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Bridges and Tunnels
A bridge is a link between two places, such as over a river, a road or a depression, that caters to pedestrians and/or vehicles. A tunnel is an underground link between two places, often underneath a riverbed, for pedestrians and/or vehicles.
4,393 Questions
How much did it cost to make the Eitaibashi bridge?
it cost lots and lots of money
Eitaibashi Bridge was built in 1698. There are not likely to be any records of its cost. The bridge was replace in 1924-1926. That bridge is called Eitai-bashi or Eitai Bridge.
What type of bridge is the anzac bridge?
The ANZAC Bridge is a striking cable-stayed bridge spanning Johnstons Bay in Sydney, Australia. Its distinctive design features two 120-meter-high towers supporting the deck with 128 stay cables, creating a visually impressive silhouette. Opened in 1995, it replaced the old Glebe Island Bridge and serves as a crucial link between Sydney's CBD and the western suburbs. The bridge's name honors the Australian and New Zealand Army Corps (ANZAC), symbolizing the shared military heritage of both nations.
Loose measure volume is the volume of a substance or material that is not tightly packed or compacted. It typically refers to the volume of a substance when it is in a loose or granular form, such as sand, gravel, or soil. It is important to consider loose measure volume when accurately estimating quantities of materials for construction or manufacturing purposes.
Fire demand refers to the amount of water required to extinguish a fire. It is calculated based on factors such as the size of the fire, the type of materials burning, and the fire's intensity. Understanding fire demand is crucial for ensuring that fire protection systems, such as sprinklers, are designed to effectively control and suppress fires.
What is difference between Harp and fan designs of cable stayed bridge?
In harp type cable stayed bridges the cables running from the deck to the tower run parallel or near parallel and attach to different points on the tower, in fan type bridges the cables all run back to the same point near the top of the tower.
The fan type bridges have less horizontal loading on the deck so a lighter and less stiff deck structure is possible but presumably you need a stronger and higher tower, or at least able to support more vertical load high up (not sure I'm not an engineer I just like the aesthetics of these structures!)
When does cross bridge cycling end?
Cross bridge cycling ends when calcium is actively transported back into the sarcoplasmic reticulum, leading to a decrease in intracellular calcium levels. This causes the tropomyosin to block the binding sites on actin, preventing myosin from interacting and forming cross bridges. This relaxation of the muscle allows the muscle fibers to return to their resting state.
What is the ratio between bentonite powder and construction water so that density will come 1.2?
The ratio of bentonite powder to construction water needed to achieve a density of 1.2 will depend on the specific properties and particle size distribution of the bentonite powder being used. It is recommended to conduct small-scale tests to determine the exact ratio required for your specific mix design. Starting with a 5-10% bentonite powder to water ratio is a common practice, but adjustments may be needed based on actual test results.
How have volcanoes helped to create hawaiian islands?
Hawaiian Islands were formed by volcanic activity as a tectonic plate moved over a hotspot, creating a chain of volcanoes. As the plate moved, new volcanoes emerged from the hotspot, each contributing to the growth of the islands over millions of years. The lava flows and eruptions from these volcanoes built up the landmass of the Hawaiian Islands.
Why Iron is used in constructing bridges and houses?
Iron is used in construction due to its strength and durability. In bridges, iron is often used because it can support heavy loads and provide stability. In houses, iron is commonly used in structural elements like beams and columns to provide strength and support to the building.
What does the land bridge theory explain form about 10000?
The land bridge theory suggests that around 10,000 years ago, a land bridge called Beringia connected Asia and North America, facilitating the migration of early humans into the Americas. This theory helps explain how humans first populated the Americas by crossing from Asia into North America.
Did the bay bridge fall in 1989 because of an earthquake?
Yes, the upper deck of the Bay Bridge in San Francisco collapsed during the Loma Prieta earthquake in 1989. The earthquake caused a section of the upper deck to collapse onto the lower deck, resulting in sections of the bridge falling into the water below. Fortunately, there were no fatalities from the bridge collapse.
What is the use of jockey in meter bridge?
In a meter bridge, the jockey is used to slide along the wire to make contact with the resistance wire and balance the bridge by finding the null point. This allows for accurate measurement of unknown resistance by comparing it with a known resistance.
What is the colour and smell of benzoic acid?
Benzoic acid looks like a very clear white powder , crystalline flakes. It smells like urine and even the smell is very irritant to eyes ! Made the experience of putting it close to my nose ! Be careful.
What are the positive and negative aspect of bridge?
Positive aspects of bridge include promoting critical thinking, improving memory and concentration, and fostering social connections. Negative aspects may include the time commitment required to learn and play the game, and the potential for disagreements or tension among partners during play.
What do you call the type of engineer that designs bridges?
civil engineers, structural engineers, and architects are the main bridge builders.
Why is steel used in buildings?
Steel is commonly used in buildings due to its high strength-to-weight ratio, which allows for tall and durable structures to be built. Steel is also versatile, easily shaped and modified to fit different architectural designs. Additionally, steel is resistant to corrosion and fire, making it a reliable material for supporting structures in buildings.
Which bridge is the strongest truss or suspension and why?
Suspension bridges are typically stronger than truss bridges because they can span longer distances and support heavier loads. The design of a suspension bridge allows for the weight to be distributed more evenly, reducing stress on the structure. Truss bridges are better suited for shorter spans and are generally lighter in weight.
It's named after nearby Mount Rainier, which at that time in the 1800's was called 'Tahoma'
Brass, an alloy of copper and zinc, is generally considered safe for everyday use. However, prolonged exposure to high levels of brass dust or fumes may cause health issues. It is important to follow proper safety precautions when working with brass to minimize any potential risks.
Constraints:
- The bridge must span a 55cm gap
- No more than 100 popsicle sticks may be used
- The sticks may not be cut
- Only elmers glue may be used
- Construction paper may be used for the deck only
- The test load is applied to a 4cm-wide section at the top of the arch.
(Well-built bridges can support over 200kg - the weight of two adults)
Structural AnalysisA bit of thought, or modelling with a computer-aided design program, shows that the bridge can be reduced to a simple triangle. The force required to break a well-constructed bridge is orders of magnitude greater than any other forces acting on it, such as its own weight, the weight of the toy car, "wind load" etc.This is not the case for a real bridge, of course, which must be designed for a variety of vehicle loads, wind loading, snow or ice buildup, earthquakes and so on. Also, because of the power law (mass increases as the cube of the size, while strength increases as the square of the size), small structures are much much stronger than their full-size counterparts.
A bit of simple physics (or CAD software) will put numbers to the forces. Simple analysis treats the sides as rigid bars, and the corners as free pivot points. One lower corner is fixed to the support, while the other is allowed to slide. The base of the triangle is in tension, while the sides are in compression. The higher the triangle, the less tension in the base. The limiting case for an infinitely high triangle is zero tension in the base, and half the test weight in compression in each side.
If the triangle is made lower, the forces increase. In the limit of a zero-height triangle, they become infinite.
Forces in Simple Triangle: 200kg weight on apex
Stresses in trianglular element, from "Felt" software. Red is under tension, blue is in compression.
So the optimal shape to minimize the forces on the bridge is an infinitely high triangle. Two problems - we have only 100 sticks, and the test jig is less than 40cm high.
The bridge is contructed of two compression elements and one tension element. A bit of experiment reveals that failure of a tension element is typically due to shearing of an overlap joint, while failure of a compression element is typically due to buckling.
Design of a tension element for the base is relatively simple - a series of sticks overlapped a suitable amount performs well. Design of a compressive element is more difficult. The element must resist buckling, and must be designed so that the stress is distributed evenly across the individual sticks. This may be acheived in part by careful assembly - the element should be perfectly straight, and all the sticks should align exactly at the ends so that they all touch the supports.
In real life, elements are often created with a complex cross-section in order to resist buckling. Three of the most common shapes are the I-beam, box section, and tube. Most real-world structures are made of these shapes.
For the stick bridge, the requirement to not cut sticks makes it difficult to create these common sections, though it is possible (though not the tube, of course).
Instead, stiff elements may be made by laminating together pairs of sticks. This also guards against weakness in individual sticks - depending on the supplier, some sticks may have grain diagonally across the stick. Since wood will split along the grain, this makes them much weaker. In this case, pairs of sticks should be laminated so that the grains cross each other.
When these designs are tested, providing the joints are well made and sufficiently overlapped, the element will typically fail by buckling. Once the element starts to buckle, failure is progressively more rapid. As the sticks depart from perfect alignment, the inside of the curve becomes more stressed than the outside, taking the inside sticks beyond their breaking strength. The joint may become delaminated, a stick may split along the grain, or a stick break across the grain.
To prevent buckling, it is necessary to make the element stiffer. This can be done by making it thicker, but the finite number of sticks puts a limit on this. Another technique that may be used is the stayed mast, borrowed from sailboat design.
In a sailboat, there are one or more masts (shown below on its side) which are under compression and subject to sideways force from the sail (this force can be many tons in strong winds). To stiffen the mast, steel cables are used together with "spreaders" to convert bending in the mast into tension in the cables which is more easily resisted.
This concept may be used in the stick bridge, to resist bending of the compressive members by staying them against the bottom tension member. This idea is shown in the third design.
ConstructionTypically, bridge elements are built first, then glued together to make two or more trusses, The trusses are then joined with cross members, and finally the paper deck is glued on. Since at each step the glue must dry, it is important to allow enough time for all the steps. At least 3 days is required, and typically much more.When glueing elements, better results will be obtained if the sticks are clamped while the glue dries. Since you want to glue many elements at the same time, you need a lot of clamps. Fortunately, good spring clamps can be obtained at a "dollar store". For single joins, clothes pegs may be used.
For laminating, pieces of thick metal or wood and steel G-clamps allow many pairs of sticks to be laminated at once. Pairs of sticks may be arranged in two layers between the metal plates to give e.g. 24 pairs in 2 layers. It is important to make sure the sticks are exactly aligned and do not slip when pressure is applied.
It is important that the final elements should be exactly straight, or they will buckle. This means they must be glued together against a straight edge such as a long piece of wood. Elements must be measured carefully and overlaps glued to bring them to the designed length.
For final assembly, a setsquare should be used to make sure that the bridge is exactly vertical and that the top load-bearing elements are exactly flat and horizontal. Any deviation - one stick protruding slightly, for instance - will concentrate stress under load and be a point of failure. Since sticks cannot be cut, any small errors in alignment may be corrected by adding glue. The load-bearing points at the bottom corners and apex can be set up on flat metal plates (which the glue won't stick to) and glue added to build up the round end of the sticks to give a flat bearing surface.
The bridge should be constructed to spread the load equally to all elements. Just thinking about it helps - imagine what happens when the weight is applied, and each stick starts pushing on the next to transfer the load to the base. Are there any sticks that aren't doing anything ? Any sticks that are doing more than their fair share of work ?
TestingTesting your design is a good idea - it helps eliminate poor designs early before you have spent too much time on them. Also, it's fun. The Richmond APEG test jig uses a car jack, cable and springs to pull evenly on the load plate, with an electronic load cell to measure the force. My test jig uses a set of bathroom scales and two threaded rods. Pieces of 2x4 are used for the cross-pieces. The upper crosspiece had to be reinforced with a metal plate as sticks would be driven into the soft wood when testing joints in pairs of sticks. Force is applied by turning the nuts on the screwed rods with a pair of wrenches.Caution - wear safety glasses and keep fingers clear. Though the stored energy in the jig is much less than in the springs of the APEG tester, forces will still exceed 100kg and elements may break suddenly.
What makes a suspension bridge strong?
First of all triangles are most probably the strongest shape and the suspension bridge has lots of triangles.
Second of all it has posts next to the posts (attached to each other by steel rope) that makes a triangle shape. (it can be rounded too)
What is the strongest type of truss bridge?
The Warren truss is commonly regarded as one of the strongest types of truss bridges due to its efficient use of materials and load distribution. Its geometric design helps evenly distribute forces throughout the structure, making it a popular choice for long-span bridges.
