Unit 4_Part 1 CSE2001 Exception Handling and Function Template and Class Temp...
All About Timber in Civil Engineering
1. A L L A B O U T
RALPH BALTAZAR & RUSELL
MANALAD
ANGELOU SUMBILLO
RACHEL TORRES
RALPH ESTEBAN
SHAIRA ANN SANTIAGO
JAMES GABRIEL R. TOLENTINO
2. REQUIREMENTS OF A GOOD PRESERVATIVES
IN TIMBER
Effortlessly and cheaply available
Does not contain any harmful
substances
Should not be affected by fungi, insects,
etc. And should also efficient to terminate
them
Should not be affected when exposed
to light, heat, water, and etc
Should not emit unpleasant smell
Can cover large area with small
quantity
Nonflammable
Non corrosive
The depth of penetration must be
6mm to 25mm only
3. Water-borne chemical
solutions comprise a
mixture of water soluble
compounds of copper
and other chemicals.
These chemicals are
generally insoluble in
water so they are usually
dissolved in petroleum or
other organic solvents in
order to penetrate wood.
4. Copper Azole
Copper Azoles use copper as a fungicide and azole as a
biocide/insecticide. Copper Azole has a green color after
treatment and will gradually weather to a honey brown.
Alkaline Copper Quaternary
ACQ also has a green to brown appearance that quickly
weathers to brown with sun exposure.
Copper Chrome Arsenic
The most widely used preservative for the treatment of
timber.
It is clean, odorless, has a slight green color and is able to be
glued and painted when dry.
5. No hazard from fire or explosion
Cheapest options available to
consumers
Leach resistant
Safe for interior use and
treatment of playground
equipment
Wood surface is left clean,
paintable and free of
objectionable odors,
Unless re-dried after treatment, the wood
is subject to warping and checking
Does not protect the wood
from excessive weathering.
May cause swelling when
applied due to presence of
water
6. highly water repellent and resistant to
weathering and can be used in highly hazardous
situations. Maintenance is not necessary.
The most important and widely used fungicide of
organic solvent preservatives
7. Can be glued depending on
the diluent or carrier
Does not cause swelling when
applied
Toxic to fungi, insects and
mold
Can be dissolved in oils having a
wide range in viscosity, vapor
pressure and color
Low solubility in water
Ease of handling and use.
Can leave an oily, unpaintable
surface, depending on the carrier
Some applications provide less physical
protection to wood than creosote
Strong odor is toxic and irritating to
plants, animals and humans
Oily, unpaintable surface
Dark color
Tendency to bleed or exude from the
wood surface.
8. W H A T I S
Stress is defined as the force per unit
area of a material.
Where:
σ = stress,
F = force applied, and
A= cross sectional area of the object.
σ = F / A
FORMULA
9. The allowable stress or allowable strength
is the maximum stress (tensile,
compressive or bending) that is allowed to
be applied on a structural material
10. Maximum Stress (psi)
Wood Species
Bending Compression
Horizontal Shear
- τ -
Perpendicular to Grain
- σ -
Parallel to Grain
- σ -
Wet Dry Wet Dry Wet Dry
Birch, Yellow 1417 1668 477 715 960 1200
Fir, Douglas 1417 1668 417 625 1360 1700
Larch, Western 1417 1668 417 625 1360 1700
Maple, Red 1271 1495 410 615 880 1100
Oak, Black 1369 1610 590 885 920 1150
Pine, Eastern
White
1222 1438 223 335 960 1200
Redwood 1320 1553 433 650 1200 1500
A Table of Maximum possible stresses of
wood species typically used in beams
11. Actual stress is the stress produced due to
impact of load on any section.
12. The first vertical load that is considered is dead
load. Dead Loads are permanent or stationary
loads which are transferred to structure
throughout the life span.
The second vertical load that is considered
in design of a structure is imposed loads or
live loads. Live Loads are either movable or
moving loads without any acceleration or
impact.
Wind Load is primarily horizontal load
caused by the movement of air relative
to earth.
Snow Loads constitute to the vertical
loads in the building. But these types of
loads are considered only in the snow fall
places.
Earthquake Loads constitute to both vertical and
horizontal forces on the building. The total vibration
caused by earthquake may be resolved into three
mutually perpendicular directions.
13. VARIATION IN THE STRENGTH OF CLEAR WOOD
EFFECT OF DEFECTS
MOISTURE CONDITION OF SERVICE
DURATION OF LOAD
OVERLOADING
14.
15. Eitai Bridge collapse in 1800 due to overloading
during festival. More than 1400+ died
16. Factor of safety is considered in designing
any structure so that the value of stresses
which can be developed in any it during
its service life does not exceed the design
strength.
27. is used for the design of reinforced concrete,
steel and timber structures.
A practice which entails the designer ensuring
that the stresses imposed on the structures
owing to the service load don’t exceed the
elastic limit of the material.
30. Resistance factor, φ
Strength reduction factor
Used to allow for the
possibility that the
resistance may be less
than computed
Depends upon the
resistance type such as
bending, tension, and
compression
31. Nominal Strength, RN
Strength of the member for a given
limit state before any safety factor or
reduction factor is applied to the
member
34. LIMIT STATE DESIGN
A STRUCTURAL ENGINEERING DESIGN METHOD
THAT CONSIDERS BOTH THE SAFETY AND
SERVICEABILITY OF STRUCTURES.
35. VARIOUS CONDITIONS IN WHICH A STRUCTURE
WOULD BE CONSIDERED TO HAVE FAILED TO
FULFILL THE PURPOSE FOR WHICH IT WAS
BUILT.
36. ULTIMATE LIMIT
STATE (ULS)
SERVICEABILITY
LIMIT STATE
(SLS)
A CATASTROPHIC STATE, WHICH
REQUIRE A LARGER RELIABILITY IN
ORDER TO REDUCE THE PROBABILITY
OF ITS OCCURRENCE TO A VERY LOW
LEVEL.
REFERS TO THE LIMITS ON
ACCEPTABLE PERFORMANCE OF THE
STRUCTURE DURING SERVICE
37. Rupture Loss of Equilibrium
ULTIMATE LIMIT STATES (ULS)
Transformation into a
Mechanism
Failure caused by
Fatigue
Collapse
