Test 4 Flashcards

Question

What type of cells make up the majority of a hardwood's microstructure?

Answer 1

Rays -Hardwood trees are more complex in structure, with a larger percentage of rays Cell structure of a hardwood. Rays (WR) constitute a large percentage of the mass of a hardwood and are sometimes strongly expressed in the grain figure.

Answer 2

Plentiful and inexpensive -Most of the lumber used today for the building structural frame comes from softwoods, which are comparatively plentiful and inexpensive.

Answer 3

Hardwood lumber -Many hardwoods show finer, more attractive patterns

Answer 4

The final moisture condition in equilibrium with its surroundings -Eventually, as water continues to evaporate from the wood, the wood arrives at a moisture content that brings it into equilibrium with its ambient surroundings—dryer, for wood used indoors or in dry outdoor climates, and more moist, for wood used outdoors and in higher humidity or wetter climates. This final moisture condition is called the equilibrium moisture content (EMC) of the wood

Answer 5

12% -In North America, the equilibrium moisture content for exterior wood averages around 12 percent

Answer 6

To make it smooth and more dimensionally precise -Lumber used in building construction is normally surfaced to make it smooth, more dimensionally precise, and safer to handle.

Answer 7

Longitudinal shrinkage -Moisture shrinkage along the length of the log (longitudinal shrinkage) is negligible for practical purposes. a simple distinction is made between parallel-to-grain shrinkage, which is negligible, and perpendicular-to-grain shrinkage, which is considerable.

Answer 8

Checks -Because tangential shrinkage [from drying] is so much greater than radial shrinkage, high internal stresses are created in a log as it dries, inevitably resulting in the formation of radial cracks called checks

Answer 9

Wane -Wane is an irregular rounding of edges or faces that is caused by sawing pieces too close to the perimeter of the log.

Answer 10

All of the other answers are correct -Common product types include boards, dimension lumber, and timbers. [All] wood members vary in size seasonally with changes in temperature and humidity.

Answer 11

Dollars per thousand board feet (MBF) -Prices of dimension lumber and timbers in North America are usually quoted on the basis of dollars per thousand board feet (abbreviated MBF or MBFM)

Answer 12

National Hardwood Lumber Association (NHLA) -The National Hardwood Lumber Association (NHLA) Grading Rules play a similar role for the governance of hardwood production in North America.

Answer 13

Hardwood -For furniture, cabinetry, interior paneling, flooring, and other fine woodwork, hardwoods (and some of the denser softwoods) are often chosen for their better stability, attractiveness, finishability, and resistance to wear.

Answer 14

To produce dimensionally stable and visually pleasing grain patterns -Quarter-sawing requires more handling of the log during sawing, produces smaller pieces from a log of the same size, and generates greater waste. [Quarter-sawing] results in boards that are more dimensionally stable and have a more visually pleasing grain figure.

Answer 15

Varies from about 30% to 200% or more -The moisture content of growing wood can vary from about 30 percent to 200 percent or more.

Answer 16

To assess the appearance or structural properties of lumber -Structural grading is used to rate the strength and stiffness properties of a piece of lumber. Appearance grading is used to rank the visual qualities of lumber intended for flooring, trim, cabinetry, and other nonstructural finish uses.

Answer 17

Appearance grading -Appearance grading is used to rank the visual qualities of lumber intended for flooring, trim, cabinetry, and other nonstructural finish uses. Naturally, it is done visually, with boards having the fewest knots, checks, splits, staining, and other defects receiving the highest grades.

Answer 18

To rate the strength and stiffness properties of lumber -Structural grading is used to rate the strength and stiffness properties of a piece of lumber.

Answer 19

Machine stress rated (MSR) lumber -In machine grading, automated devices assess the stiffness, density, or other properties of the wood to derive structural values and apply an appropriate grade stamp. Machine stress rated (MSR) lumber, machine evaluated lumber (MEL), and E-rated lumber are all machine grading processes.

Answer 20

Hem–Fir -For example, Hem–Fir, one of the highest-volume species groups marketed in North America, may include any combination of California red fir, grand fir, noble fir, Pacific silver fir, Western hemlock, and white fir.

Answer 21

Parallel to the grain -The tensile strength of a wood member with the load applied parallel to its grain may be as much as 10 to 20 times greater than its strength with the load applied across the grain.

Answer 22

Wood and steel - brick masonry, steel, and concrete. Of the four, only wood and steel have useful tensile strength.

Answer 23

Temperature and moisture conditions -the designer selects grades based on published tables of allowable stresses It is common practice to use a stronger but more expensive species group Other factors that influence the usable strength of wood include the temperature and moisture conditions under which it serves, and the size and shape of the piece

Answer 24

To make wood resistant to biological organisms -Preservative-treated wood (Figure 3.38) is impregnated with chemicals that are toxic to the biological organisms that attack the wood.

Answer 25

To create fire-retardant properties -Fire-retardant treatments (FRTs) are accomplished by pressure impregnating wood with chemical salts that reduce wood combustibility.

Answer 26

Temperature and moisture conditions -the designer selects grades based on published tables of allowable stresses It is common practice to use a stronger but more expensive species group Other factors that influence the usable strength of wood include the temperature and moisture conditions under which it serves, and the size and shape of the piece

Answer 27

Heartwood -The heartwood of some species of wood is naturally resistant to decay and insects and can often be used where preservative-treated wood would otherwise be required.

Answer 28

To reduce wood's combustibility -Fire-retardant-treated wood is permitted for use in some applications in noncombustible construction–type buildings. It is also used for exterior cladding and sheathing materials where structures are at risk of exposure to forest land wildfires.

Answer 29

They fire more reliably, and They are quickly loaded into the nail gun

Answer 30

They require less skill to use, and They offer increased productivity

Answer 31

Lightweight staples -Less costly, lightweight staples are used to attach sheathing paper and thermal insulation.

Answer 32

To fasten various materials together -Less costly, lightweight staples are used to attach sheathing paper and thermal insulation. Heavier staples may be used for fastening cabinet components, wood flooring, shingles, underlayment panels, and even structural components.

Answer 33

Heavier staples -Heavier staples may be used for fastening cabinet components, wood flooring, shingles, underlayment panels, and even structural components.

Answer 34

End nailing -End nailing is relatively weak and is useful primarily for holding framing members in alignment until gravity forces and applied sheathing make a stronger connection.

Answer 35

Their load capacity and type -Wherever machine-driven nails or staples are used to join structural components, care must be taken to ensure that fasteners of the appropriate type and adequate load capacity are used.

Answer 36

Pentachlorophenol -Pentachlorophenol is also an oil solution used to impregnate wood, and as with other oily preservatives The most widely used wood preservatives in building construction are waterborne salts Creosote is an oily derivative of coal that is widely used to treat wood

Answer 37

Greater holding power and adjustability -In comparison to nails, screws cost more and take longer to install, but they can be inserted with greater precision, can exert greater clamping force between joined pieces, have greater holding power, and can be backed out and reinserted if a component has to be adjusted or remounted.

Answer 38

Self-drilling screws -Self-drilling screws, such as the drywall screw shown here, do not require predrilled pilot holes.

Answer 39

Lag screws -Larger lag screws are used for heavier structural connections. They have square or hexagonal heads and are driven with a wrench rather than a screwdriver.

Answer 40

Bolts -Bolts are used mainly for structural connections in heavy timber framing

Answer 41

Distribute clamping force and reduce wood crushing -Flat steel disks called washers, inserted under the head and nut, distribute the clamping force from the bolt across a greater area of wood and reduce crushing of the wood fibers.

Answer 42

Split-ring connector -The split-ring connector (Figure 3.47) is inserted in matching circular grooves to mate pieces of wood clamped together with a central bolt. This connector provides greater capacity by spreading the load across a larger area of wood than can be done with one or a few bolts. (re-written on test)

Answer 43

Timber rivets -Timber rivet connections are formed by fastening steel plates to large wood members with spike-like fasteners. Unlike nails, timber rivets are oval in cross section and driven so that the wider axis of the rivet is always parallel to the grain of the timber

Answer 44

Structural adhesive -Structural wood adhesives form bonds that are at least as strong, stiff, and durable as the members they connect.

Answer 45

They are challenging to clamp and control during curing -Wood adhesives are used less on the construction site, where it is more difficult to clamp and hold glued joints and to maintain controlled temperature and humidity until the adhesive has cured.

Answer 46

Greater strength, and Reduced shrinking, swelling, checking, and splitting -Veneer... can be made into ....structural and nonstructural products with higher strength, improved stability, increased size range... than are available from traditional sawn lumber. Wood Panels are more nearly equal in strength in their two principal directions than solid wood. Shrinking, swelling, checking, and splitting are greatly reduced.

Answer 47

4 × 8 feet -Wood in thin panel form is useful for many building applications (Figure 3.33). The panel dimensions are usually 4 × 8 feet

Answer 48

Particleboard -Particleboard is manufactured in different density ranges and is made up of smaller wood particles than OSB that are compressed and bonded into panels. It is used mainly as a base material for wood veneer and plastic laminate.

Answer 49

Higher strength and stiffness -Because of the length and controlled orientation of the strands, OSB is the strongest and stiffest type of non-veneered panel. Because it can be produced from small trees and even branches, OSB is generally more economical than plywood.

Answer 50

Medium-density fiberboard (MDF) -fiberboard... is dimensionally more stable, stiffer, better able to hold fasteners, and superior in its working and finishing characteristics. (Revised on test)

Answer 51

They can be produced in larger sizes, longer lengths, and higher strengths than solid lumber. -Glue-laminated wood members, such as the beams and posts seen here, can be produced in larger sizes, longer lengths, and with higher strengths than solid sawn lumber.

Answer 52

Oriented strand board (OSB) -OSB is generally more economical than plywood. It is the material most commonly used for sheathing and subflooring of light frame wood buildings.

Answer 53

To eliminate unevenness and gaps between panels -Panels intended for use as subflooring can be manufactured with tongue-and-groove edges that eliminate unevenness in the subfloor that could telegraph through the finish flooring.

Answer 54

Self-drilling wood screw -Self-drilling wood screws do not require pilot holes and can be installed more quickly with power drivers.

Answer 55

Laminated veneer lumber (LVL) - Laminated veneer lumber (LVL) is made from thin wood veneer sheets, as wide as the member is deep, that are glued and laminated into thicker members.

Answer 56

Timber connectors -Dozens of ingenious sheet metal and metal plate devices are manufactured for joining wood members or strengthening their joints.

Answer 57

To obtain sheets for plywood production -Veneers for structural plywood panels are rotary sliced (Figure 3.35). The strip of veneer is clipped into sheets that pass through a drying kiln where, in a few minutes, their moisture content is reduced to roughly 5 percent. The sheets are then assembled into larger pieces, repaired as necessary with patches glued into the sheet to fill open defects, and graded and sorted according to quality (Figure 3.36).

Answer 58

Roughly 5 percent - The strip of veneer is clipped into sheets that pass through a drying kiln where, in a few minutes, their moisture content is reduced to roughly 5 percent. (Modified answers but same answer)

Answer 59

Grade C plugged -Plywood with a C-plugged face is used for underlayment, where a smooth substrate is required to avoid telegraphing irregularities through thin finish flooring materials.

Answer 60

Exposure 1 -The Exposure 1 bond classification signifies that the panel is suitable for temporary exposure to the weather during construction, but not for permanent exterior exposure.

Answer 61

To achieve the same structural objectives with different panel types -The purpose of the span rating system is to permit the use of different types of panels while achieving the same structural objectives. For example, under normal loading conditions, any panel with a span rating of 32/16 may be used as roof sheathing over rafters spaced 32 inches (813 mm) or as subflooring over joists spaced 16 inches (406 mm).

Answer 62

The panel can be used for roof sheathing spaced at 48 inches and subflooring spaced at 24 inches -The 48/24 span rating on this structural panel gradestamp means that the panel can be used as roof sheathing over rafters or trusses spaced at 48 inches (1220 mm) or as subflooring over joists spaced at 24 inches (610 mm).

Answer 63

Recycled plastic resins -Lumberlike products made entirely or mostly from plastic resins are called plastic lumber. When manufactured from recycled plastics, they may be called recycled plastic lumber (RPL). The use of plastic lumber reduces the demand for harvested wood and, where recycled ingredients are used, diverts solid waste from landfills. In the manufacturing of plastic lumber, one or more resins may be used alone, or mixed with rubber, wood waste, glass fiber, or other materials

Answer 64

Structural-grade plastic lumber (SGPL) -used in the construction of decks, docks, piers, other types of exterior and marine structures, and even vehicular-capacity bridges. In the manufacturing of plastic lumber, one or more resins may be used alone, or mixed with rubber, wood waste, glass fiber, or other materials The most common material used in the manufacture of plastic lumber, high-density polyethylene (HDPE

Answer 65

It is noncombustible. -Additionally, steel framing may be used in buildings for which noncombustible construction is required by the building code Steel framing members are significantly lighter in weight than the wood members to which they are structurally equivalent, an advantage

Answer 66

Water-powered sawmill and machine-made nails -Its development was accelerated by two technological breakthroughs of the period: Boards and small framing members of wood had recently become inexpensive for the first time in history because of the advent of the water-powered sawmill, and machine-made nails had become remarkably cheap compared to the hand-forged nails that preceded them.

Answer 67

They spread fire quickly between floors -The balloon frame (Figure 5.2, right) used full-length studs that ran continuously for two stories from foundation to roof. In time, it became apparent that these were too long to erect efficiently. Furthermore, the tall, hollow spaces between studs acted as multiple chimneys in a fire, spreading the blaze rapidly to the upper floors, unless they were closed off with wood or brick fireblocking at each floor line.

Answer 68

Platform frame -the platform frame (Figure 5.2, left), is now the universal standard for wood light frame construction.

Answer 69

Vulnerability to fire and decay -Wood light frame construction has its deficiencies: If ignited, it burns rapidly; if exposed to dampness, it decays.

Answer 70

Panelized concrete and steel system -Light gauge steel studs can be combined with concrete to produce thin, but relatively stiff, wall panel systems... A variety of production methods are possible that involve casting an approximately 2-inch (50-mm)-thick concrete facing onto a framework of steel studs.

Answer 71

16 inches, and 24 inches (610 mm) o.c.

Answer 72

Lighter weight and ease of installation , and Lower cost compared to wood

Answer 73

Exterior panels with waterproof glue and high-quality veneers

Answer 74

Reinforcement with glass fibers

Answer 75

Steel framing is more stable and uniform than wood framing -Steel members tend to be straighter and more uniform than wood members (Figure 12.19), and they are much more stable dimensionally because they are unaffected by changing humidity.

Answer 76

Elimination of heavy posts and beams (Thrown out but just in case)