Swimming in the bridge
With Brückeneinschwimmen are construction methods in bridge refer to operations where parts or entire bridge sections on pontoons , barges , barges or floating cranes or occasionally by means of its own buoyancy are placed floating in their final position.
Swimming in bridges is based on the old knowledge that heavy and / or large loads can be transported more easily by swimming than by land, provided that a canal, river or arm of the sea is available that has sufficiently deep water and enough space to maneuver designated points and bridge clearance heights that allow the unusual load to pass.
Methods
Bridge segments or even entire arched structures are often made next to or near the construction site on land, then pushed onto pontoons or barges on a sliding track or set down there by a mobile crane and then moved to the correct position under their installation point while floating. At the installation site, they are lifted to their final position either by cranes or strand jacks standing on the parts of the bridge that have already been built, or by floating cranes . In the case of floating cranes, the factor limiting their use today is often less the load capacity than the size and draft of the floating crane.
When Einschwimmen full arch structures, these are often pushed onto pontoons with scaffolding that already have the necessary for the final bridge height. At the installation site, only minor changes in position then have to be made with hydraulic presses . Whole arched structures are occasionally pushed onto a pontoon with only about the front third, while a feed carriage carries the other end and follows the feed movement accordingly. The pontoon is then pushed on the water to the installation site, while the feed carriage travels the same distance at the same speed on land. The Steinheim Main Bridge , the Elbe Bridge Tangermünde and the Dresden Waldschlößchen Bridge were floated in using such a procedure (see floating in the Waldschlößchen bridge ).
On suspension bridges over waterways, floating in is the usual procedure: after the suspension ropes have been laid over the pylons and fitted with hangers, individual sections of the deck girders are transported on the water, lifted in with floating cranes and attached to the hangers.
Occasionally the constructions are made buoyant by welding the load-bearing hollow boxes airtight so that they can be pulled to the installation site even in the water. One example of this is the Neuötting Inn Bridge . The large, hollow reinforced concrete pylons of the Rio-Andirrio Bridge , standing in 65 m deep water, were prefabricated on land in dry docks , dragged to their final position while floating, further concreted there and finally lowered.
Since lifting very large loads used to be difficult, the tides were often used to lift the bridge parts to the right place with the high tide and to set them down there at the onset of ebb . A similar method consisted of removing the soil under the bridge section so that pontoons could be pushed under it, which could then rise by pumping out the ballast water or with the next high tide and be pulled to the installation site.
Reasons for swimming in
There are many reasons for swimming in bridges.
The most common reason is that under the specific circumstances and the type of bridge being planned, swimming in is cheaper than another method, e.g. B. cantilever or incremental launching .
Often the waterway to be bridged may only be closed or obstructed for a short time, so that auxiliary pillars in the fairway for a traditional construction method with falsework or other assembly scaffolding are ruled out.
Often the simplest, if not the only possible method is to bring prefabricated parts or sections of the current field to the final position on the bridge construction site. The suspension bridge over the Fedafjord in Norway stands between two steep mountain slopes and can only be reached on the road through the tunnels on both sides.
Occasionally, especially with inner-city bridges such as the Pont de Choisy , there is no space for a construction site next to the bridge, so that the current bridge has to be completely or in large parts prefabricated on a more or less distant construction site and then floated in.
Sometimes, e.g. B. in bridges in estuaries, there is only water around the bridge, so swimming in is the only possibility.
In the case of steel bridges, it is often the easiest and cheapest to prefabricate large parts of the bridge in a distant steel construction company , protected from wind and weather, and then to ship them to the bridge construction site. The Samuel Beckett Bridge, designed by Santiago Calatrava , was built in Rotterdam , towed to Dublin on a pontoon and placed there on its rotating bearing. The steel bridge deck of the Pont Jacques Chaban-Delmas in Bordeaux was divided into five sections in a steel construction company at the northern end of the Adriatic, manufactured ready for installation, which was carried on barges through the Adriatic, the western Mediterranean and the Strait of Gibraltar , past and over Portugal the Biscay were dragged into the Garonne to the construction site and deposited there in their final positions with the help of the ebb tide. The middle section of the Puente Mercosur over the Orinoco , which was still under construction at the beginning of 2017, is 120 m long and weighs 2,400 t, and is to be dragged up the river on a pontoon and floated in.
In the case of concrete bridges with numerous, largely identical components, it is often the quickest and most economical to set up a precast factory in the immediate vicinity for the efficient production of these parts and then float them into place later. For example, the largely identical girders of Freyssinet's 5 Marne bridges were manufactured in one place and floated into the bridge construction sites. Eugène Freyssinet later also developed the construction of reinforced concrete box girder bridges from segments prefabricated on land, which are often floated in. Another example is the General Rafael Urdaneta Bridge, designed by Riccardo Morandi and over 8 km long, over Lake Maracaibo in Venezuela , whose large number of identical concrete girders were manufactured in a precast plant next to the bridge and then floated in.
Examples with swim-in time
| bridge | completion | Swim in | Duration (days) |
Remarks |
|---|---|---|---|---|
| Freyssinets 5 Marne bridges | 1951 | Central construction site for the girders of all 5 bridges | ||
| Strelasund crossing | 1961 | 20.-23. April 1961 | 4th | |
| General Rafael Urdaneta Bridge | 1962 | Precast plant for a bridge over 5 km long | ||
| Zeelandbrug | 1965 | Precast plant for a bridge over 5 km long | ||
| Pont de Choisy | 1965 | Precast plant outside the city center | ||
| Schwabelweis Danube Bridge | 1981 | |||
| Lessing Bridge | 1983 | |||
| Steinheim Main Bridge | 1995 | |||
| Kronprinzenbrücke | 1996 | |||
| Oresund Bridge | 1999 | September 14, 1999 | 1 | |
| Inn Bridge Neuötting | 2000 | Swim in with my own buoyancy | ||
| Wittenberg Elbe Bridge | 2000 | |||
| Tangermünde Elbe Bridge | 2001 | |||
| Koror – Babeldaob Bridge | 2001 | Suspension brackets floated in from China to Palau | ||
| Sternbrücke Magdeburg | 2004 | October 26, 2004 | 1 | |
| Syzran railway bridge | 2004 | Renewal of the Alexander Bridge from 1880 | ||
| Rio-Andirrio Bridge | 2004 | Floating in the pylons with its own buoyancy | ||
| Fedafjord Bridge | 2006 | Suspension bridge between steep mountain slopes | ||
| Tulln Danube Bridge | 2009 | June 17 and July 10, 2009 | 2 | |
| Samuel Beckett Bridge | 2009 | 5 | Swam from Rotterdam to Dublin | |
| Main bridge Volkach | 2010 | Summer 2010 | ||
| Waldschlößchenbrücke | 2010 | 3rd-19th December 2010 | 17th | With 10 days interruption due to water level |
| Pont Jacques Chaban-Delmas | 2012 | Swam in from the northern end of the Adriatic | ||
|
Osthafenbrücke (project name at the time: Mainbrücke Ost ) |
2013 | 20.-23. August 2012 | 4th |
history
The first swim-in process can no longer be determined. In England around 1822, James Dixon had planned to float in the falsework for the construction of a bridge for the Stockton and Darlington Railway over the River Tees above Stockton . The plan was not carried out because a suspension bridge was built.
The falsework was floated in during the construction of the Waterloo and London Bridges planned by John Rennie senior .
In 1848 Robert Stephenson floated the wrought iron box girders of the Conwy Railway Bridge in Wales, set them down at the base of the piers with the help of the tide and raised them about 6 m to their final position using hydraulic jacks. This was the forerunner for his Britannia Bridge , a few kilometers away , in which four 144 m long and 1800 t heavy box girders were again swum in with the help of the tides and lifted around 32 m to their final position with hydraulic jacks.
From 1857 to 1858, Isambard Kingdom Brunel used a similar technique in the construction of the Royal Albert Bridge near Plymouth in southern England.
The procedure was now well established.
The following projects include the Québec Bridge , the 195 m long and 5000 t heavy suspension girders of which were floated in, as well as the Pont de Plougastel in Brittany , built between 1926 and 1930 , with the Eugène Freyssinet a 160 m long and 300 t allowed heavy falsework to float in and set it down only with the help of the tide, and in this way used the falsework one after the other for all three arches of the bridge.
The Zeelandbrug , built between 1963 and 1965, was completely manufactured, including the pile foundation and pillars, in a precast factory and then floated in piece by piece.
In Russia, the idea of floating in during the construction of the Krasnoyarsk railway bridge was modified between 1895 and 1899: its six steel girders were not floated in, but pushed over the frozen Yenisei in winter .
See also
Web links
Individual evidence
- ^ Robert Stephenson, quoted in: Edwin Clark: The Britannia and Conway tubular bridges, ... Volume 1, Day and Son, London 1850, p. 20 ( digitized on Google Books )