D bridge
The Krupp-D-Bridge is a transportable emergency or makeshift bridge that can be assembled from pre-assembled individual components, but is also suitable for continuous operation. It was developed jointly by the Krupp and MAN companies in 1959/60 . Due to changing areas of application, the wooden roadways and normal steel roadways used first were supplemented by the flat roadway. All three types of lane were approved for a bridge class 30 according to DIN 1072. A further development made possible a bridge class 45 by changing the roadway. Further developments still take pedestrian paths on the outside of the bridge into account.
Approval and area of application
This type of bridge has been calculated and constructed according to German regulations for steel bridges and can therefore be used as a permanent bridge without any restrictions.
The D-Bridge is mostly built as a trough bridge . As a modular system, it consists of individual parts that are assembled according to requirements.
This bridge construction is composed of the following main parts:
- Main girder triangle (side panels): As side frameworks, these components form the main girders of the bridge, which take up the entire load and transfer it to the bridge bearings.
- Cross beams (connecting the side panels): These cross beams are the connecting beams between the bridge panels and direct the load on the bridge into the side panels
- Normal roadway (on the cross members): These parts are already the roadway with pavement.
The Federal Republic of Germany has 8,200 t of elements for D-bridges in its bridge stores, which corresponds to a total length of around 2,670 meters. In addition to the Bailey Bridge, the THW Bridge Construction Section also uses the D Bridge.
A fire-destroyed A 57 motorway bridge near Dormagen was replaced in 2012 by a provisional D-bridge from the federal government.
Construction methods
The following limit spans and load capacities can be built with the normal roadway:
| Gauge | span | Load capacity | |
|---|---|---|---|
| Single lane | 3.5 meters | Max. 70 meters | 30 tons |
| Two lanes | 6.0 meters | Max. 64 meters | 30 tons |
When using the flat carriageway, the span is reduced by around 30%, whereby the load-bearing capacity increases to 45 t.
Assembly
The bridge is built on a roller conveyor in front of the trench to be bridged and, as with the incremental launching method, is pushed over the trench by means of an additional front end pin.
The stem nose serves only as an assembly aid and is made in a lightweight construction. The slack during assembly is also compensated for by means of a suitable construction of this stem so that the bridge runs smoothly on the tilting roller bearing opposite .
It will be dismantled again after the bridge has been pushed forward. The dismantling of such a bridge is in the reverse manner. Due to the individual weights, the bridge can only be built with mechanical hoists ( crane ) or by groups with a larger number of people (company size). All connections are made using "fitting screws".
Construction times
These are based on the conditions on site and the available emergency services. Under normal conditions, a bridge of approx. Nine meters and a single-storey double-walled construction and approx. Ten men can be expected to take six hours to build. These times do not include feed, construction of the roller conveyor, etc.
Web links
Individual evidence
- ↑ http://www.strassen.nrw.de/ , accessed on March 8, 2012