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