What are the pros and cons of a suspension bridge?
What are two pros and cons of suspension bridges?
- Cost Effective. There is a very minimal amount of materials needed in order to construct a suspension bridge.
- Can Be Built High Up.
- Span Great Lengths.
- Has Flexibility.
- Simple Construction.
- Soft Ground Issues.
- Too Flexible.
- Cannot Support High Traffic.
What is the purpose of a suspension bridge?
Suspension bridges are world-class infrastructures, that are not only a traveling medium connecting two areas, but also an important landmark serving a valuable purpose. Suspension bridges are mega structures built to help cross over water bodies and valleys. The intricate engineering and meticulous architecture, that go into building these suspension bridges is highly commendable.
What are facts about suspension bridges?
Here Are the Pros of a Suspension Bridge
- They are budget friendly to build. Suspension bridges typically need only a minimum amount of materials to be created. ...
- They are incredibly versatile. Suspension bridges can be built in virtually any location. ...
- They are easy to maintain.
What is special about a suspension bridge?
suspension bridge, bridge with overhead cables supporting its roadway. Modern suspension bridges are light and aesthetically pleasing and can span longer distances than any other bridge form. They are also among the most expensive bridges to construct.
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What makes a suspension bridge strong?
Most of the bridge's weight (and any vehicles on the bridge) is suspended from the cables. The cables are held up only by the towers, which means that the towers support a tremendous weight (load). The steel cables are both strong and flexible. This makes long span suspension bridges susceptible to wind forces.
What are the forces acting on a suspension bridge?
The main forces in a suspension bridge are tension in the cables and compression in the towers. The deck, which is usually a truss or a box girder, is connected to the suspension cables by vertical suspender cables or rods, called hangers, which are also in tension.
What is a suspension bridge in simple words?
Definition of suspension bridge : a bridge that has its roadway suspended from two or more cables usually passing over towers and securely anchored at the ends — see bridge illustration.
Why would you use a suspension bridge?
When all the materials and circumstances are the same, suspension bridges can span longer distances than simple beam bridges. This is because the bridge deck, or roadway, is supported from above using tension in the cables and compression in the towers rather than just from bases.
How does a suspension bridge carry load?
Suspension bridges get their name from the fact that the roadway is suspended by cables from two tall towers. Most of the weight is supported by the two towers. They, in turn, pass the compression forces from the cables directly into the ground. Suspension bridges also have smaller cables called suspenders.
What is the strongest type of bridge?
Which type of bridge is strongest? Even though the truss bridge design has been around for literally centuries it is widely regarded as the strongest type of bridge.
Are suspension bridges safe?
There are downsides to suspension bridges like this Most suspension bridges have a truss system built into them beneath the road to keep it more rigid and less apt to sway and twist. But suspension bridges have to be somewhat flexible during high winds. Otherwise, they may break.
How long do suspension bridges last?
The roadway hangs suspended below, with all its weight pulling on the main cables. And these bridges are built to last; some of them are more than 100 years old, including New York City's Brooklyn Bridge. San Francisco's Golden Gate Bridge is more than 70 years old. But none of these bridges will last forever.
How much can a suspension bridge hold?
The maximum upward deflection is 5.8 ft (1.8 m). The maximum transverse deflection, at center span is 27.7 ft (8.4 m). Live load capacity per lineal foot is 4,000 lbs (1,814.4 kg).
What is 1 disadvantage of a suspension bridge?
Heavy Loads: Flexibility also becomes an obstacle once significant, focused loads are concerned. Suspension bridges do not seem to be usually used for regional rail crossings that carry most weight loads that add dangerous stress to the structure.
What are the pros and cons of a suspension bridge?
Pros of a Suspension BridgeIt can span over long distances. ... It is inexpensive to build. ... It is easy to maintain. ... It is incredibly versatile. ... It is aesthetically pleasing. ... It is vulnerable to the wind. ... It has load limitations. ... It costs time and money.More items...•
What are the weaknesses of a suspension bridge?
List of the Disadvantages of Suspension BridgesSuspension bridges can struggle to support focused heavy weights. ... There is less flexibility with a suspension bridge. ... High winds can cause a suspension bridge to start vibrating. ... Some access below the deck may be necessary during construction.More items...
What four forces act on a bridge?
Bridges must be able to withstand several types of forces. The two most common to model bridges are compression and tension, pushing and pulling respectively. The other two are torsion (twisting) and shear.
How do we apply forces to bridges?
1:294:46How Bridge Balance Forces? | Different Type of Forces on BridgeYouTubeStart of suggested clipEnd of suggested clipCalled compression a pushing or squeezing force acting inward. And tension a pulling our stretchingMoreCalled compression a pushing or squeezing force acting inward. And tension a pulling our stretching force acting outward channeling the load the total weight of the bridge.
What is an internal force on a bridge?
Internal forces occur within the bridge, through tension, compression, bending, etc. External forces are applied to the outside of the bridge, and can be static or dynamic. The static load of the bridge is the bridge itself, and the weight of its members and components.
How does gravity affect bridges?
The gravity dilemma. The most profound force affecting bridges is gravity, which is constantly pulling at them, trying to drag them down to earth. Gravity isn't such a big deal when it comes to buildings, including large ones like skyscrapers, because the ground below them is always pushing back.
Why did suspension bridges fail?
Early suspension bridges would also fail because of the bridge decks which were constructed thin and without a full understanding of aerodynamic forces. Heavy winds could shake the bridge deck and without the proper dampening, it could even be destroyed in moderate winds.
What is the purpose of the supporting cables on a bridge?
Their job is to transfer the deck’s weight to the towers through the main supporting cables. The main supporting cables are the graceful cable arcs that run from the towers to the anchorages located at each of the bridge’s ends.
What is the most famous suspension bridge in the world?
Perhaps the most famous suspension bridge in the world is San Francisco’s Golden Gate Bridge. The expansive bridge with its monolith towers and crisscross cables is a beauty to behold – but many do not know how these beautiful structures actually work.
How many feet did the Spanish bridges span?
They wove twisted grass to create beautiful bridges which the Spanish explorers discovered. Some of their remarkable grass suspension bridges spanned over 150 feet and crossed deep gorges. The success of the suspension bridge has resulted in a quickly evolving means of construction.
What is the main support cable?
The main support cables are positioned from the towers to the anchorages which tend to be either concrete block or solid rock . The job of the anchorages is to pull the towers outward with the same force as the bridge deck is pulling them together.
What is a suspension bridge?
The suspension bridge is easy to recognize for its slender, distinctive shape. Most suspension bridges have two long pairs of long, narrow towers with cables hanging gracefully between them. These main support cables are strung with smaller, vertical cables to hold up the main bridge deck. The main cables descend into supports at either end of the bridge, often holding up two smaller decks to the outside of the main towers.
How do cables work on a bridge?
The main cables are strung with vertical cables that attach to the deck. These cables support the deck of the bridge, transferring the weight to the towers at the end. The main cables continue past the tower, and are anchored past the far ends of the bridge. They are carefully balanced so that the force pulling inward on the towers is equal to the force pulling outward. As a result, the weight pulls directly down into the base of the tower. The towers can be fairly thin, since they aren't being pulled to either side. The deck can also be thin, since it is being supported by the cables.
What are the weaknesses of suspension bridges?
Suspension bridges have a few weaknesses that have caused disaster in the past. One of the most serious problems is the main cable. Early suspension bridges were sometimes made using chain links of heavy steel for the main cable. If only one chain link failed, the whole bridge would collapse, as what happened to the Silver Bridge in 1967, killing 46 people. Nowadays, suspension bridges use bundles of cables. If one or two of the cables fails, the bridge still stays intact.
What is the Tacoma narrows bridge?
The Tacoma Narrows Bridge was a more famous and spectacular lesson in design. The deck was not thick or stable enough, and would start to oscillate in a moderate wind. Eventually, in a fairly heavy wind, the bridge shook itself apart. Nowadays, suspension bridges are built with a more thick and rigid design to prevent excessive motion.
How does a suspension bridge work?
With a suspension bridge, the road is supported by a stiffening girder, which spreads out the weight of the traffic, so avoiding excessive sag under an exceptional load. If you hang something on a washing line away from the centre, the point will not only sag but it will also move towards the nearest end (try it!). Similarly, as a heavy load travels over a suspension bridge, it will not only dip downwards at the point of the load, it will also move longitudinally towards the nearest tower.
How does a heavy load move over a suspension bridge?
Similarly, as a heavy load travels over a suspension bridge, it will not only dip downwards at the point of the load, it will also move longitudinally towards the nearest tower. If you stand on the walkway of the Severn Bridge, you can feel it moving as the traffic travels over it.
What is the tension on the Severn Bridge?
On the Severn Bridge, the two main cables act a bit like a washing line. The tension in a washing line supports the weight of the clothes that are pegged to it. In a similar way, the tensions in the main cables of the bridge, which are held in place by huge anchorages at each end, support the weight of the deck and traffic upon it.
How does tension in a cable work?
The tension in the main cables carries the whole weight of the bridge deck and the traffic. This tension is resisted by the anchorages at each end, just as the tension in a washing line is resisted by whatever it is tied to at each end. And because the main cables are held up by the towers, the weight of the whole bridge is transferred through ...
What is a suspension bridge?
suspension bridge. A suspension bridge, with forces of tension represented by red lines and forces of compression by green lines.
How are suspension bridges made?
When bridges requiring piers are built over a body of water, foundations are made by sinking caissons into the riverbed and filling them with concrete. Caissons are large boxes or cylinders that have been made from wood, metal, or concrete. In the case of suspension bridges, towers are built atop the caissons. The early suspension-bridge towers were stone, but now they are either steel or concrete. Next, the anchorages are built on both ends, usually of reinforced concrete with embedded steel eyebars to which the cables will be fastened. An eyebar is a length of metal with a hole (or “eye”) at the ends. Cables for some of the first suspension bridges were made of linked wrought-iron eyebars; now, however, cables are generally made of thousands of steel wires spun together at the construction site. Spinning is done by rope pulleys that carry each wire across the top of the towers to the opposite anchorage and back. The wires are then bundled and covered to prevent corrosion. When the cables are complete, suspenders are hung, and finally the deck is erected—usually by floating deck sections out on ships, hoisting them with cranes, and securing them to the suspenders.
What is deflection theory?
Since the early 20th century, deflection theory has been used in the design of suspension bridges to calculate how the horizontal deck and curved cables work together to carry loads.
What is a caisson?
Caissons are large boxes or cylinders that have been made from wood, metal, or concrete. In the case of suspension bridges, towers are built atop the caissons. The early suspension-bridge towers were stone, but now they are either steel or concrete.
Which is the longest suspension bridge in the world?
In 2019 China completed the second and third longest suspension bridges in the world: the Yangsigang Yangtze River Bridge, spanning 1,700 metres (5,577 feet) in Wuhan ( Hubei ), and the Nansha Bridge, ...
When were cable bridges invented?
A cable-braced bridge was developed by German engineers at Cologne, Düsseldorf, and elsewhere in the 1950s and ’60s; in this form a single tower at the midpoint supports the roadway by means of a number of cables. Another development of the 1960s, aimed at reducing time of construction, was cable fabricated in the shop. By the late 1980s, three suspension bridges (the Golden Gate, in San Francisco, the Verrazano-Narrows, in New York City, and the Humber Bridge, near Hull, England) had main-span lengths of more than 1,200 metres (4,000 feet).
Which bridge is the most expensive to build?
Though suspension bridges can be made strong enough to support freight trains, they have nearly all been designed for automobile traffic. George Washington Bridge. The George Washington Bridge, a vehicular suspension bridge across the Hudson River, U.S.
What is a suspension bridge?
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. The basic structural components of a suspension bridge system include stiffening girders/trusses, the main suspension cables, main towers, and the anchorages for the cables at each end of the bridge. The main cables are suspended between towers and are finally connected to the anchorage or the bridge itself, and vertical suspenders carry the weight of the deck and the traffic load on it. Like other cable supported bridges, the superstructure of suspension bridges is constructed without false work as the cable erection method is used. The main load carrying member is the main cables, which are tension members made of high-strength steel. The whole cross-section of the main cable is highly efficient in carrying the loads and buckling is not problem. Therefore, the deadweight of the bridge structure can be greatly reduced and longer span becomes possible. In addition, the esthetic appearance of suspension bridges is another advantage in comparison with other types of bridges. The structural components, classification, analytical method, and construction method of suspension bridges are discussed in this chapter.
How long does a suspension bridge last?
When an engineer designs a suspension bridge over a river, he or she will start with a precise engineering drawing and then, based on well-established mathematical models, assess the strength of materials and corrosion resistance needed to ensure the structure will stand for some anticipated lifetime, e.g., 100 years. The strength of materials and corrosion resistance are compiled in widely accepted handbooks containing data obtained through rigorous testing. The engineer can confidently design the bridge from computer models and handbook data. The bridge will stand and function appropriately for 100 years. Moreover, such a bridge manufactured according to a given set of design criteria and specifications should perform approximately the same whether it crosses a river in Seattle, Birmingham or Boston.
What is required to hold a suspension bridge in place?
Suspension bridges require the uplift and horizontal forces at the bridge ends to be either held in place by tiedown shafts, rock anchored mats, or very large gravity anchorages or anchor blocks.
How is a deck suspended?
The deck is suspended by strong ropes running from the deck level to the main cables. The main cables can consist of parallel strong wires that are aerially spun in place or prefabricated wire ropes. The deck can be stiffened by a truss or by girder elements.
What is the purpose of stiffening elements?
The purpose of the stiffening element is to ensure aerodynamic stability and to limit the local angel changes in the deck. Suspension bridges are used for spans of 300– 2300 m. The bridge can be erected without any ground-based towers.
Which procedure described for cable-stayed bridges should be adopted?
Pylons and Girders: the same procedure described for cable-stayed bridges should be adopted.
Where is the Vincent Thomas Bridge?
The Vincent Thomas Bridge is a suspension bridge located in Los Angeles Harbor, San Pedro, California. The bridge superstructure consists of a main span of approximately 457 m, two suspended side spans of 154 m each, and a 10-span approach of approximately 545 m length on either end. The total bridge length is approximately 1850 m. The bridge was completed in 1964, and in 1980 was instrumented with 26 accelerometers as part of a seismic upgrading project. The strong-motion instrumentation was installed and is maintained by the California Division of Mines and Geology. Figure 7.7 shows the elevation and plan view of the sensor locations. A summary of the sensor locations and numbering is presented in Table 7.4.
How far can a suspension bridge span?
Suspension bridges can easily cross distances between 2,000 and 7,000 feet (610 and 2,134 meters), enabling them to span distances beyond the scope of other bridge designs. Given the complexity of their design and the materials needed to build them, however, they're often the most costly bridge option as well.
What is the name of the bridge that suspends the roadway?
Regine Mahaux/Photodisc/ Getty Images. As the name implies, suspension bridges, like the Golden Gate Bridge or Brooklyn Bridge, suspend the roadway by cables, ropes or chains from two tall towers.
What is a bridge anchor?
Bridge anchorages are essentially solid rock or massive concrete blocks in which the bridge is grounded. Tensional force passes to the anchorages and into the ground. Advertisement. In addition to the cables, almost all suspension bridges feature a supporting truss system beneath the bridge deck called a deck truss.
What is a suspension bridge?
As the name indicates, a suspension bridge is the one in which the bridge deck slab suspends between two towers, or in other words, in a suspension bridge, the deck slab is hanging between two towers of the bridge. In shape and structural components used in construction, it is very much similar to the cable-stayed bridge structure.
What are the components of a suspension bridge?
The structural components of a suspension bridge include Piers (in the form of large towers), main supporting cables (which are often called “catenary”).
How do bridge towers carry the load of the bridge deck slab?
The towers carry the whole load of the bridge deck slab from either side, by taking it from the main supporting cables and transferring it to the foundation, which is further transferred to the subsoil under it .
How many towers are there on a suspension bridge?
From which the cables support the bridge deck slab, on either side, while in case of a suspension bridge, two towers are constructed from which the cables extents and support the bridge deck slab.
Why are suspension bridges so attractive?
Suspension bridges can be visually appealing from the aesthetic viewpoint. The parabolic shape of the cable and the shape of the structure provides an aesthetically pleasing experience, which results in increased tourism, affecting the economy of the country as a whole.
How are wires tied together?
Once all the wires are placed, it is then tied together by wrapping it with steel wires and finally coating it with resin compound, to prevent corrosion. After the main cables are constructed, the suspenders (vertical steel short ropes) are put in place from the main cables.
Why are anchor blocks fixed on both ends of a bridge?
In parallel with the construction of towers, the anchor blocks are fixed on both ends of the bridge in order to anchor the main supporting cables.
How to Unlock Timberborn Suspension Bridges
You unlock Timberborn Suspension Bridges by spending Science points. You'll first need to build an Inventor and put a Beaver to work generating Science. You can speed this process up by building and staffing multiple Inventor Buildings.
How to Build Timberborn Suspension Bridges
Building Timberborn Suspension Bridges may seem somewhat unintuitive at first, but it will make sense once you understand how they work. Suspension Bridges are one "half" of a bridge. A 1 x 2 Suspension Bridge, for example, is 1 block wide and 2 blocks long -- you can put these two halves together to cross a 4 block wide gap.
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