Dbd-Test 2- Ballast Review

Front 1

wood structural system

Back 1

oldest and most common systems

Front 2

one-way system

Back 2

load xmited through structural members in one direction at a time

Front 3

wood joists

Back 3

typicaly 2x members
spaced at 12-16-24 in
span 20-25ft.

Front 4

bridging

Back 4

used to stabalize bottom chord of joist

Front 5

plank and beam framing

Back 5

uses solid wood beams, 4-6in nominal widths betw. girders of bearing walls, spaced at 4-6-8ft.
span 10-20 ft.

Front 6

glu-lam

Back 6

3/4-1 1/2" pieces flued together
span 15-60ft.

better appearance, less defects

Front 7

wood truss

Back 7

depth of 12-36in.
span 24-40t
space @ 24in. oc.

Front 8

steel ductility

Back 8

can tolerate some deformation and return to its orifinal shape, will bend before it breaks

Front 9

beam and girder

Back 9

large members (girders) spanning between vertical supports with smaller beams betweeen
spans 25-40ft
beams spaced @ 8-10ft

Front 10

open web steel joist

Back 10

joist spanning betw bearing wall or beam

Front 11

standard joist

Back 11

standard span- 60ft.
depth- 8-30in

Front 12

long span joist

Back 12

long span- 96 ft.
depth- 18-72in

Front 13

deep long span joist

Back 13

deep long span- 144ft.
depth 18-72in

Front 14

floor joist

Back 14

spaced @ 2-4 ft. oc.

Front 15

roof joist

Back 15

spaced at 4-6 ft oc.

Front 16

lift slab construction

Back 16

precast on site, one slab on another and jacked into place and attached to columns

Front 17

tilt up panel construction

Back 17

precast on site and tilted into position

Front 18

concrete one way system

Back 18

CIP, slab and beams xfer load in one direction, usually to an interm. beam and then to a girder

Front 19

concrete two way system

Back 19

CIP, most are designed for use in a rect. bay where distance btw columns is approx. the same
flat plate, flat slab, and waffle slab

Front 20

conc. beam and girder

Back 20

spans 15-30 ft.
simple to form and allow penetrations

Front 21

flat plate

Back 21

two-way system, slab designed and reinforced to xmit loads in both directions to the columns
spans up to 25 ft.
slab depth from 6-12 in.

Front 22

flat slab

Back 22

two way system, slab is thickened at columns to resist shear failure. column capital of cone or pyramid used to dissipate shear and bending moments
spans up to 30 ft.

Front 23

waffle slab

Back 23

two way system, forms of prefab. mtl or fiberglass that allow quick construction
span up to 40 ft.

Front 24

precast unit connections

Back 24

made in field by using cast weld plates

Front 25

precast production

Back 25

prestressed, w/ high strength stl cables stretched in the form. after conc reaches min. strength cables released providing built in compressive stress that resists forces of dead and live loads

Front 26

camber

Back 26

built in curvature of beams that is reduced when loaded

Front 27

post tensioned concrete

Back 27

on site fabrication, tendons in form are stressed after the concrete has been poured. use hydraulic jacks to stress;
100-250 psi for slabs
200-500 psi for beams

Front 28

masonry reinforcing

Back 28

horizontal and vertical, strengthens wall and controls shrinkage cracks

Front 29

thickness of masonry wall

Back 29

determines slenderness ratio, flexural strength and fire resistance

Front 30

slenderness ratio

Back 30

ratio of walls unsupported height to its thickness, indication of the ability of the wall to resist buckling

Front 31

flexural strength

Back 31

resistance to lateral forces (wind)

Front 32

composite construction

Back 32

consits of two or more materials desined to act together to resist loads

Front 33

headed stud anchors

Back 33

xfer load btw. concrete and steel making the material act as one unit

Front 34

considerations for non-structural envelope

Back 34

weight of the envelope and ow the loads will be xfered to the frame
must allow for expansion and contraction due to temperture and movement of frame

Front 35

structural frame movement

Back 35

steel frame does not present much problem, concrete and wood move
concrete will creep, deform to loads
wood will shrink, but not as big an issue as dealing with smaller structure

Front 36

arches

Back 36

fixed or hinged supports, primarily subjected to compressive forces
functional shape is a parabola
spans:
wood- 50-240 ft.
concrete- 20-320 ft.
steel- 50-500 ft.

Front 37

funicular shape

Back 37

shape of arch to resist loads only in compression

Front 38

thrust

Back 38

horizontal forces acting on arch supports attempting to spread the arch outward. must be resisted by either tie rods or foundations that prevent the spread

Front 39

thrust is inversely proportion to...

Back 39

the rise, or height of the arch
if height reduce by 1/2, the thrust increase by 2

Front 40

hinge supports

Back 40

allow arch to remain flexible and avoid ending stress under live loading

Front 41

three hinge arch

Back 41

at apex, allows the structure to be statically determinate

Front 42

rigid frame

Back 42

beam is partially restrained by columns and is more rigid to vertical bending forces and both columns resist lateral forces because they are tied together. columns then must resist thrust

Front 43

gabled frame

Back 43

does not req. horiz. beam. develop high moment and often increase the depth at connections

Front 44

space frame

Back 44

efficient at enclosing large horizontal space.
span up to 350 ft.
span to depth ratio from 20:1 to 30:1`

Front 45

folded plate

Back 45

act as beams btw support
depth 3-6 in.
span 30-100 ft (more w/ reinforced conc.)

Front 46

thin shelled structure

Back 46

curved surface that resists loads through tension, compression and shear
depth 3-6"
span:
dome- 40-200'
hyperbolic paraboloid- 30-160'

Front 47

suspension cable

Back 47

similar and opposite to arches. reaction forces are verticle and outward. can only resist in tension, and a secondary system must be used for lateral forces

Front 48

unanticipated loads

Back 48

changes in building use
extra people or equipment
unusual snow or rain loads
degradation of the structure

Front 49

fire resistance considerations

Back 49

combustibility of the framing
loss of strength when subjected to intense heat

Front 50

wish to create a building with highly irregular form...

Back 50

simple floor and roof framing, fab on-site:
sitecast concrete w/o beams or ribs
LGMF
platform frame
masonry construction w/ concrete slab or wood floor framing

Front 51

wish to leave structure exposed while retaining high fire resistence...

Back 51

inhearently fire resistance:
all concrete systems
heavy timber frame
mill construction

Front 52

wish to allow column placements that deviate from a regular grid...

Back 52

systems w/o beams or joists in the floor or roof:
sitecast concrete two way flat plate or slab
space frame

Front 53

wish to minimize floor thickness to reduce total building height or reduce floor spandrel depth on the building facade...

Back 53

use thin system, concrete slab w/o ribs:
sitecast concrete two way
precast hollow core or soild slab
posttension one way slab

Front 54

wish to minimize area occupied by columns or bearing walls...

Back 54

long span systems:
wood truss
glulam beam and arch
steel frame
stl joists
rigid stl frame
stl. trusses
sitecast concrete waffle slab, when posttensioned
precast concrete single or double tees

Front 55

wisht to allow for changes to building over time...

Back 55

short span one way systems, easy to modify:
LGMF
wood system
masonry construction
sitecast oneway slab or one way joist construction (not posttension)
precast slab

Front 56

wish to permit construction under adverse weather conditions...

Back 56

not dependant upon on site chemical processes such as concrete curing:
steel system
wood system
precast systems that minimize sitecast concrete toppings

Front 57

wish to minimize on site erection time...

Back 57

highly preprocessed, prefab or modular components:
single story rigid stl frame
conventional steel frame with hinge connections
precast concrete
heavy timber

Front 58

wish to minimize construction time for a one or two story building...

Back 58

lightweight and easy to form or prefab and easy to assemble:
steel system
heavy timber
platform frame

Front 59

wish to minimize construction time for a 4-20 story building...

Back 59

precast concrete
convential steel frame

if no lead time, site cast

Front 60

wist to minimize construction time for a building 30 story or more...

Back 60

strong, lightweight, prefab and easy to assemble:
steel fame
precast or sitecast in some regions

Front 61

wish to minimize need for diagonal bracing or shear walls

Back 61

system of forming rigid joints:
sitecast concrete
steel frame with welded connections
single story rigid frame

Front 62

wish to minimize the dead load on the building foundation...

Back 62

lightweight or short span system:
steel system
wood system

Front 63

wish to mimimize structural distess due to unstable foundation conditions...

Back 63

frame systems w/o rigid joints:
steel frame w/ bolted connections
heavy timber frame
precast concrete systems
platform framing

Front 64

wish to minimize the number of seperate trades and contracts req. to complete the building...

Back 64

systems that incorporate many function in a complete wall system:
masonry construction, incl. mill or ordinary constructions
precast concrete loadbearing wall panel systems

Front 65

wish to provide concealed space w/i the structure itself for ducts, pipes, wires and other mechanical systems...

Back 65

systems w/ natrual hollow spaces:
truss and open web joist
LGMF
platform framing

Front 66

dynamic loads

Back 66

loads such as wind that vary. in calculations these are assumed to be static loads

Front 67

reduction in live load

Back 67

IBC allows live load to be reduced in most cases. may not be reduced for any public assembly occupancy with load less than or equal to 100psf or for any memeber supporting one floor of a parking garage

Front 68

adjusted load (L) limitations

Back 68

L must not be less than:
0.5Lo for members supporting one floor
0.4Lo for members supporting more than one floor
0.8Lo for members supporting more than one floor with a live load exceeding 100psf

Front 69

live load reduction formula

Back 69

R=r(A-150)

Front 70

live load reduction limitations

Back 70

reduction cannot exceed 40% for horiz. members, 60% for vertical members
cannot exceed percentage of formula:
R=23.1(1 + [D/Lo])

Front 71

load combinations

Back 71

IBC requires several combination of load factors be analyzed to determine the most critical case

Front 72

A

Back 72

area of floor or roof, sq. ft.

Front 73

At

Back 73

tributary roof area supported by a structural member, sq ft

Front 74

AsubT

Back 74

tributary floor area supported by a structural area, sq ft

Front 75

D

Back 75

dead load, lbf/ sq ft

Front 76

E

Back 76

earthquake or seismic load, lbf/sq ft

Front 77

f sub1

Back 77

floor live load occupancy combination factor

Front 78

f sub2

Back 78

snow load roof shape combination factor

Front 79

F

Back 79

roof slope, in/ft

Front 80

h

Back 80

depth of retaining wall, ft

Front 81

K subLL

Back 81

live load element factor

Front 82

L

Back 82

floor live load, lbf/sq ft

Front 83

Lo

Back 83

unreduced floor live load, lbf/sq ft

Front 84

Lr

Back 84

roof live load

Front 85

p (wind)

Back 85

direct wind pressure, lbf/sq ft

Front 86

p (soil)

Back 86

max soil pressure o retaining wall, lbf/sq ft

Front 87

P

Back 87

lateral soil force, lbf/sq ft

Front 88

q

Back 88

lateral soil pressure, lbf/sq ft

Front 89

r

Back 89

rate of reduction of live load

Front 90

R (floor load)

Back 90

allowable reduction of floor live load, %

Front 91

R (rain)

Back 91

rain load, lbf/sq ft

Front 92

R sub1

Back 92

roof area reduction factor

Front 93

R sub2

Back 93

roof slope reduction factor

Front 94

S

Back 94

snow load, lbf/sq ft

Front 95

v

Back 95

wind velocity, lbf/sq ft

Front 96

w

Back 96

uniform total load, lbf/sq ft

Front 97

W

Back 97

wind load, lbf/sq ft

Front 98

boring depth

Back 98

Borings must extend to firm Strata (go through unsuitable foundation soil) and then extend at least 20 feet more into bearable soil.

Front 99

Borings are not taken directly under proposed columns.

Back 99

true

Front 100

soil report includes

Back 100

1.Bearing capacity of soil.
2.Foundation design recommendations.
3.Paving design recommendations.
4.Compaction of soil.
5.Lateral strength (active, passive, and coefficient of friction).
6.Permeability.
7.Frost depth.

Front 101

Surface investigations: (Danger Flags)

Back 101

High Water Table.
Presence of trouble soils: Peat, soft clay, loose silt, or fine water bearing sands.
Rock close to the surface (require blasting for excavations).
Dumps or Fills.
Evidence of slides or subsidence.

Front 102

soil condition- nearby buildings

Back 102

require shoring or earth and existing foundations.

Front 103

soil conditions- rock outcropping

Back 103

indicate bedrock, good for bearing and frost resistance, bad for excavations.

Front 104

soil conditions- water (lake)

Back 104

Water (lake) – indicate high water table, some waterproofing of foundations is required.

Front 105

soil conditions- level terrain

Back 105

Level Terrain – easy site work, fair bearing, but poor drainage.

Front 106

soil conditions- gentle slopes

Back 106

Gentle Slopes – easy site work, and excellent drainage.

Front 107

soil conditions- convex terrain (ridges)

Back 107

Convex Terrain (Ridge) – dry solid place to build.

Front 108

soil conditions- concave terrain (valley)

Back 108

Concave Terrain (Valley) – wet soft place to build.

Front 109

soil conditions- steep terrain

Back 109

Steep Terrain – costly excavations, potential erosion, and sliding soils.

Front 110

soil conditions- foliage

Back 110

Foliage – some trees indicate moist soil. Large trees indicate solid ground.

Front 111

Soil is classified on the basis of

Back 111

1.Percentage of gravel, sand, and fines.
2.Shape of grain.
3.Plasticity and compressibility characteristics.

Front 112

Spread Footings:

Back 112

Used for most buildings where the loads are light and / or there are strong shallow soils.
At columns there are single spot square pads where bearing walls have an elongation form. These are almost always reinforced.
These footing deliver the load directly to the supporting soils.
Area of spread footing is obtained by dividing the applied force by the soils safe bearing capacity (f=P/A).
Generally suitable for low rise buildings (1-4 Stories).
Requires firm soil conditions that are capable of supporting the building on the area of the spread footings.
When needed footings at columns can be connected together with grade beams to provide more lateral stability in earthquakes.
These are most widely used because they are most economical.
Depth of footings should be below the top soil, and frost line, on compacted fill or firm native soil.
Spread footings should be above the water table.
Concrete spread footings are at least as thick as the width of the stem.

Front 113

Drilled Piers or Caissons:

Back 113

For expansive soils with low to medium loads, or high loads with rock not too far down, drilled caissons (piers) and grade beams can be used.
The caissons might be straight or belled out at bottom to spread the load.
The grade beam is designed to span across the piers and transfer the loads over to a column foundation.
Caissons deliver the load to soil of stronger capacity which is located not too far down.

Front 114

Piles:

Back 114

for expansive soils or soils that are compressive with heavy loads where deep soils can not take the building load and where soil of better capacity if found deep below.

There are two types of piles.

1.Friction piles – used where there is no reasonable bearing stratum and they rely on resistance from skin of pile against the soil.

2.End bearing – which transfer directly to soil of good bearing capacity.

Front 115

Mat Foundations:

Back 115

Reinforced concrete raft or mats can be used for small light load buildings on very weak or expansive soils such as clays.
They are often post tensioned concrete.
They allow the building to float on or in the soil like a raft.
Can be used for buildings that are 10-20 stories tall where it provides resistance against overturning.
Can be used where soil requires such a large bearing area and the footing might be spread to the extant that it becomes more economical to pour one large slab (thick), more economical – less forms.
It is used in lieu of driving piles because can be less expensive and less obtrusive (i.e. less impact on surrounding areas).
Usually used over expansive clays, silts to let foundation settle without great differences.

Front 116

ALLOWABLE STRESS DESIGN.

Back 116

A method of proportioning structural members, such that elastically computed stresses produced in the members by nominal loads do not exceed specified allowable stresses (also called working stress design).

Front 117

BALCONY, EXTERIOR.

Back 117

An exterior floor projecting from and supported by a structure without additional independent supports.

Front 118

BASE SHEAR.

Back 118

Total design lateral force or shear at the base.

Front 119

BOUNDARY MEMBERS.

Back 119

Portions along wall and diaphragm edges strengthened by longitudinal and transverse reinforcement and/or structural steel members.

Front 120

CANTILEVERED COLUMN SYSTEM.

Back 120

A structural system relying on column elements that cantilever from a fixed base and have minimal rotational resistance capacity at the top with lateral forces applied essentially at the top and are used for lateral resistance.

Front 121

COLLECTOR ELEMENTS.

Back 121

Members that serve to transfer forces between floor diaphragms and members of the lateral-force-resisting system.

Front 122

CONFINED REGION.

Back 122

The portion of a reinforced concrete component in which the concrete is confined by closely spaced special transverse reinforcement restraining the concrete in directions perpendicular to the applied stress.

Front 123

COUPLING BEAM.

Back 123

A beam that is used to connect adjacent concrete wall piers to make them act together as a unit to resist lateral loads.

Front 124

DEAD LOADS.

Back 124

The weight of materials of construction incorporated into the building, including but not limited to walls, floors, roofs, ceilings, stairways, built-in partitions, finishes, cladding, and other similarly incorporated architectural and structural items, and fixed service equipment, including the weight of cranes.

Front 125

DECK

Back 125

An exterior floor supported on at least two opposing sides by an adjacent structure, and/or posts, piers or other independent supports.

Front 126

DEFORMABILITY

Back 126

The ratio of the ultimate deformation to the limit deformation.

Front 127

DESIGN STRENGTH.

Back 127

The product of the nominal strength and a resistance factor (or strength reduction factor).

Front 128

DIAPHRAGM, FLEXIBLE.

Back 128

A diaphragm is flexible for the purpose of distribution of story shear and torsional moment when the lateral deformation of the diaphragm is more than two times the average story drift of the associated story, determined by comparing the computed maximum in-plane deflection of the diaphragm itself under lateral load with the story drift of adjoining vertical-resisting elements under equivalent tributary lateral load.

Front 129

DIAPHRAGM, RIGID.

Back 129

A diaphragm that does not conform to the definition of flexible diaphragm.

Front 130

DURATION OF LOAD.

Back 130

The period of continuous application of a given load, or the aggregate of periods of intermittent applications of the same load.

Front 131

Ductile element.

Back 131

An element capable of sustaining large cyclic deformations beyond the attainment of its nominal strength without any significant loss of strength.

Front 132

Limited ductile element.

Back 132

An element that is capable of sustaining moderate cyclic deformations beyond the attainment of nominal strength without significant loss of strength.

Front 133

Nonductile element.

Back 133

An element having a mode of failure that results in an abrupt loss of resistance when the element is deformed beyond the deformation corresponding to the development of its nominal strength. Nonductile elements cannot reliably sustain significant deformation beyond that attained at their nominal strength

Front 134

EQUIPMENT SUPPORT.

Back 134

Those structural members or assemblies of members or manufactured elements, including braces, frames, lugs, snuggers, hangers or saddles, that transmit gravity load and operating load between the equipment and the structure.

Front 135

ESSENTIAL FACILITIES.

Back 135

Buildings and other structures that are intended to remain operational in the event of extreme environmental loading from flood, wind, snow or earthquakes.

Front 136

FACTORED LOAD.

Back 136

The product of a nominal load and a load factor.

Front 137

FLEXIBLE EQUIPMENT CONNECTIONS.

Back 137

Those connections between equipment components that permit rotational and/or translational movement without degradation of performance.

Front 138

Braced frame.

Back 138

An essentially vertical truss, or its equivalent, of the concentric or eccentric type that is provided in a building frame system or dual frame system to resist shear.

Front 139

Concentrically braced frame (CBF).

Back 139

A braced frame in which the members are subjected primarily to axial forces.

Front 140

Eccentrically braced frame (EBF).

Back 140

A diagonally braced frame in which at least one end of each brace frames into a beam a short distance from a beam-column or from another diagonal brace.

Front 141

Ordinary concentrically braced frame (OCBF).

Back 141

A steel concentrically braced frame in which members and connections are designed in accordance with the provisions of AISC Seismic without modification.

Front 142

Special concentrically braced frame (SCBF).

Back 142

A steel or composite steel and concrete concentrically braced frame in which members and connections are designed for ductile behavior.

Front 143

Intermediate moment frame (IMF).

Back 143

A moment frame in which members and joints are capable of resisting forces by flexure as well as along the axis of the members.

Front 144

Ordinary moment frame (OMF).

Back 144

A moment frame in which members and joints are capable of resisting forces by flexure as well as along the axis of the members.

Front 145

Special moment frame (SMF).

Back 145

A moment frame in which members and joints are capable of resisting forces by flexure as well as along the axis of the members.

Front 146

Building frame system.

Back 146

A structural system with an essentially complete space frame system providing support for vertical loads. Seismic force resistance is provided by shear walls or braced frames.

Front 147

Dual frame system.

Back 147

A structural system with an essentially complete space frame system providing support for vertical loads. Seismic force resistance is provided by a moment-resisting frame and shear walls or braced frames.

Front 148

Space frame system.

Back 148

A structural system composed of interconnected members, other than bearing walls, that is capable of supporting vertical loads and that also may provide resistance to seismic forces.

Front 149

IMPACT LOAD.

Back 149

The load resulting from moving machinery, elevators, craneways, vehicles, and other similar forces and kinetic loads, pressure and possible surcharge from fixed or moving loads.

Front 150

JOINT

Back 150

A portion of a column bounded by the highest and lowest surfaces of the other members framing into it.

Front 151

LIMIT STATE.

Back 151

A condition beyond which a structure or member becomes unfit for service and is judged to be no longer useful for its intended function (serviceability limit state) or to be unsafe (strength limit state).

Front 152

LIVE LOADS.

Back 152

Those loads produced by the use and occupancy of the building or other structure and do not include construction or environmental loads such as wind load, snow load, rain load, earthquake load, flood load or dead load.

Front 153

LIVE LOADS (ROOF).

Back 153

Those loads produced (1) during maintenance by workers, equipment and materials; and (2) during the life of the structure by movable objects such as planters and by people.

Front 154

LOAD AND RESISTANCE FACTOR DESIGN (LRFD).

Back 154

A method of proportioning structural members and their connections using load and resistance factors such that no applicable limit state is reached when the structure is subjected to appropriate load combinations. The term "LRFD" is used in the design of steel and wood structures.

Front 155

LOAD FACTOR.

Back 155

A factor that accounts for deviations of the actual load from the nominal load, for uncertainties in the analysis that transforms the load into a load effect, and for the probability that more than one extreme load will occur simultaneously.

Front 156

LOADS

Back 156

Forces or other actions that result from the weight of building materials, occupants and their possessions, environmental effects, differential movement, and restrained dimensional changes. Permanent loads are those loads in which variations over time are rare or of small magnitude. Other loads are variable loads (see also "Nominal loads").

Front 157

LOADS EFFECTS.

Back 157

Forces and deformations produced in structural members by the applied loads.

Front 158

NOMINAL LOADS.

Back 158

The magnitudes of the loads specified in this chapter (dead, live, soil, wind, snow, rain, flood and earthquake).

Front 159

P-DELTA EFFECT.

Back 159

The second order effect on shears, axial forces and moments of frame members induced by axial loads on a laterally displaced building frame.

Front 160

PANEL (PART OF A STRUCTURE).

Back 160

The section of a floor, wall or roof comprised between the supporting frame of two adjacent rows of columns and girders or column bands of floor or roof construction.

Front 161

RESISTANCE FACTOR.

Back 161

A factor that accounts for deviations of the actual strength from the nominal strength and the manner and consequences of failure (also called strength reduction factor).

Front 162

SHALLOW ANCHORS.

Back 162

Shallow anchors are those with embedment length-to-diameter ratios of less than 8.

Front 163

SHEAR PANEL.

Back 163

A floor, roof or wall component sheathed to act as a shear wall or diaphragm.

Front 164

SHEAR WALL.

Back 164

A wall designed to resist lateral forces parallel to the plane of the wall.

Front 165

SPECIAL TRANSVERSE REINFORCEMENT.

Back 165

Rein-forcement composed of spirals, closed stirrups, or hoops and supplementary cross-ties provided to restrain the concrete and qualify the portion of the component, where used, as a confined region.

Front 166

STRENGTH, NOMINAL.

Back 166

The capacity of a structure or member to resist the effects of loads, as determined by computations using specified material strengths and dimensions and formulas derived from accepted principles of structural mechanics or by field tests or laboratory tests of scaled models, allowing for modeling effects and differences between laboratory and field conditions.

Front 167

STRENGTH, REQUIRED.

Back 167

Strength of a member, cross section or connection required to resist factored loads or related internal moments and forces in such combinations as stipulated by these provisions.

Front 168

STRENGTH DESIGN.

Back 168

A method of proportioning structural members such that the computed forces produced in the members by factored loads do not exceed the member design strength (also called load and resistance factor design.) The term "strength design" is used in the design of concrete and masonry structural elements.

Front 169

wind loading

Back 169

affected by:
wind velocity
height of wind above the ground
(wind speed taken at 10m above ground, will be more at higher points)
surroundings (taken into account by variables in code)
shape of building

Front 170

wind effects

Back 170

positive pressure windward side, negative on leeward side (suction)
local areas may be greater or less

Front 171

earthquake general effects

Back 171

lateral and vertical movement
(lateral the most important and vertical is generally ignored)

Front 172

dynamic structural analysis

Back 172

use computer to model the building and earthquakes to study the response

Front 173

dynamic load

Back 173

treated as a static load multiplied by an impact factor

Front 174

resonant load

Back 174

rythmic application of force to a structure with the same fundamental period as the structure itself
utilize dampenner to minimize the effect

Front 175

fundamental period

Back 175

time taken for a structure to complete one full oscillation

Front 176

coefficient of expansion

Back 176

amount of change in a material expressed in inches per inch per degree F

Front 177

retaining walls

Back 177

minimum lateral pressures are given by code
must resist these forces in addition to other vertical loads at the top of wall
must be designed to resist sliding by 1.5x the lateral force and resist overturn by at least 1.5x the overturn moment

Front 178

pressure at bottom of retaining wall

Back 178

P=p(h/2)

lateral force= max soil pressure (height of wall/ 2)

Front 179

hydrostatic pressure

Back 179

load developed by water
62 lbf/sq ft

Front 180

b

Back 180

base of recatngular section , in

Front 181

d

Back 181

depth of rectangular section, in

Front 182

e

Back 182

total deformation (strain), in

Front 183

E

Back 183

modulus of elasticity, lbf/sq ft

Front 184

f

Back 184

unit stress, lbf/sq ft

Front 185

F

Back 185

force, lbf

Front 186

I

Back 186

moment of inertia, in to 4th

Front 187

In

Back 187

moment of inertia of transferred area, in to 4th

Front 188

Ir

Back 188

moment of inertia of area about neutral axis, in to 4th

Front 189

L

Back 189

original length, in

Front 190

P

Back 190

total force, lbf

Front 191

R

Back 191

reaction force, lbf

Front 192

W

Back 192

weight, lbf

Front 193

fish symbol

Back 193

coefficient of linear expansion,
in/in-degree F

Front 194

squiggly E

Back 194

unit strain, decimal

Front 195

statics

Back 195

mechanics dealing with bodies at equilibrium

Front 196

principles of equilibrium for buildings

Back 196

sum of all vertical forces acting on a body must equal zero
sum of al horizontal forces actin on a body must equal zero
sum of all moments acting on a body must equal zero

Front 197

vector quantity

Back 197

direction and magnitude of a force

Front 198

stress

Back 198

resistance to external forces
tension
compression
shear

Front 199

shear

Back 199

stress in which particles of a member slide past each other
force acts parallel to the area resisting the force

Front 200

stress formula

Back 200

f=P/A

stress= total force/ total area

Front 201

torsion

Back 201

type of shear in which the member is twisted

Front 202

bending

Back 202

combination of tension and compression

Front 203

thermal stress formula

Back 203

e= fishy x delta T

Front 204

internal thermal stress

Back 204

not dependent on cross section if only force applied

Front 205

strain

Back 205

deformation of a material caused by external forces

Front 206

hookes law

Back 206

strain is directly proportional to the stess up to a certain point

Front 207

elastic limit

Back 207

point at which material will change shape at a faster ratio than the applied force
above this limit the member will be permenently deformed, even when force is removed

Front 208

yield point

Back 208

point at which the material continues to deform with very little increase in load

Front 209

ultimate strength

Back 209

stess just before the member ruptures

Front 210

modulus of elasticity

Back 210

measure of a materials resistance to deformation (stiffness)

Front 211

moment

Back 211

tendancy of a force to cause rotation about a point. dependent on force by the perpendicular distance acting on the point, shown in lbf

Front 212

centroid

Back 212

point on a plane (at cross section of member) that corresponds to the center of gravity

Front 213

moment of inertia

Back 213

measure of the bending stiffness of a structural members cross-sectional shape

Front 214

neutral axis

Back 214

asix passing through the centroid

Front 215

load combinations

Back 215

some structural materials are designed using strength design, some w/ allowable stress design

Front 216

c

Back 216

distance from extreme fiber in bending to neutral axis, in

Front 217

f

Back 217

allowable fiber stress in bending, lbf/in sq

Front 218

f sub b

Back 218

extreme fiber stress in bending, lbf/in sq

Front 219

Fa

Back 219

allowable axial unit stress, lbf/in sq

Front 220

M

Back 220

bending moment, in-lbf

Front 221

Q

Back 221

statical moment about neutral axis of the area above the plan under consideration, in cubed

Front 222

r

Back 222

radius of gyration, in

Front 223

S

Back 223

section modulus, in cubed

Front 224

v sub h

Back 224

horizontal shera stress, lbf/in sq

Front 225

V

Back 225

vertical shearing force, lbf

Front 226

basic theory of bending

Back 226

internal resisting moments at any pont in the beam must equal the bending moments produced by the external loads on the beam

Front 227

section modulus

Back 227

ratio of the beams moment of inertia to the distance from the neutral axis to the outermost part of the section (extreme fiber)
S=I/ c
S=M/ f

Front 228

horizontal shear causes problem in...

Back 228

wood beam where the horizontal fibers may split and shear

Front 229

selection of beam size dependent on...

Back 229

bending and horizontal shear, but not affected by deflection

Front 230

kip

Back 230

1000 pounds

Front 231

uniformly distr. loads

Back 231

resultant force is at the center of load

Front 232

statically determinate

Back 232

the reactions can be found using the equations of equilibrium

Front 233

total load

Back 233

total load= W= wL

total load= uniform distr. load x length of beam

Front 234

principles of equilibrium

Back 234

sum:
-vertical forces = 0
-horiz. forces = 0
-moments acting on the body = 0

Front 235

shear diagram provides...

Back 235

maximum shear
point on the beam where the value of shear is zero

Front 236

maximum moment occurs...

Back 236

where the shear diagram passes through zero, and is indicated by the high point on the moment diagram

Front 237

shear diagram vs moment diagram

Back 237

shear: horizontal line between two concentrated loads or reactions
moment: straight constant sloped line

Front 238

deflection

Back 238

change in vertical position of a beam due to a load

Front 239

deflection limitations

Back 239

1/360 of the beam span for live load
1/240 for total, live and dead load

Front 240

column buckle

Back 240

tendancy of long, slender column to bend laterally under load

Front 241

column considerations

Back 241

buckling
combined forces- compressive + lateral loads
flexural stress- caused by load eccentricity

Front 242

radius of gyration

Back 242

combine the properties of area and moment of inertia
for non symmetic columns there are two radii, the lesser is the more important

Front 243

slenderness ratio

Back 243

most important factor in column design

= l/ r
=length of column/ radius of gyration

Front 244

Eulers equation

Back 244

give the max. stress a column can resist w/o buckling
not applicable to all materials w/o adjustment

Front 245

column types

Back 245

short compressive members
intermediate columns
slender columns

Front 246

column fixed ends

Back 246

fixed against rotation and movement from side to side (translate)- strongest
able to rotate but not translate
translate but not rotate
free to rotate and translate

weakest is column free at one end

Front 247

truss

Back 247

composed of straight member to form triangles
typ depth to span: 1:10-1:20
spaced at 10-40ft oc depending on the capabilities of the purlins

Front 248

trusses are subject to buckling...

Back 248

must be installed w/ bridging

Front 249

truss types

Back 249

flat truss
pitched truss
bowstring truss
scissors truss

Front 250

net area

Back 250

area of member minus the area of bolt hole

Front 251

truss members to be designed...

Back 251

concentric, so the member is symmetric on both sides of the centroid axis in the plane of the truss

Front 252

horizontal force formula (truss)

Back 252

Fx= F cos a

Front 253

vertical force formula (truss)

Back 253

Fy= F cos b

Front 254

methods to determine force in truss

Back 254

method of joints
method of sections
graphic method

Front 255

first step in designing a foundation

Back 255

determine bearing capacity of underlying soil, through exploration and testing

Front 256

water in soil

Back 256

reduce load carrying capacity in general

Front 257

hydrostatic pressure

Back 257

puts additional loads on the structural elements
makes waterproofing more difficult because the pressure tends to force water into any imperfection in the structure

Front 258

minimize problems w/ excess soil moisture

Back 258

slope the ground away and drain from the bldg
below grade: drain tile, gravel, open-web matting at foundation
underslab: large gravel below slab

Front 259

soil treatment to increase bearing capacity or decrease settlement

Back 259

drainage
fill- remove and replace
compaction-
densification- vibration, weight, pounding piles and filling displacement w/ sand
surcharging- load site with fill material to settle and remove

Front 260

additional soil concerns

Back 260

frost
expansive soil- caissons to soil below, grade beams spanning btwn piers
repose- natural slope of soil, max. practical angle of grade w/o other means of holding back soil

Front 261

types of foundations

Back 261

spread footings
pile or caissons

Front 262

independant column footing

Back 262

supports single column
size of footing found by dividing total load by bearing capacity of soil

Front 263

combined footing

Back 263

support 2 or more columns where spaced too closely for independent

Front 264

strap footing

Back 264

variation on combined, where columns are far apar

Front 265

raft foundation

Back 265

low soil bearing, two way slab below with support columns above

Front 266

pile foundation

Back 266

xfer load through unsuitable soil to secure bearing

Front 267

pier

Back 267

drilled piles or caissons
formed by drilling out a hole and filling w/ concrete

Front 268

pile cap

Back 268

xfers load from building to piles located in groups or a line beneath cap

Front 269

pile group

Back 269

designed so that centroid of group is located w/ center of gravity of the column load

Front 270

grade beam

Back 270

xfer building loads to piles drilled in a line
often w/ expansive soils at surface. form creates a void btwn beam and soil to avoid vertical pressures from soil

Front 271

unit loading

Back 271

verify that soil bearing in not exceeded and diff. settlement is eliminated

Front 272

footing shear

Back 272

if a column punches through the footing

Front 273

footing bending

Back 273

when lower surface cracks under flexural loading

Front 274

footing design factors

Back 274

unit loading
shear
bending

Front 275

footing tendancies

Back 275

act like inverted beams w/ upward soil pressure resisted by downward column load
causes bending in upward direction, with top fiber in compression and bottom in tension

Front 276

area of spread footing

Back 276

divide total wall or column load (plus own weight and soil weight) by allowable soil bearing pressure
additional formulas take into account live, lateral, fluid loads, etc

Front 277

required footing strength load

Back 277

U, equals 1.4D + 1.7L
(1.4 actual dead load + 1.7 actual live load)

Front 278

effective depth of footing

Back 278

d, distance from top of footing to the centroid of reinforcing steel

Front 279

width and thicknees of footings designed to...

Back 279

resist the wall load and shear force using only strength of unreinforced concrete
not economical to provide tension reinforcing

Front 280

types of retaining walls

Back 280

gravity
cantilever
conterfort

Front 281

cantilevered retaining wall

Back 281

arm, heel and toe act as cant. slabs. thickness and reinforcement increase with length as greater moments are developed
limit to 20-25' high

Front 282

counterfort wall

Back 282

reinforce concrete web that acts as diagonal bracing (winston salem walls)

Front 283

earth pressure (P) on retaining wall increases...

Back 283

proportionall with the depth from the surface at zero to greatest at base of wall in a triangular distribution

Front 284

retaining wall surcharges

Back 284

additional dead and live loads acting on retaining wall (i.e. nearby driveway)

Front 285

retaining wall failure

Back 285

overturn or sliding
use a safety factor of 1.5 to avoid

Front 286

eliminate or reduce buildup of water behind retaining wall by...

Back 286

providing weeps
layer of gravel next to wall
install drain is necessary

Front 287

majority of failure...

Back 287

in connections, not member

Front 288

wood connection design variables

Back 288

load bearing capacity of the connector
species of wood
load type
weather fire resistant treated
angle of load to grain
critical net section
type of shear the joint is subjected to
spacing fo connectors
end and edge distances

Front 289

species and density of wood determines...

Back 289

type of connector

Front 290

wood connector types

Back 290

timber connector- split ring and shear plate (type A,B,C,D)
screws, nails, spikes, mtl plates, etc (type I, II, III, IV)

Front 291

design value for connectors can be adjusted...

Back 291

for duration of loading. wood can carry greater max. loads for short duration than for long

Front 292

wood design values are for...

Back 292

seasoned, dry wood, less than 19% moisture

Front 293

service conditions

Back 293

environment in which wood joint will be used
any conditions other than dry or continuously wet reduce holding power of connection

Front 294

angle of load

Back 294

angle of connector to grain of wood. important variable in design

Front 295

hankinson formula

Back 295

provides compressive stress at specified angle

Front 296

critical net section

Back 296

section where wood is removed for connector, load must be checked against this section

Front 297

min. connector spacing

Back 297

given by National Design Specification for Wood Construction

Front 298

end distance

Back 298

distance measured parallel to the grain from the center of the connector to the square cut end of the member

Front 299

edge distance

Back 299

distance from the edge of the member to the center of the connector closest to the edge of the member measured perpendicular to the edge

Front 300

perpendicular grain loading

Back 300

make distinction btwn loaded and unloaded edges, min. values given in tables

Front 301

fastener orientation

Back 301

fastener loaded lateraly in side grain where the holding power is the greatest
not allowed in end grain by code

Front 302

increase nails and screws by....

Back 302

25% if a metal side plate is used

Front 303

lag screw

Back 303

threaded w/ a point, but head like a bolt

Front 304

bolt design variables

Back 304

thickness of main and side members
ratio of bolt length in main member to bolt diameter
number of members joined

Front 305

split ring

Back 305

2 1/2 or 4" diam. and are cut through in one lace in the circumference to form a tongue and slot

Front 306

shear plate

Back 306

2 5/8 or 4" diam. and are flat plates w/ a flange extending from the face of the plate. a 3/4 or 7/8" bolt extends through the hole to hold the members together
can hold either 2 pieces of wood or peice of wood and piece of stl
spec. suited for construction that must be disassembled

Front 307

common methods of stl connections

Back 307

bolting and welding

Front 308

bearing type connection

Back 308

resist shear load on the bolt through friction betw surfaces but may also produce direct bearing btw the stl being fastended and the sides of the bolts
holes slightly larger and over time may slip and bear on bolt

Front 309

slip critical connections

Back 309

those where any amount of slip would be detrimental to the serviceability of the structure
entire load taken by friction
the nuts are tightended to develop a high tensile stress in the bolt, causing the connected members to develop a high friction btw them that resists the shear

Front 310

bolt thread classifications

Back 310

included or excluded in shear plane, affects the amount of material to resist shear

Front 311

bolt types

Back 311

ASTM A307- unfinished bolts (low load bearing)
A325 and A490- high strength bolts (must be used in slip critical connection)

Front 312

bolt used conditions

Back 312

SC- slip critical
N- bearing type
X- bearing type
S- bolt in single shear
D- bolt in double shear

Front 313

standard round holes

Back 313

1/16 larger than diam of bolt
5/8" larger w/ high strength

Front 314

oversize holes

Back 314

3/16 larger than 7/8 bolts
1/4 larger than 1" bolts
5/16 larger than 1 1/8" bolts

only used in slip critical connections

Front 315

short slotted holes

Back 315

1/16 wider than bolt diam. and length that does not exceed hole by more tahn 1/16

Front 316

long slotted holes

Back 316

1/16 wider than bolt and length not to exceed 2.5x bolt diam.
only used on one of the joints, other must be standard or welded

Front 317

slotted hole connections

Back 317

used where some amount of adjustment is req.

Front 318

net area

Back 318

area reduced in beam from bolt holes
increase tendancy for shear failure parallet to the load and tension failure perpendicular to the load

Front 319

total tearing force

Back 319

sum required to cause both shear and tension failure in a beam at a bolt connection, shown as Tt

Front 320

typ, the angle used to connect beam to column...

Back 320

is shop welded to column and bolted to the other member in the field
slotted holes sometimes used to allow minor adjustments

Front 321

moment connection (steel)

Back 321

welding more suitable, but can be accomplished with bolted T-Sections

Front 322

bolt spacing for steel

Back 322

min. spacing is 2 2/3x the diam. of the bolt being used, w/ 3x being the pref. dim.

Front 323

edge distance for steel

Back 323

1.25" for all bolts having a diam. up to 1"

Front 324

reasons for using weld

Back 324

gross section can be used, not net
efficient construction, no angles, bolts, wrenches, etc.
more practical for moment connections

Front 325

to hold member in place to complete connection...

Back 325

bolting is often used w/ welding

Front 326

electric arc weld

Back 326

most common in buildings
electrode from power source connects to members being joined, other electrode in the welding rod.
base metal and the end of electrod melt into joint due to intense heat

Front 327

penetration

Back 327

depth from the surface of the base metal to the point where fusion stops

Front 328

types of electrodes

Back 328

E60- 18 ksi
E70- 21 ksi

Front 329

common weld type

Back 329

fillet most common- isosceles triangle w/ the two equal legs being the sides of the weld
butt joint- throat dim. is the thickness of the material is both are same thickness

Front 330

weld on both side

Back 330

symbol repeated above and below line

Front 331

field weld symbol

Back 331

flag place at the junction of teh horiz line and the arrowhead line. circle at the joint indicates weld all around

Front 332

weld load

Back 332

fillet- considered shear regardless of direction of load
butt weld- allowable stress is same as base metal

Front 333

AISC weld design req.

Back 333

max size of fillet is 1/16" less that nominal thickness of material connected
minimum length must not be less that 4x the weld size
intermittent weld must be at least 1 1/2"
min. size of fillet welds are given by table

Front 334

no connectors in...

Back 334

CIP concrete

Front 335

precast constr. connectors

Back 335

embed weld plates

Front 336

CIP conc. joints

Back 336

reinforcing bars
keyed joints

Front 337

dowel

Back 337

reinforcing only used to connect two pours

Front 338

keyed joint

Back 338

used alone or w/ reinforcing to strengthen a joint betw pours

Front 339

precast movement joint

Back 339

precast typically bear on elastomeric bearing pads (UNL)

Front 340

concrete shear connector

Back 340

anchors a composite system. often called headed anchor studs

Front 341

IBC requires construction method based on...

Back 341

rational anlaysis in accordance with well established principles of mechanics and that analysis provide a bath from point of origin to load resisting elements

Front 342

anchorage

Back 342

resiste the uplift and sliding forces on a structure

Front 343

IBC live load provisions

Back 343

design floors to accomodate concentrated loads
where unif. dead and live loads, design may be limited to full dead load on all spans and full live load on adjacent spans
live floor loads in commercial and industrial buildings must be posted
interior walls, partitions over 6' must be designed to resist all loads on them, but not less than 5psf perpendicular

Front 344

IBC office building distr live load

Back 344

20 psf
access floors may be design to take an additional 10 psf

Front 345

IBC wind tunnel req.

Back 345

for buildings sensitive to dynamic effects, wind load ocillations, and over 400ft.

Front 346

IBC req. use of higher load...

Back 346

between earthquake and wind loads

Front 347

repetitive use

Back 347

a factor equal to 1.15 is used when several beam members are used together

Front 348

duration of load

Back 348

amount of stress a wood member can withstand is dependent on the time during which the load producing the stress acts

Front 349

fire retardent treatment affects

Back 349

design values for wood members must be obtained from manuf. treatement reduces bearing capacity of members

Front 350

size factor adjustment

Back 350

IBC req. forces parallel w/ grain to be multiplied by size factors given

Front 351

IBC allowable stress for bolts

Back 351

based on type of load

Front 352

IBC allowable stress for welds

Back 352

based on either yield strnth of base metal or nom. tensile strength of the weld mtl.

Front 353

IBC concrete req.

Back 353

complex and detailed covering formwork, reinforcing, mixing placing and curing

Front 354

IBC important concrete factors

Back 354

ultimate load above dead and live load
strength reduction factor

Front 355

IBC concrete sample req/

Back 355

sample taken not less than once per day, nor less than on ce per 150 sq yd., nor less than once for each 5000 sq ft of surface area for wall and slab
no test can be less tha 500 psi below compressive strength value

Front 356

IBC wood req

Back 356

bottom of joist 18" above ground, girder 12" unless treated or natural resistant
provide 1/2" airspace around girder in masonry or concrete unless treated
foundation plates and sills must be treated or redwood
crawl space must be ventilated, min. 1sq ft for every 150 sq ft
all stuct. wood must be weather protected
fire stops req. at ceiling and floor levels at 10ft. intervals vert and horiz
fire stops req in concealed spaces in stairway and vert. openings

Front 357

IBC stl construction req.

Back 357

roof syst. w/o proper drainage slope must be invest. for stability under ponding
horiz framing desinged for deflection and ponding

Front 358

IBC conc construction req.

Back 358

constr. loads cannot be supported or shoring removed until conc has sufficient strength to support its own weight
limits on amount and placement of conduits and pipe penetrations to not decrease the load resisting area
size and bending of reinforcement between the concrete and steel
min. concrete cover over reinforcing

Front 359

steel fire reaction

Back 359

non combustible but loses strength under high heat
must be protected, unless 25ft above floor

Front 360

Type IV construction

Back 360

heavy timber construction
col. at least 8" in any dim.
beams and girders 6" wide x 10" deep
floor decking min. 3" deep

Front 361

wind load type

Back 361

resonant load (ocillating load) perpendicular to the direction of the wind

Front 362

fundamental period

Back 362

time it takes the structur to complete one full swing from side to side

Front 363

wind measurement

Back 363

fastest mile wind- average speed of a column of air 1 mi long over a given point, measured w/ anemometer
three second peak gust wind- max peak gust at 33 ft abive ground
ASCE 7 speed- ultimate wind sped that would occur every 700 years

Front 364

surface conditions affecting wind load

Back 364

open country- most sever wind as there is nothing to slow the wind
suburban areas
metropolitan areas

Front 365

gradien height

Back 365

height above which the friction from the ground and other obstruction no longer affects wind speed
open country- 900 ft
suburb- 1200 ft
metro- 1500 ft

Front 366

adjacent buildings on wind load

Back 366

ASCE does not allow reduction due to adjacency, but will affect a wind tunnel test

Front 367

wind G factor

Back 367

takes into account both atmospheric and aerodynamic effects
value of G= .85 for rigid structures

Front 368

wind Kz factor

Back 368

combines effects of height, exposure and wind gusting into one factor

Front 369

wind exposures

Back 369

D- most severe, flat unobstructed facing large body of water at least 500ft or 10x the building height (exclude hurricane areas)
C- open terrain w/ scatter obstructions, less than 30ft heigh and inlcudes all hurricane areas
B- urban and suburban wooded area w/ obstruction upwind for at least 2630 ft or 10x the height, whichever greatest

Front 370

wind Kz factor on bldg sides

Back 370

varies w/ theigh on the wineward side
leeward side Kh is used over the entire surface- Kh= Kz at the mean roof height

Front 371

wind Cp factor

Back 371

account for differing effect of wind on various parts of the building
Cpi- evaluate internal pressures
= +/-0.18 for enclosed bldg
= +/-0.55 for partially enclosed bldg

Front 372

ASCE 7 methods

Back 372

method 1- normal force method
method 2- projected area method

Front 373

normal force method

Back 373

must be used for gabled rigid frames and may be used for any structure
wind forces act simultaneous normal to all ext. surfaces. on leeward side, heigh is taken at the mean roof heigh and constant for the full height of bldg

Front 374

projected are method

Back 374

assume horiz pressure act on the full vert projected area of the structure and that vert pressures act simult. on the full horiz projected area

Front 375

wind stagnation factor

Back 375

q factor- effect of wind speed on pressure
based on the 3-sec. peak gust wind at heigh of 33 ft.

Front 376

Kzt

Back 376

topographic factor accounting for hills and escarpements. level ground = 1.0

Front 377

Kd

Back 377

accounts for type of structure being analyzed, use 0.85 for buildings

Front 378

importance factor

Back 378

I= safety factor for essential facilities that must be safe and usable for emergency purposes

Front 379

component wind loads

Back 379

higher pressures are experienced by individual elements than on building as a whole and must be reviewed seperately

Front 380

lateral force distribution (wind)

Back 380

wind strikes side of building, pressure xfer through cladding to connections with floor and roof. horizontal surfaces (diaphragms) xfer to lateral force resisters (side walls, interior walls or frame)

Front 381

diaphragm

Back 381

horizontal surface, floor or roof that xfers load to vertical load bearing system

Front 382

shear wall

Back 382

walls designed to carry horizontal shear to foundations
act as beams cantilevered out of the ground, deeper section is more efficient and req less struct. material

Front 383

bent

Back 383

column and beam lines designed to carry wind loads to foundations

Front 384

diaphragm chords

Back 384

extreme fibers of diaphragm experiencing compression (windward) and tension (leeward)
useful to see as a sideways acting beam

Front 385

framing methods resisting both wind and earthquake forces

Back 385

moment resisting frame
knee bracing
x-brace/ chevron
portal frame
framed tube
trussed tube
combined stl/shear wall

Front 386

moment resisting frame-

Back 386

simplest, w/ connections btwn col and beams. welds or gusset plts with higher loads.
used for low-rise and high rise under 30-story

Front 387

x-brace/ chevron

Back 387

useful for resisting both directions, typically tension members.
chevron results in lower horizontal drift overall

Front 388

knee bracing

Back 388

short diagonal struts, sim. in depth to gusset plt

Front 389

portal frame

Back 389

trusses at each floor level w/ knee braces connecting the truss to the column

Front 390

framed tube

Back 390

creates a large cant. tube from the ground

Front 391

trussed tube

Back 391

combination of rigid fame and diag braces on the exterior wall
(john hancock)
x brace spans 5-10 floors

Front 392

stl/shear wall combo

Back 392

steel frame carries most of the vertical loads while the shear wall xmit lateral loads to the foundation

Front 393

variations to basic framing methods

Back 393

incorporate belt trusses at intermed. floors and tapered buildings

Front 394

concrete rigid frames systems

Back 394

can be built but moment resisting connections are difficult and are limited to 20-30 stories

Front 395

chord force

Back 395

force distributed along the depth of a diagram. determines the type of connection btwn the diaphragm and the shear wall

Front 396

overturning moment (wind)

Back 396

lateral force that the shear walls and building must resist. additionally shear wall must be attached to foundation and footings in such a way to prevent uplift and/or sliding on the footing

Front 397

drift

Back 397

lateral displacement of building caused by lateral load from true vertical line
max drift= 0.0025x the story height

Front 398

in all connections, the resisting moment...

Back 398

increases with increased distance btwn centroids of the top and bottom portions of the connection

Front 399

due to the strength of earthquake forces...

Back 399

no building can be economically designed to completely resist all loads in a major earthquake w/o damage

Front 400

earthquake design approach

Back 400

structure should not collapse
components of building should not cause other damage or personal injury even though they are damaged
should be able to withstand minor EQ w/o damage

Front 401

methods of seismic design

Back 401

simplified analysis
equivilant lateral force
dynamic analysis

Front 402

equivilent lateral force method

Back 402

treats seismic loads as equivalent lateral loads acting on various level of the building

Front 403

dynamic method

Back 403

uses computer to mathematically model the building

Front 404

simplified analysis

Back 404

only be used in seismic zone A and zone B for 3-story light framed buildings and other 2-story buildings in group 1

Front 405

equiv. lateral force categories

Back 405

used for buildings in seismic categories A,B and C
used in D, E, and F if:
regular structure w/ T<3.5T
irregular structure w/ T<3.5T and having only plan irregularities 2,3,4,5 or vert irregularities 4 or 5

Front 406

hypocenter

Back 406

stress is at a max. several miles below the surface of the earth

Front 407

epicenter

Back 407

point on the earth surface directly above the hypocenter

Front 408

type of EQ waves

Back 408

P- pressure waves
S- shear waves
surface waves

Front 409

pressure waves

Back 409

relatively small movement in the direction of wave travel

Front 410

shear waves

Back 410

produce a sideways or up-and-down motion that shakes the ground in three dirctions

Front 411

surface waves

Back 411

travel at or near the surface and can cause both vert and horiz earth movement

Front 412

ground movement measurement

Back 412

acceleration
velocity
displacement

Front 413

acceleration of the ground

Back 413

induces forces on a structure

Front 414

vertical EQ forces

Back 414

weight of a structure is usually enough to resist vertical forces. side-to-side movement causes the most damage

Front 415

EQ scale

Back 415

require measure of acceleration or duration of EQ

Front 416

strong motion accelerograph

Back 416

provides objective quantified data useful for building design
used for research on EQ reactions and specifies amounts to be installed

Front 417

IBC EQ maps

Back 417

give the mapped spectral response acceleration at a period of 0.2 and 1.0 sec.

Front 418

period of lateral motion dependant on...

Back 418

mass and stiffness of the building

Front 419

lateral force induced

Back 419

flexible, long period buildings have less
stiff, short period buildings have more

Front 420

as a building moves, the forces applied to it are...

Back 420

xmitted through the structure to the foundation absorbed by the building components or released i nother ways such as collapse of structural elements

Front 421

goal of seismic design is to...

Back 421

build a structure that can safely xfer the loads to the foundation and back to the ground and absorv some of the energy present rather than suffering damage

Front 422

ductility

Back 422

ability of structure to absorb some of the energy

Front 423

ductility of steel

Back 423

has the ability to deform under a load above the elastic limit w/o collapsing

Front 424

IBC load resisting structural systems

Back 424

table 1617.2 gives structural types, R factor and max heigh of each type of system

Front 425

bearing wall system

Back 425

system w/o a complete vertical load carrying space frame in which the lateral loads are resisted by shear walls or braced frames

Front 426

shear wall symmetry

Back 426

important aspect of shear walls and vertical elements in general that determines whether torsional effects are produced
does not need to be symmetrical, but is preferred

Front 427

interior shear walls

Back 427

not as efficient from structural point of view, interior shear walls do leave exterior open for windows

Front 428

shear wall openings

Back 428

may have them, but calculations become difficult as larger percent of open area is used

Front 429

building frame system

Back 429

essentially complete space frame that provides support for gravity loads in which lateral loads are resisted by shear walls or braced frames

Front 430

braced frame

Back 430

truss system of the concentric or eccentric type in which the lateral forces are resisted through axial stresses in the members
can be placed on interior or exterior of structure

Front 431

bracing in one direction

Back 431

member must work as either compression or tension

Front 432

x-bracing

Back 432

tension diagonal members, with one member in tension while the other has no load; opposite for other direction

Front 433

moment resisting frame system

Back 433

carry lateral loads primarily by flexure in the members and joints

Front 434

special moment resisting frame

Back 434

specially detailed moment resist frame to provide ductile behavior and comply with IBC

Front 435

intermediate moment resisting frame

Back 435

fewer restrictions than special frames, but cannot be used in seismic design category D, E or F

Front 436

dual system

Back 436

essentially complete frame provides support for gravity loads and resistance to lateral loads is provided by a specially detailed moment resisting frame and shear walls or braced frames

Front 437

diaphragm

Back 437

acts as a horizontal beam resisting forces with shear and bending force
flexible and rigid

Front 438

types of horizontal members

Back 438

diaphragm, trussed frames, horiz. moment resisting frames

Front 439

flexible diagphragm

Back 439

has max. lateral deformation more than two times the average story drift of that story
wood deck, mtl deck (depend on detailing)

Front 440

rigid diaphragm

Back 440

shear foces xmitted from the diaph. to the vert elements will be in proportion to the relative stiffness of the vert elements (assuming no torsion)
concrete floor, composite steel deck

Front 441

building configuration

Back 441

refers to overall building size and shape and the size and arrangement of primary structural frame as well as the size and location of the nonsturctural components of the building that may affect its structural performance

Front 442

horizontal and vertical irregularities

Back 442

specifically defined by IBC so it is clear which structures must be designed with the dynamic method and which by static analysis method

Front 443

irregular building

Back 443

generally req desingn by the dynamic method and additional detailed desing req are imposed depending on the type of irregularity

Front 444

torsional irregularity

Back 444

notes that diaphragms are not flexible

Front 445

non parallel systems

Back 445

includes buildings in which a column forms part of two or more intersecting lateral force resisting systems, unless the axial load due to seismic forces actin in either directio is less than 20% of the colun allowable axial load

Front 446

lateral forces on a portion of a building...

Back 446

are assumed to be unifromly distributed and can be resolved into a single line of action acting on a building

Front 447

for symmetric buildings w/ vert resisting element of equal regiditys, lines of later forces pass through...

Back 447

the same point

Front 448

if shear wall or other vert. elements are not symmetric or of unequal rigidity, the resultant of their resisting forces...

Back 448

does not coincide with the applied force. since the force acting in the opposite direction acts with eccentricity, torsion force is developed

Front 449

accidental torsion

Back 449

IBC req symmetrical buildings have some amount of torsion designed for
requires the mass at each level to be assumed displace from center of mass by a distance of 5%

Front 450

plan irregularities

Back 450

can create torsion and concentration of streess, both of which shuld be avoided whenever possible

Front 451

reentrant corner

Back 451

stress concentrated at the inside corner of shape
since the center of mass and center of rigidity do not coincide there is an eccentricitty est. that results in twisting of the entire struct

Front 452

reentrant corner resolution

Back 452

portions of the building can be seperated w/ a seismic joint, tied together across the connection or inside corner splayed

Front 453

ideal seismic elevation

Back 453

symmetrical, continuous and matches other elevations; setbacks to be avoided, corners

Front 454

discontinuous shear wall

Back 454

elevation problem, shear wall stops before reaching the foundation or offsets

Front 455

soft story

Back 455

elevation problem, when ground floor is weaker than floors above. can happen anywhere, but is most serious at ground.
can happen if:
columns do not extend to ground
heavy ext cladding above first story and ground open

Front 456

with elevation irregularities...

Back 456

when earthquake load occur forces and deformation are concentrated on weak floor instead of being uniformly distributed

Front 457

soft story fixes

Back 457

extra horiz and diag bracing
framing above to be same as below, making lighter more flexible intermediate levels

Front 458

determine base shear

Back 458

or total later force using equivalent lateral force procedure

Front 459

total lateral force formula

Back 459

V= CsW

total lateral force= seismic response coefficient x weight of building given in W factor

Front 460

W factor

Back 460

total dead load of the building
warehouse/storage: 25% of dead load must be added
partition loads shall not be less than 10 psf
20% of flat roof snaow load must be added where the snow load exceds 30 psi
total weight of permanent equip must be added

Front 461

once total base shear is known

Back 461

it is used to determine the force on the various building elements

Front 462

displacement taking place during EQ

Back 462

results in an inverted force triangle varyingg from zero at the base to max. at the top

Front 463

EQ: the sum of loads at each floor equals the...

Back 463

total base shear:

Front 464

EQ: the greatest force is at the top of the building, ...

Back 464

the shear increases from zero at the top to its max. at the base

Front 465

IBC req. for tall buildings w/o uniform disttribution

Back 465

the height variable in the distribution equation be raised by an exponential power

Front 466

IBC req. attachement of elements beyond structural frame

Back 466

includes connections, partitions to floors, ceilings, millwork, equipment, piping, ducts, suspended lighting

Front 467

rigid elements

Back 467

have a fixed base period less than or eq. to 0.06 sec.

Front 468

nonrigid elements

Back 468

flexibly supported items have a fixed base period greater than 0.06 sec.

Front 469

EQ: overturn moment

Back 469

due to the inertial force acting through the center of mass of the building there is a tendency for the moment created by the force acting above the based

Front 470

EQ overturn: dead weight of building is...

Back 470

normally sufficient to resist the overturn force, but must be checked. only 90% of dead weight may be used.

Front 471

story drift

Back 471

displacement of one level relative to the level above or below

Front 472

EQ: response displacement

Back 472

static analysis shal be used to determine

Front 473

drift

Back 473

is the limiting factor for earthquakes in order to ensure that exterior facades do not break or crack excessively

Front 474

long span systems

Back 474

over 60 ft
one way and two way

Front 475

long span issues

Back 475

temperature
expansion and contraction
shipping
deflection
lack of redundancy

Front 476

redundancy

Back 476

failure of one portion would cause a larger area of damage if not overall failure

Front 477

one way long span systems

Back 477

linear members that span in one direction and resist loads primarily by beam action or bending

Front 478

two way long span systems

Back 478

distribute loads to supports in both directions and involve complex 3D methods of resisting loads

Front 479

types of one way systems

Back 479

most are steel or concrete
wood are either truss or glulam beams

Front 480

steel girders

Back 480

span up to 72ft. and can be strengthened by adding stl plates to top of bottom of beam

Front 481

plate girder

Back 481

beam built up of plt and angles welded together. efficient due to the flanges being seperated resulting in a high moment of inertia
often 8ft deep or more

Front 482

plate girders as roof beams

Back 482

can be tapered to the middle where the moment is the greatest

Front 483

rigid frame

Back 483

structura systme in which the vertical and horizontal members and joints resist load primarily by flexure and moments are xferd from beams to columns
long span rigid system has a sloped roof w/ a rigid moment resisting connection btwn columns and roof

Front 484

pinned connection

Back 484

allows frame to be determinate and does not develop secondary stresses from temperature differences

Front 485

tapering structural system

Back 485

moment is greatest at the junction where more material is needed to resist forces in the structure

Front 486

long span trusses

Back 486

good for long span due to stress in compression and tension rather than bending
high strength to weight ratio
relatively lightweight
prefabed
efficient use of material

Front 487

long span steel joists

Back 487

LH and DLH series
LH- suitalbe for floor support
DLH- suitable for roof support

standardized sizes by Steel Joist Institute

Front 488

joist bearing depth

Back 488

5 in bearing for LH and DLH up to 17" deep
7.5" for DLH above 17

Front 489

joist camber

Back 489

rise in the beam at center to account for deflection
1/4 per 20' length to 8.5" for 144' span

Front 490

joist bearing systems

Back 490

joist can bear on steel, concrete, masonry or joist girders

Front 491

joist girder

Back 491

depts of 20-120 in.
spacn up to 100'

Front 492

vierendeel truss

Back 492

composed of s series of rigid rect frmaes
no diagonals and must resist bending as well as tension and compression
must use larger members than a truss
may req. knee bracing

Front 493

prestressed concrete longspan

Back 493

reduced cracking and deflection and allows longer spans w/ smaller sections

Front 494

prestressed types

Back 494

single tee, double tee, AASHTO girder

Front 495

AASHTO

Back 495

american association of state highway and transportation officials

Front 496

single tee

Back 496

4-8ft wide
8-12" web
depths from 1-4'
span of up to 120'

Front 497

double tee

Back 497

8-10' wide
8-32" web
span up to 60-80'
function as both structure and decking

Front 498

arches

Back 498

one of oldest longspan systems
mainly compressive force w/ some bending

Front 499

long span design and selection criteria

Back 499

function
cost and economy
shipping
acoustics
assembly and erection
fire protection

Front 500

cost considerations of long span

Back 500

structural system
material
labor
equipment
construction time
integration w/ building systems

Front 501

structural costs

Back 501

cheaper to build more columns than deeper beams
more efficient to design for compression and tension than for flexure, x-bracing,
deeper bending membera are more efficient that shallow ones

Front 502

construction time costs

Back 502

anything that speeds construction results in substantial cost savings

Front 503

shipping limits

Back 503

60ft. for truck shipping
80 ft. for rail shipping

max height for truck is 14ft.

Front 504

assembly costs

Back 504

at times stress on members is greater for erection than under use
w/o redundancy, erection seq. is important
size of members need to be considered in relation to crane limitations

Front 505

long span technical considerations

Back 505

connections
envelope attachment
ponding
temperature movement and stresses
tolerances
stability
shop drawing review
construction observation

Front 506

long span connections

Back 506

most failure at these locations
less redundancy, so more critical
verify no changes by fabricator per shops
must observe installation

Front 507

long span envelope attachment

Back 507

more prone to larger movement stresses
temperature, deflection, moment rotation greater in long span

Front 508

ponding considerations

Back 508

if roof deflects and does not allow drainage as designed, deflection can increase and ponding become worse
require appropriate slope or camber desinged to allow for long term deflection

Front 509

temperture movement

Back 509

increases in proportion to the length of the member
more critical if exposed to weather

Front 510

long span stability

Back 510

often need temporary shoring to assure stability when complete system not in place

Front 511

two way structural system

Back 511

distr. loads in two directions and all members are required. load is distributed to more supports and is therefore more efficient than one way
square is most effiecient shape
when proportion approaches 2:1, the short dimension carries almost all of the load
allows for some amount of redunancy

Front 512

long span two way systems used primarily for...

Back 512

roofs due to primary shape

Front 513

long span two way types

Back 513

space frame
domes- geodesic, thin shelled
hyberbolic paraboloids
barrel vault
lamella arch
folded plates
suspended cable structures

Front 514

space frame

Back 514

3 dimensional structure xfers load through network of nodal connections
efficient due to large number of members in primarily tension and compression
redundancy of members

Front 515

offset grid

Back 515

type of space frame
bottom grid offset from top by one half bay

Front 516

space frame optimum depth to module ratio

Back 516

0.707:1

Front 517

space frame connections

Back 517

sollow or soild sections w/ screws
bolted/welded bent plates
prefab units over spanning members

Front 518

space frame supports

Back 518

can be supported an any node
best is symmetrical
can cantilever 15-30% of span

Front 519

dome types

Back 519

geodesic
frame dome
thin shell

Front 520

dome forces

Back 520

meridian lines act as individual arches xfering loads to the ground through compression, meridians are supported by horizontal hoops
very shallow low rise domes- all compression, not tensile forces
high rise dome- under loads meridian compress at top and expand in lower (tension in hoops) if hoops large enough, no thrust passed on to foundation

Front 521

dome stress changes from compression to tension

Back 521

under dead load at 52 degrees
under snow load at 45 degrees

Front 522

framed dome

Back 522

areas between meridians and hoops braced w/ diagonal members

Front 523

geodesic dome

Back 523

designed by buckminster fuller
spherical space frames
enclose greatest surface area w/ least surface area

Front 524

thin shelled structures

Back 524

strength is a result of ability to support loads through compression tension and shear in the plane of the shell
single or double curve

Front 525

single curved thin shell dome

Back 525

barrel vault
w/ end frames act as a curved beam, w/ compression at top and tensions at bottom
w/o end frames, vault will deform inward. vault will req. additional thickness

Front 526

lamella roof

Back 526

single curved barrel vault w/ rounded hips ,created by intersecting grids of parallel skewed arches covering a rectangular area

Front 527

double curved thin shell dome types

Back 527

synclastic shell- curves on the same side of the surface (dome)
anticlastic shell- main curves on opposite sides of the surface (hyperbolic paraboloid)

Front 528

double curved thin shell dome

Back 528

stable for either symmetric or asymmetric loads. behave similar to frame domes

Front 529

hyperbolic paraboloid

Back 529

anticlastic shell formed by moving a vertical parabola along an upward curving parabola perpendicular to it

Front 530

hyperbolic paraboloid characteristics

Back 530

thin shells can be made w/ minimal thickness and very efficient
not often used in US due to labor intensive construction

Front 531

membrane structures

Back 531

can only resist forces in tension
must be anchored to compression taking members
loads change due to wind

Front 532

counteract membrane forces

Back 532

prestress the membrane w/ anticlastic shapes

Front 533

air supported structures

Back 533

pneumatic roof
air supported rather than by cables

Front 534

folded plate structure

Back 534

thin slab bent to increase load capacity
in longitudinal direction folded plate acts as a beam
requires a stiffening slab at each end to compensate for additional stress

Front 535

suspension structures

Back 535

cable structures support span, efficient as the full cable section is used in resistance

Front 536

the sag of a suspension structure cable is...

Back 536

inversely related to the amount of tensile force

Front 537

ideal proportion of cable sag

Back 537

1/2 the span so that it create an angle of 45 deg.

Front 538

structural lumber

Back 538

primary concern is the amount of stress that a particular grad of lumber of a species will carry

Front 539

beams and stringers

Back 539

members 5in wide or greater w/ depth of 2" greater than width

Front 540

post and timbers

Back 540

5in by 5" or larger w/ a depth not more than 2" greater than width

Front 541

visual graded design values

Back 541

based on the species of wood, size category, grade and direction of loading
also whether used alone or in group

Front 542

repetitive member loading

Back 542

at least 3 members spaced not more than 24 in apart with some method of distr. load

Front 543

moisture content

Back 543

weight of water in wood as a graction of the weight of oven-dry wood

Front 544

fiber saturation point

Back 544

when cell walls are completely saturated but no water exist in the cell cavities
abgout 30% moisture content

Front 545

ideal moisture content

Back 545

the same as exposed prevailing humidity

Front 546

wood shrinks

Back 546

prependicular to the grain, very little parallel

Front 547

wood beam flexure

Back 547

S= M/Fb

Moment/ extreme fiber stress in bending

Front 548

wood design shear

Back 548

must be checked against the design unit shear stressw Fv
shear will always occur before vertical shear so only necessary to check vert. if beam is notched at supports

Front 549

wood deflection

Back 549

not as stiff as other materials and must be checked

Front 550

wood deflection reduction

Back 550

code allows 1/2 reduction, but common practice to use full load for long term deflection

Front 551

notched beam

Back 551

cannot exceed 1/6 the depth of the member and cannnot be located in middle third of the span
when at supports, notch can be 1/4 of the beam

Front 552

wood size factor

Back 552

as depth of a beam increase ther is a light decrease in bending strength

Front 553

lateral support

Back 553

to allow for tendency to buckle laterally, code allows a reduction if aspects are not met
(sheating at compression edge, bridging at tension)

Front 554

wood bearing

Back 554

1 1/2" bearing on wood or metal
3" bearing on masonry

Front 555

wood slenderness ratio

Back 555

laterally unsupported length divided by the least dimension of the column

Front 556

wood joists

Back 556

standardized sizes and design values typically referenced from tables

Front 557

glulam grades

Back 557

do not affect structural characteristics, but are aesthetic

Front 558

two methods of structural stl design

Back 558

allowable stress design
load and resistance factor design

Front 559

disadvantage to stl structure

Back 559

reduction in stregth due to exposure to fire
will rust

Front 560

most common steel type

Back 560

ASTM A572, yeild point of 50 kips

Front 561

design of steel beams

Back 561

finding the lightest weight section that will resist bending and shear forces and have a minimum amount of deflection for the use

Front 562

lateral support

Back 562

support of top member that tends to buckle
steel deck, conc. slab, other beams provide support

Front 563

compact or non-compact sections

Back 563

based on yeild strength of the steel and width to thickness ratio
if non compact lower bending stress must be used

Front 564

stl shear design

Back 564

typically the bending stress is enough to account for shear, but needs to be checked for short heavily loaded beams w/ heavy loads near supports

Front 565

stl deflections design

Back 565

beam may sag enough to be objectionable for use

Front 566

stl slenderness ratio

Back 566

slenderness= length of column/ radius of gyration

Front 567

plate girder

Back 567

stl plate as a web and stl plates welded to it for flanges
thin web req. vert stiffeners to prevent buckling

Front 568

concrete design

Back 568

more complicated than steel or wood
assumptions must be made and then tested
use strength design method

Front 569

min. concrete mix

Back 569

0.35 to 0.40 by weight
4-4.5 gallons of water per 94 lb sack

Front 570

aggregate percentage

Back 570

70-75% of mix by volume

Front 571

typ design strength

Back 571

2000, 3000 or 4000

Front 572

conc. admixtures

Back 572

air entraining
accelerators
plasticizers

Front 573

concrete combination loads and strength reduction reduce...

Back 573

probability of failure to about 1: 100,000

Front 574

because of the many combinations possible with the load and reduction factors....

Back 574

there is no single structural solution to a concrete design problem

Front 575

because a concrete beam is made up of two materials...

Back 575

the neutral axis is not at the midpoint of the beams depth and changes as the load on the beam is increased

Front 576

effective depth of concrete beam

Back 576

distance from the top of the beam to the centroid of the reinforcing stl

Front 577

strength method of concrete design

Back 577

to resist the bending moment caused by a load, the values of T and C will equal but will act in opposite directions
current thinking requires that steel strength T be designed to fail prior to concrete strength

Front 578

T (reinforcing stl resistance) reduction

Back 578

reduce steel by 3/4 so that stl fails first
safety factor increases total loads so that concrete stregth is well above necessary amount

Front 579

if there are no functional or architectrual needs for a shallow beam...

Back 579

reducing the steel percentage and increasing the beam depth generally results i a more economical design and may reduce deflection

Front 580

economical concrete beam depth

Back 580

2 to 3x the width

Front 581

min clr btwn reinforcing and edge of beam

Back 581

1 1/2"

Front 582

concrete beam shear failure

Back 582

often shown as diagonal cracking near support
also referred to as diagonal tension stress

Front 583

concrete beam shear reinforcement

Back 583

web reinforcement:
bend up tension stel near the supports at a 45 degree angle
vertical stirrups, forming a U around the tension steel

Front 584

double reinforced beams

Back 584

reinforcement located in the top, compression, edge of a beam
reasons:
low strength concrete
reduces long term deflections caused by concrete creep
may just be used to support stirrups prior to concrete pour
in case of unexpected negative force on a positive member

Front 585

concrete beam lateral ties

Back 585

encircle the compression and tension steel on all four sides across the top of the compression reinforcement to form a secure tie

Front 586

concrete/rebar connection

Back 586

due to mechanical (deformation in bars) means and chemical bonding

Front 587

one of primary safety req. is that there is...

Back 587

sufficient length of stl bar from any point of stress to the end of the bar to develop the necessary bond

Front 588

development length

Back 588

primarily dependent on the strenghth of concrete, the strength of steel, the size of the bar, the amount of concrete surround the bar and amount of transverse reinforcement surround the bar

Front 589

case I equation use

Back 589

clear cover is not lesss than the bar diameter and the clear spacing is not less than two times the bar diameter
clear cover is not less than the bar diameter and the transverse reinforcing meets the minimum for ties or stirrups

Front 590

min. development length

Back 590

12 in.

Front 591

concrete beam deflections

Back 591

due to strength design method used and higher strength concretes and steels, both result in smaller structural members that are less stiff than in the past

Front 592

two phases of concrete deflection

Back 592

immediate deflection- cause by normal dead and live loads
long-term deflection- caused by shrinkage and creep. may be two or more rimes the initial deflection

Front 593

concrete continuity

Back 593

extension of a structural member over one or more supports
typically continuous in vertical and horizontal directions

Front 594

continuous beam

Back 594

statically indeterminant, but more efficient than a simply supported beam as the adjacent span tend to counteract each other to an extent

Front 595

T-beam

Back 595

effective shape of beam and slab poured together
if neutral axis is equal to or less thant the slab thicknees the sections is designed as a solid beam
if teh neutral axis is in the web, special analysis is needed

Front 596

isolated T-beam

Back 596

flange thickness shall not be less than one half the width of the web and the total flange wiedth shall not be more than four rimes the web width

Front 597

symmetrical T-beams

Back 597

smalle of three conditions determines the effective width:
not to exceed on-fourth the span of the beam
overhanging slab width shall not exceed 8x the thickness of the slab
nto to exceed one-half the clear distance to the next beam

Front 598

edge T-beams

Back 598

effective overhanging slabg portion shal not exced 1/12 the span of the beam
overhanging slab shall not exceed 6x the thickness of the slab
not to exceed one-half the clear distance to the next beam

Front 599

one way slab

Back 599

reinforcement run in one direction perpendicular to the beams supporting
need extra reinforcement to resist shrinkage and temperature changes

Front 600

two way slab

Back 600

reinforcement run in both directions
more efficient because the applied loasds are distributed in all directions
supports must be near square for efficientcy
when raio of length to width approaches 2:1 begins to act as a one way slab regardless

Front 601

temperature steel

Back 601

min. amount of reinforcement set by ACI code

Front 602

concrete compressive members

Back 602

tied columns and spiral columns

Front 603

concrete column design

Back 603

primary concern w/ buckling caused by axial load
typical length to width ratio of 8:12, so slenderness ratio not usually an issue

Front 604

conc column reinforcement

Back 604

tends to fail by buckling and pushing out the concrete coverr at face of column
lateral ties used to prevent this and hold longitudinal steel in place prior to pour

Front 605

tied column

Back 605

vertical steel running parallel to the length of the column near its faces w/ lateral reinforcement consisting of individual rebgars tied to the vertical reinforcement
usually used for square or rectangle shapes

Front 606

strength reduction factor for tied column

Back 606

0.70

Front 607

spiral column

Back 607

cont. spiral of steel in lieu of individual lateral ties

Front 608

spiral pitch

Back 608

dimension between center lines of turns. must be between 1 and 3" clr btwn rebars

Front 609

strength reduction factor for spiral column

Back 609

0.75, because spiral columns are slightly stronger than tied of same size and reinforcement
also more ductile and will fail in stages

Front 610

load bearing wall type

Back 610

vertical load bearing
shear walls
retaining walls

Front 611

allowable stress of masonry wall

Back 611

not only by masonry strength but by slenderness ratio

Front 612

load at wall opening

Back 612

lintel only carries load directly above opening at 45 degree angle
if floor load falls w/i this triangle, than lintel carries as well

Front 613

CIP concrete wall

Back 613

must be anchored to intersectin elements (floors roofs etc)
min ratio for vert rinf. area to gross conc area
min ratio for horiz reinf.
walls more than 10" exc. foundation walls, must have two layers of reinf
reinf. cannot be more than 3x wall thickness
no less than two bars around all openings
min. thickness of bearing walls not less than 1/25 of height
resul of the load must fall w/i the mid one third of the wall thickness

Front 614

building envelope

Back 614

exterior cladding and its attachment must resist:
dead load
horizontal wind load
seismic load

Front 615

suction on a wall cladding element...

Back 615

can be greater than the inward force caused by wind