Topic 3 Flashcards
What are vector and scalar quantities? Providde 3 examples for both.
Vector - Has mangitude and direction
Example
- displacement
- acceleration
- velocity
- force
Scalar - only has magnitude
Example
- mass
- area
- volume
- density
- speed
what is reinforced concert and what are its material properties of it?
Concrete can be reinforced by steel rods, bars, or mesh to absorb the tensile and shear stresses put upon. On its own concrete can handle high levels of compressive stress, but in situations where tensile or shear stress is present, in earthquakes, it is weak.
What is pre-tensioning? What does it do?
Is when steel cables are strechted before the concrete is poured. When the cables are still in tension the concrete is poured and cured. once cured the steel is realsed, putting the concrete understand compression stress, causing it to buoy (into an arch), this increases the concrete tensil force. As when in tension, concrete goes back into neutral.
Name some civil-engineering sub-disciplines.
- structural
- construction
- environmental
- costal
- earthquake
- water source
What is a construction engineer do?
Oversees the design and building process of construction projects.
Ensure buildings, projects, and construction teams are safe.
They may also help design infrastructure systems, such as roads, dams, water supply systems and buildings.
What does a structural engineer do?
Addresses the design, construction, and maintenance of public works.
Pays the most attention to infrastructures, such as bridges, tunnels, transportation routes, water treatment facilities and government buildings.
What does an earthquake engineer do?
Make roads and buildings safer in the event of major earthquakes. This includes both improving the design of new buildings and bridges as well as strengthening older units to incorporate the latest advances in seismic and structural engineering.
What does an environmental engineer do?
Assess the impact on air, water, soil, and noise levels in the vicinity of engineering projects, plan and design equipment and processes for the treatment and safe disposal of waste material, and assess what may cause problems for the environment in the long term.
What are some impacts engineered structures and civil engineering have on the environment?
- deforestation
- habitat loss
- pollution
- biodiversity decrease
- interpurtion of water
- use of fossil fuels
what impacts can the environment have on civil structures?
- Erosion
- wildlife (pests)
- natural elements (wind, rain etc.)
- landslides
What are some examples of commonly used materials in civil engineering?
Explain engineering properties, lifecycle, and environmental impacts.
Concrete:
- high compressive strength
- pre-tensioning = + tensile strength
- made from sand, cement, water, and gravel(also made from synthetic materials)
- very environmentally unfriendly (accounts for 5% of global carbon emissions), can be recycled
Wood/timber: Insulative, Thermal conductive, hard, Aesthetic - readily available - Sustainable + renewable - Energy is effective in producing - can be recycled
Glass: transparency, heat resistance, pressure and breakage resistance, and chemical resistance.
- very sustainable
- fully recyclable
- hard, brittle
Mild steel:
- High tensile strength.
- High impact strength.
- Good ductility and weldability.
- A magnetic metal due to its ferrite content.
- Good malleability with cold-forming possibilities.
- Fully recyclable
- steel product has high environmental impacts
Cast iron:
- is hard and tough
- can be recycled without losing its material properties
- mining for the ore cause pollution
Acrylic Polymethyl Methacrylate :
outstanding strength, stiffness, and optical clarity
- not sustainable
- production requires the petrochemical industry (meaning synthetic materials)
- is recyclable
- not biodegradable
Order steel in order from less carbon % to most. Also, provide carbon percentages
Low carbon steel = 0.07% - 0.15% Mild steel = 0.15% - 0.3% Medium steel = 0.3% - 0.6% High carbon steel = 0.6% - 1.25% Ultra high carbon steel = 1.25% - 2.5%
Name the 3 types of bar assemblies
- unstable
- stable
- redundant
What is built-in / planned obsolescence and the issues around sustainability / reliability / ethical / environmental
The policy of planning or designing a product with an artificially limited useful life or a purposely frail design.
Environmental issues:
- increased production
- waste
- pollution
- not recycling
Ethical issues:
perpetuating a “buy new and often buy” mentality and limiting consumer autonomy to keep products longer by hard-wiring a “self-destruct” button in products
Reliability Issues:
What materials were in common use throughout ancient civilizations such as the ancient Romans, Greeks, and Egyptians
stone, lime, thatch, wood, mud, bricks, marble,
Name 3 hardness tests and 2 impact tests and explain the difference between the two types of tests
Hardness (a pyramid or spherical indentor)
- Brinells
- Vickers
- Rockwell
Impact (with a pendulum)
- Izod
- Charpy
Hardness tests a material’s ability to resist scratching and indentations. While Impact testing measures how tough material is, identifying how much shock impact can withstand.
What is the purpose of a roller anchor for a bridge?
allows the bridge structure to expand and contract with temperature changes.
How can having a modular domed-shaped structure help communities living in extreme weather?
Shape:
- run-off, no water/snow/dust/ash build up
- modular meaning additional spaces can be added or removed.
- Due to its circular shape, there is nothing for the wind to hold onto
materials
- transparent/translucent materials allow for light to pass through, stimulating an open space, and providing sunlight and heat.
- insulative
- durable material
construction/placement
- streamline/grouped together for additional warmth/protection against stong winds
Explain how the Halley IV British research station in the antarctic was built and designed as it was?
Shape
- Modular, sections can be removed and added
- is streamlined/aerodynamic, wind will blow along with the structure and not against it
- not fully rectangular, and allows for snow run-off
- standing on legs, limit snow build up to only feet
features
- lots of windows
- hydraulic legs allow for height to lengthen and shorten.
materials
- insulative materials include
- outside is made of metal, to protect against the harsh climate
Do you know what
- 3D-printed buildings / micro-modular housing / prefabrication and assembly on site / smart structures / intelligent structures systems / automation
are and why they are helpful?
yes/no
What are the properties of concrete on its own?
High compressive strength, impact resistant, durable
what are the elements of the engineering problem-solving process, in order?
- identify problem
- explore
- develop
- refine
- solution
What are the benefits of having a round building?
- Less embodied energy
- Uses less energy efficiency
- Earthquake and wind resistance
- Less expensive/cost effective
- Natural Climate Control
- Better Acoustics
What are the mechanical properties of Glass?
Lifecycle and sustainability
Glass is
- brittle
- transparent
- Chemical resistant
- High fire resistance
- conductive
- high strength
- hard
- long-lasting
process: Glass is made out of the sand, soda ash and limestone (made from natural ingredients)
- 100% recyclable
- it requires more fossils fuels to produce initially
- it takes a long time to decompose
What are the mechanical properties of timber?
Lifecycle and sustainability
Timber is
- aesthetic
- renewable
- hard
- good quality timber has good tensile and compressive strength
- tough
can be reused and recycled
What are the mechanical properties of mild steel?
Lifecycle and sustainability
mild steel is
- High tensile strength
- High impact strength
- Good ductility and weldability
- Magnetic
- conductive
Steel is
- 100% recyclable (can be used over and over again and doesn’t reduce mechanical properties)
- uses 75% less energy to recycle mild steel than produce it
What are the mechanical properties of cast iron?
Lifecycle and sustainability
- hard
- brittle
- high tensile strength
- can be recycled without losing any of its properties \
- has lower CO2 and energy consumption than PVCs and aluminum
What are the mechanical properties of acrylic?
Lifecycle and sustainability
Excellent clarity. Lightweight. Good impact resistance. Outstanding thermal insulator. UV resistant. Easy to heat-form.
- not sustainable
- can be recycled but releases a lot of gas
- acrylic production releases a lot of emission, harmful to the planet
