Name. Form.. Teacher. THIS PROJECT WILL RUN FOR. WEEKS AND NEEDS TO BE COMPLETED BY DESIGN AND TECHNOLOGY THE NATIONAL CURRICULUM LEVEL

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1 Name. Form.. Teacher. DESIGN AND TECHNOLOGY THIS PROJECT WILL RUN FOR. WEEKS AND NEEDS TO BE COMPLETED BY. THE NATIONAL CURRICULUM LEVEL FROM YOUR PREVIOUS PROJECT WAS: MY TARGET FROM MY ASSESSMENT STAMP: PREVIOUS PROJECT WAS:

2 Design Brief Structures are all around us. We take them for granted but life would be so much harder for us all if they didn't exist. Structures fall into 2 main groups and. structures make up the built environment, which includes shelter in the form of buildings, transport in the form of vehicles, roads and bridges. Other manufactured structures such as clothing and furniture are designed to improve the everyday quality of our lives. The natural environment with its plants, animals, birds, fish and insects is a great resource of structures that have evolved over millions of years. The ways in which structures like flowers, fruit, eggs and shells contain and safely protect their contents is truly amazing. Looking at natural structures has helped modern engineers and designers develop more sophisticated and complex structures designed to support huge weights or span great expanses. Task On the mind map below add different structures into the two headings: NATURAL STRUCTURES MANUFACTURED

3 The structures / buildings shown below are famous and well known. Write the name of each structure / building under each picture. If you cannot think of the name of the structure / building, write the name of the country you think it is in. Can you think of any more famous structures/buildings? Write their names and the countries they are in below:

4 Loads and Forces All structures are designed to withstand forces applied to them, without permanently changing shape or collapsing. This means that strength and some degree of flexibility are important. These forces are called loads, which can be static e.g. The weight of the structure itself, or dynamic, which is caused by movement e.g. Car driving over a bridge. Structures are constructed so that they distribute and spread loads to more than one place, in order to ensure stability. External forces such as wind, air, gas and water also apply loads to structures. Task There are different types of force which can be applied in different directions. Complete the following by describing the type of movement that each of the forces exerts on a structure. COMPRESSION TENSION BENDING TORSION SHEAR CENTRIFUGUAL

5 Types of Bridges Bridges are needed for a variety of reasons. Generally, they bridge a gap between the banks of a river or they span the distance between two sides of a valley. They are made from materials including stone and steel. Bridges can carry people, cars, lorries, railways and even rivers. Box Girder Bridges Box girder bridges are quite common and a basic example is seen here. They are usually manufactured from prefabricated steel girders. This means that the girders are manufactured in a factory and transported to the location of the bridge, where they are fixed together. The steel girders of a bridge are fixed together normally with large nuts and bolts. Sometimes rivets are used although these are seen on older structures. Each side of the bridge is composed of three triangles. Each triangle is made up of three steel girders bolted together. This is called triangulation and produces a structure of great strength. Suspension Bridges A typical suspension bridge can be seen below. A suspension bridge is composed of a roadway (sometimes called a deck) suspended by steel cables. The four towers hold up the steel cables which in turn hold up the roadway. The steel cables are held in position by enormous concrete anchor blocks. These are at either end of the bridge. Each anchor block weighs more than the amount of cable it has to hold as well as a large proportion of the weight of the roadway. The anchor blocks must also be heavy enough to hold up the number of vehicles that are expected to be on the roadway at anytime. Cable Stay Bridges A scientific understanding of the properties of modern materials and the availability of computer software have made it possible to construct new types of bridges. A typical cable stay bridge can be seen below. These are modern bridges designed using computer aided design (CAD). Unlike suspension bridges, cable stay bridges do not need anchor blocks. The cables are fixed to either side of each tower - this means that the weight of each side of the bridge counter balances the opposite side. The absence of anchor blocks substantially reduces the amount of materials needed and the cost of building the bridge. Also, the towers tend to be positioned down the centre of the roadway and half as many towers are needed compared to suspension bridges.

6 Triangulation and Modelling Many structures are based on a frame. Some examples are shown below. 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. Below are two examples of frames that you can make from card or even paper. When you have made then press down lightly with one hand. You will probably find that they can take some pressure from above. The square frame above is strong when pressure is straight down on it. If pressure is from the side it tends to be weak and it can collapse. A triangular frame is very strong. Many structures and buildings are often made up of this type of shape. Man-made structures are often based on this TRIANGULATION. Glue a piece of card on the top and bottom of the frame. This will make the frame even more rigid. To test the strength of each frame, place a book on the top and if it survives place more books on top. Task 1. The incomplete drawing below, represents a simple wooden triangulated bridge. Complete the drawing so that triangulation is clearly seen. 2. Why is triangulation an excellent way of building structures such as bridges and towers? 3. Name two famous structures that rely on triangulation for their strength. 4. Collect a number of photographs/diagrams of structures that rely on triangulation for their strength. For each explain how triangulation is used.

7 Case Study The Tacoma Narrows Suspension Bridge On November 7, 1940, at approximately 11:00 AM, the first Tacoma Narrows bridge collapsed due to wind-induced. The bridge was across the Tacoma Narrows in Puget Sound near the city of Tacoma, Washington. It had only been open for traffic a few months. As the began to increase the bridge began to and this slowly became worse until the middle of the bridge fell apart. This photograph shows the motion of the centre span just before the failed. The drastic (twisting) movement is seen in this picture taken from the Tacoma end of the suspension span. When the twisting was at its, the elevation of the at the left was 28 feet (8.5m) higher than the sidewalk at the right. This photograph shows the same part of the bridge except at this point in time the had dropped to the as the bridge twisted in the wind. A few after the first piece of fell, this 600 foot section dropped into the water below, turning down as it crashed in. The floor assembly and the solid have been twisted and. The square object in mid air (near the centre of the photograph) is a 25 foot (7.6m) section of concrete pavement. Can you see the car in the top right corner? Word Bank Girders wind minutes torsional structure suspension maximum sway pavement warped Sound vibrations motion left Puget span twisting concrete bridge upside

8 Structures and the Environment The environment can be damaged when structures are being built. This can happen in a number of ways: 1. Grass land/farm land is destroyed as the structure is built on top of it. 2. Lorries and trucks are used to transport materials to the building site - these create pollution from exhaust fumes and also noise pollution. 3. The raw materials (iron, stone etc...) used to build the structures have to be taken from places such as quarries and mines and this can damage the landscape. 4. Factories process the raw materials, for example, iron ore is converted to steel in steel mills. This process of converting raw materials into materials that can be used to build structures uses a lot of energy and cause pollution to the atmosphere. 5. The local natural environment is changed to such an extent that the wildlife that once thrived in the area can no longer live or survive there. Protection of the Environment The building of structures can also benefit the environment and even improve it. Take for example the Humber Bridge, near Hull in Yorkshire. This was once the longest suspension bridge in the world and it spans the River Humber. Before its construction cars and lorries had to make a trip of approximately fifty miles to bypass the River Humber. This meant that thousands of vehicles, every day used up petrol and diesel making this long journey, which created pollution. When the bridge was finished cars and lorries could travel across the bridge, saving thousands of gallons of fuel each year. There was less pollution as a result. You have probably seen modern windmills which are used to produce electricity from the wind. These are complex structures and are expensive to build as they are composed of materials such as steel and concrete. As you may have read earlier, building structures can damage the environment. However, once a modern 'wind generator' is built it can last for many years producing clean electricity. Electricity that once would have been produced by burning oil or coal which pollutes the atmosphere. Usually building the structure damages the local environment but over the lifetime of the structure and environment can benefit from it. Questions 1. Give an example of a structure and explain how it benefits the environment: 2. List the materials required to build these structures and explain where they come from. 3. Explain how quarrying / mining the materials followed by the processing of these materials affects the environment. 4. How does the transport of these materials from the quarry/ min/ factory to the construction site affect the environment? 5. Describe how you would project the environment if you were to be in charge of building a bridge across a river.

9 Bridge Design The diagram opposite and photograph below show the shape and form of an art straw bridge. You are going to work through a number of simple practical exercises which will include making and testing the model bridge with weights. The model bridge shows good use of triangulation. Look closely at the diagram as it clearly shows the arrangement of triangles that make up the bridge. A triangle is a very strong shape and this is why it is often used the build structures such as bridges and many buildings. Task Design a bridge that will span the two sides of the valley drawn below. You could use a design based on a suspension bridge, cable stay, a girder bridge or a completely new design. You must produce a range of different bridge designs that you could construct yourselves using Art Straws, cotton and hot glue guns.

10 Bridge Design Continued Task requirements Your task is to design a bridge that must span a gap of 30cm (between two desks). It must not exceed 40cm in length or 5cm in width. You will be allowed art straws to make your members out of, one sheet of card and 1metre length of cotton. Evaluation Evaluation Evaluation

11 Bridge Construction An understanding of the terms, struts, and ties is important, as these can be mentioned in examinations. All structures have forces acting on them. You should have an understanding of tensile, compressive and shear forces (see previous sheet). The part of the structure that has a tensile force acting on it is called a TIE and the part that has a compressive force acting on it is called a STRUT. WALL The beam is held in position by a steel rod. The weight of the beam is stretching the rod (tensile force). ROOF The roof beams are under pressure from the weight of the tiles on the roof (compressive force). The floor beam is being stretched (tensile force). FLAGPOLE The wires on either side of the flagpole are being stretched (tensile force). Final Bridge Design:

12 Bridge Testing The bridges constructed by a class can be tested and the data collected (number of weights successfully supported). This can be presented in the form of a table and a graph or pictogram. Testing your Bridge: Bridge Description Bridge #Weight (g) Load Carried (kg) Load Bridge Ratio= Overall Position in Class Build Quality of model (1-5) Evaluation your Bridge: Good aspects of my bridge were Bad aspects of my bridge were Where on the bridge did the structural failure occur? Which type of forces were acting upon the bridge to make it collapse? What improvements would you make to the design of the bridge?

13 Structures Project Test 1. What are the two main groups of all structures? (4) Name 3 structures for each of the above 2 groups. (6) What are the 3 different types of structures? (3) What do the terms static and dynamic mean when applied to a structure? (4) 5. Name these forces and write an explanation for each one (12) 6. Which is the strongest shape? (1) 7. Explain and draw what the following are: (12) Beam Member Strut Tie Column Cantilever 8. Give two ways in which structures damage the environment? (4) Name two suspension bridges: (4) /40

14 Key Words Research, Designing, Planning, Making, Modelling, Structure, Manufactured, Load, Forces, natural, Compression, Tension, Bending, Torsion, Shear, Strength, Centrifugal, Suspension, Stability, Static, Dynamic, Triangulation, Beam, Member, Strut, Tie, Column, Cantilever, Shell, Frame, Mass, Elevation, Destructive, Flexibility, Template, Environment, Mass, Testing, Weight. Homework Tasks Homework 1: Collect as many images as you can for both manufactured structures and Natural structures. Using a piece of A3 paper, divided it into half (one side for Natural and the other for Manufactured structures) and produce an image board (page of pictures and words). Homework 2: Using the internet or books produce a research sheet or booklet on a famous and well known building/ structure. You should include pictures and information. Focus on some of the most interesting facts e.g. height, weight, time taken to construct, how it was built, when it was built, etc. Homework 3: Collect pictures of different types of bridges, explain what type of bridge they are and what type of structure. How do the features help the bridge to withstand the forces that are acting on them? Do they have any features that you could use on your own bridge designs? Present your work neatly on A4 paper. Homework 4: Structures and the Environment. Complete the homework sheet in your folders. Homework 5: Produce an accurate scale drawing of the bridge you have constructed, include as many measurements as possible. You could draw your bridge from the front, side and top (orthographic) to show more detail. Homework 6: Complete all your folder work and revise for the test.

15 Researching the task Specification Initial Ideas Design development Planning Evaluation High quality making using tools, equipment and processes Level4 Level 5 Level 6 Level 7 Level 8 Generate ideas by collecting and using information. Use some ideas from others designing to inform your own work. Take user s views about aesthetics and technical issues into account as you respond to briefs. Communicate alternative ideas using words, labelled sketches and models, showing that you are aware of constraints. Identify what is working well and what could be improved to overcome technical problems. Produce step-by-step plans. Identify what is working well and what could be improved to overcome technical problems. Reflect on your designs as they develop, recognising the significance of knowledge and previous experience. Select and use a range of tools and equipment. Apply your knowledge and understanding of materials and components, and work with them with some accuracy, paying attention to quality of finish and to function. Develop ideas by drawing on and using various sources of information Show you are aware of constraints as you apply knowledge and understanding of materials, ingredients and techniques. Clarify ideas through discussion, drawing and modelling showing understanding of aesthetic and economic dimensions. Respond to briefs showing understanding of how culture and society are reflected in familiar products when developing your ideas. Use understanding of others designing as you develop your work. Work from your own detailed plans, modifying where appropriate. Check your work as it develops, solve technical problems and show some evidence of creativity as you modify your approach in the light of progress. Test and evaluate your products, showing you understand the situations in which the products will function. Work with a range of tools, materials, ingredients, equipment, components and processes with some precision. Use a range of sources of information, and show that you understand the form and the function of familiar products as they develop and model ideas. Develop detailed criteria for your products and use these to explore proposals. Respond creatively to briefs, exploring and testing your design thinking. Recognise the significance of others designing and modify your approaches accordingly. Apply your knowledge and understanding by responding to several aspects to the problem. Produce plans that outline alternative methods of making process. Evaluate how you have used information sources, using the results of your research to inform your judgements when developing products. Evaluate your products as they are being used, and ways of improving them. Work with a range of tools, materials, ingredients, equipment, components and processes, showing that you understand their characteristics. Use a wide range of appropriate sources of information. Investigate form, function and production processes as you respond creatively to briefs Use your understanding of others designing to inform your own as you communicate creative ideas. Apply your knowledge and understanding, recognising the different needs of a range of users, and search for trends and patterns in existing solutions as you develop fully realistic products. Produce plans that predict the time needed to carry out the main stages of making products. Select appropriate techniques to evaluate how your products would perform when used and modify your products in the light of this evaluation to improve their performance. Provide a sound explanation for any change from the design proposal. Work with a range of tools, materials, ingredients, equipment, components and processes, taking full account of their characteristics. Adapt your methods of manufacture to changing circumstances as you solve technical problems. Use your understanding of others designing by reinterpreting and applying learning in new contexts. Identify a broad range of criteria for evaluating your products, clearly relating your findings to environmental, ethical, social and cultural dimensions. Identify conflicting demands on a product and respond creatively to briefs, suggesting ways forward and explaining how your ideas address these demands. Use a range of strategies to fully develop and model appropriate ideas, responding to information you have identified. When applying knowledge you make decisions on materials and techniques based on your understanding of physical properties and working characteristics. Carry out processes accurately and consistently. Use accurate testing to inform your judgements when solving technical problems. Identify a broad range of criteria for evaluating your products, clearly relating your findings to environmental, ethical, and social and cultural dimensions. Organise your work so that you can carry out processes accurately and consistently, and use tools, equipment, materials, ingredients and components with precision. National Curriculum Levels