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WorksheetsDesign and Technology Y11UK or 10th grade US general knowled
Total questions: 31
Worksheet time: 32mins
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. What type of structure early bridges were made of
timber frame structure
stone structure
it was just beams spanning the length of the gap
a rope structure
At the same time as wood beam bridges and wood frame bridges, stone slab bridges were also used widely. They are still used today as they are very strong especially if used to cross small gaps. Select the correct statements.
A single slab spans the length of a wide river
A single long slab spans the length of a wide stream or small river
Several small slabs span the length of a wide river
Small pillars of stone can be embedded in the river bed to support the weight of long flat stone slabs laid across them. In this way wide gaps can be crossed.
It is a fact that arches are used in underground structures such as sewage and vaults of Egypt, Babylon, Greek and Assyrian civilizations. However, the use of Keystone in arches (also called a tombstone) begins with Roman civilization. They found out that .........
without the Keystone, the arch will still be able to stand
the Keystone is the stone at the apex of the arches and that without it the entire structure would collapse.
in arch design, the Keystone is not the key element for standing the arch.
the Keystone plays a role in distributing all weight down the side support blocks in the columns
In arch building construction...
a skilled stone mason would shape the slabs and place them around a door vault without the need to use a wooden frame template to support the work.
several stones will be arranged in a mount shape to support the build work and be removed from underneath when the arch is completed
a wooden frame template would be put in place to support the stones positioned along the vault.
Such is the strength of stone arch technology that many of the monuments built in roman times can still be seen today such as the ....
Trajan's colomun
the Colosseum
the Pantheon
In roman bridge and aqueduct construction roman engineers..........
developed techniques such as constructing rows of arches on top of other arches. This meant that they could build high bridges and aqueducts by stacking rows of arches on top of each other.
used accurately cut stones on external faces, filling also the cavities with other perfectly shape slabs rather than gravel, sand and rough stone
used aqueducts to transport water across valleys to towns. these aqueducts were so well built that did not need a slight incline (angle) in order for the water to flow down hill, by the force of gravity.
A Box Girder Bridge is a bridge where the key beams consist of girders shaped like a hollow box. Box girders....
are made of structural steel, pre-stressed concrete, reinforced concrete or composite of steel.
are mostly used for short span bridges where the actual self weight of the bridges has to be kept to a minimum.
comprises two concrete slabs — top and bottom. The slabs are connected by an array of vertical bridge stems, also known as webs. These webs can be vertical or inclined.
are generally used for the construction of buildings.
footbridges use an all-steel configuration as the entire cross section including the parapets can be fabricated.
Advantages of box girders:
A simple design input
Have high strength and torsional stiffness that give greater and better suitability for horizontally curved bridges
Box decks can be easily cast in situ ( the work site) rather than having to be prefabricated in a factory and transported to the site for assembly.
the pre-stressed cement can be poured in one single go across the whole length of the gap avoiding the need to pour it to form one single segment of the structure at the time.
On the stormy night of 28 December 1879, the central spans of the Tay bridge collapsed into the Firth of Tay at Dundee in Scotland. An inquire into the engineering disaster demonstrates that...
The fall of the bridge was occasioned by the insufficiency of the cross bracing and its fastenings to sustain the force of the gale.
the major design fault was its ability to withstand wind pressure and that trains were no required to slow down over high bridges in strong gales conditions.
the designing of the bridge was a smooth and linear process that did not involve as it is often the case multiple changes to the original design.
the casters of the girders as shown in the pictures did not take short cuts and kept to the original plan of using wrought iron instead of the cast one option.
cast iron is very brittle and cracks under tension whilst wrought iron is very durable. This design flaw in the use of materials with different properties led to the collapse of the Tay Bridge.
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. What type of bridge am I?
a chain bridge
a cable stay bridge
a cantilever bridge
a suspension bridge
This type of bridge is used where a wide gap / distanced is to be crossed and typical examples are the Golden Gate Bridge in San Francisco, the Akashi Kaikyo Bridge in Japan and the Humber Bridge in the UK. The Akashi Kaikyo suspension Bridge is over a distance of four miles in length and each tower is nearly as high as the Eiffel Tower (three hundred metres). These are all typical examples of a...?
a cantilever bridge
a suspension bridge
a cable stay bridge
truss bridge
tied arch bridge
One of the main reasons for building a cable stay bridge is ...
that the deck is entirely supported by vertical cables.
that it is more stable in the wind than a suspension bridge but also it is less expensive to construct.
the advantage over suspension bridges of achieving increased rigidity, with less sway.
a design which has the weight of the bridge deck supported by towers to which run several cables.
A cantilever bridge is a bridge built using cantilevers, A cantilever bridge is a bridge built using cantilevers however.. ...............select the correct statements.
A simple cantilever span is formed by two cantilever arms extending from opposite sides of an obstacle to be crossed, meeting at the center.
large cantilever bridges designed to handle road or rail traffic use simple beams rather than trusses built from structural steel, or box girders built from prestressed concrete
cantilevers are structures that project vertically into space, supported on only one end.
a common way to construct steel truss and pre-stressed concrete cantilever spans is to counterbalance each cantilever arm with another cantilever arm projecting the opposite direction, forming a balanced cantilever.
in a common variant, the suspended span, the cantilever arms do not meet in the center; instead, they support a central truss bridge which rests on the ends of the cantilever arms.
select the cantilever bridge
Select the cable stay bridge
Select the box girder bridge examples
Select the correct statement
A rigid frame structure is one of the strongest shapes known to man
A triangular form is one of the weakest shapes known to man
The square is the most rigid frame structure. Engineers have known for a long time that whenever they need a light, strong, rigid structure they cannot do better than use a framework of squares.
A triangular form is one of the strongest shapes known to man. It is not surprising then that ‘triangulation’ is used in the construction of buildings and structures.,
Select an example of triangulation from the options
When ----- are used in multiples, a new flexibility emerges from the rigidity of the singular shape and they gain free-form three dimensional sculptural abilities that are not possible in any other shapes. This enables them to form infinite structures from simple angular variations. What shape am I?
a dodecahedron
a pentagon
an hexagon
a triangle
traingulation is very common in free form architecture. Is so important because, when it is quite easy to create curved surface in a 3D modelling asoftware, it is very complicated to construct this surface in the real word, out of steel, concrete, glass etc. This complications are caused by a number of reasons. Select the true or false statements
a square shape is the ultimate solution, it is a very simple and stable shape, and it has been used in building structures for centuries like in the Eiffel Tower, its structure is a mesh of squares.
in current methods of manufacturing is quite straightforward and practical to manufacture a curvy and organic structure using triangles whilst is quite complicated to build a box like shape.
The emergence of triangulation is probably due to a digital familiarity and an increase in 3D modelling which is all done using mesh surfaces which are tessellated with triangles.
when architects are trying to construct free form curved surface they often choose to construct its very accurate approximation out of triangles.
A structure is something that supports an object or a load.
A structure must:
• be strong enough to support its own weight and any load that is put on it
• be stable (not topple over easily when a force acts on it)
• resist without losing more shape than expected. Select the correct statement.
Triangulation is used to make frame structures non rigid. When forces are applied to a simple four-sided structure, it cannot be forced out of shape quite easily. A structure which behaves in this way is said to be rigid.
By adding an extra bar or member, the structure then cannot be forced out of shape, and is said to be rigid.The additional member has formed two triangles in the structure. This is known as triangulation. The triangle is the most rigid frame structure.
When forces are applied to a triangulated structure it can be forced out of shape quite easily. A structure which behaves in this way is said to be non-rigid.
In construction Usually the four main walls of the house are constructed and then structural roof timbers are set in position. These form triangles made out of trusses that hold up the felt and slates that are added later. In structural engineering a truss
is formed by a combination of struts and ties.
truss and a strut in construction are identified as the same part
A truss and tie are identified as the same component in house building
In roof construction using triangulated structures is often convenient remove the tie component to bring down costs.
All structures have forces acting on them. You should have an understanding of tensile, compressive and shear forces. The part of the structure that has a ....
compressive force acting on it is called a STRUT.
tensile force acting on it is called a TIE
tensile force acting on it is called a strut
compressive force acting on it is called a Tie.
Aerodynamics is the study of ...
forces and the motion of objects through the air.
objects that are stationary.
is the study of how air moves around things
the design of furniture and machinery.
Drag is the aerodynamic force .....
that counteract earth's natural downwards force
that opposes an aircraft's motion through the air.
that allows an aircraft to lift off
In aerodynamics ........... is produced as air passes over the surfaces of the of an aircraft. This in turn slows it down.
gravity
resistance
thrust
In timber manufacturing what happens after the threes have been harvested?
When possible they are stored on clearing to allow moisture to evaporate
They are transported to windmills.
In the tropics they are floated in rivers to sawmills.
Logs are rough sawn on the spot to make it easier for transportation.
What is conversion in timber manufacturing?
Is when logs are broken down through rough sawing.
Is when threes are converted into logs
It happens when green wood is used to make products.
What is the seasoning process in timber manufacturing?
Seasoning is the process of allowing logs to retain their moisture.
It occurs when 50% of its water content is removed through drying.
seasoning occurs when logs quire more moisture.
What are hardwoods?
They are sometimes called broad-leaf trees
They tend to be light-pale in colour
They are used for interior joinery and roof shingles.
They loose their leaves seasonally in winter
What are softwoods?
Tend to be more expensive and take longer to mature.
They are from trees that have needles and exposed seeds
They are tree that stay green all year around.
They are deciduous and have flat leaves that fall in autumn
They go under the name of coniferous trees.
