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
THERMAL PROPERTIES
THERMAL CONDUCTIVITY
SPECIFIC HEAT
THERMAL DIFFUSIVITY
COEFFICIENT OF THERMAL EXPANSION
measure of the rate at which
heat flows through a material.
THERMAL CONDUCTIVITY
The thermal conductivity of wood
depends on several items including
a. GRAIN ORIENTATION
b. MOISTURE CONTENT
c. SPECIFIC GRAVITY
d. EXTRACTIVE CONTENT
e. STRUCTURAL IRREGULARITIES
is the ratio of the quantity
of heat required to raise the temperature of the
material one degree to that required to raise the
temperature of an equal mass of water one degree.
SPECIFIC HEAT
s a measure of the rate at which a
material absorbs heat from its surroundings.
THERMAL DIFFUSIVITY
a measure of
dimensional changes caused by a temperature
variance.
THERMAL COEFFICIENT EXPANSION
is a good electrical insulator
AIR DRY WOOD
MECHANICAL PROPERTIES
MODULUS OF ELASTICITY
STRENGTH PROPERTIES
LOAD DURATION
DAMPING CAPACITY
TESTING TO DETERMINE MECHANICAL
PROPERTIES
Flexure Test of Structural Members (ASTM D198)
Flexure Test of Small, Clear Specimen (ASTM D143)
Flexure Test of Structural Members (ASTM D198)
FLEXURE (BENDING)
COMPRESSION (SHORT COLUMN)
COMPRESSION (LONG COLUMN)
TENSION
Flexure Test of Small, Clear Specimen (ASTM D143)
STATIC BENDING (FLEXURE)
IMPACT BENDING
COMPRESSION PARALLEL TO THE GRAIN
COMPRESSION PERPENDICULAR TO THE GRAIN
TENSION PARALLEL TO THE GRAIN
TENSION PERPENDICULAR TO THE GRAIN
Steel products used in construction can be classified
as follows:
STRUCTURAL STEEL (VERTICAL COLUMNS)
COLD-FORMED STEEL (TRUSSES AND DECKING)
FASTENING PRODUCTS
REINFORCING STEEL (REBARS)
MISCELLANEOUS PRODUCTS
) produced by
continuous casting and hot rolling for large structural
shapes, plates, and sheet steel.
STRUCTURAL STEEL
produced
by cold-forming of sheet steel into desired shapes.
COLD FORMED STEEL
used for structural
connections, including bolts, nuts, and washers.
FASTENING PRODUCTS
use in concrete
reinforcement
REINFORCING STEEL
use in such
applications as forms and pans
MISCELLANEOUS PRODUCTS
Advantages of Steel
STRENGTH AND STIFFNESS
UNIFORMITY & PERMANENCE
DUCTILITY & TOUGHNESS
SUSTAINABILITY
THREE PHASES OF STEEL PRODUCTION
- reducing iron ore to pig iron
- refining pig iron (and scrap
steel from recycling) to steel - forming the steel into
products the materials used to produce pig iron are coal,
limestone, and iron ore.
Steel members have a high strength per unit weight ratio.
STRENGTH AND STIFFNESS
Steel properties do not change appreciably with time.
UNIFORMITY AND PERMANENCE
Steel has a remarkable ability to withstand
* Large inelastic deformations(ductility)
* Large amounts of energy(toughness)
DUCTILITY AND TOUGHNESS
Structural steel produced in the U.S. contains 93.3%
recycled steel scrap.
-At the end of the life of a given building, 98% of the steel is
recyclable.
SUSTAINABILITY
y is a metal made by combining two or more
metallic elements.
ALLOY
l is an alloy of iron and carbon.
STEEL
Alloys are added to steel to alter the character of
steel.
ALLOYING AGENTS
used in hot-rolled structural
shapes, plates, and bars.
STRUCTURAL STEEL
used for structural
framing of floors, walls, and roofs as well as interior
partitions and exterior curtain wall applications.
COLD FORMED STEEL
Since concrete has negligible tensile strength,
structural concrete members subjected to tensile and
flexural stresses must be reinforced.
REINFORCING STEEL
Reinforcing steel (rebar) is manufactured in three
forms:
PLAIN BARS
DEFORM BARS
PLAIN WIRE FABRICS
are round, without surface deformations.
provide only limited bond with the concrete
and therefore are not typically used in sections
subjected to tension or bending.
PLAIN BARS
have protrusions (deformations) at the
surface; thus, they ensure a good bond between the
bar and the concrete.
DEFORM BARS
develop the anchorage in concrete
at the welded intersections, while deformed wire
fabrics develop anchorage through deformations and
at the welded intersections.
PLAIN WIRE FABRICS
there are four marking
symbols IN BAR IDENTIFICATION CODES
LETTER CODE FOR MANUFACTURER
NUMERICAL CODE FOR BAR SIZE
LETTER CODE FOR TYPE OF STEEL
GRADE
MECHANICAL TESTING OF STEEL
TENSILE TEST
TORSION TEST
CHARPY V NOTCH IMPACT TEST
BEND TEST
HARDNESS TEST
ULTRASONIC TESTING
performed to determine the yield
strength, yield point, ultimate
(tensile) strength, elongation, and
reduction of area
TENSILE TEST
used to
determine the shear modulus of structural materials.
TORSION TEST
used to measure the toughness of the material, or the
energy required to fracture a V-notched simply
supported specimen.
CHARPY V NOTCH IMPACT TEST
The ductility to accommodate bending is
checked by performing the semi guided
The test evaluates the ability of steel, or
a weld, to resist cracking during bending.
BEND TEST
a measure of a
material’s resistance to localized
plastic deformation, such as a
small dent or scratch on the surface
of the material.
HARDNESS
a nondestructive method
for detecting flaws in materials. It is particularly useful
for the evaluation of welds.
ULTRASONIC TESTING
done at the project site.
FIELD TESTING
Other types of field testing include:
SOIL AND AGGREGATE SAMPLING AND TESTING
CONCRETE SAMPLING AND TESTING
Soil and Aggregate Sampling and Testing
Compaction and Density
* Bearing Ratio
* Permeability Testing
Concrete Sampling and Testing
- Air Entrainment Testing
- Slump Testing
- Temperatures
- Unit Weight
describes the processes for
preparing untreated aggregate and disturbed soil
samples, as received from the field, for the required
tests.
SOIL AND AGGREGATE SAMPLING TESTING
crucial for
creating strong concrete that can weather the
elements. IT prevents the expansion of
water within hardened concrete from causing
cracking, scaling, and other concrete damage during
freeze-thaw cycles
AIR ENTRAINMENT TESTING
determine the workability or consistency of concrete
mix prepared at the laboratory or the construction site
during the progress of the work.
SLUMP TESTING/ CONCRETE SLUMP TEST
