- Grade 300E (fy = 300MPa)
- mild steel
- Grade 500E (fy = 500Mpa)
- alloyed or tempered
- Grade 500L (low ductility)
- Grade 500N (normal ductility)
- Grade 500E (earthquake)
- yield strength of N/L grades not tightly controlled
- low ultimate strain
- low ratio of ultimate to yield strength
- Prestressing (prevent cracks)
- very low porosity concrete (SCMs, low w/c ratio)
- galvanised rebar
- stainless rebar
- cathodic protection
- non-metallic reinforcement
- Not a routine product
- Useful for:
1. Very corrosive environments
2. Situations where steel cannot be used
- GFRP most common alternative
The forest are managed responsibly, i.e. The volume used is less than the volume grown (use less)
carbon
Softwoods & Hardwoods
Coniferous / Evergreen plants
Deciduous / Broad-leaved plants
- Rimu
- Totara
- Taraire
- Tawhai
- Kauri
- Puriri
- Matai
- Towai
- Tawa
- Pukatea
- Rewarewa
- Rata
- Tawhero
Puriri & Rewarewa
Softwoods
Softwoods:
- Faster
- Cheaper
- Timber industry relies on softwood species more
Hardwoods:
- Used in limited cases
By using its density value as density is the indicator of strength. Related to such things as; hardness, ease of machining and nailing resistance.
The ratio of the density of wood to the density of water. It is customary to use oven-dry weight and current volume.
- knot
- slope of grain
- resin pocket
- check
- split
- compression wood
- wane
- Moment Resisting Frame
- Concentrically Braced Frame
- Eccentrically Braced Frame
- I section
- C or Channel Section
- Tee section
- Angle section
SHS = Structural/Square Hollow Section
RHS = Rectangular Hollow Section
CHS = Circular Hollow Section
- Iron ore and carbon mixed at 1600 degrees celcius
- Reduction reaction gives pig iron
- Pig iron contains up to 5% carbon and other elements
- Slag residue used in road making, aggregate etc
- Excess Co2 bottled for industrial use
- Electricity cogenerated from iron and steel making process: 60% of total used for NZ steel
Concentrically braced frame
- Oxygen is pushed through pig iron to remove most of the carbon
- Excess oxygen is removed by adding aluminium and silicon
- killed steels = all oxygen removed
- Molten steel then rolled into final shape
- Controlled rolling
good for static & earthquake, bad for fatigue loading
1. Beams
2. Columns
3. Piles
plate to plate connection, full strength not required, weaker, bad in fatigue vs expensive, full strength of weakest member, good for static/earthquake/fatigue
- Principal two elements are iron & carbon
- Carbon content for structural steels < 0.8%
- Max carbon content for any steel < 3%
(Carbon content strongly influences behaviour)
- Uneven cooling of hot rolled sections
- Cutting of edges
- Welding of pieces together
Is the smallest volume element of a space lattice
concentrated and heavy long term compression load, earthquake resistance
- returns to its og dimension
- aka the target region for the design structures for in-service condition
- a permamant deformation remains.
- aka the target region for design structurs for the ultimate limit state condition
Characterised by a rapid crack proagation without significant plastic deformation
- Characterised by tearing of metal and signifcant plastic deformation
- Can be grey & fibrous
- Associated with overload of the structure or large discontinuities
- Applied slowly so that ut cayses minimal dynamic effects in the structure (for eg - fatigue failure)
- Load is constant
- Building loads = static loads
= Repeatd load
- aka it fluctuates in magnitude over time
examples: trucks, trains, people, conveyor systens, cranes, furniture, warehouse material, snow & water
The deterioration of a material under repeated cycles of stress or/and strain, resulting in cracking & fracture
- Most significant = large number of cycles at small strains / stresses
- 80-90% of all steel failures fatigue failure joints that are more susceptible to fatigue
- Fatigue failure occurs with tall signs due to the window force
The temp at which the fracture behaviour changes from ductile to brittle
- 50% ductile & 50% brittle = transtion zone
in metals when these metals are below transition temp
- Fillet weld
- Incomplete penetration butt weld
- Complete penetration butt weld
- Simple (rotate under design actions without moment)
- Semi - rigid (carry moment but weaker than beams)
- Rigid (no rotation under design actions)
- Flanges resist moment-induced and direct axial forces
- Web resists shear and moment due to eccentric shear transfer
- Bolt and weld failure suppressed
- Sawn timber
- Glulam (glue laminated timber)
- LVL (laminated veneer lumber)
- Ignition
- Growth
- Burning
- Decay
Protects from the rain and allows air movement behind
- closed
- sheltered
- exposed
requires that materials, components & construction methods allow the building to function for its specified intended life of not less than 50 years for structural and inaccessible elements.
- insect & marine borers
- fungi
- moisture fluctuations
- ultraviolet light
- bacteria
- mechanical abrasion
- chemicals
- panels made from boards
- laid in perpendicular pattern
- dimensionally stable
- good thermal resistance
- allows prefabrication of building components
Laminated veneer lumber
- a derivative of plywood
- all laminations are laid in one direction pressed together
- very strong and stiff material (good for beams)
- not as good to connect
- some cross-ply LVL frabricated is better for members other than beams
- laminations are glued together
- laminations are typically 45 mm - need to be thinner if theres curvature
- not all glue is of the same service class
- sawn lumber
- glulam
- panelling (sheating)
- engineered wood poles
wood which moisture content is in equilibrium with the ambient air relative humidity
wood which moisture content has been reduced to 15-19%
- uses logs peeled
- veneer is laid at various angles
- gives stability & strength
- different grades for strength & visual finish
- used for flooring and lateral bracing, gussets in moment resisting frames and plywood boxed beams
No
extends the life of timber by modifying its resistance to agents
- Untreated
- H1.1
- H1.2
- H2
- H3.1
- H3.2
- H4
- H5
- H6