Altwipfergrund valley bridge
|Altwipfergrund valley bridge|
|Convicted||Federal motorway 71|
|Subjugated||Alte Wipfra , forest path|
|construction||Prestressed concrete box
bridge web made of trapezoidal sheet metal
|overall length||280 m / 278 m|
|width||2 × 14.25 m|
|Longest span||115 m|
|Construction height||2.8 m to 6.0 m|
|building-costs||23 million DM|
|start of building||1999|
The Altwipfergrund viaduct is a 280 m or 278 m long girder bridge . It is the first large bridge in Germany with webs made of trapezoidal steel profiles and a pre-stressed deck and floor slab made of reinforced concrete , which is also known as a hybrid construction.
The bridge lies in the course of the BAB 71 in the Thuringian Forest between the junctions Ilmenau -Ost and West and spans the Altwipfergrund with a nature reserve at a height of about 35 m. The bridge with two separate superstructures was built between 1999 and 2001.
The abutments and pillars are founded on large bored piles . The piles have a diameter of 1.20 m and lengths of up to 25 m. The pillars with a maximum height of 25 m up to the lower edge of the superstructure have a full cross-section. The dimensions of the pillars are reduced by a suit down to 5.5 m × 3.0 m below the superstructure.
The spans for the north superstructure are 81.47 m and 81.35 m in the peripheral fields and 115 m in the central field. The superstructures are unicellular, haunched prestressed girders of longitudinal prestressed road and floor panels. The bars are made of trapezoidal steel sheet with a height of 70 cm. This enabled the weight of the superstructure to be reduced and the effect of the prestressing to be improved. The pre-tensioning consists of a mixed construction with internal and external tensioning cables . The rest point of movement in the longitudinal direction is in the middle of the bridge, where the pillars are immovably connected to the superstructure. The construction height of the box girders is 2.8 m in the middle of the field and increases to 6.0 m up to the pillars. The two superstructures are together 28.5 m wide.
The bridge was the balance beam in the cantilever made. The length of the front section was 6.57 m. First, the trapezoidal girder webs were installed, followed by the manufacture of the floor slab and finally the concreting of the road slab.
- DEGES: Bridge structures in the new federal states . Ernst & Sohn, Berlin 2004, ISBN 3-433-01700-X .