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Materials And Structures Principals > Weeks 5-7 > Flashcards

Weeks 5-7 Flashcards

1
Q

What are the 5 different kinds of forces (kN)?

A

Compression
Shear
Bending
Torsion
Tension

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2
Q

What is the Definition of SS - Secondary Structure?

A

The portion of the structure that is not part of either the primary lateral or primary gravity structure, yet is required to transfer inertial and gravity loads for which assessment/design by a structural engineer would be expected.

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3
Q

What is the definition of Non-Structural - NS?

A

Element within the building that is not considered to be part of either the primary or secondary structure.

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4
Q

What is the botanical species of Pine?

A

Pinus Radiata

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5
Q

Is pine durable or not?

A

Naturally not, needs to be treated to become more durable.

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6
Q

How many species of pine are there?

A

90-100

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7
Q

Are the genus pinus monoecious?

A

Yes, they have both male and female flowers on type same plant.

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8
Q

What is the botanical species name of Douglas Fir?

A

Pseudotruga Menziesii.

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9
Q

Is Douglas fir more durable than pine?

A

Yes, slightly.

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10
Q

Where is the Douglas Fir commonly found in NZ?

A

In the northern to centre of the South Island. Not as widely available as Pine.

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11
Q

How many species are there of the Douglas Fir?

A

Around 40 species. Over 75% are found in the South Island.

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12
Q

Which wood produces more plywood than any other?

A

Douglas Fir. The also produce vast quantities of veneer.

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13
Q

What is the Botanical species name of Western Red Cedar?

A

Thuja plicata D. Don.

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14
Q

Is Red cedar used for cladding often?

A

Yes due to its lighter weight. It also carries less health risks.

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15
Q

How many species of red cedar are there?

A

14, and only 4 true Cedars in North America.

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16
Q

Is Western Red Cedar a true Cedar?

A

No it belongs in the monophylectice genus.

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17
Q

What happens to the timber found in New Zealand the further north you move?

A

It becomes denser and stronger. Especially in Northland.

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18
Q

What is all wood composed of?

A

Cellulose and Lignin. It shrinks as it dries and swells as it absorbs moisture caused by humidity and temperature in general. HYGROSCOPIC.

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19
Q

What does anisotropic mean?

A

When something moves in two main directions with the movement dependant on the direction or orientation of the grain - aka wood.

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20
Q

At what percentage of moisture content do dimensional changes to wood take place?

A

0%-30% either through wetting or drying until EMC (equilibrium moisture content) is achieved.

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21
Q

Define tangential movement.

A

Where the wood moves along the lines of the growth rings in the timber - side to side movement.

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22
Q

Define Radial movement.

A

This is the movement perpendicular to the growth rings. It will also move along the length of the timber (longitudinally) but this movement is small enough to be ignored.

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23
Q

In a live tree, there is bigger mass of water to wood. True or false?

A

True.

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24
Q

What is FSP?

A

Fibre saturation point. Which is usually between 25% to 30%

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25
Q

How much more durability does heat treatment add to wood?

A

Durability inproves by 3 or 4 times.

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26
Q

Is Timber drying efficient?

A

No - it is a power consuming process - costs up to 30% of total costs for sawn timber and up to 70% in most wood processing industries.

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27
Q

What is timber drying currently?

A

The distribution of the moisture and temp fields in the bulk of the blank for making INTERNAL MECHANICAL STRESSES and can cause CRACKING.

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28
Q

What is the issue with modern kiln methods of using high temperatures to shorten the drying process?

A

It can lead to fast capillary water transport and subsequently redistribution and accumulation of dissolved substances at the surface. This can be used as nutrients for fungi and mould growth can start earlier on the kiln dried timber than air dried timber. It can also cause discolouration.

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29
Q

Due to the presence of spiral grain and high longitudinal shrinkage in the juvenile wood of radiata pine, what happens to it during the drying process?

A

Warping that cause up to 40% of rejections. Twisting is the major cause of warp rejection of pin radiata.

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30
Q

What does CDK stand for?

A

Continuous dry kiln

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31
Q

What does MC stand for?

A

Moisture content.

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32
Q

What is the general guide of time needed for drying depending on thickness?

A

25mm - 24 hrs
32mm - 38 hrs
40mm - 55 hrs
50mm - 60 hrs
100mm - 7 days

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33
Q

What is dehumidification drying a form of?

A

Kiln drying.

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34
Q

Is dehumidification kiln drying efficient?

A

Yes very - moisture is removed from the dryer buy condensing the moisture on cold coils. When the water is condensed, heat is released which is then put back into the dryer and used to evaporate more water from the timber.

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35
Q

What are the typical characteristics of dehumidification?

A

Run on low temps of 35-44 degrees
Time needed for drying is between 2-6 weeks depending on timber species.
Timbers best suited for this process are rimu, Matai, Macrocarpa and Beech

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36
Q

What is heat required for in dry kiln? 4 purposes

A

Warm the wood and water in wood
Evaporate moisture from the wood
Replace the heat lost from the kiln structure by conduction or radiation
In kilns with vents, to warm the fresh air entering the kiln.

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37
Q

What are two remote options?

A

Hot Water - low upfront cost
Solar / Greenhouse

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38
Q

What are the two groups of defects?

A

Timber processing/seasoning defects and natural defects

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39
Q

Distortions result of an inherent weakness in timber or bad conversion that even if reversal is achieved, it is only temporary. What are the 8 types of warping?

A

Bowing - a curvature along the face (often when insufficient piling sticks are used during seasoning)

Springing - a curvature along the edge of the board where the face remains flat. (Often occurs through bad conversion or curved grain)

Winding - is a twisting of the board and often occurs in wood which is not converted parallel to the pith of the tree

Cupping - is a curvature across the width of the board and is where the wood shrinks more tangentially than it does radially.

Shaking (or splitting) - fissures (separation of wood fibres) which develop along the grain of a piece of wood (usually the ends) as a result of the surface or ends of the wood drying out too fast during seasoning.

Collapse - caused by the cells collapsing through being kiln dried too rapidly.

Case hardening - timber being too rapidly kiln dried. The outside of the board is dried but moisture is trapped in the centre cells of the wood.

Honeycombing - occurs when there is internal splitting that may occur when the inner corse of the case-hardened timber subsequently dried out.

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40
Q

What are the 5 main types of natural defects?

A

Shakes - caused by the separation of wood fibres along the grain developed in a standing tree or felling or prior to seasoning. Forms as a form of stress relief.

Waney edge - where the bark is left on the edge of the converted wood

Knots - end sections of the branches where the grow out of the trunk. Live knots refer to them being firm in their sockets and show no signs of decay, while dead knots are the reverse.

Upsets caused initially by lightning strike, subsequently by jarring when it is felled.

Sloping grain - where grain doesn’t run parallel tot eh edge of the timber. Cannot be used for structural timber.

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41
Q

What are the 4 types of shakes?

A

Heart shakes
Star shakes
Radial Shakes
Cup shakes

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42
Q

What are the two testing methods?

A

Non-destructive Testing (NDT)

Destructive Testing (DT)

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43
Q

What are forms of NDT?

A

Visual inspection
Sounding
Stress Wave Timers
Ultrasound
Near Infra-Red Spectroscopy
Radioscopy

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44
Q

What are two types of Destructive testing?

A

Probing
Drilling and coring.

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45
Q

What are the 3 groups that timber is classified under?

A

Native softwoods
Hardwood
Softwood

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46
Q

After the 3 classifications what are the 4 grades they will be sorted in?

A

Appearance
Structural
Cuttings
Box

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47
Q

Orange colour marking indicates?

A

Cutting grade

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48
Q

Chocolate colour markings indicate?

A

Select A grade

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49
Q

Green colour markings indicate?

A

Dressing grade

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50
Q

Purple colour markings indicate?

A

Merchantable grade

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51
Q

Black colour markings indicate?

A

No.1 Framing grade

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52
Q

Yellow colour markings indicate?

A

No.2 Framing grade

53
Q

Silver colour markings indicate?

A

Engineering grade

54
Q

Red colour markings indicate?

A

Box grade.

55
Q

What are the Hazard class specifications of treated timber relevant to the building industry?

A

H1.1
H1.2
H3.1 LOSP-based preservatives (Light organic solvents)
H3.2 all preservatives containing copper
H4
H5

56
Q

Which is the native borer of NZ?

A

Two Tooted longhorn borer.

57
Q

What are the 11 different types of timber treatments?

A

Chromated Copper Arsenate (CCA) oxide - 1
CCA salt - 2
Boron - 11
TBTO - 56
Copper Naphthenate - 57
Copper Azole - 58
TBTN - 58
IPBC - 63
LOSP: Propicaonazole + Tebuconazole - 64
Synthetic Pryrethroids : Permethrin - 70
Alkaline Copper Quaternary (ACQ) - 90

58
Q

What are Timber applied for LVL?

A

Laminated veneer lumber - it is added as an additive to glue.

59
Q

What is a hazard of Boron?

A

Cannot be used underground or in water because it leeches.

60
Q

What is LOSP?

A

White Spirits based wood preservative impregnated into wood using a controlled process call Vacuum Pressure Impregnation (VPI)

61
Q

What hazard classes can LOSP treated timber be used for?

A

H1.1 and H1.2
H2 (AUS only)
H3.1
H3.2

62
Q

What are the 4 different pathways humans can be expoed to contaminants in soil?

A

Primary pathways
Secondary Pathways
Contaminant Leaching/runoff pathways
Vapour Intrusion into the house from the contaminated soil

63
Q

What does HAIL stand for?

A

Hazardous Activities and Industries List - it is a database or properties where info is help regarding to current or past land uses that have the potential to contaminate land.

64
Q

Offcuts and saw dust should not be used for what?

A

Burning for domestic heating or cooking
Mulching
Animal bedding

65
Q

What temperatures is class as Thermal treatment (aging)?

A

Below 150%

66
Q

What temperature is considered Thermal modification?

A

150 to 240 degrees

67
Q

Above 240 degrees is considered what?

A

Thermal degradation.

68
Q

Explain the Thermal modification process.

A

The process of confining timber in a stainless steel chamber where wood is rapidly raised to 100 degrees to reduce moisture content to almost 0. Thermal modification then begins by brings the temp up to 185-215 degrees and kept at this temp for a couple of hours in low ocean and steam to prevent burning and initiate chemical changes.

The temp is then lowered using water to cool it and return some moisture content between 4 % - 6%. Whole process takes around 65 hours. Some last up to 110 hours (depending on species)

69
Q

What are the advantages of TMT?

A

Improves dimensional stability
Improves resistance to fungal decay
Changes the colour of the wood throughout
Extend durability and usability of the materials

70
Q

What are the disadvantages of TMT

A

Less resistant to impact and abrasion
Remains vulnerable to termites
Exposure to UV or rain can increase discolouration
Can be more costly compared to pressure treated timber

71
Q

What is another type of TMT?

A

Accoya

72
Q

What species of wood is naturally resistant to insect attack?

A

Macrocarpa

73
Q

Posts and beams is used for…

A

Foundations and structure mainly on used on exterior applications

74
Q

Kiln dried is typically used for…

A

Internal framing components.

75
Q

Treated Wet or wet timber is used for…

A

retaining wall as joists or framing use.

76
Q

What are the making properties of metal?

A

Shiny and silver
Tough
Good Conductor of heat and electricity
Pure elements - most of the 85 naturally occurring elements int he universe are metals.

77
Q

What is a valence electron?

A

And outer shell electron

78
Q

What are the properties of metal bonds?

A

Metallic lustre - photons of light are loosely held by electrons that oscillate and readily return from higher to lower levels of energy by releasing energy thus becoming a source of light radiations.

Electrical conductivity. - potential difference is app[lied to the metal sheet and the free mobile electrons in the metallic crystal start moving towards the positive electrode.

Thermal Conductivity - kinetic everyday of electron increase due to metal being heated - these electron move rapidly to cooler parts and transfer the kinetic energy by colliding with other electrons, therefore heat travels from hotter to cooler parts of the metals.

High tensile strength - resists stretching without breaking.

Hardness of metals -strength of metallic bonds. (More valence electrons)

Opaqueness

Melting and boiling points

Malleability and ductility

79
Q

Name the 9 different mechanical properties of metal

A

Hardness - resist permanent distortion
brittleness
Malleability
Ductility
Elasticity
Toughness - resist tearing and stretching
Fusibility
Conductivity
Density

80
Q

Name the 9 types of Physical properties of metal

A

Strong and hard
Lustre
Heat Conductores
Electric Conductors
Dense
Sonorous sound
High Melting Points
High Boiling Ports
Opaque

81
Q

What are the two classes of metal?

A

Ferrous and non Ferrous

82
Q

Ferrous metals are?

A

Iron-based
Magnetic properties
Can be corroded easily

83
Q

Non Ferrous Metals are?

A

No Iron Based
Not magnetic
Less likely to corrode

84
Q

Properties of ferrous metals depend on the control of what?

A

Carbon

85
Q

What are 6 different ways to shape metal?

A

Casting
Pressing
Rolling
Extruding and drawing
Spinning
Forging

86
Q

Tempering steel often perform on what metal?

A

Steel - in a process called quenching.

87
Q

What happens when Carbon content increases?

A

Strength and hardness increases but becomes more brittle and les weldable.

88
Q

Stainless steel is an alloy with a minimum of how much chromium content?

A

10.5%

89
Q

Corrosion resistance depends on what?

A

Chemical Composition
Steel Structures
Surface condition

90
Q

What does three common types of hot rolled steel?

A

Universal Beam (UB) and Universal Column (UC) and Mild steel channels (PFC)

91
Q

What can ground screws be an alternative to?

A

Concrete slab foundation in expansive soils.

92
Q

What factors affect the magnitude of earthquake forces on buildings?

A

Types of soils
Degree of Building Rigidity
Type of Building lateral load-resisting system
Ductility of the building.

93
Q

What are the types of bracings used to strengthen building against earthquakes?

A

Gable end bracing, cross or sheet bracing.

94
Q

Definition of cladding

A

The outside or exterior weather resistant surface of a building. When required by an acceptable solution, the cladding system should include a drawing cavity.

95
Q

Define Flashing

A

A strip or sleeve of impervious material dressed or fitted to provide a barrier to moisture entry, or to provide cover to a join where water could otherwise penetrate into a building.

96
Q

What are 4 types of profiles of roll cladding?

A

Five rib
Six Rib
Medium Rib
High Rib

97
Q

Why do manufacturers add coatings to their products?

A

To extend durability and mitigate corrosion. The amount in weight is called coating mass

98
Q

What does BMT stand for?

A

Base Metal thickness.

99
Q

What are the two measurements of BMT?

A

Preferred thickness and allowable tolerance in association with such thickness.

100
Q

What are other materials that can be used for cladding besides steel and zinc coated steel?

A

Aluminium
Stainless Steel
Zinc
Copper

101
Q

Cladding systems must meet the objective of the which clauses of NZBC

A

B1
B2
E2
E3
F2
H1
C

102
Q

What do we refer to for metal claddings that are fixed to metal framing?

A

NASH building Envelope Solutions 2019.

103
Q

Define corrugate.

A

A profiled sheet formed into a series of sinusoidal or circular curves

104
Q

Define Trapezoidal.

A

Profiled roof or wall cladding with longitudal ribs angle similarly to a trapezoid

105
Q

What are two roof systems that can reduce condensation in your roof?

A

A warm roof
A cold roof

106
Q

What are fasteners, anchors and adhesives used for?

A

To temporarily or permanently fasten materials together.

107
Q

Nails longer than 16d are commonly referred to as what?

A

Spikes

108
Q

What are the forces related to nails?

A

Lateral loading and withdrawal.

109
Q

What are the two effects that makes up load-bearing behaviour?

A

The dowel effect of the bolt which depends on the bolts resistance to tension and the resistance of the wood crushing

The tension all effect of the bolt with depends on the bolt’s resistance to tension and the presence of friction between the abutting surfaces.

This is known as yield theory.

110
Q

What did Moller apply the yield theory to in the 1950’s?

A

Nailed joints. This is quite often referred to as Moller’s theory.

111
Q

What does the withdrawal strength of a nail driven into a substrate depend on?

A

The fastener diameter, type depth of penetration of the fastener and the friction between the fastener and the material which it comes in contact with (coefficient friction). Some manufacturers may intend to increase friction by adding mechanically rolled sharp rings.

112
Q

How many classes of metal fasteners are there according to the Australian standards?

A

4 classes - 1 being the least important to 4 being the most.

113
Q

What is the definition of corrosion?

A

Deterioration of metals through oxidation or electro chemical reaction due to moisture int he environment or electrolytes between dissimilar metals.

114
Q

What is Galvanic corrosion?

A

Electro-galvanic action is corrosion caused when two dissimilar metals are in contact in a demo environment.

115
Q

What is Crevice corrosion?

A

Corrosion that occurs between aluminium or zinc surfaces when damp and in close contact, or in fissures created in stainless steel.

116
Q

What are the different Fasteners Head Types?

A

Round
D Head
RounDrive
Dome
DekFast
CladFast
THead
FinishHead

117
Q

What are the 6 different Fastener Shank/point types?

A

Smooth - most common
Screw/Twist - good for pallets
Ring - good for softwood
Diamond - most common but may contribute to splitting Timbers
Blunt Chisel - Eliminates timber splitting but not suitable for clinching applications
Conical - Designed for penetrating steel.

118
Q

What are Wire Dogs?

A

Typically made from Zinc coated 4.9mm galvanised wire - can handle up to 3.58kN per pair. Can also be manufactured from 304 stainless steel, but has slightly reduced uplift capability of 3.42 kN per pair.

119
Q

What are the 3 different types of Wire dogs?

A

LH - Left handed Z nails
RH - Right handed Z nails
Staple also known as U nails

120
Q

What are the benefits of Wire Dogs?

A

They have been proven to be the strongest and most economical timber fastener of it type on the NZ market.

121
Q

When are wire dogs typically used?

A

In wind uplift situations, such as truss or rafter to top plate, and top plate to stud connections.

122
Q

Can you twist wire dogs to adapt it’s shape?

A

No, this will damage the material’s mechanical properties.

123
Q

What are nail plates?

A

Nail plates or knuckle nail plates are flat strips of galvanised steel which have been punched to create multiple small prongs on one side.

Can be used as reinforcement, prefabrication of structural elements, and to fix splicing of timber beams.

124
Q

What two categories do solid rivets fall into?

A

Pure metals and Alloys.

125
Q

In buildings, what are rivets used as?

A

Secondary fixings

126
Q

What are the 7 different types of rivet heads?

A

Snap head - most common
Pan head - heavy engineering
Conical head - Light fixing
CounterSunk head - flat surface
Flat head - small and light
Buffercated - Chains
Hollow - Moving parts

127
Q

What are the three different types of Blind Rivet heads?

A

Dome head
Large flange head
120 degree Countersunk head

128
Q

When are blind rivet heads used?

A

The dome and 120 countersunk headed blind rivets are selected for wherever a vapour or liquid tight fastener is required. The provide 100% mandrel retention.

129
Q

What is the minimum diameter of a rivet?

A

4mm

Materials And Structures Principals (2 decks)

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