Timeline of three longest spans
Encyclopedia
This is the timeline of the 3 longest man-made spans
in the world, all categories, that at least have the strength to carry some persons. It can be the span of any type of bridge
, aerial tramway
, powerline
, structural ceiling
or dome
etc.
When several structures of the same length exists, the oldest is counted as the longest.
Some more rules for this timeline follows as: Only the length of the horizontal projection of the span, that is the distance that can be measured on a map, counts. When the two supports have different height above the sea level the distance between them is longer than the horizontal projection of the distance, but this longer distance doesn't count. This is because it is more difficult to build a 100m horizontal span than a 100m span that is tilted let's say 45 degrees, as if it was the support for an escalator
. The stress in the material is higher for the horizontal span, creating higher engineering difficulty, so only the length of the span perpendicular
to the force of gravity counts. For many structures in the timeline it is unfortunately not known if the stated length is the desired horizontal projected length, or the direct "laser beam" length.
Spanning structures in water counts only if they would still be standing if the water was removed.
The longest 5376 m Ameralik Span
and others have pylons
that are not completely man-made. The lines are attached to small man-made pylons that in turn stand on the mountain, which forms the rest of the height of the pylons required for a span of this huge length. If the present man-made pylons were placed in a flat area there would be no span, because the lines would touch the ground. It could be argued that this span should not appear in the timeline because the pylons are not completely man-made. However, as the focus of the engineering design task here is not to make something that is tall, but to make something that is long, it is concluded that this type of span is enough man-made to be in this timeline.
The spans of ancient structures are short. It would have been easy for somebody to tie a long rope
between two poles and this way create a very long ancient span. However, the ancient people had no reason to do this, and if they did it's not documented and therefore not in this timeline. Only with the discovery of electricity and radio communication people had a reason for tying a wire between two poles, thus creating the simplest form of long spans.
The span of Pantheon, Rome
is not 43.3 m because there is a hole at the top of 9.1 m, so the span have been reduced with the size of the hole to 34.2 m. The span of any structure is measured the following way: Place the largest possible imaginary horizontal circular disk under or inside the structure, barely touching any load-bearing pillars or walls, or parts used to stabilize the structure like wires. The disk must also not encircle any objects of this kind. At least one diameter
of the disk have to be completely covered, that is rain-sheltered, by the structure. The span of the structure is diameter of the disk. Now, if the structure contains a hole at the center of the disk, as in the case of Pantheon, the span is measured by using a second largest possible imaginary horizontal circular disk that is smaller than the first disk and completely encirceled by it. At least one diameter of the second disk have to be completely covered by the structure. The span of the structure is diameter of the second disk. Applying this method of measurement to Pantheon gives the previously stated result 34.2 m. The method works for many types of structures.
Note: almost all information in this timeline have uncertainty.
Span (architecture)
Span is the distance between two intermediate supports for a structure, e.g. a beam or a bridge.A span can be closed by a solid beam or of a rope...
in the world, all categories, that at least have the strength to carry some persons. It can be the span of any type of bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
, aerial tramway
Aerial tramway
An aerial tramway , cable car , ropeway or aerial tram is a type of aerial lift which uses one or two stationary ropes for support while a third moving rope provides propulsion...
, powerline
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...
, structural ceiling
Ceiling
A ceiling is an overhead interior surface that covers the upper limit of a room. It is generally not a structural element, but a finished surface concealing the underside of the floor or roof structure above....
or dome
Dome
A dome is a structural element of architecture that resembles the hollow upper half of a sphere. Dome structures made of various materials have a long architectural lineage extending into prehistory....
etc.
Overview
In this timeline, only spans that were still standing a particular year are considered for that year. This is perhaps more fair than a timeline of the records of all time, because the old figures might be incorrect. At the points when the old spans falls, new spans with more certain figures are allowed to appear in the timeline. This is a top 3 list of existing longest spans per day.When several structures of the same length exists, the oldest is counted as the longest.
Some more rules for this timeline follows as: Only the length of the horizontal projection of the span, that is the distance that can be measured on a map, counts. When the two supports have different height above the sea level the distance between them is longer than the horizontal projection of the distance, but this longer distance doesn't count. This is because it is more difficult to build a 100m horizontal span than a 100m span that is tilted let's say 45 degrees, as if it was the support for an escalator
Escalator
An escalator is a moving staircase – a conveyor transport device for carrying people between floors of a building. The device consists of a motor-driven chain of individual, linked steps that move up or down on tracks, allowing the step treads to remain horizontal.Escalators are used around the...
. The stress in the material is higher for the horizontal span, creating higher engineering difficulty, so only the length of the span perpendicular
Perpendicular
In geometry, two lines or planes are considered perpendicular to each other if they form congruent adjacent angles . The term may be used as a noun or adjective...
to the force of gravity counts. For many structures in the timeline it is unfortunately not known if the stated length is the desired horizontal projected length, or the direct "laser beam" length.
Spanning structures in water counts only if they would still be standing if the water was removed.
The longest 5376 m Ameralik Span
Ameralik Span
The Ameralik Span is the longest span of an electrical overhead powerline in the world. It is situated near Nuuk on Greenland and crosses Ameralik fjord with a span width of 5,376 metres at...
and others have pylons
Electricity pylon
A transmission tower is a tall structure, usually a steel lattice tower, used to support an overhead power line. They are used in high-voltage AC and DC systems, and come in a wide variety of shapes and sizes...
that are not completely man-made. The lines are attached to small man-made pylons that in turn stand on the mountain, which forms the rest of the height of the pylons required for a span of this huge length. If the present man-made pylons were placed in a flat area there would be no span, because the lines would touch the ground. It could be argued that this span should not appear in the timeline because the pylons are not completely man-made. However, as the focus of the engineering design task here is not to make something that is tall, but to make something that is long, it is concluded that this type of span is enough man-made to be in this timeline.
The spans of ancient structures are short. It would have been easy for somebody to tie a long rope
Rope
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...
between two poles and this way create a very long ancient span. However, the ancient people had no reason to do this, and if they did it's not documented and therefore not in this timeline. Only with the discovery of electricity and radio communication people had a reason for tying a wire between two poles, thus creating the simplest form of long spans.
The span of Pantheon, Rome
Pantheon, Rome
The Pantheon ,Rarely Pantheum. This appears in Pliny's Natural History in describing this edifice: Agrippae Pantheum decoravit Diogenes Atheniensis; in columnis templi eius Caryatides probantur inter pauca operum, sicut in fastigio posita signa, sed propter altitudinem loci minus celebrata.from ,...
is not 43.3 m because there is a hole at the top of 9.1 m, so the span have been reduced with the size of the hole to 34.2 m. The span of any structure is measured the following way: Place the largest possible imaginary horizontal circular disk under or inside the structure, barely touching any load-bearing pillars or walls, or parts used to stabilize the structure like wires. The disk must also not encircle any objects of this kind. At least one diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
of the disk have to be completely covered, that is rain-sheltered, by the structure. The span of the structure is diameter of the disk. Now, if the structure contains a hole at the center of the disk, as in the case of Pantheon, the span is measured by using a second largest possible imaginary horizontal circular disk that is smaller than the first disk and completely encirceled by it. At least one diameter of the second disk have to be completely covered by the structure. The span of the structure is diameter of the second disk. Applying this method of measurement to Pantheon gives the previously stated result 34.2 m. The method works for many types of structures.
Note: almost all information in this timeline have uncertainty.
Known incorrect construction years
In the timeline above, some completion years are given which are known to be incorrect. The following guesses were used to generate the graphic, but should not be taken as definitive.| Incorrect year | Structure |
|---|---|
| 2009 | Sognefjord 2 Span Sognefjord Span The Sognefjord Spans are the second, third, and fourth longest spans in the world situated east of Hermansverk and are part of different powerlines. As Sognefjord Span is a deep valley the pylons of these spans are not taller than ordinary pylons... |
| 1993 | Ameralik Span Ameralik Span The Ameralik Span is the longest span of an electrical overhead powerline in the world. It is situated near Nuuk on Greenland and crosses Ameralik fjord with a span width of 5,376 metres at... |
| 1975 | Sognefjord 1 Span Sognefjord Span The Sognefjord Spans are the second, third, and fourth longest spans in the world situated east of Hermansverk and are part of different powerlines. As Sognefjord Span is a deep valley the pylons of these spans are not taller than ordinary pylons... |
| 1971 | Omega transmitter Bratland |
| 1930 | Dismantling of Carquinez Strait Powerline Crossing Carquinez Strait Powerline Crossing Carquinez Strait Powerline Crossing was the world's first powerline crossing of a large river. It was built in 1901 for a 60 kV powerline operated by Bay Counties Power Companyto deliver electric power to Oakland, California. For this a crossing of Carquinez Strait was required, which has at its... because then Benicia–Martinez Railroad Bridge was built |
| 1836 | Rebuilding of Port-Sainte-Marie Bridge |
| 1350 | Apurimac bridge Inca rope bridge Inca rope bridges were simple suspension bridges over canyons and gorges to provide access for the Inca Empire. Bridges of this type were suitable for use since the Inca people did not use wheeled transport—traffic was limited to pedestrians and livestock. The bridges were an integral part... |
| 675–825 | Maya Bridge at Yaxchilan Maya Bridge at Yaxchilan Academics have speculated that the Maya may have built a suspension bridge across the Usumacinta river. If so, the Maya Bridge at Yaxchilan would have been the longest bridge discovered in the ancient world, dating from its construction by the Maya civilization in the late 7th century at Yaxchilan... |
See also
- List of spans
- List of longest suspension bridge spans
- List of longest cantilever bridges
- Arch bridgeArch bridgeAn arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side...
External links
- http://www.bridgemeister.com/index.htm
- http://en.structurae.de/index.cfm
- Port-Sainte-Marie Bridge http://www.bridgemeister.com/bridge.php?bid=1765
- Philadelphia Footbridge http://www.bridgemeister.com/bridge.php?bid=20
- http://www.bhutanstudies.org.bt/admin/pubFiles/Chakzampa.pdf Chakzam/Iron Bridge p78, Tashigang Bridge p94, Phuntsholing Bridge p69
- :pt:Ponte do Porto, http://en.structurae.de/structures/data/index.cfm?id=s0020363