WOOD, STEEL, AND FIELD TEST Flashcards
, because of its availability, relatively low
cost, ease of use, and durability (if properly designed),
continues to be an important civil engineering
material.
WOOD
used extensively for buildings,
bridges, utility poles, floors, roofs, trusses, and piles.
WOOD
Civil engineering applications include both
natural wood and engineered wood products, such as
LAMINATES, PLYWOOD, AND STRAND BOARD
Wood has a distinct structure that affects its
use as a construction material. Civil and construction
engineers need to understand the way the tree grows
and the anisotropic nature of wood to properly design
and construct wood structures
STRUCTURE OF WOOD
The concentric layers in the stem of
exogenous trees
GROWTH RINGS OR ANNUAL RINGS
The wood produced in one growing season
constitutes
SINGLE GROWTH RING
produced by rapid growth
during the spring
EARLYWOOD
from summer growth.
LATEWOOD
the weight of water in the specimen expressed as a
percentage of the oven-dry weight of the wood
MOISTURE CONTENT
Physical properties such as ______ depend on the
moisture content of wood
weight, shrinkage, and strength
Moisture exists in wood as either
BOUND OR FREE WATER
held within the cell wall by
adsorption forces, whereas free water exists as either
condensed water or water vapor in the cell cavities. In
green wood, the cell walls are saturated.
BOUND WATER
The
level of saturation at which the cell walls are
completely saturated, but no free water exists in the
cell cavities, is called
FIBER SATURATION POINT (FSP)
harvested from forests as logs.
They are transported to sawmills, where they are cut
into dimensional shapes to produce a variety of
products for engineering applications
WOOD
VARIETY OF WOOD PRODUCTS
Dimension Lumber
Heavy Timber
Round Stock
Engineered wood
Specialty items
typically used for
studs, sill and top plates, joists, beams, rafters,
trusses, and decking.
Dimension Lumber
used for heavy frame
construction, landscaping, railroad ties, and marine
construction.
Heavy Timbers
used for building poles, marine piling, and utility
poles.
Round Stock
consists of products
manufactured by bonding together wood strands,
veneers, lumber, and other forms of wood fiber to
produce a larger and 1 The current standards for
dimension lumber and heavy timber standards were
implemented in 1970.
Engineered Wood
Structural engineered wood products include
the following:
- structural panels including plywood,
oriented strand board, and composite panels - structural glued laminated timber (glulam),
- structural composite lumber
- composite structural members.
are milled and fabricated
products to reduce on-site construction time,
includes lattice, handrails, spindles, radius edge
decking, and turned posts.
SPECIALTY ITEMS
PHYSICAL PROPERTIES
SPECIFIC GRAVITY AND DENSITY
depends on cell size, cell wall
thickness, and number and types of cells. Regardless
of species, the substance composing the cell walls
has a specific gravity of 1.5.
SPECIFIC GRAVITY
ranges from 160 kg/m3 for balsa
to 1335 kg/m3 for black ironwood. Most wood types
have densities in the range of 300 to 700 kg/m3.
DRY DENSITY
