Threshold substitute carrier procedure

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The sleeper substitute carrier process (SETV) enables the construction of railway bridges in the existing route network. It was developed by Fritz Räbiger and Albert Seeger around 1960 and is still used today.

Areas of application

The SETV is used when a bridge has to be built "under the rolling wheel" and only short blocking times are possible during construction and the train speed when driving on the construction site should not be significantly reduced. The SETV assumes that the new structure can be built next to the track structure and that it can be pressed in or pushed in under the tracks.

The method is particularly suitable for multi-track sections of track and in the track area of ​​train stations, if a significant hindrance to the operation is to be absolutely excluded, if railway bridges have to be built in the switch area or if there is not enough space for the assembly of auxiliary bridges between the new structure and the upper edge of the rails stands.

In comparison to other construction methods, experience has shown that, in addition to avoiding operational hindrances and thus eliminating operational difficulties, significant construction cost savings are also possible.

The SETV was newly regulated in the guidelines and guidelines of the Deutsche Bahn from 2005.

Course of the procedure

With the SETV, the new bridge structure is built outside the track area and pushed under the tracks without dismantling the tracks and generally without restricting the line speed (up to 90 km / h).

For this purpose, “sleeper substitute girders” are inserted into the sleeper fields of the tracks, which are connected outside the track area by welded-on spar girders. The angle of intersection between the track and the underpass and any existing switches are irrelevant for this construction method. On the top of the bridge or frame structure to be pushed in, sliding sleepers are installed in a gravel or ballast bed, on which the sleeper replacement girders slide.

The bridge superstructures or the reinforced concrete frames are pushed in with the help of presses. The shunting presses are supported against assembly frames or against abutments. It is easily possible to interrupt the advance of the structures for a longer period of time, for example in order to mount or concret further superstructure sections or frame segments if space is limited.

When a bridge superstructure or a frame structure is pushed in, the structure slides under the sleeper replacement girders, so that their original mounting on the track body changes into mounting on the sliding sleepers of the carriageway slab during advance. The friction between sleeper substitute girders and sliding sleepers that arises when being pushed in causes horizontal forces in the sleeper substitute girders, which are transferred to the spar girders outside the track area and from them to driven piles behind the abutments.

When inserting reinforced concrete frames for larger underpasses in track areas without switches, it can be useful to work with so-called sleeper replacement large girders, which are only installed in every third to sixth sleeper field and support the tracks via small auxiliary bridges. The sliding girders take on the role of sliding sleepers.

History of the threshold substitute carrier procedure

The process was developed around 1960 by Fritz Räbiger and Albert Seeger , who at that time were working as construction technicians at the Hanover Federal Railway Directorate, and was first used in Hanover in March 1962.

literature

  • Fritz Räbiger, Munich, The pressing of railway bridges through railway embankments with special consideration of the railway operation , article published in: Der Tiefbau , trade journal for process engineering and construction, issue 4, April 1965
  • Albert Seeger, Hanover, Newer technical measures to limit operational hindrances on bridge construction sites , February 1965, special edition bridge construction
  • Hans Siebke, Deutsche Bundesbahn Hauptverwaltung Frankfurt, How to build, renew, widen, lengthen railway bridges under the rolling wheel , article published in: acier-stahl , issue 2, 1980
  • DB Netz AG, module 804.4120 , threshold substitute carrier procedure , principles and rules, valid from January 1, 2005
  • DB Netz AG, Module 804.9051 , planning and installation instructions for the sleeper replacement carrier method , guide drawings , valid from January 1, 2005
  • Rolf H. Pfeifer, Tristan M. Mölter, manual railway bridges, principles for planning and construction as well as information on construction methods , Verlag DVV Media Group GmbH / Eurailpress, ISBN 978-3-7771-0378-5 , 2008

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