Presentation on theme: "Investigating Structures and Materials Structures Activity."— Presentation transcript:
Investigating Structures and Materials Structures Activity
Tarr Steps – A Prehistoric Beam Bridge, Devon, UK Mode of transport – foot; material - stone 1.Take one span of the bridge and use the drawing tools to indicate which part is in tension and which is in compression? Also draw forces on the beam. 2.Is stone good in compression or tension? 3.Why do you think this bridge is still standing?
Trestle Bridge – Noojee, Victoria Rail bridge constructed from wood. About 100 years old 1.On various members, draw where they may be in tension and compression. 2.Is this structure good in compression or tension? What is the difference in strength between wood in tension and compression? How does wood act under load? (Is it brittle or tough?)
Arch bridge – Avenel, Victoria Originally used by horse and cart – 100+ years old stone structure Arch construction a technique perfected by the ancient Romans 1.Draw an arch and indicate where the load is distributed on the arch. 2.Why is the arch such an effective structure? 3.Is the structure designed for tension or compression?
Railway bridge - Malmsbury Another example of an arch bridge What does the keystone do?
Inverted brick arch – Old Post Office, Bendigo Located adjacent to foundations 1.Draw the forces acting on the structure. 2.What effect does inverting the arch have on the load?
Some information on the arch
Arch Bridge – Wycoller, England 1.Draw the forces acting on the right-hand arch. Is it in compression or tension? 2.List some possible reasons for the left-hand arch being on a lean.
Suspension Bridge – Ambyne, Victoria Originally used by horse and cart, now motor vehicles; constructed from wood and steel 1.Draw on the photograph which segments are in tension, which are in compression. 2.Why are wood and steel used in their particular locations? What effect would replacing the wood sections with steel and the steel sections with wood have? 3.How could we strengthen this bridge?
Cable staid bridge - Tasmania Use - Motor vehicles; constructed from steel and concrete 1.Identify the main parts of the bridge. 2.Identify areas of compression and tension. 3.Why are steel and concrete used in a structure such as this? 4.Why would a truss be used in this structure?
Truss Bridge – Walhalla, Victoria Used for motor vehicles; constructed from steel and concrete 1.Draw one section of the truss shown above. On this indicate which member would be in compression and which would be in tension. 2.Why is the truss made from steel only? Could parts of it could be constructed of other materials? 3.If the load was decreased significantly, which materials could the bridge be constructed from?
Railway overpass under construction – Princes Highway between Morwell and Traralgon Constructed from steel and concrete Note the rail tunnel in the background – this is a reinforced earth structure, comprising a steel core with compacted earth surrounding it 1.Why are the piers made from reinforced concrete? 2.How would the load be distributed around the reinforced earth structure?
Swing Bridge - near Sale, Victoria Steel bridge swings so that two cantilever spans are present 1.Draw the areas of tension and compression on the bridge in both the closed position (as shown) and when allowing river traffic to pass. 2.What properties of the bridge prevent it from failing when in use?
North Arm Bridge – Lakes Entrance Use - motor vehicles; constructed from reinforced and prestressed concrete 1.How does prestressing work? Why would you used prestressing?
Cantilever Verandah Draw a diagram of each of the two verandahs and show where the forces may be in the structures. Why would one have supports holding it up and the other one not have supports? If this was constructed from reinforced concrete, where would the reinforcing best be placed?
Foundations Why would these foundations be spread?