Columns/rigid Frames/trusses

Front 1

Intermediate Column

Back 1

column that falls in between short and slender and can crush and buckle

Front 2

support coefficient (k)

Back 2

in Euler's equation- counts for the type of connector- k factor

Front 3

K factor

Back 3

Effective Length Factor - values for K vary depending on the load and type of supports of a member.

Front 4

effective legnth(le)

Back 4

In Euler's equation, effective length = KL (where L is length) strength of column decreases as K increases.

Front 5

beam-column

Back 5

A beam which transmits an axial load as well as a transverse load.

Front 6

coulmn tie

Back 6

similar to stirrups

Front 7

spiral tie

Back 7

like a turn-buckle

Front 8

eccentricity

Back 8

moment created by a shear connection (distance between connection and centroid of column)

Front 9

Pe (effect) moment

Back 9

eccentric loading caused when moment is transferred at a point other than centroid of column

Front 10

rigid frame (portal)

Back 10

single span bay with fixed connections to ground

Front 11

pinned frame

Back 11

bay with pin connections at ground

Front 12

fixed frame

Back 12

same as rigid frame?

Front 13

frame wracking

Back 13

the tendency of all studs in a wall to move in the same direction as in a parallelogram
-can be prevented by laying plywood panels or diagonal bracing

Front 14

overturning moment

Back 14

external moments cause a structure (footing) to overturn

Front 15

sidesway

Back 15

lateral movement under lateral loads or eccentric vertical loads

Front 16

three-hinge arch

Back 16

arch with pin connection (hinges) at apex and supports
later developed into Vierendeel truss

Front 17

tubular truss

Back 17

trusses composed of round hollow tubes, often used in space frames

Front 18

vierendeel truss/frame

Back 18

truss with rectangular openings and no diagonals where you can vary the thickness of the web or the width of the openings

Front 19

castellated beam

Back 19

beam which is divided lengthwise by a zigzag cut, then welded together so as to join the peaks of both halves, thus increasing its depth and strength.

Front 20

plate girder

Back 20

built-up wide flange

Front 21

composite construction

Back 21

two or more materials acting as one

Front 22

shear stud

Back 22

bolt-like tie that keys steel to concrete - in beam to slab connection - prevents sliding

Front 23

diaphragm

Back 23

planar system attached to frame to transfer later loads to shear walls of frame (plywood panels, concrete slab, etc.)

Front 24

flitch beam

Back 24

Beam made up of a steel plate sandwiched between two wood beams, the three layers being held together with bolts.


*Because flitch beams are significantly stronger than wood alone, they:

* require less depth than a wood-only beam of the same strength
* are much lighter than a steel beam of the same size
* can still be attached (e.g. nailed) to the rest of a wooden structure

Front 25

sandwich panel

Back 25

Composite materials that are fabricated by attaching two thin but stiff skins to a lightweight but thick core.

*Ikea Shelf

Front 26

tube structure

Back 26

Assembly of columns and beams that forms a rigid frame that amounts to a dense and strong structural wall along the exterior of the building and resists lateral loads.

Front 27

framed tube structure

Back 27

simplest tube structure with structure pulled to perimeter

*World Trade Center

Front 28

braced tube structure

Back 28

fewer and farther spaced exterior columns, bracing along exterior wall (diagonal) ties it together

*John Hancock Center

Front 29

bundled tube structure

Back 29

several tubes tied together to resist later loads

*Sears Tower

Front 30

chord-top & bottom

Back 30

horizontal elements that run along top and bottom of a truss

Front 31

web

Back 31

vertical member of a truss

Front 32

panel

Back 32

one section of a truss (horizontal, vertical and diagonal members)

Front 33

panel points

Back 33

joints where panels (sections) come together in a truss

load should always be placed on or hung from here, not in center of panel

Front 34

flat truss

Back 34

truss with parallel top and bottom chords

Front 35

howe truss

Back 35

truss with diagonals in compression
(if flat howe they point up and to the center)
(if pitched howe they point up toward the supports)

Front 36

pratt truss

Back 36

truss with diagonal members in tension
(flat they point up toward supports)
(pitched they point up toward center)

Front 37

warren truss

Back 37

truss with alternating diagonals in tension and compression

Front 38

quadrangular truss

Back 38

truss where diagonals are oriented to be in tension where needed (shear at supports) and compression where needed (bending at center)

Front 39

pitched truss

Back 39

triangular truss

Front 40

belgian truss

Back 40

simple triangular truss

Front 41

scissors truss

Back 41

triangular truss with triangular bottom chord, used for cathedral ceilings (more interior ceiling height)

Front 42

method of joints

Back 42

x

Front 43

method of sections

Back 43

x

Front 44

king post truss

Back 44

pitched truss with only one vertical member at apex (in compression)

Front 45

queen post truss

Back 45

king post truss but with two more diagonal supports (in tension?)

Front 46

fink truss

Back 46

pitched truss with no vertical members (only diagonals and chords)

Front 47

bowstring truss

Back 47

truss with arched top chord

Front 48

The best shape for a cross-section of a single story, axial-loaded column is? Why?

Back 48

x

Front 49

Does the strength of the material used in a column effect it's buckling load?

Back 49

x

Front 50

Draw a typical critical stress vs. slenderness ratio curve for a column showing long, intermediate and short column action

Back 50

Front 51

List 2 ways you can vary the capacity of a column in a multistory building without increasing the overall cross-sectional dimension in reinforced concrete and 2 ways in steel:

Back 51

Concrete:
1- stronger concrete 2- more rebar
Steel
1- different cross-section at bottom
2- increase strength of steel at bottom

Front 52

What 3 components of a reinforced concrete column can be manipulated to reduce the size of it's cross-section?

Back 52

x

Front 53

What are 2 methods used to prevent the rebars in a circular concrete column from buckling?

Back 53

x

Front 54

What is the difference in function between stirrups and column ties in reinforced concrete members?

Back 54

stirrups and column ties similar- column ties in a vertical member to prevent buckling
stirrups in horizontal member to prevent bending

Front 55

If stirrups are needed in a concrete column, how would they normally be spaced? Describe two ways of splicing rebars.

Back 55

x

Front 56

What determines whether the spacing of the ties in a concrete column is uniform or varied?

Back 56

point load- even spacing
uniform load- varied spacing (closer at ends, farther in middle)

Front 57

List three ways of putting a column into bending.

Back 57

Wind Load
Lateral Load
Fixed End Moment

Front 58

What is the advantage of using spaced columns/ beams-columns for design purposes?

Back 58

x

Front 59

Detail and explain the reasons behind the type of connection between the floor trusses and the columns of Centre Pompidou in Paris

Back 59

Continuous Columns that bring the load to the centroid of the column, minimizing eccentricity

Front 60

Describe how lateral stability was achieved in Centre Pompidou

Back 60

diaphragms and diagonal bracing at exterior of building

Front 61

List 3 potential methods in which lateral stability could have been achieved in Phillip Johnson's Glass House:

Back 61

1 cantilever off of central core
2 diaphragm
3 frame

Front 62

Draw the moment diagram for these rigid frames/ beam assemblies:

Back 62

x

Front 63

What effect (if any) does [increasing or decreasing] the stiffenss of the [beam or column] in a rigid frame (under uniform gravity load) have on the moment in the beams [beams or columns]?

Back 63

increasing stiffness decreases moment
decreasing stiffness increases moment

Front 64

Will the (thickness of the web members) in a vierendeel truss increase or decreases as they get closer to the supports of the truss? Why?
-openings in the web

Back 64

x

Front 65

How is thrust developed in frames under vertical loads? If the base connections are made rigid, instead of pinned, what effect, if any, does this have on the thrust? on the beam's moment

Back 65

x

Front 66

List 3 ways of resisting thrust in a single bay rigid frame that will be subjected to uniform gravity loads:

Back 66

x

Front 67

Draw the typical detail for connecting a steel H-section to a concrete foundation that results in a pinned connection.

Back 67

x

Front 68

How would you detail the reinforcing in the column of a reinforced concrete frame at it's foundation to achieve an effective pinned connection (example: Maillart's bridges).

Back 68

Front 69

Why do unsymmetrical vertical loads tend to cause sidesway in single bay rigid frames?

Back 69

insufficient lateral support in only one bay

Front 70

Define sidesway in a frame. What two loading conditions can cause it?

Back 70

eccentric vertical loading and lateral loading

Front 71

How many and where are plastic hinges formed in order to create a mechanism in the following strucutres: pinned-end beam, fixed-end beam, pinned rigid frame, fixed rigid frame:

Back 71

x

Front 72

How many plastic hinges are needed to create a mechanism of a rigid frame with pinned foundations? Where are these formed along the profile of the frame?

Back 72

x

Front 73

What forces in a rigid frame balance the overturning moment caused by the wind? Diagram these:

Back 73

x

Front 74

List 5 causes of compression in the columns of rigid frames:

Back 74

x

Front 75

List 4 disadvantages of fixed connections:

Back 75

x

Front 76

Are rigid-framed structures less susceptible to thermal movements that simple-braced structures? why?

Back 76

x

Front 77

Sketch the ideal shape of a vierendeel truss pinned or fixed? What 2 advantages do these trusses have?

Back 77

x

Front 78

What is a castellated beam? Explain the advantage of this type of beam when used with a concrete floor slab in composite action:

Back 78

x

Front 79

What added efficiency can be gained in composite floor construction by using a castellated beam instead of a rolled section?

Back 79

x

Front 80

What is a shear stud and what function does it perform

Back 80

x

Front 81

Briefly explain the reason for the failure of the roof in the Kemper Arena in Kansas City. How was it repaired

Back 81

x

Front 82

Briefly describe the principle of highrise tube structures and where and why you would locate a building's columns in plan based on this idea

Back 82

x

Front 83

Why were the windows in the World Trade Center so much narrower than those in the Sears Tower?

Back 83

x

Front 84

Draw the end panel of both a flat pratt and a flat howe truss. Describe the theory behind the configuration of each:

Back 84

x

Front 85

Draw a Quadrangular truss with eight panels and explain the principles behind its configuration:

Back 85

x

Front 86

Why is it advisable to load a truss only at it's panel points whenever possible?

Back 86

x

Front 87

What 2 effects on a truss of a given span does increasing the number of its panels have?

Back 87

x

Front 88

Discuss the offsetting cost factors that come into play in choosing either a beam or a truss to span a given distance:

Back 88

x

Front 89

beam grid

Back 89

x

Front 90

biaxial bending

Back 90

x

Front 91

torsion

Back 91

x

Front 92

skew grid

Back 92

x

Front 93

lamella arch

Back 93

x

Front 94

truss grid

Back 94

x

Front 95

space truss/frame

Back 95

truss-like, lightweight rigid structure constructed from interlocking struts in a geometric pattern.

Front 96

unistrut system

Back 96

support structure to be adjusted or moved to suit the desired requirements unlike welded structures.

Front 97

mero system

Back 97

provides concentric connections for space truss bars in any direction.

Front 98

geodesic dome

Back 98

almost spherical shell structure based on a network of great circles (geodesics) lying approximately on the surface of a sphere. The geodesics intersect to form triangular elements that have local triangular rigidity and also distribute the stress across the entire structure. When completed to form a full sphere, it is known as a geodesic sphere.

*make pentagons at connections
*icosohedron a 20 sided triangle.

Front 99

dome of decreasing circles

Back 99

x

Front 100

radial dome

Back 100

x

Front 101

tensegrity

Back 101

Integrity of structures as being based in a synergy between balanced tension and compression components.

Front 102

one-way slab

Back 102

A concrete floor slab between 2 walls or beams in which the main reinforcement runs in only one direction and the supports are parallel

Front 103

two-way slab

Back 103

A concrete floor slab in which the main reinforcement runs in two directions and the supports are on all 4 sides

Front 104

flat plate

Back 104

x

Front 105

flat slab

Back 105

x

Front 106

punching shear

Back 106

when a plane rests on a point load that load wants to puncture plane

Front 107

mushroom capital

Back 107

additional mass at column capital helps to distribute punching shear across plane

Front 108

drop panel

Back 108

On the lower side of a flat concrete slab, the thickened portion which surrounds a column, column capital, or bracket.

Front 109

shearhead

Back 109

x

Front 110

membrane stress

Back 110

Stress which is equivalent to the average stress across the cross section involved and normal to the reference plane.

Front 111

shrinkage reinforcing

Back 111

often wire mesh - typically in one way slab at center to prevent bending

Front 112

temperature reinforcing

Back 112

x

Front 113

column strip

Back 113

x

Front 114

middle strip

Back 114

x

Front 115

synclastic

Back 115

Refers to a surface with the same kind of convex or concave curvature in all directions through all points (as in a hemi-spherical dome)

Front 116

anticlastic

Back 116

Of a double-curved surface, of which the two curvatures (transverse to each other) lie in opposite directions, convex in length and concave in breadth, or vice versa

Front 117

ribbed slab

Back 117

x

Front 118

concrete joist system

Back 118

x

Front 119

concrete pan system

Back 119

x

Front 120

wide-module joist system

Back 120

joist systems with a clear spacing between the ribs of more than 30 inches

Front 121

waffle slab

Back 121

A concrete slab which is reinforced by ribs in two directions, forming a waffle-like pattern.

Front 122

What is the advantage of beam-grid systems versus parallel beam systems? List two structural implications of this advantage.

Back 122

x

Front 123

What are the three types of stress developed in beam grids?

Back 123

x

Front 124

Draw the shape (plan) of a structural bay that is ideal for a two-way structural system.

Back 124

square

Front 125

Which of the beam(s) in the beam grid shown on the board carries the largest load? Why? Assume uniform load, constant section and rigid connections.

Back 125

x

Front 126

Describe how torsion is developed in beam grids.

Back 126

x

Front 127

Define torsion. Does the modulus of elasticity or the shear modulus of a material measure a material's resistance to torsion?

Back 127

x

Front 128

Would a beam grid of WF sections have the same capacity as a beam grid of rectangular sections? Why?

Back 128

x

Front 129

Is a wide flange section a good section to resist torsion? Why? Would fixing its supports affect its torsional resistance? Why?

Back 129

x

Front 130

Why are skew grids are more efficient than rectilinear grids in rectangular bays?

Back 130

x

Front 131

What is a lamella roof?

Back 131

x

Front 132

List three advantages that space trusses have over parallel trusses. What disadvantage do they have?

Back 132

x

Front 133

Is it more efficient to support a truss grid at the top or bottom chord? Why?

Back 133

top chord - tension

Front 134

What is the difference between a space truss and a space frame.

Back 134

x

Front 135

Must the columns for a space frame be equally spaced? Why?

Back 135

x

Front 136

What two geometric solids are utilized in the planning of Unistrut's spaceframe system?

Back 136

x

Front 137

The triangle is the basic element to the truss as what is the basic solid to a space frame?

Back 137

x

Front 138

Using one point, two point, and four points of supports per column, list six ways of supporting a space frame in descending magnitude of allowable loads?

Back 138

x

Front 139

What off-the-shelf space frame system best accommodates a radial geometry?

Back 139

sandwich panel -

Front 140

Draw three different types of connections used in off-the-shelf space frame systems:

Back 140

x

Front 141

What two types of stress are absent in one-way slabs that are present in the other three types of flat concrete floors?

Back 141

torsion and membrane stress??

Front 142

Define punching shear and diagram the stresses that cause it. What can be done to offset it in a flat slab and a flat plate?

Back 142

x

Front 143

Describe how torsion is developed in two-way slabs.

Back 143

x

Front 144

Describe the method of structurally analyzing a one-way slab.

Back 144

beams in one direction - act like beams

Front 145

Where is the reinforcing steel located (with respect to the depth of the concrete) in a column/middle strip zone of a flat plate?

Back 145

x

Front 146

What is the maximum size that an opening can be in a column strip/middle strip zone of a flat plate without the need of an additional drop beam?

Back 146

x

Front 147

What are the four types of stress developed in flat plate action?

Back 147

x

Front 148

What advantage is there in using a high strength concrete in the columns of a flat plate system? How can you tell if a higher strength concrete was used in the columns than was used in the plate?

Back 148

columns can then be thinner - the higher strength concrete is darker in color due to a higher cement content

Front 149

What is the difference between a two-way slab and a flat slab?

Back 149

x

Front 150

Discuss the difference between the structural distribution of loads on a flat plate and that on a two-way slab.

Back 150

x

Front 151

For a given span and loading, would a flat plate or flat slab require a thicker plane of concrete? Why?

Back 151

x

Front 152

What two factors contribute to a plate's high reserve of strength?

Back 152

x

Front 153

List four conceptual approaches in stiffening a plate.

Back 153

x

Front 154

What is the shallowest floor structure presently in use?

Back 154

flat plate

Front 155

In waffle slabs, what can be done to increase the depth of the concrete to accommodate additional steel required in column areas?

Back 155

x

Front 156

What can you do in a concrete joist floor system if the shear at the ends of the joists exceeds their capacities, without adding stirrups to the joists?

Back 156

increase the bulk at the shear connection- increase cross section at shear connection

Front 157

Is it a good practice to cantilever a waffle slab?

Back 157

x