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Teacher Development ProgramBringing schools and Engineering together
Year 12 – Civil Structures Module
This Module
Student Learnings
The Syllabus-HSC Modules
Syllabus- Objectives and Outcomes
Engineering Scope H1.1:
Engineers and engineering are indispensable contributors to Australian prosperity and lifestyles. Engineering services are embodied in almost every good or service consumed or used by Australians, now and in the future. Engineers are the enablers of productivity growth through their role in converting “brilliant ideas” into new products, new processes and new services. Engineers also ensure that society gets the most out of existing facilities through optimising their operations and maintenance. http://www.engineersaustralia.org.au/sites/default/files/shado/Resources/statistical_overview_2015.pdf
Syllabus- Objectives and OutcomesH1.1. describes the scope of engineering and critically analyses current innovations
Engineering Scope H1.1: Critical Analysis of current innovation. Innovation is defined as:“The process of translating an idea or invention into a good or service that creates value or for which customers will pay. To be called an innovation, an idea must be replicable at an economical cost and must satisfy a specific need.” http://www.businessdictionary.com/definition/innovation.html
Engineering Solutions must be analysed to be:• Repeatable- (when tested over and over in same facility)• Reproducible- (when tested in different facilities)
Engineering MaterialsH1.2 - differentiates between the properties and structures of materials and justifies the selection of materials in engineering applications. H2.1 – determines suitable properties, uses and applications of materials, components and processes in engineering.
Material propertiesClassification:- 4 main groups:1. Metals- Iron, Steel, Copper etc.2. Polymers- Bakelite, PVC3. Ceramics- Glass, Abrasives 4. Composites- Concrete, Fibreglass, FRP
• Early Humans- Stone Age• ~9000 BCE- Copper age• ~3000 BCE- Bronze age• ~1200 BCE- Iron age
Ages of Materials
Drinking Horn-Animal products
Water vessel-Ceramic
Simple engineered items- over time
Drinking Glass
Weapons-Timber- Bow & Arrows
Composite- Bow & Arrows
Iron Steel
Hot-Rolled
Cold RolledCold-Rolled
Hot-Rolled
Galvanised
Protection
Steel
Dimension stone
Concrete Block
Clay Bricks/Tiles
Masonry- Concrete, Clay, Dimension Stone
Concrete Pavers and Roof Tiles
A long chain molecule
Construction
Medical
Transport Clothing
Products
Polymers
Composites-Use
Composites-Use
Composites-Fire risk managed by testing and design
Composites - Concrete
Concrete the material:• Strong in compression / weak in tension• Brittle material will crack- controlled by joints etc.• Reinforcement in tension zones mainly• Cover to reinforcement important for durability• Lifecycle- potential for 100 years or more• Commonly 10 to 40 years project dependent
• Can form a composite with any other compatible material- steel, plastic, fibres, corn husk, straw, hemp etc. depending on properties sought.
CROSS LAMINATED TIMBER CLT
• https://www.bing.com/videos/search?q=cross+laminated+timber+youtube&view=detail&mid=33D5D736619CCD390EB533D5D736619CCD390EB5&FORM=VIRE
Compression
Tension
Bending
Torsion Shear
Important Material Properties
Concrete Compression
Bend tests
Important Material Properties
Tension-Bottom
Compression-Top
In-service quality of material?
Technological changeH4.1- investigates the extent of technological change in engineering. Changes in technology for analysis and deign (model of the physical world)
Advances in technology and analysis systems have allowed better understanding of materials and allowed more efficient structures.
How do buildings resist lateral loads?
Outriggers allow activation of more of the structure and increases the efficiency of the structure.
Teacher Development ProgramBringing schools and engineering togetherH4.3 – applies understanding of social, environmental and cultural implications of technological change in engineering to the analysis of specific engineering problems.
Engineering Innovation in Civil Structures and their Effect on People’s Lives• Large buildings have allowed for apartments and businesses to work in better environments. • Bridges allow people to cross water ways easily and quickly.
Impacts of bridges include: • More direct travel across waterways, gorges • Quicker travel times • Less fuel used in traveling, cheaper • Job opportunities in design and construction • Pylons may disturb waterways • Negative impact on boating
Teacher Development ProgramBringing schools and engineering together
Construction and Processing Materials used in Civil Structures Over Time• Timber • Stone – Strong in compression but heavy • Cast Iron • Steel – Corrodes, strong in tension and compression • Concrete – artificial rock – relatively strong in compression
Environmental implications from the use of materials in civil structures• Timer – Deforestation • Stone – Needs to be quarried, cut, transported • Steel – Pollutants from smelting • Concrete
Teacher Development ProgramBringing schools and engineering together
Trusses
Teacher Development ProgramBringing schools and engineering together
Teacher Development ProgramBringing schools and engineering togetherH3.3 – develops and uses specialist techniques in the application of graphics as a communications tool
Truss Analysis – Pin jointed frames.No transfer of bending at the joints. Axial forces only
(1) Method of joints• This involves working around the truss, solving one joint at a time to find the axial forces in each of the members.• This method requires the understanding of the sum of vertical and horizontal forces = zero. It usually requires the
application of trigonometry and simultaneous equations. (The first two equations of equilibrium)• The concept of axial forces in a member (No bending)
Teacher Development ProgramBringing schools and engineering together
(2) Method of sections• This involves cutting the truss at a discrete location in order to fint the forces in the members at the particular cut. • This technique required the understanding of the theory of moments about a point = zero. (The third equation of
equilibrium)• The concept of axial forces in a member (No bending)
Teacher Development ProgramBringing schools and engineering together
Simple beam Analysis – Concepts of flexural (bending) actions.
Teacher Development ProgramBringing schools and engineering together
Shear force and bending moment diagrams• Here is a beam (top), with the corresponding shear force diagram (middle), and bending moment
diagram (bottom) subject to a point load
Teacher Development ProgramBringing schools and engineering together
Shear force and bending moment for a beam subject to a uniformly distributed load.
Teacher Development ProgramBringing schools and engineering together
Concept of shear force and bending moment
• Sum of vertical forces = zero• Sum of moments = zero
• Satisfy equations of equilibrium
Teacher Development ProgramBringing schools and engineering together
Bending stress induced by point loads only
Teacher Development ProgramBringing schools and engineering together
Stress and Strain• Shear Stress
– Shear stress occurs when you apply shear force. – Eg. If a bolt is supporting a load perpendicular to the bolt of 10kN, and it has a
diameter of 10mm, what is the shear stress?
• Shear stress = 127MPa
Teacher Development ProgramBringing schools and engineering together
Yield stress, Proof stress, Toughness, Young’s modulus, Hooke’s law, Engineering applications• Yield stress occurs when there is an increase in strain without an increase in stress.
• Proof stress is the amount of stress necessary to bring a permanent strain in the material.
• Toughness is a measure of the ability of a material to absorb energy.
• Hooke’s law is , it calculates Young’s modulus of elasticity.
Factor of Safety• A factor of safety is how many times stronger the material or structure is than it needs to be.
Teacher Development ProgramBringing schools and engineering together
Teacher Development ProgramBringing schools and engineering togetherH3.1 – demonstrates proficiency in the use of mathematical, scientific and graphical methods to analyse and solve problems of engineering practice.
• The study of a Higher level of Mathematics is very important for carrying out engineering calculations.
• Civil (structural) engineering is about modelling the physical world to understand it’s behaviour by the use of applied mathematics.
• Calculus, for example, is just one key part of mathematics that is used for determining the bending moment and shear forces ( and therefore stresses) in structures.
• The accurate calculation is very important in the analysis (understanding forces) and design (sizing elements to withstand the forces).
• Manual (hand) calculations is still very much used and taught in 3rd year engineering degrees. It allows simple checking of output of computer analysis for sensibility and errors.
Teacher Development ProgramBringing schools and engineering together
• For the simple beam with a distributed load (w) shown, the shear force at C is taken as:
Teacher Development ProgramBringing schools and engineering together
Teacher Development ProgramBringing schools and engineering together
Teacher Development ProgramBringing schools and engineering together
Calculus and the use of Differentiation and Integration
Error between model and physical world
Suggested Class Exercise
Summary
• Engineers Australia is your link with the Engineering Profession / Industry
• These Presentations and forums can provide important networking opportunities with other teaching professionals
• Engineers Australia can assist in providing exciting ways of presenting concepts with real world examples and applications.
• We encourage a link of support with exam assessors
• We emphasise that pathways to engineering exist for all students- Professional, Technical, Trade, VET
Pathways to Engineering
Engineers Australia is the trusted voice of the profession. We are the global home for engineering professionals renowned as leaders in shaping a sustainable world.
engineersaustralia.org.au