Alsleben bridge over the Saale
Coordinates: 51 ° 42 ′ 5 " N , 11 ° 40 ′ 58" E
| Alsleben bridge over the Saale | ||
|---|---|---|
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| use | Road bridge L 85 | |
| Crossing of | Saale | |
| place | Alsleben | |
| construction | Prestressed - arch bridge | |
| overall length | 154.45 m | |
| width | 10.88 m | |
| Number of openings | six | |
| Longest span | 68 m | |
| Arrow height | 11.33 m | |
| Arrow ratio | 1: 6 | |
| Clear height | 5.25 m above HSW | |
| start of building | 1928 | |
| completion | 1928 | |
| planner | Franz Dischinger | |
| location | ||
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The Saalebrücke Alsleben is a listed road bridge that connects Alsleben , located on the left bank of the Saale , in the Saale-Wipper community in the Salzlandkreis in Saxony-Anhalt, with the right bank and the town of Mukrena there . The bridge has two lanes and a narrow walkway on each side. It is considered the first prestressed reinforced concrete bridge with a subsequent bond.
The next bridges upstream are the railway bridge between Könnern and Belleben on the Halle – Halberstadt route and the bridge on Landesstraße 154 at Georgsburg between Könnern and Nelbe, seven kilometers away by road . Shortly after the Alsleben lock, the former Alsleben railway bridge follows downstream and, after another two and a half kilometers, the Beesedau bridge on the BAB 14 .
history
A ferry initially operated between Alsleben and Mukrena, which was replaced by a pontoon bridge in 1867 . As early as 1891 there were complaints that it could no longer cope with the increased traffic. Considerations about building a permanent bridge failed due to financing issues and became obsolete due to the First World War .
It was not until 1927 that the city of Alsleben took the final decision to build the bridge and commissioned the Leipzig branch of Dyckerhoff & Widmann with its planning, which was largely worked out by Franz Dischinger . After a tender, Dywidag also received the construction contract.
Construction work began in mid-March 1928 and was completed in December of the same year. The ceremonial handover of traffic took place on December 20, 1928.
description
The main bridge is a reinforced concrete - arch bridge with suspended roadway, with a span crossed m of the 68 extending here on the right side of the flow channel. Your right pillar is therefore on the bank, your left almost 30 m from the other bank in the water.
From the left bank, two concrete arches with an overhead roadway and spans of 26.10 m and 28.60 m respectively above the flood bed and above the shallow water create the connection to the main bridge. On the right side are three foreland arches with spans of 11.50 + 10.50 + 9.75 m.
The main bridge has a width of 10.88 m between the parapets, which is divided into 6 m for the carriageway and 1.5 m each for the walkways as well as the space required for the hanging rods and the curbs.
The total of 154.45 m long bridge is straight in plan with the exception of the approach bridges on the right bank, which describe an extremely narrow curve with a radius of around 40 m for today's conditions.
Originally the bridge had a clearance height of 4.50 m, which resulted from the difference between the highest navigable water level set at + 65.51 m NN and the lower edge of the river superstructure at + 70.01 m NN. After the waterway expansion between 1933 and 1942, a bridge clearance height of 5.25 m above HSW is now shown.
Technical details
The main opening is bridged by two reinforced concrete arches arranged parallel to one another, which are designed as pre-stressed two-hinged arches with a tension band and subsequent connection.
The parabolic two-hinged arches have an arrow ratio of 1: 6 with a span of 68.00 m and an arrow height of 11.33 m. The arch supports have an I-shaped cross section. Their height of 1.80 m at the top increases towards the fighters by 10 cm to 1.90 m. Their straps are 0.90 m wide, the webs are 0.45 m thick.
The horizontal thrust of the arches is transmitted by special components outside the arch feet to steel tension straps that are inserted into a U-shaped recess in the side members of the deck. These drawstrings were first laid open as long as the arches and the roadway during construction of falsework were worn. When equipping and lowering the falsework, the tension straps were gradually tightened with hydraulic presses so that they took over the horizontal thrust of the arches from their own weight. As a result, the deck and the two side members remained unencumbered by the shear forces of the arches. Then the drawstrings were concreted in their recesses. Dischinger applied for a patent for this method, which he had first used at the Saale Bridge, in 1928.
In each of the arches, 13 hanging rods 44 × 44 cm made of reinforced concrete with four round steel bars each are suspended, which carry the deck. A wind bracing made of diagonally crossed reinforced concrete rods is inserted between the arches. The horizontal forces are transmitted to the deck slab via two vertical wind portals next to the third suspension rod.
The arches, their wind bracing including portals and the hangers were provided with a plaster layer of blast furnace cement immediately after the formwork was removed.
The railing is also designed as a reinforced concrete parapet, which forms a striking, continuous horizontal line in the view.
The two openings on the left side of the river were designed as reinforced concrete three-hinged arches on which the deck slab is elevated by means of transverse walls. The gussets were closed by concrete discs.
Further development
Bridge fees had to be paid to use the bridge, but this was never enough to cover the financing costs.
Shortly before the end of the Second World War , on the night of April 13-14, 1945, the second arch on the left was blown up by the Wehrmacht, before Alsleben was occupied by American troops a day later. As early as June 17, 1945, however, the reconstruction of the blasted arch was commissioned, which was completed on October 21, 1945, despite the great difficulties in procuring the necessary building materials, equipment and vehicles.
The bridge money was abolished by the now incumbent Soviet military administration on July 27, 1946.
A detailed examination of the bridge in 1992 showed considerable damage, so that a thorough repair was necessary between 1997 and 2000.
Web links
- Saalebrücke, Alsleben, Saxony-Anhalt, Germany, 1928 on great-engineers.de on the website of the Brandenburg Technical University Cottbus - Senftenberg
- Friedrich Standfuß: The Saale Bridge in Alsleben - Documentation of the building history (PDF, 1.4 MB) (printout from the conference proceedings 10th Dresden Bridge Construction Symposium 2000, pp. 39–62)
- Alsleben Pictures along the Saale on the website of the municipality of Alsleben
Individual evidence
- ↑ Saalebrücke, Alsleben, Saxony-Anhalt, Germany, 1928 on great-engineers.de on the website of the Brandenburg Technical University Cottbus - Senftenberg
- ↑ Unless otherwise stated, the information in this article is based on the text by Friedrich Standfuß: The Saale Bridge in Alsleben - documentation of the history of construction (see web links)
- ↑ Federal waterway map DBWK 1000 ( memento of the original from February 25, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. of the Federal Ministry of Transport and Digital Infrastructure, as of February 2014 (PDF, 5.9 MB)
- ↑ Saale Bridge in Alsleben . Reference sheet from torkret (PDF, 777 KB)
