Extradosed bridge

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Gantertal Bridge , engineer: Christian Menn , example of an extradosed bridge
Sunnibergbrücke , engineer: Christian Menn, example of an extradosed bridge

As Extradosed bridge (extradosed bridge) a relatively new construct is prestressed concrete bridges referred to, wherein the tendons outside of the cross section of the platform girder via a low pylon be performed and thereby the bearing behavior of a cable-stayed bridge and a girder bridge is combined. The name is originally derived from the French term "extrados" for "arch back", which was adopted into English.

description

Externally, extradosed bridges differ from cable-stayed bridges in that they have low pylons and flat inclined stay cables or tendons. With this arrangement, the inner lever arm for the tendons is set much more favorably. The flat inclined stay cables look like an overhead haunch . They carry the superstructure from a relatively low pylon and at the same time prestress the superstructure. The pylons can be much lower than they would have to be in a pure cable-stayed bridge. Their height is usually only 1/10 to 1/12 of the main span. The stay cables usually do not extend to the middle of the main opening, but leave the middle fifth free. The superstructure requires a lower overall height than a girder bridge with internal prestressing. The support system can also be referred to as a “spanned continuous beam”.

Also with regard to the span of bridges, extradosed bridges are an intermediate link between girder bridges and cable-stayed bridges. Girder bridges are considered economical for small spans of 100 to 200 m.

history

A forerunner was the Werksbrücke West (Höchst) (1972) designed by Ulrich Finsterwalder and Herbert Schambeck , the main opening of which could not be attached to the entire length of the cable-stayed bridge due to lack of space. It has so-called concrete sails on the opposite northern pier , in which the tendons for the northern part of the cantilever girders are arranged.

Christian Menn designed Built in 1976-1980, the Ganter , without, however, in the 1979 article published the term extradosed to use. It has stay cables sheathed by concrete disks.

During the reinforcement of the bridge over the San near Rzuchow ( Polish: Most w Rzuchowie ), a village belonging to the rural municipality of Leżajsk in the Subcarpathian Voivodeship in Poland, in 1980 , the external tensioning cables attached to the side were routed over low pylons. Since the reinforcement was completed before the Ganter Bridge, some see this bridge as the first extradosed bridge.

In 1983 or 1984, Jacques Mathivat first presented a bridge in the (unrealized) design for the Viaduc de l'Arrêt Darré , the longitudinal bracing of which is openly guided over a low pylon. In a French article that first appeared in 1987, he coined the term précontrainte extradossée for it. This article appeared in a similar form in 1988 in the English version usually cited in the literature.

Some extradosed bridges

literature

  • Thomas Vogel, Peter Marti (Ed.): Christian Menn - Bridge Builder 2nd, supplemented edition, vdf Hochschulverlag, Zurich 2009, ISBN 978-3-7281-3137-9 (= Society for Civil Engineering. Volume 3).

Web links

Individual evidence

  1. Karsten Geissler: Bridge Construction Manual . Ernst & Sohn, Berlin 2014, ISBN 978-3-433-02903-9 , pp. 323 .
  2. Christian Menn, Hans Rigendinger: Ganter. In: Schweizer Ingenieur und Architekt , Volume 97, Issue 38, 1979, p. 733 ( http://doi.org/10.5169/seals-85537 )
  3. Grażyna Łagoda, Marek Łagoda: Nowe typy konstrukcji - w mostownictwie XXI wieku on nbi.com.pl
  4. Jacques Mathivat: Évolution récente des ponts en béton Précontraint. In: IABSE reports = Rapports AIPC = IVBH Reports , Volume 55, 1987, pp. 318–329, 328 ( http://doi.org/10.5169/seals-42743 )
  5. Jacques Mathivat, WF Crozier: Recent developments in prestressed concrete bridges. In: FIP Notes , No. 2, 1988, pp. 15-21
  6. José Benjumea, Gustavo Chio, Esperanza Maldonado: Structural behavior and design criteria of extradosed bridges: general insight and state of the art on scielo.conicyt.cl
  7. Ponte dos Socorridos. In: Structurae
  8. Odawara Bridge. In: Structurae
  9. Natorigawa Bridge. In: Structurae
  10. Shin Karato Bridge. In: Structurae
  11. Tsukuhara Bridge. In: Structurae
  12. Marcelo Fernan Bridge. In: Structurae
  13. ^ Sapporo Extradosed Railway Bridge. In: Structurae
  14. Waschmühltal Bridge. In: Structurae
  15. St. Croix Crossing