Elbow bridge

an elbow bridge is from one or more elbows existing bridge. The elbow is loaded in such a way by thrust forces that practically no tensions develop. Therefore one can use building material, which cannot take up or few traction powers, like stone (brick-work) and concrete. So one could build elbow bridges, Gewölbe and domes in the antiquity and achieved thereby larger spans than with bars. In addition, steel becomes related as material for elbow bridges.

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example

Eine Bogenbrücke, im Bau befindlich
an elbow bridge, under construction this

elbow bridge in Wehlen (Saxonian Switzerland) is in building. The sandstone right parallelepipeds would hold without mortars and would carry, because the thrust forces run only within the elbow. One sees also the strong counter bearings at the sides.

Actually however the stones are embedded in concrete. The bridge would break down otherwise under individual or asymmetrical loads. In addition the roadway is missing with this bridge. - In the background is still another older elbow bridge.

roadway

elbow bridge also in the center of lying roadway over the railway port of Duisburg - Ruhr place

the actual elbow is mostly not passable and/or. for general traffic not accessibly. The roadway is at trailers below the elbow or on columns (Stehern) up confessing ore over the bridge. It can be attached also in the center between them (like for example with the new Svinesundbrücke).

Therefore one differentiates several kinds from elbow bridges:

  • with roadway with roadway
  • also in the center
  • of lying roadway with a tieback (
  • false elbow), lying lying down, above, see down

static principle

the static principle of the elbow bridge exists in the fact that the vertical loads, those by dead load, traffic etc. result, however from thrust forces in the elbow into the building ground to be led. The counter bearings must take up therefore beside perpendicular loads above all also horizontal loads; they are pressed apart by the thrust forces of the elbow (the elbow thrust). With several elbows these thrust forces at the internal columns waive themselves next to each other and work then only at the outside counter bearings.

Horizontal forces the affecting the counter bearings are all the larger, the flatter the elbow are. Such flat elbows are very elegant, but they presuppose very solid lateral counter bearings.

Continuous girder bridges with the static system “bar on two supports” have against it with vertical loads only vertical bearing forces.

there are

false elbow bridges contrary to the genuine elbow with “false” elbow bridges also traction powers in the wing unit. The roadway is here firmly attached at the elbow ends and takes the horizontal forces from the elbow on instead of it into the counter bearings to lead. “One can build false one” elbow bridges therefore also with less load-carrying building ground. False elbow bridges consist usually of steel or prestressed concrete, because the material can take up also traction powers. Actually so a bridge is a bar on two supports, which has arc-shaped framework, which could be also a trapezoid or a rectangle.

examples of well-known elbow bridges

see also

Web on the left of

Commons: Category: Arch of bridges - pictures, videos and/or audio files
 

  > German to English > de.wikipedia.org (Machine translated into English)