchored to concrete compression ring. Roof resists air pressure inside and wind outside.

Hint 27

An incredible 100,000 square foot inflatable roof made of a special vinyl membrane, with stiffening steel cables anchored to a concrete compression ring around the perimeter. The roof was designed to resist wind forces, as well as the air pressure inside the pavilion. This building was a pioneering effort by engineer David Geiger in the field of pneumatic structure.

Front 28

Munich Olympic Stadium

Back 28

Frei Otto,
1972

Series of steel cable nets stretched between steel masts anchored to the ground with steel cables. Plexiglas covers net surface.

Hint 28

It is an immense high-tech tent! A tensile structure. A series of steel cable nets was stretched between steel masts that were anchored to the ground by steel cables. The net surfaces, covered with Plexiglas, were shapes of double curvature for stability.

Front 29

Federal Reserve Bank Building, Minneapolis

Back 29

Gunnar Birkets,
1972

Two sets of cables are catenary shape.

Hint 29

Two sets of cables, draped in the shape of a catenary, supports the building’s vertical loads and are anchored to 2 concrete towers (275’ span)

Catenary = funicular shape for an unloaded cable, determined & dictated by the weight of the cable. More Sag > Less Thrust.

Front 30

World Trade Center, NY

Back 30

Minoru Yamasaki,
1972

110 stories each tower, exterior columns at 3’ o.c. connected by spandrels.

Hint 30

The structure system comprised exterior columns only three feet apart connected by deep spandrels, so that the entire tower became an immense hollow cantilever tube.

Front 31

Sears Tower, IL

Back 31

SOM, Skifmore,Owings and Merrill
1976

Bundle of 9 tubes, each tower is a cantilevered tube.

Hint 31

Is Bundle of 9 tubes, each tower is a cantilevered tube.

Front 32

Felix Candela

Back 32

Thin shell concrete roofs.

Candella believed that strength should come from form not mass. This belief led to an extensive exploration of tensile shell structures. His nickname became "The Shell Builder" because of this structural favoritism.

Front 33

Gustave Eiffel

Back 33

Designer of Eiffel Tower.

Eiffel was a master of elegantly constructed wrought-iron lattices, which formed the basis of his bridge constructions and led to his project for the Eiffel Tower. He was mainly recognized as an engineer and bridge builder.

Front 34

Eudene Freyssinet

Back 34

He developed pre-stressed concrete.
Considered the "father of pre-stressed concrete"

Airship hangars at Orly Airport, France (1921) The skin has a corrugated cross section that allows efficient resistance to secondary bending moment.

Front 35

Fazlur Khan

Back 35

SOM Eingineer Structural ideas.

Known as "Einstein of Structural Engineering", designer of John Hancock Center and Sears Tower.

Front 36

Robert Maillart

Back 36

Known for his radical use of reinforced concrete which revolutionized masonry arch bridge design.

Primarily an engineer, Maillart gained notoriety through his innovative bridge designs. Maillart utilized the structural strength and expressive potential of reinforced concrete to generate a modern form for his bridges. To avoid structural beams and arches, he established a structural form based on both flat and curved concrete slabs reinforced with steel.

Front 37

Pier Luigi Nervi

Back 37

Internationally renowned for his design of large-span structures built of reinforced concrete.

Alcanzó su mayor desarrollo en el Palacio de Exposiciones de Turín (1948-1950).

Front 38

John Roeblin 1806-1869 and his son Washington Roeblin 1837-1929

Back 38

A pioneer in the construction of suspension bridges. Best known for building of Brooklyn Bridge.

In 1841 Roebling invented the twisted wire-rope cable, an invention which foreshadowed the use of wire cable supports for the decks of suspension bridges. Because the cable could support long spans and extremely heavy loads, Roebling quickly gained a reputation as a quality bridge engineer.

Front 39

Eduardo Torroja

Back 39

Roof for the Zarzuela Hippodrome 1925. Site cast concrete. Long span. Cantilevered concrete barrel Shell.

Front 40

Othmar Ammann

Back 40

Master bridge engineer

Bronx Whitestone Bridge is a suspension bridge that crosses the East River and connects the boroughs of Queens and The Bronx. The bridge was opened to traffic with four lanes on April 29, 1939.

Front 41

Benjamin Baker

Back 41

Designer of the Forth Bridge in Scotland.

The main spans comprise two 680 feet cantilever arms supporting a central 350 ft span girder bridges. The three great four-tower cantilever structures are 340 ft (104 m) tall, each 70 ft diameter foot resting on separate foundations.

Front 42

Horst Berger and Frei Otto

Back 42

Design of tent structures.

Denver International Airport. Tensile Architecture

Front 43

James Eads

Back 43

Eads Bridge 1874 over the Mississippi, the first major structure built of steel.

Front 44

Buckminster Fuller

Back 44

Inventor of the geodesic dome.

A geodesic dome is an almost spherical structure based on a network of struts arranged on great circles (geodesics) lying on the surface of a sphere. The geodesics intersect to form triangular elements that create local triangular rigidity and distribute the stress. It is the only man made structure that gets stronger as it increases in size.

Front 45

TY Lin

Back 45

Master of prestressed concrete.

Front 46

Elisha Graves Otis

Back 46

Inventor of passenger elevator.

Front 47

Auguste Perret

Back 47

Father of reinforced concrete.

Notre Dame du Raincy, France 1922. Reinforced concrete. Shallow concrete vaulted ceilings and gossamer window walls.

Front 48

Thomas Telford

Back 48

Eingineer of iron bridges.

Pont Cysyllte Aqueduct 1805. Masonry and cast iron. 1000 foot aqueduct with cast iron canal trough and tow path on 19 masonry piers 120' high.

Front 49

Home Life Insurance Building, Chicago

Back 49

William Jenney = Designer of steel frame buildings.

The Home Insurance Building was one first from an iron skeleton designed multistoried buildings, that with its ten floors over the height usual five to six projectiles exceeded. The steel frameing was fireproofed with masonry, and the exterior masonry facings were supported on steel frame.

Front 50

Marshall Field Warehouse, Chicago

Back 50

Harry Hobson Richardson,

Building Type: commercial warehouse Construction System: cut stone bearing masonry
Notes: Block scale coherent ordering of facade creating a strong presence without use of historical detail.

Richardson used the textured monochromatic surface of the granite and brownstone masonry to provide visual interest, supplemented only by a chamfer at the corners and an enriched terminal cornice.

Front 51

Wainright Building, St.Louis

Back 51

Louis Sullivan,
Building Type: early skyscraper, commercial office tower
Construction System: steel frame clad in masonry
Note: An early tall building (10 stories) with an all steel frame. The Chicago School.

Front 52

Monadnock Building, Chicago

Back 52

John Root,
Building Type: early skyscraper, commercial office tower Construction System: bearing masonry
In spite of Root's artistic achievement in making the tall building a unified, coherent statement, it was structurally traditional, employing cast iron and wrought iron framing only for window spandrels and the internal frame. Consequently the walls at ground level had to be six feet thick to carry the upper floors (18 inches thick at the top); this massive bulk then rested on an immense iron and reinforced concrete raft.

Front 53

Reliance Building, Chicago

Back 53

Building Type: early skyscraper, commercial office tower
Construction System: steel frame clad with terra cotta
Note: A key precedent for the modern skyscraper.

It consisted of a riveted steel-frame superstructure, hollow-tile flooring on steel joists, plaster fire-proofing, perimeter bay windows filled with plate glass, steel-trussed wind bracing and bedrock concrete caissons sometimes extending for as much as 125 feet beneath the footing.

Front 54

Guaranty Building, Buffalo

Back 54

The Guaranty Building stunningly illustrates Sullivan’s famous statement that “form follows function.” The building’s intricate terra cotta ornamentation, for example, accentuates its structure. The piers between the windows form strong vertical lines that draw the eye upward to the dominant cornice. Yet, despite the technological advancements that made the skyscraper possible (such as structural steel and elevators), Sullivan strove to connect it with the natural world. His ornamentation for the Guaranty Building was inspired by flowers, seedpods, and even, at the top of the building, the spreading branches of a tree.

Front 55

Carson, Pirie, Scott Department Store, Chicago

Back 55

One of the most important structures in early modern architecture, famed for its influential modular construction and design. Visionary architect Louis Sullivan shaped this commercial building--originally built for the Schlesinger and Mayer department store--into a dramatically animated structure that inseparably merges beauty and function. The ornament of the lower two stories is frozen in cast iron, while at the same time giving the impression of being in fluid motion. It is an excellent example of Sullivan's genius for architectural ornament.

Front 56

Metropolitan Life, NY

Back 56

Napoleon Le Brun & Son,
World's tallest building from 1909 - 1913

Front 57

Woolworth Building, NY

Back 57

Cass Gilbert,
Building Type: corporate headquarters, early skyscraper
Construction System: terra cotta cladding
Note: 60 story tower with Gothic ornamentation.

Front 58

Chrisler Building, NY

Back 58

William Van Allen,
Building Type: skyscraper, commercial office tower
Construction System: steel frame, metal cladding
Notes: Stainless steel metal ornamented top. Automobile-derived ornamental details. Elegant lobby.

Front 59

Daily News, NY

Back 59

Raymond Hood,
Building Type: Newspaper offices and printing plant
Construction System: steel frame, brick cladding

Front 60

Empire State Building, NY

Back 60

Shreve, Lamb / Harmon,
Building Type: commercial office tower, skyscraper
Construction System: steel frame, stone cladding
Notes: 102 floors, 1252 feet, 381 meters high. Effective use of setbacks to emphasize tower

Front 61

Philadelphia Saving Fund Society

Back 61

Howe & Lescaze,
Building Type: corporate headquarters, skyscraper, commercial office tower
Construction System: steel frame, granite, limestone, & brick cladding
Note: "Philadelphia Saving Fund Society". elegant, subtly sculpted slab masses. "a summation of European Modernism"

Front 62

Rockefeller Center, NY

Back 62

Raymond Hood,
Building Type: skyscraper complex, commercial office towers
Construction System: steel frame, stone cladding
Note: Family of forms example, a fine urban ensemble, with a famous sunken plaza with outdoor skating rink. With others, including Wallace K. Harrison, Max Abramovitz, the firms of Reinhard & Hormeister and Corbett, Harrison, & MacMurray.

Front 63

Paramount, San Francisco

Back 63

Paramount, San Francisco
The Paramount, located in the South Market area of downtown San Francisco, is the tallest precast concrete building in a high seismic zone in the United States. The striking 39-story residential apartment tower, completed in 2001 by Pankow Residential Builders II, L.P., includes 486 apartments and parking for 350 cars in a total of 660,000 square feet of building area. The Paramount is also the first significant application of the Precast Hybrid Moment Resistant Frame (PHMRF) System.
In simple terms, the make-up of the joint using the PHMRF system allows it to work like a shock absorber to accommodate and counter the seismic forces that cause a building to sway when an earthquake strikes.

Front 64

Tacoma Narrows Bridge Disaster

Back 64

Stiffening the deck laterally provides resistance to wind
The bridge was an unusually light design, and, as engineers discovered, peculiarly sensitive to high winds. Rather than resist them, as most modern bridges do, the Tacoma Narrows tended to sway and vibrate. This progressively worsened due to harmonic phenomena.

Front 65

Hyatt Regency Hotel, Kansas

Back 65

Two suspended walkways. 113 dead, 1981 injured. In terms of casualties, the most devastating structural collapse ever to take place un USA.
Experts found that the design of critical connections in two walkways had been changed from the original plans and did not meet local building codes. Their findings led the American Society of Civil Engineers to adopt a document that for the first time assigned responsibility for various aspects of the construction process.

Front 66

Area of a Circle

Back 66

 r2

Front 67

Area of a Triangle

Back 67

1/2 b h

Front 68

Equilibrium

Back 68

M = 0; V = 0; H = 0

Front 69

Force

Back 69

F= M/d
(moment/distance)

Front 70

Retaining wall design

Back 70

F= (w h2)/2

Force on the wall=
(fluid pressure prov.)(height)2 /2

Front 71

pcf

Back 71

=psf/ ft

Front 72

SHEAR DIAGRAM SHEAR FORCE

Back 72

R = V = (w l)/ 2

shear resisting force=
(uniform load per ft) X (distance)/ 2

Front 73

BEARING TYPE SHEAR CONNECTIONS

Back 73

R = Fv Abolts

Resistance = (allow.shear stress) X (A of bolt cross sections x # of bolts)

Front 74

stress

Back 74

Stress= P / A

Front 75

moment about a point to find equilibrium

Back 75

M= Fd

Moment= force x distance

Front 76

Moment Uniform Load

Back 76

M= w Lsq/ 8

moment= (uniform load x length sq)/ 8

Front 77

POINT/CONCENTRATED LOAD AT THE CENTER OF A MEMBER

Back 77

M= P L/4

Moment= (point load x length)/ 4

Front 78

ECCENTRIC LOAD

Back 78

M= Pe

Moment= force x eccentricity

Front 79

Section Modulus

Back 79

S= (b dsq)/ 6 in cub.

S= M/ Fb

Section Modulus= Moment in Inches/ Bending Stress

Moment and Stress in kips

Front 80

Section Modulus for Roof Beam

Back 80

S= M/ (Fb x 1.25)

Sect Mod= Moment/ Bending Stress x 1.25

Front 81

Section Modulus (by Inertia)

Back 81

S= I / c

Section Modulus= Moment of Inertia/ dist from extreme fiber to neutral axis

Front 82

Moment of Inertia

Back 82

I= b d cub/ 12 in(4th)

Front 83

Moment of Inertia of a rectangle

Back 83

I= b d cub/ 3 in(4th)

Front 84

Moment of Inertia at base

Back 84

Ibase= I + A y2 in4

I @ Base = I + Area X (dist. from centroid to base)2

Front 85

center of area

Back 85

Use the formula M = A d derived from M=Fd to find X and Y

Sum A = Sum of Areas of ALL members

Front 86

BENDING / FLEXURAL STRESS

Back 86

fb= M / S

Bending Stress= Moment/ Section Modulus

Front 87

BENDING / FLEXURAL STRESS per moment of inertia

Back 87

fb= M c/ I

Bending Stress= Moment x (dist. from extr. fiber)/ Moment of Inertia

greater the c, greater the Bending Stress

Front 88

Axial Stress formula

Back 88

fa= P / A

Axial Tension or Compr. Stress=
Axial Tension Force in lbs or kips/ Area inches

Front 89

Axial Stress

Back 89

same at both tension and compression

Front 90

Shear Stress formula

Back 90

fv= 1.5 V / A

Actual Shear Stress=
1.5 x shear force/ Area

Front 91

Shear stress

Back 91

max. shear stress occurs at the neutral axis
shear stress is the same at both vertical and horizontal

Front 92

Notching on Tension side of a Wood Beam

Back 92

fv= (1.5 V/ b d') x (d/d')

d= overall d of beam
d'= d of the beam that is notched

use actual, not nominal dimensions

Front 93

Short heavily loaded Beams & Beams with large loads at supports

Back 93

fv= V/ dt

Actual Shear Stress = Shear Force/ (depth of beam) X (thickness of beam)

Front 94

SHORTENING OF A COL. OR ELONGATION OF A HORIZ. MEMBER

Back 94

delta= P L/ A E

shortening/ elongation= Force x length/ (A of cross-section of member X Modulus of Elasticity)

Front 95

DEFLECTION OF A BEAM

Back 95

delta= 5 w L(4th)/ 384 E I

deflection= 5 x (w in lbs) X (Length in feet X12”)4/
(384) X 12” X Modulus of Elasticity X Moment of Inertia

Front 96

strain

Back 96

E= delta/ L

strain= deflection/ orig. length

Front 97

Modulus of Elasticity

Back 97

E= f/e

Modulus of Elasticity= Stress/ Strain

Front 98

SHORTENING OR ELONGATION DUE TO CHANGE IN TEMPERATURE

Back 98

delta= e L delta-t

Thermal Elongation = (Coeff.of thermal linear expansion) X (Orig.Length) X (Temp Change)

Front 99

THERMAL STRENGTH IN A RESTRAINED MEMBER

Back 99

ft = E e delta-t

Thermal Stress in a restrained member = E X Coeff. of linear expansion X Change in Temp

Front 100

slenderness ratio- steel column

Back 100

SR = k l / r

Slenderness Ratio = (end cond.) X Unbraced length in inches / radius of gyration

kl is the effective length in feet

slenderness ratio should be <or=200 for a steel column

Front 101

slenderness ratio- wood column

Back 101

SR = k l / b

Slenderness Ratio = (k =1) X (Unbraced Length in inches) / cross-section width of rectangle

ratio should <or= 50 for a wood column

Front 102

radius of gyration

Back 102

r= sq rt I / Area

radius of gyration = sq rt of moment of inertia/ area

Front 103

retaining wall formula

Back 103

F= w h2 / 2

force exerted on= (fluid pressure at top of soil) X (height)2 / 2

Front 104

resisting moment

Back 104

Rm = 1.5 Mot

DL Resisting Moment= 1.5(Overturning Moment of the Retaining Wall)

Front 105

Factor of Safety for the resisting Moment

Back 105

FS= Rm / Mot

Factor of Safety= Resisting Moment/ Overturning Moment

Front 106

Factor of Safety amount

Back 106

<or= 1.5

Front 107

Sliding of Retaining Wall

Back 107

FS against Sliding = Sliding Resistance (#) / Force causing tendency to Sliding (#)

Front 108

Sliding Resistance

Back 108

Sliding Resistance = (Total Vert. Load in # on Ftg) X (Coeff. of Friction)

Front 109

Force causing Sliding

Back 109

Force causing Sliding = (Earth pressure in # @ Base of Ftg) X (h in ft) / (2) ft

Front 110

Bending Moment retaining wall

Back 110

M= (F) h / 3

Bending Moment = Force X (ht at resultant force)

Bending Moment occurs at 1/3rd the height of the retaining wall, where resultant force occurs.

Front 111

Throat of Weld

Back 111

Throat of Weld = Weld Size X (.707)

Front 112

Capacity of Weld

Back 112

Capacity of Weld = (Allow. Stress)(Throat)(Weld Size)(Total Weld Length)

Allow. Stress = 18 ksi for E60 electrode weld for ASTM A-36 base plate.

21 ksi for E70 electrode weld for ASTM A-36 base plate

Front 113

Stress in throat of weld

Back 113

f t= P / A

Stress in throat of weld= (Compressive/Tensile Force of the Weld)/ (.707) X (Weld Size) X (Total Weld Length)

Front 114

Ultimate Load for Concrete

Back 114

U = 1.4DL + 1.7LL

Ultimate Load = 1.4(Dead Load) + 1.7(Live Load)

Front 115

Ultimate Moment for Concrete

Back 115

MU = 1.4 MDL + 1.7 MLL

Ultimate Moment = 1.4(Dead Load Moment) + 1.7(Live Load Moment)

Front 116

percentage of steel to achieve a balanced design

Back 116

percentage of steel to achieve a balanced design= (area of tensile reinforcemnt)/ (beam width) X (d)

Front 117

live load reduction

Back 117

R = r (A – 150)

Live Load Reduction = (rate of reduction) X {(Tributary Area) – 150

rate of reduction= 0.08 for floors

Front 118

Rmax

Back 118

40% for single level floors
60% for multi level floors

R = 23.1 (1 + DL) / LL

Front 119

Thrust- 3 hinged arch

Back 119

Thrust = w L2 / 8 h

Thrust in a 3 hinged arch = uniform load X (length)2 / 8 x height

Front 120

Accessories

Back 120

Are extra items that can be furnished in addition to the base joist or joist girder. They include: headers, top chord extensions, extended ends, ceiling extensions, bottom chord extensions, sloped end bearings, bridging, bridging anchors, joist girder bottom chord bracing, or angle units (joist substitutes).

Front 121

ADL

Back 121

Abbrevation for 'After Dead Load is Applied'

Front 122

Alignment Chart for Columns

Back 122

A nomograph for estimating the effective length factor, K, of columns in an unbraced frame. Note that the chart is based upon assumptions of idealized conditions which seldom exist in real structures.

Front 123

Amplitude

Back 123

A measure of floor vibration. It is the magnitude or total distance traveled by each oscillation of the vibration.

Front 124

Amplification Factor

Back 124

A multiplier of the value of moment or deflection in the unbraced length of an axially loaded member to reflect secondary values generated by the eccentricity of the load.

Front 125

Anchor Bolt

Back 125

A long 'L' shaped bolt which is set in concrete and used to anchor columns or other members to a foundation or other support.

Front 126

Anchor Bolt Plan

Back 126

A plan view showing the size, location, and projection of all anchor bolts.

Front 127

Anchorage

Back 127

The process of fastening a joist or joist girder to a masonry, concrete, or steel support by either bolting or welding.

Front 128

Angle

Back 128

A hot rolled shape called an Angle with symbol L which has equal legs or unequal legs

Front 129

Apex

Back 129

The highest point on a joist or joist girder where the sloped chords meet. See also Peak

Front 130

Approval Plans

Back 130

Plans sent by the joist manufacturer to the buyer, engineer, architect, contractor or other person for approval. The plans may include a framing plan, elevations, sections, and a material list.

Front 131

ASD (Allowable Stress Design)

Back 131

A structural design method whereby a structural element is designed so that the unit stresses computed under the action of working or service loads do not exceed specified allowable values. See Working Stress Design and Elastic Design.

Front 132

Aspect Ratio

Back 132

For any rectangular configuration, the ratio of the lengths of the sides.

Front 133

Automatic Welding

Back 133

A welding procedure using a machine to make a weld.

Front 134

Auxiliary Load

Back 134

Any dynamic live loads such as cranes, monorails, and material handling systems.

Front 135

Axial Force

Back 135

A force tending to elongate or shorten a member.

Front 136

Axial Compression

Back 136

An axial force causing compression in a member.

Front 137

Axial Load

Back 137

A load whose line of action passes through the centroid of the member's cross-sectional area and is perpendicular to the plane of the section.

Front 138

Axial Strut Load

Back 138

A structural member designed to transfer a axial tension or compression load only.

Front 139

Axial Tension

Back 139

An axial force causing tension in a member.

Front 140

Backing Bar

Back 140

A welding aid used to prevent melting through of a joint when preforming, for example, a complete-joint penetration groove weld.

Front 141

Ballast Roof

Back 141

A roof which has selected material, such as crushed stone, placed on its surface to hold down the roof from wind forces.

Front 142

Bar

Back 142

A square or round piece of solid steel which is usually 6 inches or less in width.

Front 143

Base Metal

Back 143

The metal to be welded or cut.

Front 144

Base Plate

Back 144

A steel plate welded to the base of a column which distributes the column loads over an area of foundation large enough to prevent crushing of the concrete and usually secured by anchor bolts.

Front 145

Basement

Back 145

Any floor below the first story in a building.

Front 146

Batten

Back 146

A small piece of angle or plate welded to the heels of a two angle web member or any two parallel components to tie them together and usually located at the middle of the member.

Front 147

Bay

Back 147

The distance between the main frames of a building.

Front 148

Base Ply

Back 148

Is one layer of felt fastened to the deck over which a built-up roof is applied.

Front 149

Beam

Back 149

A structural member, usually horizontal, whose main function is to carry loads transverse to its longitudinal axis. These loads usually cause bending of the beam member. Some types of beams are simple, continuous, and cantilever.

Front 150

Beam-Column

Back 150

A structural member whose main function is to carry loads both parallel and transverse to its longitudinal axis.

Front 151

Bearing

Back 151

1) The distance that the bearing shoe or seat of a joist or joist girder extends over its masonry, concrete, or steel support 2) A structural support, usually a beam or wall, that is designed by the specifying professional to carry reactions to the foundation

Front 152

Bearing Plate

Back 152

The steel plate used for a joist or joist girder to bear on when they are supported by masonry or concrete supports. This plate transfers the joist reaction to the supporting structure and must be sized accordingly.

Front 153

Bearing Wall

Back 153

A wall which is supporting any vertical loads i2n addition to its own weight.

Front 154

Bending Moment

Back 154

The condition in the analysis of the internal stresses across the cross section of a member when it is subjected to forces which cause it to bend.

Front 155

Bending Stress

Back 155

Is zero at the neutral axis and assumed to increase linearly to a maximum at the outer fibers of the section.
Formula in the elastic range: Bending stress (in psi)=(M * c)/I, where 'M' is the bending moment at the section in in-lbs, 'I' is the moment of inertia of the section in inches^4, and 'c' is the distance from the neutral axis to the point at which the stress is desired in inches.

Front 156

Bent

Back 156

The plane of beam or joist girder members which support loads and the columns which support these members.

Front 157

Bevel Cut

Back 157

Bevel Cut

Front 158

BG-Type Joist Girder

Back 158

A type of Joist Girder where joists are located at all panel points where vertical webs and diagonal webs intersect the top chord.

Front 159

Biaxial Bending

Back 159

Bending of a structural member about two perpendicular axes at the same time.

Front 160

Bifurcation

Back 160

The phenomenon whereby a perfectly straight member may either assume a deflected position, deflect then twist out of plane, or may remain in an undeflected configuration.

Front 161

Bill of Lading

Back 161

A list that gives each part or mark number, quantity, length of material, total weight, or other description of each piece of material that is shipped to a jobsite. The receiver compares each item on this list to what is on the truck and signs the statement. See also Shipping List.

Front 162

Bill of Materials

Back 162

A list of items or components used for fabrication and accounting purposes. See Cut-List.

Front 163

Blasting

Back 163

A method of cleaning or of roughening a surface by a forceable stream of sharp angular abrasive.

Front 164

Bolted Splice

Back 164

The connection between two structural members joined at their ends by bolting to form a single, longer member.

Front 165

Bond Beam

Back 165

The top course of block of a masonry wall filled with concrete and reinforcing steel and used to support roof loads.

Front 166

Bottom Bearing

Back 166

A bearing condition where the joist or joist girder bears on its bottom chord and not at an underslung condition.

Front 167

Bottom Chord

Back 167

The bottom members of a joist or joist girder.

Front 168

Bottom Chord Extension (BCX)

Back 168

The two angle extended part of a joist bottom chord from the first bottom chord panel point towards the end of the joist.

Front 169

Bottom Chord Strut

Back 169

A bottom chord of a joist or joist girder designed to transfer a axial tension or compression load.

Front 170

Boundary Condition

Back 170

An idealization to model how a structure is attached to its "external" points of support, for example, pin, fixed, roller, or shear release.

Front 171

Bow String Joist

Back 171

A non-standard type of joist where the top chord is curved and the bottom chord is straight or level.

Front 172

Bow's Notation

Back 172

Used in a graphical analysis of a joist or joist girder. It is a notation for denoting truss joints, members, loads, and forces. Capital letters are placed in the spaces between truss members and between forces. Each member and load is then designated by the letters on opposite sides of it.

Front 173

Braced Frame

Back 173

A frame which resists lateral loads by the use of diagonal bracing, K-braces, or other system of bracing.

Front 174

Bracket

Back 174

A structural support attached to a column or wall on which to fasten another structural member.

Front 175

Bridge Crane

Back 175

In general, is a member connected to a joist to brace it from lateral movement. See Horizontal Bridging and Diagonal Bridging.

Front 176

Bridging Anchor

Back 176

An angle or bent plate attached to a wall where the bridging will be attached or anchored, either by welding or bolting. The ends of all bridging lines terminating at walls or beams shall be anchored thereto.

Front 177

Bridging Clip

Back 177

A small piece of angle or plate with a hole or slot that is welded to the top and bottom chord angles so that bridging may be attached.

Front 178

Bridging Diagram

Back 178

A diagram of the profile of a joist used to show the number and location of the rows of bridging.

Front 179

Brittle Fracture

Back 179

The tearing or splitting of a member with little or no prior ductile deformation.

Front 180

BTU (British Thermal Unit)

Back 180

The amount of heat required to raise the temperature of one pound of water by one degree farenheit.

Front 181

Buckling Load

Back 181

The load at which a straight member under compression transfers to a deflected position.

Front 182

Building

Back 182

Any structure used for support or for shelter.

Front 183

Building Code

Back 183

Regulations established by a recognized agency describing design loads, procedures, quality of materials, and construction details for buildings for the protection of the public.

Front 184

Building Designer

Back 184

A registered architect or registered engineer who is responsible for the design of a structure. See Specifying Professional.

Front 185

Building Official

Back 185

The officer or other authority which has the duty of administration and enforcement of a building code.

Front 186

Built-Up Roof

Back 186

A type of roof composed of two or more layers of alternating felt, tar and asphalt.

Front 187

Built-Up Section

Back 187

A structural member made up from individual flat plates welded together or any structural metal elements that are welded or bolted together.

Front 188

Butt Plate

Back 188

The end plate of a structural member usually used to rest or butt against a like plate of another member in forming a connection.

Front 189

C Shapes

Back 189

A hot rolled shape called an American Standard Channel with symbol C.

Front 190

"C" Section

Back 190

A structural member cold-formed from sheet steel in the shape of a block "C" which can be used by itself or back to back with another C Section.

Front 191

Calipers

Back 191

A mechanical instrument usually having a pair of pivoted legs adjustable to any distance and used to measure thichness, distances between surfaces, and any internal or external diameter which is inaccessible with a scale.

Front 192

Camber

Back 192

Camber is an upward curvature of the chords of a joist or joist girder induced during shop fabrication to compensate for deflection due to loading conditions. Note, this is in addition to the pitch of the top chord.

Front 193

Canopy

Back 193

A projecting member that is supported at one end only.

Front 194

Cant Strip

Back 194

A deck accessory which is a short piece of gage steel used at 45 degrees where a wall or parapet meets the end of deck.

Front 195

Canted Seat

Back 195

A seat which is sloped perpendicular to the member which most joist manufactures do not do. Usually the steel contractor furnishes a bent plate shim to provide level bearing for the seat.

Front 196

Cantilever

Back 196

The part of a member that extends freely over a support which is not supported at its end.

Front 197

Cap Plate

Back 197

A steel plate welded to the top of a column which a joist, joist girder, or other structural member can bear on.

Front 198

Catwalk

Back 198

Suspended structural framing used to provide access to and between areas below a roof and above a floor.

Front 199

Ceiling Extension

Back 199

Is similar to a bottom chord extension except that only one angle of the joist bottom chord is extended from the first bottom chord panel point towards the end of the joist.

Front 200

Centerline Span (or Center-to-Center)

Back 200

A theoretical span definition which is the distance between the actual centerlines of a beam, column, joist, or joist girder.

Front 201

Centroid

Back 201

The point in a member at the intersection of two perpendicular axes so located that the moments of the areas on opposite sides of an axis about that axis is zero.

Front 202

Certified Welder

Back 202

A welder who has been certified by a competent experienced welding inspector or a recognized testing facility in the field of welding. The welder must be certified to make certain welds under qualified procedures. The welder must be qualified for each position, type weld, electrode, and thickness of base metal that is to be welded in the shop or field.

Front 203

Change Order

Back 203

A written document which modifies the plans, specifications, or price of a construction contract.

Front 204

Channel

Back 204

A hot rolled structural shape the looks like "[". There are American Standard Channels designated by (C) and Miscellaneous Channels designated by (MC).

Front 205

Chord

Back 205

The two angle top or bottom member of a joist or joist girder, usually with a gap between the angles.

Front 206

Cladding

Back 206

The exterior covering of the structural members of a building.

Front 207

Clear Span

Back 207

The actual clear distance or opening between supports for a structural member, i.e., the distance between walls or the distance between the edges of flanges of beams.

Front 208

Clevis

Back 208

A U-shaped yoke with internal threads in one end which can be attached to a threaded rod and the other end a connection with a hole used for a pin or bolt attchment.

Front 209

Clip Angle

Back 209

A structural angle which attaches to the side of a wall, column, beam, etc. where a joist, joist girder, or other structural member bears.

Front 210

Closure Strip

Back 210

A floor deck accessory made of gage metal which is placed over the ends of deck so that concrete cannot run out of the flutes of the deck.

Front 211

Coefficient of (Linear) Expansion

Back 211

The change in length, per unit, for a change of one degree of temperature.

Front 212

Cold-Formed

Back 212

The process of forming a structural section by bending sheet or strip steel in roll-forming machines without the use of heat.

Front 213

Collateral Load

Back 213

All additional dead loads other than the weight of the building, such as sprinklers, pipes, ceilings, and mechanical or electrical components.

Front 214

Column

Back 214

Is a main vertical member carrying axial loads, which can be combined with bending and shear, from the main roof beams or girders to the foundation. These structural members carry loads parallel to its longitudinal axis.

Front 215

Column Curve

Back 215

A curve which shows the relationship between axial column strength and slenderness ratio.

Front 216

Compact Section

Back 216

A steel section whose flanges must be continuously connected to the webs and the width-thickness ratios of its compression element can not exceed the limiting width-thichness ratios designated in the AISC Manual.

Front 217

Composite Beam

Back 217

A steel beam and a concrete slab connected, usually by shear stud connectors, so that they act together to resist the load on the beam.

Front 218

Compression

Back 218

A condition caused by the action of squeezing or shortening of a component.

Front 219

Compression Member

Back 219

Any member in which the primary stress is longitudinal compression.

Front 220

Concentrated Load

Back 220

A single load or force that has such a small contact area as to be negligible compared with the entire surface area of the supporting member and applied at a certain point on the structure.

Front 221

Connection

Back 221

A joint connected by welds or bolts used to transmit forces between two or more members. See also Splice.

Front 222

Continuity

Back 222

The term given to a structural system denoting the transfer of loads and stresses from member to member as if there were no connections.

Front 223

Continuous Span

Back 223

A span that extends over several supports and having more than two points.

Front 224

Continuous Weld

Back 224

A weld which extends continuously from one end of a joint to the other.

Front 225

Contract

Back 225

A legal document or agreement, enforceable by law, between two or more parties for the doing of something specified, such as the building of a building or furnishing materials.

Front 226

Conventional Framing

Back 226

Framing using conventional joist, beams, columns, masonry walls, etc. instead of framing used in Metal Building construction.

Front 227

Coping

Back 227

The process of removing certain sections of a structural steel member to allow easier fitup to the supporting structural member.

Front 228

Corbel

Back 228

Successive courses of masonry projecting from the face of a wall to increase its thickness or to form a shelf or ledge for a structural member to bear on.

Front 229

Cover Plate

Back 229

A long plate usually welded to the top or bottom flange of a rolled steel beam or to the bottom chord of a joist or joist girder to increase the load carrying capacity of that member.

Front 230

Coverage

Back 230

The width of a deck sheet, i.e., 30 inches or 36 inches.

Front 231

Crane

Back 231

1) A machine used to move material by means of a hoist. 2) A machine that can usually move and is used to lift heavy materials or to lift members that are to be erected in a structure.

Front 232

Creep

Back 232

A time-dependent deformation of a structural member under a sustained constant load.

Front 233

Cricket

Back 233

A ridge or drainage diverting roof framing.

Front 234

Crimped Angle Web

Back 234

A regular angel whose ends have been 'crimped' in the shape of a 'U' whose out-to-out distance is usually one inch. The actual crimped portion of the angle is only a few inches on each end and the end is inserted between top or bottom chord members to be welded.

Front 235

Critical Load

Back 235

The load at which deflection of a member or structure occurs as determined by stability analysis.

Front 236

Curb

Back 236

A raised edge of a concrete floor slab or support for a mechanical unit.

Front 237

Curtain Wall

Back 237

A non-load bearing exterior wall which carries only its own weight and wind load.

Front 238

Curvature

Back 238

The rotation per unit length of a member due to bending forces.

Front 239

Cut-List

Back 239

A list of components with dimensions used for fabrication and accounting purposes. See Bill of Materials.

Front 240

Damping

Back 240

For floor vibrations, it is the rate of decay of amplitude.

Front 241

Dead Load

Back 241

Loads due to the weight of the components making up the structure and that are intended to remain permanently in place.

Front 242

Deck

Back 242

A floor or roof covering made out of gage metal attached by welding or mechanical means to joists, beams, purlins, or other structural members and can be galvanized, painted, or unpainted.

Front 243

Deck Type

Back 243

The specific type of deck to be specified, such as Type "B" Wide Rib, Type "F" Intermediate, Type "N" Deep Rib, Type "A" Narrow Rib, Composite, Cellular, etc.

Front 244

Deflection

Back 244

The displacement of a structural member or system under load.

Front 245

Deformation

Back 245

The act of distorting or changing the shape or dimensions of a structural element or body resulting from forces or stresses.

Front 246

Depth of Joist

Back 246

The out-to-out distance from the top of the top chord to the bottom of the bottom chord taken a some reference location, usually at the midspan of the joist or joist girder.

Front 247

Design Length

Back 247

The 'span' of a joist or joist girder in feet minus 0.3333 feet.

Front 248

Design Loads

Back 248

The loads specified in the contract drawings or specifications which a building is to be designed for.

Front 249

Design Strength

Back 249

The resistance provided by a structure, member, or connection to the forces imposed on it.

Front 250

Diagonal Bracing

Back 250

Structural members which are inclined and are usually carrying axial load which enable a structural frame to behave as a truss to resist horizontal loads.

Front 251

Diagonal Bridging

Back 251

Two angles or other structural shapes connected from the top chord of one joist to the bottom chord of the next joist to form an 'X' shape whose l/r ratio cannot exceed 200. The bridging members are almost always connected at their point of intersection.

Front 252

Diaphragm

Back 252

Roof panel or decking, metal wall, or floor slab which provides a larger in-plane shear stiffness and strength adequate to transmit horizontal forces to the resisting structural system.

Front 253

Diaphragm Action

Back 253

The resistance to a racking affect or in-plane shear forces offered by roof deck, panels, or other structural members when properly attached to a structural frame.

Front 254

Double Curvature

Back 254

When end moments on a structural member produce a bending effect which cause the member to form an S shape or has a reversal in curvature.

Front 255

Downstanding Leg

Back 255

The leg of a structural angle which is projecting down from you when viewing.

Front 256

Drift

Back 256

The lateral movement or deflection of a structure.

Front 257

Drift Index

Back 257

The ratio of the lateral deflection to the height of the building.

Front 258

Drift Pin

Back 258

A tapered pin used during the erection process to align holes in steel members which are to be connected by bolting.

Front 259

Ductility

Back 259

Is the ability of a material to withstand large inelastic deformations without fracture. Structural steel has considerable ductility.

Front 260

Ductility Factor

Back 260

The ratio of the total deformation at maximum load to the elastic-limit deformation.

Front 261

Dynamic Load

Back 261

A load that varies with time which includes repeative loads, seismic loads, and other loads created by rapid movement.

Front 262

Eave

Back 262

The line along the sidewall of a building formed by the intersection of the plane of the roof and the plane of the wall.

Front 263

Eave Strut

Back 263

A structural member located at the eave of a building which supports a roof and/or wall panels.

Front 264

Eccentric

Back 264

The condition that exists when a load is applied on a line of action that does not pass through the centroid of the body it is applied to.

Front 265

Eccentricity

Back 265

The distance between a line of action of force and the centroid of the member it is applied to.

Front 266

Edge Angle

Back 266

1) A structural angle that is connected around the edge of a joist extension or other member 2) An angle used around the sides of a floor to contain the concrete when it is being poured which is also called a Pour Stop.

Front 267

Edge Distance

Back 267

The distance from the center of a hole to the edge of a connected part.

Front 268

Edge Strip

Back 268

The width or region around the edges of a building where uplift values are higher than in the interior of the roof.

Front 269

Effective Depth

Back 269

The distance from the centroid of the top chord to the centroid of the bottom chord.

Front 270

Effective Length

Back 270

The equivalent length, KL, used in compression formulas. This method estimates the interaction effects of the total frame on a compression member by using K factors to equate the strength of a framed compression member of length L to an equivalent pin-ended member of length KL subject to axial load only.

Front 271

Effective Length Factor (K)

Back 271

The ratio between the effective length and the unbraced length of a member measured between center of gravities of the bracing members. K values are given for several idealized conditions in which joint rotation and translation are realized.

Front 272

Effective Moment of Inertia

Back 272

The moment of inertia of the cross section of a member that remains elastic when partial plastification takes place. See Moment of Inertia.

Front 273

Effective Width

Back 273

The transverse distance indicating the amount of slab that acts in conjuction with the supporting member.

Front 274

Elastic Analysis

Back 274

The analysis of a member which assumes that material deformation disappears on removal of the force that produced it and the material returns to its original state.

Front 275

Electrode

Back 275

The device through which current is conducted thru to the arc or base metal during the process of welding.

Front 276

Embedment

Back 276

A steel member such as a plate, bolt, stud, or bar cast into a concrete structure which is used to transmit applied loads to the concrete.

Front 277

End Diagonal or Web

Back 277

The first web member on either end of a joist or joist girder which begins at the top chord at the seat and ends at the first bottom chord panel point.

Front 278

End Lap

Back 278

The lap at the end of a sheet of deck which bears over the primary support (joist or beam).

Front 279

End Moment

Back 279

A moment which is generated at one end or both ends of a joist, joist girder, or beam due to continuous frame action which can be caused by wind, live load, or dead load moment.

Front 280

End Panel

Back 280

The distance from the panel point at thejoist seat to the first top chord panel point towards the interior.

Front 281

End Wall

Back 281

An exterior wall which is perpendicular to the ridge of the building.

Front 282

Envelope

Back 282

A graphical plot indicating the maximum magnitude of an internal force effect such as flexual stess, shear stress, axial stress, torsional stress, etc. due to a series of load combinations.

Front 283

EOD

Back 283

Abbreviation for 'Edge of Deck'.

Front 284

EOS

Back 284

Abbreviation for 'Edge of Slab'.

Front 285

Equations of Equilibrium

Back 285

The equations relating a state of static equilibrium of a member or structure when the resultant of all forces and moments are equal to zero. Three equations must be fulfilled simultaneously: Sum of the forces in the X-direction must equal zero, sum of the forces in the Y-direction must equal zero, and the sum of the moments about any point must equal zero for a two dimensional structure.

Front 286

Equivalent Uniform Load

Back 286

A uniform load (in plf) derived from the maximum reaction (in lbs) or the maximum moment (in inch-lbs) of a member carrying various loads.
Formula: Weq= 2 * max. reaction (in lbs) divided by length (in feet) or
Weq=(8 * max. moment) divided by (lenght^2 (in feet) * 12)

Front 287

Erection Plan

Back 287

Floor or roof plans that identify individual marks, components, and accessories furnished by the joist manufactures in a detailed mannner to permit proper erection of the joist and joist girders. See Framing Plan and Placing Plan.

Front 288

Extended End

Back 288

The extended part of a joist top chord with also the seat angles extended from the end of the jost extension back into the joist maintaining the standard 2 1/2 inch end bearing depth over the entire length of the extension.

Front 289

Factor of Safety

Back 289

Is the ratio of the ultimate load for a member divided by the allowable load for a member and must always be greater than unity.

Front 290

Factored Load

Back 290

The product of the nominal load and a load factor.

Front 291

Farside

Back 291

For joists and joist girders, when looking at the member with the tagged end to the right, it is the side that is opposite the side you see first.

Front 292

Fascia

Back 292

The flat surface located at the outer end of a roof overhang or cantilever end or also a decorative trim or panel which projects from the face of a wall.

Front 293

Fastener

Back 293

Term for a connecting device such as a weld, bolt, rivet, etc.

Front 294

FC

Back 294

Abbreviation for 'Field Cut'.

Front 295

Filler

Back 295

A rod, plate, or angle welded between a two angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member. See Tie or Plug.

Front 296

Finish Strip

Back 296

A roof deck accessory made out of gage metal for finishing out runs of deck for small areas of coverage where full sheet coverage is impractical.

Front 297

Fire Proofing

Back 297

The process of coating a structural steel member with a fire retardant material to make the member resistant to fire.

Front 298

Fire-Resistance

Back 298

The ability of a joist or other structural member to resist a fire due to the type of protection it has, such as membrane protection or spray on protection. There are hundreds of floor-ceiling or roof-ceiling assemblies with their fire-resistance rating given in the Underwriters Laboratory Fire Directory.

Front 299

Fixed-End Support

Back 299

A condition where no rotation or horizontal or vertical movement can occur at that end. This type of support has no degrees of freedom. Three reactive forces exist at the rigidly fixed end. See also Rigid Connection.

Front 300

Flange

Back 300

The projecting edge of a structural member.

Front 301

Flashing

Back 301

Pieces of sheet metal or the like used to cover and protect joints, etc. where a roof comes in contact with a wall or chimney.

Front 302

Flute

Back 302

The fold or bend in a sheet of deck which forms a groove or furrow.

Front 303

FMS (Factory Mutual System)

Back 303

A leader in property loss prevention engineering and adjustment. It helps companies prevent and control property loss through research, engineering, and education.

Front 304

Footing

Back 304

A concrete pad or mat located under a column, wall, or other structural member that distributes loads from that member into the supporting soil.

Front 305

Foundation

Back 305

The substructure which supports a building or other structure.

Front 306

Free-Body Diagram

Back 306

A diagram on which all of the external forces acting on a body are shown at their respective points of application.

Front 307

Frequency

Back 307

A measure of floor vibration. It is the speed of the oscillations of vibration and is expressed in cycles per secong or Hz (Hertz).

Front 308

G-Type Joist Girder

Back 308

A type of Joist Girder where joists are located at panel points where diagonal webs intersect the top chord only.

Front 309

Gable

Back 309

The triangular portion of a roof located above the elevation of the eave line of a double sloped roof.

Front 310

Gable Joist

Back 310

A non-standard type of joist where the top chord is double pitched at an extreme pitch (say 3/12) and the bottom chord is straight or level.

Front 311

Gage

Back 311

1) The thickness of a sheet of deck or 2) The distance from centerline hole to centerline hole across a set of holes, usually perpendicular to the joist or joist girder.

Front 312

Galvanized

Back 312

The process of coating steel with zinc for corrosion resistance.

Front 313

Gambrel

Back 313

A roof having two slopes on each side, the lower slope usually steeper than the upper one.

Front 314

Girder

Back 314

A main horizontal, primary structural member spanning between two main supports which carries other members or vertical loads.

Front 315

Girt

Back 315

A horizontal structural member that is attached to the sidewall or endwall columns supporting sheeting or paneling.

Front 316

Grillage Beam

Back 316

A short beam used like a bearing plate to distribute large reactive loads to a wall such as the load from a joist girder.

Front 317

Gusset Plate

Back 317

A steel plate used to connect structural steel members or to reinforce members. It is usually inserted between the top or bottom chord of a joist or joist girder.

Front 318

H-Series Joist

Back 318

H-Series Joist

Front 319

Hardness

Back 319

Is a measure of the resistance of a material to scratching and indention.

Front 320

Heel

Back 320

The outside point of a structural angle where the two perpendicular legs intersect.

Front 321

High Strength Bolts

Back 321

A structural steel bolt having a tensile strength greater than 100,000 pounds per square inch, usually A325 or A490.

Front 322

High Strength Steel

Back 322

Structural steel having a yield stress greater than 36,000 pounds per square inch.

Front 323

Hinge Support

Back 323

This type of support has one degree of freedom, it can freely rotate about its axis but it cannot displace in any direction. Two mutually perpendicular reactive forces exist at the hinge and their lines of action pass through the center of the hinge. See Pin Connection or Support.

Front 324

Hip Roof

Back 324

A roof which slopes from all four sides of a building. The line where two adjacent sloping sides intersect is called the 'hip'.

Front 325

Hip and Valley

Back 325

A system of roof framing where support members form valleys and ridges.

Front 326

Hoist

Back 326

A chain or electric lifting device usually attached to a trolly which travels along a monorail or bridge crane.

Front 327

Hooke's Law

Back 327

The linear relationship of forces and deformations, or stresses and strains.

Front 328

Horizontal Bridging

Back 328

A continuous angle or other structural shape connected to the top and bottom chord of a joist horizontally whose l/r ratio cannot exceed 300.

Front 329

Horizontal Shear Stress

Back 329

Is zero at the outer fibers of a section and is maximum at the neutral axis. It tends to cause one part of the section to slide past the other.
Formula: Horizontal Shear stress (in psi)=(V * Q)/I*t, where 'V' is the external vertical shear on the section in lbs, 'I' is the moment of inertia of the section in inches^4, 'Q' is the statical moment about the neutral axis of the entire section of that portion of the cross-section lying outside of the cutting plane and 't' is the width at the cutting plane.

Front 330

Hot-Rolled Shapes

Back 330

Structural steel sections which are formed by rolling mills from molten steel which can be angles, channels, W Shapes, S Shapes, etc.

Front 331

HP Shapes

Back 331

A hot rolled shape with symbol HP used for bearing piles which have essentially parallel flanges and equal web and flange thickness.

Front 332

Hysteresis

Back 332

A term that describes the behavior of a structural member subjected to reversed, repeated load into the inelastic range whose plot of load verses displacement is characterized by loops. The amount of energy dissipated during inelastic loading is indicated by the enclosed area within these loops.

Front 333

Ice Dam

Back 333

A dam or blockage formed on a roof by the buildup of ice along the eave of a building.

Front 334

Impact Factor

Back 334

The factor by which the static weight is increased by dynamic application.

Front 335

Impact Load

Back 335

A weight that is dropped or a dynamic load generated by movement of a live load such as vehicles, craneways, etc.

Front 336

Impact Strength

Back 336

The ability of a material to absorb the energy of a load delivered rapidly to a member.

Front 337

Impact Wrench

Back 337

A pneumatic device used to tighten nuts on bolts.

Front 338

Inclusions

Back 338

Nonmetallic material which is entrapped in sound metal.

Front 339

Inelastic Action

Back 339

Deformation of a material which does not disappear when the force that produced it is removed.

Front 340

Inflection Point

Back 340

Represent a point of zero moment in structural member.

Front 341

Influence Line

Back 341

An influence line is a curve whose ordinates give the values of some particular function (shear, moment, reaction, etc.) in an element due to a unit load acting at the point corresponding to the particular ordinate being considered. Influence lines for statically determinate structures are straight lines and for statically indeterminate structures the lines are curved and their construction involves considerable analysis.

Front 342

Instability

Back 342

A condition reached when a structure or structural member is loaded in which continued deformation results in a decrease in its load-resisting capacity.

Front 343

Intermittent Weld

Back 343

A weld which is not continuous. It is broken by recurring unwelded spaces.

Front 344

Internal Pressure

Back 344

The pressure inside a building which is a function of the wind velocity and the number and locations of openings.

Front 345

Interior Bearing

Back 345

Bearing supports which are interior to two exterior supports.

Front 346

Isotropic

Back 346

A material having equal physical properties along all axes.

Front 347

J-Series Joist

Back 347

A series of joist adopted in 1961 so proportioned that the allowable tension or bending stress does not exceed 22,000 psi and was made from A36 steel.

Front 348

Jack Truss

Back 348

A joist girder that is supporting another joist girder.

Front 349

JBE

Back 349

Abbreviation for 'Joist Bearing Elevation'.

Front 350

Jib Crane

Back 350

A cantilevered boom or beam with a hoist and trolly used to pick up loads in all or part of a circle around which it is attached

Front 351

Jig

Back 351

A device which holds work or pieces of materal in a certain position until rigidly fastened or welded during the fabrication process.

Front 352

Joint Penetration

Back 352

The minimum depth the weld metal extends from its face into a joint.

Front 353

Joist

Back 353

A structural load-carrying member with an open web system which supports floors and roofs utilizing hot-rolled or cold-formed steel and is designed as a simple span member.

Front 354

Joist Designation

Back 354

A standard way of communicating the joist safe uniformly distributed load-carrying capacities for a given span such as 16K5 or 24K10 where the first number is the nominal joist depth at midspan and the last number is the chord size. See Longspan Designation and Joist Girder Designation.

Front 355

Joist Girder

Back 355

A primary structural load-carrying member with an open web system designed as a simple span supporting equally spaced concentrated loads of a floor or roof system acting at the panel points of the joist girder and utilizing hot-rolled or cold-formed steel.

Front 356

Joist Girder Designation

Back 356

A standard way of communicating the girder design loads such as 48G6N10.5K where the first number is the nominal girder depth at midspan, 6N is the number of joist spaces on the span of girder, and 10.5K is the kip load on each panel point of the girder. The approximate dead load weight of the member is included in the kip load. See Joist Designation and Longspan Designation.

Front 357

Joist Substitute

Back 357

A structural member which is intended for use at very short spans (10 feet or less) where open web steel joists are impractical. They are usually used for short spans in skewed bays, over corridors, or for outriggers. It can be made up of two or four angles to form channel sections or box sections. See Angle Unit.

Front 358

K-Distance

Back 358

The distance from the outside fiber of a rolled steel beam to the web toe of the fillet of a rolled shape.

Front 359

K-Series Joist

Back 359

A series of joist adopted in 1986 based on a load/span type of determination.

Front 360

Kicker

Back 360

A structural member used to brace a joist or beam usually at an angle.

Front 361

Kip

Back 361

A unit of weight equal to 1000 pounds.

Front 362

Knee Brace

Back 362

A structural brace positioned diagonally between a beam or column and a joist panel point.

Front 363

Knife Plate Seat

Back 363

A vertical plate used as a joist seat whose width is small for bearing purposes. It is used for hip and valley bearing conditions, canted seat conditions, and extreme skewed conditions.

Front 364

Lamellar Tearing

Back 364

Is a separation or crack in the base metal caused by through-thickness weld shrinkage strains of adjacent weld metal.

Front 365

Lateral Buckling

Back 365

Also called lateral-torsional buckling. This is buckling of a member involving lateral deflection and twist.

Front 366

Lateral Bracing

Back 366

Members, fasteners, or welds which brace a member at certain locations to prevent lateral movement.

Front 367

Leeward

Back 367

The direction toward which the wind is blowing, which is opposite the side from which the wind blows. Opposite of windward.

Front 368

Leg

Back 368

The flat projecting part of a structural angle.

Front 369

Leveling Plate

Back 369

A steel plate used on top of a foundation on which a structural column can be placed.

Front 370

Live Load

Back 370

Loads on a member that are not permanent and are likely to be moved at some point in the life of the structure. They can be loads produced by the use and occupancy of the building. These loads do not include dead load, wind load, snow load, or seismic load.

Front 371

Longitudinal

Back 371

The direction extending along the long axis of the member.

Front 372

Longspan Joist

Back 372

A structural load-carrying member with an open web system which supports floors and roofs utilizing hot-rolled or cold-formed steel and is designed as a simple span member. These carry higher loads than a regular joist.

Front 373

Loose Angle Strut

Back 373

A single or double angle either welded or bolted at the first bottom chord panel point and extended to brace another member such as a beam, joist girder, frame, or wall.

Front 374

LRFD (Load and Resistance Factor Design)

Back 374

A method of proportioning structural members such that no limit state is exceeded when all appropriate load combinations have been applied.

Front 375

M Shapes

Back 375

A hot rolled shape called a Miscellaneous Shape with symbol M that cannot be identified as W, HP, or S Shapes.

Front 376

Major Axis

Back 376

The axis of a structural member possessing the largest section modulus and radius of gyration, thus having the greatest flexural and axial compressive strength.

Front 377

Maxwell Diagram

Back 377

A graphical method of determining stresses in a truss by combining force polygons of all the joints into one stress diagram.

Front 378

MBMA (Metal Building Manufacturers Association)

Back 378

An association of manufacturers of metal building systems whose objectives are to compile and publish recommended design standards which will insure high quality metal buildings.

Front 379

Member Release

Back 379

An idealization to model how members are attached to "each other". It designates whether forces and moments at the ends of a member are considered fixed to or released from the member's point of attachment.

Front 380

Metal Building System

Back 380

A building system consisting of a group of coordinated components which have been designed for a certain loading. These components are mass produced and assembled in various combinations with other structural materials to produce a building.

Front 381

Meuller-Breslau Principle

Back 381

Is a simple method to draw approximate shapes of influence lines.

Front 382

Mezzanine

Back 382

A low floor between two stories in a building, usually just above the ground floor.

Front 383

Mil

Back 383

A measurement of thickness of paint. One mil=.001 of an inch.

Front 384

Milled

Back 384

A surface which has been accurately sawed or finised to a true plane.

Front 385

Mill Test Report

Back 385

A report of a heat of steel that indicates the customer's order number, grade of steel, number and dimensions of pieces shipped, and the chemical compositional makeup of hot rolled structural steel members. It also indicates physical properties, such as, yield strength, tensile strength, elongation, impact, and ultimate strength.

Front 386

Minor Axis

Back 386

The axis of a structural member possessing the smallest section modulus and radius of gyration, thus having the least flexural and axial compressive strength.

Front 387

Miter Cut

Back 387

A single cut made at an angle to the member length. See Bevel Cut.

Front 388

Modulus of Elasticity (E)

Back 388

Is the slope of the straight-line portion of the stress-strain curve in the elastic range found by dividing the unit stress in ksi by the unit strain in in/in. For all structural steels, the value is usually taken as 29,000 ksi. This is also called Young's Modulus.

Front 389

Moment

Back 389

The tendency of a force to cause a rotation about a point or axis which in turn produces bending stresses.

Front 390

Moment Connection

Back 390

A connection designed to transfer moment as well as axial and shear forces between connecting members.

Front 391

vMoment Diagram

Back 391

A diagram that represents graphically the moment at every point along the length of a member.

Front 392

Moment of Inertia (I)

Back 392

A physical property of a member which helps define rigidity or stiffness and is expressed in inches raised to the fourth power. It is a measure of the resistance to rotation offered by a section's geometry and size.

Front 393

Moment Plate

Back 393

A welded steel plate used to develop a rigid connection to the supporting member so that moment transfer can occur.

Front 394

Monorail

Back 394

Usually a single rail support for a material handling system.

Front 395

Nailers

Back 395

Strips of lumber attached to the top chord of a joist so plywood or other flooring can be nailed at 36 inches maximum on center.

Front 396

Nearside

Back 396

For joists and joist girders, when looking at the member with the tagged end to the right, it is the side you see first and is closest to you.

Front 397

Neutral Axis

Back 397

The surface in a member where the stresses change from compression to tension, i.e., represents zero strain and therefore zero stress. The neutral axis is perpendicular to the line of applied force.

Front 398

NFPA (National Fire Protection Association)

Back 398

An international nonprofit organization to reduce the burden of fire on the quality of life by proposing codes and standards, research, and education on fire related issues.

Front 399

Noncompact Section

Back 399

A steel section which does not qualify as a compact section and the width-thickness ratios of its compression elements do not exceed the values designated in the AISC Manual.

Front 400

Nonrigid Structure

Back 400

A structure which cannot maintain its shape and may undergo large displacements and would collapse under its own weight when not supported externally.

Front 401

Offset Ridge

Back 401

When the ridge of a joist that has the top chord pitched two ways is not in the center of the member or bay.

Front 402

One-third Increase

Back 402

When designing steel members for forces produced by wind or seismic conditions, the allowable stresses in the design formulas may be increased 1/3 above the values otherwise provided.

Front 403

Outrigger

Back 403

A structural member which is usually perpendicular to a joist and attaches under the outstanding leg of one of the joist top chord angles. It then bears on a beam or wall and cantilevers across, similar to a top chord extension.

Front 404

Outstanding Leg

Back 404

The leg of a structural angle which is projecting toward or away from you when viewing.

Front 405

Overhang

Back 405

The extension of the top chord of a joist beyond the outside of the bearing support. See Top Chord Extension.

Front 406

P-Delta Effect

Back 406

The secondary effect of column axial loads and lateral deflection on the moments in structural members.

Front 407

Pack Out

Back 407

When joists are erected in multiple bays, they begin to hit each other end to end (or pack out) because the center to center of beam is not true or the joists are to long.

Front 408

Parallel Chord

Back 408

Type of joist or joist girder which has its top and bottom chords parallel to each other. The member can be sloped and still have parallel chords.

Front 409

Partially Restrained

Back 409

A type of connection that displays a moment rotation behavior that can neither be described as pinned nor fixed.

Front 410

Pilaster

Back 410

A reinforced or enlarged portion of a masonry wall to provide support for vertical roof loads or lateral loads on the wall.

Front 411

Pin Connection or Support

Back 411

A connection where no moment is transfered from one member to another, only axial and shear forces. This type of support has one degree of freedom, it can freely rotate about its axis but it cannot displace in any direction. Two mutually perpendicular reactive forces exist at the pin and their lines of action pass through the center of the pin. See Hinge Support.

Front 412

Pipe Bridge

Back 412

A structural system where two joists are used to carry loads such as piping or ducts. The two joists have to have diagonal bridging and their top and bottom chords have to be laced together with structural members to provide stability for the whole structure,

Front 413

Plastic Design

Back 413

A design concept based on multiplying the actual design loads by a suitable load factor and then using the yield stress as the maximum stress in any member.

Front 414

Plate

Back 414

A thin, flat piece of metal of uniform thickness usually over 8 inches to 48 inches in width.

Front 415

Plate Girder

Back 415

A built-up structural beam.

Front 416

Plug

Back 416

A rod, plate, or angle welded between a two angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member. See Tie or Filler.

Front 417

Plug Weld

Back 417

A weld in a slot in a piece of steel which overlaps another piece. A principle use for a plug weld is to transmit shear in a lap joint. See Slot Weld and Puddle Weld.

Front 418

Poisson's Ratio

Back 418

Defined as the ratio of the unit lateral strain to the unit longitudinal strain. It is constant for a material within the elastic range. For structural steel, the value is usually taken as 0.3. It gradually increases beyond the proportional limit, approaching 0.5.

Front 419

Polar Moment of Inertia (J)

Back 419

Is the sum of any two moments of inertia about axes at right angles to each other. It is taken about an axis which is perpendicular to the plane of the other two axes.

Front 420

Portal Frame

Back 420

A rigid frame structure which is designed to resist longitudial loads where diagonal bracing is not permitted. It has rigidity and stability in its plane.

Front 421

Pour Stop

Back 421

An angle used around the sides of a floor to contain the concrete when it is being poured.

Front 422

Powder Actuated

Back 422

A fastening method which uses a powdered charge to imbed the fastener into the member.

Front 423

Prefabricate

Back 423

To manufacture or construct parts or sections of structural assemblies beforehand that are ready for quick assembly and erection at a jobsite.

Front 424

Press Brake

Back 424

A machine used in cold-forming metal sheet or strip into a desired cross section or structural shape.

Front 425

Principle of Superposition

Back 425

States that the resultant is the algebraic sum of the effects when applied separately.

Front 426

Prismatic Beam

Back 426

A beam with uniform cross section.

Front 427

Proportional Limit

Back 427

The point on a stress-strain curve where the linear relationship between stress and strain ends and usually coincides with the material yield point.

Front 428

Purlin

Back 428

Usually a cold-formed horizontal structural member attached perpendicular to the joist top chord or main frames of a building for support of the roof deck.

Front 429

Radius of Gyration (r)

Back 429

Is the distance from the neutral axis of a section to an imaginary point at which the whole area of the section could be concentrated and still have the same moment of inertia.
Formula: The square root of (the moment of inertia in inches^4 divided by the area of the section in inches^2) expressed in inches.

Front 430

Rake

Back 430

The edge of a roof which intersects the gable part of a roof.

Front 431

Reaction

Back 431

The force or moment developed at the points of a support.

Front 432

Redundants

Back 432

The reactions which are not necessary for static equilibrium.

Front 433

Relaxation

Back 433

Is a decrease in load or stress of a member under a sustained constant deformation.

Front 434

Residual Stress

Back 434

Pre induced stresses within a structural member due to uneven cooling of the shape after hot-rolling.

Front 435

Rib

Back 435

A fabricated fold or bend in a sheet of deck which projects up from a horizontal plane.

Front 436

Ridge

Back 436

The highest point on the roof of a building formed by two intersecting slopes or the horizontal line made by the top surfaces of the two intersecting sloping roof surfaces.

Front 437

Rigid Connection

Back 437

A connection where moment is transfered from one member to another. See also Fixed-End Support.

Front 438

Rigid Frame or Structure

Back 438

A structural framing system consisting of members joined together with moment or rigid connections which maintain their original angular relationship under load without the need for bracing in its plane. See Frame and Stability.

Front 439

Rod

Back 439

A smooth solid round bar used for the web system of a bar joist.

Front 440

Roller Support

Back 440

This type of support has two degrees of freedom, it can freely rotate about its axis or displace in one direction in the plane. Only one reactive force exists at a roller which acts perpendicular to the path of the displacement and its line of action passes through the center of the roller.

Front 441

Saddle Angle

Back 441

The angle connection or seat on the end of a header or frame which bears from the side on the top chord of a joist. This angle should be designed to carry the reaction of the header or frame to the center of the joist and must rest on and weld to both top chord angles.

Front 442

Sag Rod

Back 442

A tension member used to limit the deflection of a girt or purlin in the direction of the weak axis.

Front 443

Scab On

Back 443

A member fastened or welded to another member for reinforcement.

Front 444

Scissor Joist

Back 444

A non-standard type of joist where both the top chord and bottom chord are double pitched and parallel with each other.

Front 445

Scuttle

Back 445

A framed opening in a roof used for access to the roof from inside a building.

Front 446

Seat Depth

Back 446

The out-to-out depth of the end bearing shoe or seat of a joist or joist girder which is the distance from the top of the top chord to the bottom of the bearing seat angle or plate.

Front 447

Section Modulus (S)

Back 447

A physical property of strength of a structural member. It relates bending moment and maximum bending stress within the elastic range. Formula: S=I/c where 'I' is the moment of inertia of the cross-section about the neutral axis in inches^4 and 'c' is the distance from the neutal axis to the outermost fibers.

Front 448

Seimic Load

Back 448

Are assumed lateral forces acting in any horizontal direction that produce stresses or deformations in a structural member due to the dynamic action of an earthquake.

Front 449

Self Tapping Screw

Back 449

A mechanical fastener for attaching deck, panels, or other materials to a structure which taps its own threads in a predrilled hole.

Front 450

Set Back

Back 450

The distance from the outside edge of an angle or other member to the edge of a gusset plate or angle welded near the end.

Front 451

Shear

Back 451

A condition or force causing two contacting parts of a material to slide past each other in opposite directions parallel to their plane of contact.

Front 452

Shear Center

Back 452

The point in a cross section of a structural member to which a load may be applied and not induce any torsional stress in the cross section.

Front 453

Shear Diagram

Back 453

A diagram that represents graphically the shear at every point along the length of a member.

Front 454

Shear Release

Back 454

A boundary condition which constrains a member end from axial displacement and rotation but allows movement in a direction perpendicular to the members longitudinal axis.

Front 455

Shear Stud Connector

Back 455

A steel device used in composite design which is welded to the top flange of a beam or top chord of a joist which transfers shear from a concrete slab to the supporting member.

Front 456

Shear Wall

Back 456

A wall that resists horizontal shear forces applied in the plane of the wall.

Front 457

Shim

Back 457

A piece of steel used to level a joist seat. It can be a bent plate, flat plate or rod.

Front 458

Shore

Back 458

The process of temporarily supporting a structure or structural member with auxiliary members.

Front 459

Side Lap

Back 459

The lap at the sides of a sheet of deck and is attached by side lap screws or welds between supports.

Front 460

Simple or Single Span

Back 460

A span with supports at each end, no intermediate support, that restrain only against vertical displacement with the ends of the member being free to rotate.

Front 461

Single Curvature

Back 461

When moments produce a deformed or bent shape of a structural member having a smooth continuous curve or arc.

Front 462

Skew

Back 462

The condition when two entities come together at an angle which is not 90 degrees or perpendicular to each other.

Front 463

Slag

Back 463

A non-metallic byproduct of the welding process forming a hard crust over the molten steel which should be chipped away for inspection of a weld.

Front 464

Slender Element Section

Back 464

A steel section whose width-thickness ratios of any compression element exceeds the values of a noncompact section.

Front 465

Slenderness Ratio

Back 465

The ratio of the effective length of a column to the radius of gyration of the column about the same axis of bending.

Front 466

Slip-Critical Joint

Back 466

A bolted joint in which the slip resistance of the connection is required.

Front 467

Special Design

Back 467

A design required by a loading diagram or other special notes because a standard joist or joist girder cannot be specified from a load table.

Front 468

Square

Back 468

In deck terminology, it is the term for 100 square feet of deck or roofing surface.
Formula: number of squares = sum of(length of deck sheet in feet * width of deck sheet in feet * number of pieces)divided by 100.

Front 469

Stabilizer Plate

Back 469

A steel plate at a column or wall inserted between the end of a bottom chord of a joist or joist girder to weld the bottom chord to or to restrain the bottom chord from lateral movement.

Front 470

Statically Determinate

Back 470

A member or structure that can be analyzed and the reactions and forces determined from the equations of equilibrium.

Front 471

Statically Indeterminate

Back 471

A member or structure that cannot be analyzed soley by the equations of statics. It contains unknowns in excess of the number of equilibrium equations available. Additional equations must be written based on a knowledge of elastic deformations.

Front 472

Stiffener

Back 472

A member used to strengthen another member against buckling or to distribute load or to transfer shear. Usually a flat bar, plate, or angle welded perpendicular to the longitudinal axis of the member.

Front 473

Strain Hardening

Back 473

The condition when ductile steel exhibits the capacity to resist additional load than that which caused initial yielding after undergoing deformation at or just above the yield point.

Front 474

Stress Concentration

Back 474

A localized stress which is considerably higher than average due to sudden changes in loading or sudden changes in geometry.

Front 475

Strong Axis

Back 475

The cross section which has the major principal axis.

Front 476

Strut

Back 476

A structural member used as a brace to resist axial forces.

Front 477

Sump Pan

Back 477

A metal deck accessory used at drain locations to close the opening where holes are cut in the metal deck.

Front 478

Superimposed Load

Back 478

Usually means a load that is in addition to the dead weight of the bar joists and bridging.

Front 479

Sweep

Back 479

The curvature of a structural member in the perpendicular transverse direction of its vertical axis.

Front 480

Tangent Modulus

Back 480

The slope of the stress-strain curve of a material in the inelastic range at any given stress level.

Front 481

Tempory Structure

Back 481

Anything which is built which will not become part of the permanent structural system and will eventually be removed before or after the completion of the structure.

Front 482

Tensile Strength

Back 482

The longitudinal pulling stress a material can withstand without tearing apart or the maximum tensile stress the material can sustain.

Front 483

Tension

Back 483

A condition caused by the action of stretching or pulling of a component.

Front 484

Tensile Strength

Back 484

Or ultimate strength, is the largest unit stress a material can achieve in a tensile test.

Front 485

Thrust

Back 485

The horizontal component of a reaction or an outward horizontal force.

Front 486

Tie

Back 486

A rod, plate, or angle welded between a two angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member. See Filler or Plug.

Front 487

Tie Joist

Back 487

A joist that is bolted at a column.

Front 488

Tilted Joist

Back 488

A joist which is supported in a manner such that the vertical axes of the joist is not perpendicular with respect to the ground.

Front 489

Toe

Back 489

The outside points of each leg of a structural angle.

Front 490

Toe of Fillet

Back 490

1) The end or termination edge of a fillet weld 2)The end or termination edge of a rolled section fillet.

Front 491

Toe of Weld

Back 491

The junction between the face of a weld and the base metal.

Front 492

Ton

Back 492

A unit of weight equal to 2000 pounds.

Front 493

Top Chord

Back 493

The top member of a joist or joist girder.

Front 494

Top Chord Bearing

Back 494

The bearing condition of a joist or joist girder that bears on its top chord seat.

Front 495

Top Chord Extension (TCX)

Back 495

The extended part of a joist top chord only. This type has only the two top chord angles extended past the joist seat. See Overhang.

Front 496

Torque Wrench

Back 496

A wrench containing an adjustable mechanism for measuring and controlling the amount of turning force exerted when used to tighten nuts and bolts.

Front 497

Torsion Loads

Back 497

A load that causes a member to twist about its longitudinal axis. Simple torsion is produced by a couple or moment in a plane perpendicular to the axis.

Front 498

Toughness

Back 498

The ability of a steel to absorb large amounts of energy without being readily damaged.

Front 499

Transverse

Back 499

Crossing from side to side or placed crosswise.

Front 500

Tribuitary Width or Area

Back 500

The design area which contributes load to a structural member. It is one half the distance between members on either side of the member.

Front 501

Trimmer Joist

Back 501

One of the joists supporting a header. The header applies a concentrated load at that point on the trimmer joist.

Front 502

Truss

Back 502

In general, a structural load-carrying member with an open web system designed as a simple span with each member designed to carry a tension or compression force. The entire structure act will act like a beam.

Front 503

Turnbuckle

Back 503

A rotating sleeve or link with internal screw threads at each end and used to tighten or connect the ends of a rod.

Front 504

Turn-of-the-Nut-Method

Back 504

A method for pre-tensioning high-strength bolts by the rotation of the wrench a predetermined amount after the nut has been tightened to a snug fit.

Front 505

Ultimate Load

Back 505

The force necessary to cause rupture.

Front 506

Ultimate Strength

Back 506

The maximum stress attained by a structural member prior to rupture which is the ultimate load divided by the orginial cross-sectional area of the member.

Front 507

Unbraced Frame

Back 507

A frame providing resistance to lateral load by the bending resistance of the frame members and their connections.

Front 508

Unbraced Length

Back 508

vThe distance between points of bracing of a structural member, measured between the centers of gravity of the bracing members.

Front 509

Unbraced Top Chord

Back 509

The specific length where the top chord of a joist has no lateral bracing by deck, bridging, or any other means.

Front 510

Undercut

Back 510

A notch or groove melted into the base metal next to the toe or root of a weld and left unfilled by weld metal.

Front 511

Underslung

Back 511

Description of a joist which is suspended from upper support points where most of the mass of steel is below the actual support points.

Front 512

UNO

Back 512

Abbrevation for 'Unless Noted Otherwise'.

Front 513

Uplift

Back 513

The wind load on a member which causes a load in the upward direction. The gross uplift is determined from various codes and is generally a horizontal wind pressure multiplied by a factor to establish the uplift pressure. The net uplift is the gross uplift minus the allowable portion of dead load including the weight of the joist and is the load that the specifying professional shall indicate to the joist manufacturer.

Front 514

Uplift Bridging

Back 514

The bridging required by uplift design. Usually always required at the first bottom chord panel point of a K-Series, LH- or DLH-Series joist and at other locations along the bottom chord as required by design.

Front 515

Upstanding Leg

Back 515

The leg of a structural angle which is projecting up from you when viewing.

Front 516

Valley

Back 516

The angle formed by two sloping sides of a roof.

Front 517

Vapor Barrier

Back 517

A physical membrane which prevents moisture or water vapor from penetrating to the other side.

Front 518

Varying Distributed Load

Back 518

A load or force, for practical purposes, that may be considered varying over the surface of the member, for example a snow drift.

Front 519

VG-Type Joist Girder

Back 519

A type of Joist Girder where joists are located at panel points where vertical webs intersect the top chord only. This type of girder is used for ducts to pass thru since the joists do not interfere with their passage.

Front 520

Vibration

Back 520

The oscillating, reciprocating, or other periodic motion of a rigid or elastic body or medium such as a floor when its position or state of equilibrium has been changed.

Front 521

Wall Anchor

Back 521

A small piece of angle or other structural material that is usually bolted to a wall to which a starter joist or bridging angle is welded or bolted to.

Front 522

Washer

Back 522

A flat ring of metal with a hole in the middle used to give thickness to a joint or to distribute pressure under the head of a nut or bolt.

Front 523

Weak Axis

Back 523

The cross section which has the minor principal axis.

Front 524

Weathering Steel

Back 524

A type of high-strength steel which can be used in normal outdoor environments without being painted. Should not be used in corrosive or marine environments.

Front 525

Web

Back 525

1) The vertical or diagonal members joined at the top and bottom chords of a joist or joist girder to form triangular patterns or 2) The portion of a structural member between the flanges.

Front 526

Web Buckling

Back 526

The buckling of a web plate.

Front 527

Web Crippling

Back 527

The local failure of a web plate in the region of a concentrated load or reaction.

Front 528

Welded Splice

Back 528

A splice between two materials which has the joint made continuous by the process of welding.

Front 529

Welding

Back 529

The process of joining materials together, usually by heating the materials to a suitable temperature.

Front 530

Weldability

Back 530

Is the ability of a steel to be welded without its basic mechanical properties being changed.

Front 531

Welding Washer

Back 531

A metal device with a hole through it to allow for plug welding of deck to structural steel.

Front 532

Wind Column

Back 532

A vertical member supporting a wall system designed to withstand horizontal wind loads. Usually between two main vertial load carrying columns.

Front 533

Wind Load

Back 533

A force or lateral pressure in pounds per square foot that is applied to a member due to wind blowing in any direction.

Front 534

Windward

Back 534

The direction or side toward the wind. Opposite of leeward.

Front 535

Working Load

Back 535

Also called service load, is the actual load that is acting on the structure.

Front 536

Working Point

Back 536

The point where two or more centroid lines of structural members intersect.

Front 537

WSD (Working Stress Design)

Back 537

A structural design method whereby a structural element is designed so that the unit stresses computed under the action of working or service loads do not exceed the specified allowable values. See Allowable Stress Design and Elastic Design.

Front 538

X-Brace

Back 538

Structural bracing which resembles the letter "X".

Front 539

Yield Point (Fy)

Back 539

Is that unit stress at which the stress-strain curve exhibits a definite increase in strain without an increase in stress which is less than the maximum attainable stress.

Front 540

Young's Modulus

Back 540

See Modulus of Elasticity.