Structures

What do we understand when we talk about structures in Design and

technology?

Lesson Objectives: To understand the forces and the parts that form structures.

Plan of Lesson:

Setting the learning objectives 2 mins

Starter Task – exploring different ways of making paper stronger 5 mins

What are structures and what parts and forces are there 8 mins

Existing structures from various cultures 5 mins

Introduction to task and brief 5 mins

Making your own towers 20 mins

Testing the weight of your towers 10 mins

Evaluation-What worked, what didn’t work, how could they be made better- information on struts and ties 5 mins

What is a structure?Definition

• A Structure is an object or a collection of objects put together in a particular way to withstand load.

Examples of man-made structures

Bridges

BuildingsRoof Trusses

Brackets

Play equipment i.e climbing frames, slides

Scaffolding

Tables

Chairs

Examples of structures in nature

• Snails shell• Trees• Coral• Cob-webs• Skeleton• Beaver Dams

Starter task- Making paper stronger

• How can you make your piece of paper stronger?

• Think of different shapes that you can use and different ways of folding paper

FRAMES

Many structures are based on a frame. We use frames every day ,for example, a stool is a frame on which we sit.

Buildings are based on frames and this is why they can be built very high. Everywhere we look in towns and cities we see examples of structures based on frames.

Can you name any famous structures, anywhere in the world, that are based on a frame ?

The square frame is strong when pressure is straightdown on it. If pressure is from the side it tends to beweak and it can collapse. A triangular frame is very strong. Many structures andbuildings are often made up of this type of shape.

Forces• Tension• Tension is when something is being pulled or

stretched

CompressionThis is when something is squashed like if you stand on a coke can, your leg is compressing the can.

Shear ForceThis is when two forces are going in two different directions. The arms of the scissors move in different directions from the pin.

TorsionTorsion is when something is being twisted.

Struts and TiesAll structures have forces acting on them. The part of the structure that has a tension acting on it is called a TIE and the part that hascompression acting on it is called a STRUT.

WallThe beam is held in position by a steel rod. The weight of the beam is stretching (pulling) the rod. Which type of force is this?

RoofThe roof beams are being pushed down from the weight of the tiles on the roof. What is the force that pushes?

FlagpoleThe wires on either side of the flagpole are being stretched. Why is the pole being compressed?

The Egyptian Pyramid• Built around 2600 B.C.• From over 2 million blocks of stone• They have a square base and triangular sides• Tombs for pharaohs

Examples of structures

The Eiffel Tower (France)Examples of structures

• Built between 1887- 1889• 9441 tons of wrought iron• 324 meters tall• 18038 pieces of wrought iron were joined

together to create the Eiffel Tower• During strong winds, the Eiffel Tower

sways up to 15 c.ms at its top

The Spinnaker Tower (England)Examples of structures

• It was opened in 2005• 1200 tons of steel was used to construct the Spinnaker• The spire is 27m tall• The Tower’s ‘legs’ are constructed from concrete• The total weight of the Tower is heavier than 30,000

tons• 115m up and in high winds, the Tower can move

approximately 15 c.ms

Teams

Team 1 – Lance & BiffTeam 2 – Annie’s Team 3 – Chris & PeterTeam 4 – Josie & Ben

Brighton i360

Designed by Marks Barfield also responsible for the the London Eye. Will (hopefully) boost tourism in Brighton especially during the Olympics. Visitors will be able to enjoy 360 degree panoramic views of Brighton and on a clear day can see up to 25 miles along the South coast. Intended to be:

A unique experienceA gentle landmarkA visitor destinationA catalyst for long-term regeneration

Brighton needs YOU! The original plans for the Brighton i360 observation tower have been scrapped due to lack of funding and fears it will attract extra terrestrials. Brighton council have turned to YOU and your team mate to build a new (cheaper) observation tower for the sea front from the range of materials provided. They are pretty relaxed about the design of the new tower and the methods you use to build it. HOWEVER! The tower must meet the following conditions; It must be at least 300mm height (it can be as wide as you wish)It must hold a minimum weight of 100g It must have an observation pod on top (use the cup provided)You may only use materials provided ( and cannot swap or steal from other groups)It must NOT fall down when the minimum weight is added. If the tower doesn’t meet these specifications, Brighton will not have a new tower and your team will

FAIL

Planning and DesignThink about the different ways you can design the tower, draw your design ideas below and select the one you think will be most successful.

De-brief

• What worked well?• What challenges did you encounter and

how did you overcome them? • Did you build the tallest tower you could?

Why or why not? • How similar is your design to others in the

room?