Pylon (bridge construction)

Different types of pylons for two rope levels

Types of pylons for a rope level: Cantilever pylon towers; A pylon

In bridge construction, a pylon is the towering component over which the suspension ropes run or on which the stay cables of stay cable bridges are anchored.

description

The pylons bear the weight of the superstructure, i.e. the weight of the suspension cables and hangers or stay cables and the weight of the bridge deck, as well as the traffic loads, i.e. the weight of the vehicles and people on the bridge. They also absorb the forces in the transverse direction that are caused, for example, by the wind.

The pylons of suspension bridges are regularly wide constructions with two stems, since the two suspension cables with their hangers are usually arranged over the outer edges of the bridge deck. The two posts made of sheet steel or reinforced concrete have hollow cross-sections and are designed as a rigid frame. They therefore have either diagonal struts (St. Andrew's crosses) or cross bars, at least one upper bar and one below the roadway girder, which is usually used to support it. The pylons can be clamped in the foundation or articulated on it.

Cable-stayed bridges often have pylons in the shape of an “A”, an upside-down “Y” or profiles reminiscent of a rhombus, which also have hollow cross-sections and are made of sheet steel or reinforced concrete. Their shape usually results from the optimization of the costs of the overall structure.

Depending on the span of the bridge, they can protrude very high above the roadway. The pylon of the New Danube Bridge in Bratislava has a tower restaurant on its top .

history

The pylons of the early suspension bridges of the 19th century consisted mostly of massive, brick portals, which were designed in all possible variants of the architectural styles of the time: Some were reminiscent of the gate systems of Egyptian temples , others of Roman triumphal arches or medieval castle entrances.

With the introduction of steel and lighter construction methods, delicate pylons emerged, often still with neo-Gothic decorative elements, but these soon disappeared. The development went to slim pillars, which were stiffened by diagonal struts ( St. Andrew's cross ) or a few cross bars. In the end, only a simple framework was occasionally left.

The development of concrete construction and especially the construction of high pillars with sliding formwork led to pylons made of reinforced concrete, in which the individual pillars were initially concreted without lateral bracing and only later provided with often only two crossbars.

Pylons of chain and suspension bridges

Chain Bridge , Budapest, Hungary (1849)
San Francisco Oakland Bay Bridge , USA (1936)
Bronx-Whitestone Bridge , New York City, USA (1939)
Storebæltsbroen , Great Belt, Denmark (1998)
Akashi Kaikyō Bridge , Kobe, Japan (1998)

Pylons of cable-stayed bridges

Rheinkniebrücke , Düsseldorf (1969)
Severinsbrücke , Cologne (1959)
Puente Internacional del Guadiana ; Portugal-Spain (1991)
Köhlbrand Bridge , Hamburg (1974)
Seto-Ōhashi , Seto Inland Sea , Japan (1988)
Airport bridge (2002). Because of its proximity to Düsseldorf Airport , two particularly low pylons were constructed.

Web links

Commons : Pylon (bridge construction) - collection of images

Wiktionary: Pylon - explanations of meanings, word origins, synonyms, translations

Individual evidence

^ Gerhard Mehlhorn (Ed.): Handbook bridges . 2nd edition, Springer-Verlag, Berlin Heidelberg 2010, ISBN 978-3-642-04422-9 , p. 452
^ Gerhard Mehlhorn (Ed.): Handbook bridges . 2nd edition, Springer-Verlag, Berlin Heidelberg 2010, ISBN 978-3-642-04422-9 , p. 418

[1] Gerhard Mehlhorn (Ed.): Handbook bridges . 2nd edition, Springer-Verlag, Berlin Heidelberg 2010, ISBN 978-3-642-04422-9 , p. 452

[2] Gerhard Mehlhorn (Ed.): Handbook bridges . 2nd edition, Springer-Verlag, Berlin Heidelberg 2010, ISBN 978-3-642-04422-9 , p. 418