Schnaittach Viaduct
Coordinates: 49 ° 34 ′ 26 ″ N , 11 ° 20 ′ 18 ″ E
 Schnaittach Viaduct
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| Convicted | Federal motorway 9 | |
| Subjugated | State road 2241 and the Neunkirchen a Sand – Simmelsdorf-Hüttenbach railway line | |
| place | Schnaittach | |
| construction | Prestressed concrete box girder bridge | |
| overall length | 1287.6 m / 1139.6 m | |
| width | 2 × 17.5 m | |
| Longest span | 105 m | |
| Construction height | 5.6 to 3.0 m | |
| height | 30 m | |
| start of building | 1995 | |
| completion | 1998 | |
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The Schnaittach Viaduct is a 1288 m long bridge on Autobahn 9 . It is the second longest bridge in Bavaria after the 1315 m long Loisach Bridge in Ohlstadt . It was rebuilt between 1995 and 1998 as part of the six-lane expansion of Autobahn 9 ( German Unity Transport Project No. 12 ), at a cost of around 49 million euros.
The bridge is located between the Hormersdorf and Schnaittach junctions and crosses the Schnaittach valley north of Schnaittach. At a height of a maximum of 30 m with 15 or 13 fields, among other things, the state road 2241 between Schnaittach and Simmelsdorf, the parallel Schnaittach valley railway as well as field and farm roads are spanned.
The bridge is part of the Hienberg ascent of the BAB 9, which overcomes a height difference of 180 m between the Franconian Alb and the Rednitz basin with a maximum of 4.5% longitudinal slope. The motorway will be split into two different routes, which run on the western and eastern slopes of the Hienberg. Accordingly, the superstructures of each directional carriageway diverge after about 700 m at the northern end of the Schnaittach viaduct and have different lengths.
Foundation and substructures
The abutments and the pillars are founded on large bored piles with a diameter of 1.5 m and a foot expansion of 2.4 m deep. Up to 11 piles with lengths of 11 m to 16 m are arranged under pile head plates with dimensions up to 15.3 m in length, 10.1 m in width and 2.5 m in thickness. The piers with a double-sided taper of 1:30 have an accessible reinforced concrete hollow cross-section . To accommodate the bearings , the pier heads widen at the top to the external dimensions of 8.6 m × 4.2 m. The standard spacing of the pillars is 18 m.
Superstructures
The two adjacent superstructures of the prestressed concrete bridge are continuous girders with a box-girder cross-section and a construction height of 5.6 m in the area of the 105 m long fields. This is reduced to 3.0 m or 3.8 m in accordance with the reduced spans in the direction of the abutments. The floor slab of the box girder is 8.1 m wide, the deck slab 17.5 m. The superstructure is prestressed in the longitudinal and transverse directions . The spans for the longer 15-span western superstructure are 40.8 m + 60.0 m + 70.0 m + 90.0 m + 5 × 105.0 m + 4 × 90.0 m + 80.0 m + 61.8 m, the 13-field eastern superstructure has spans of 62.8 m + 80.0 m + 2 × 90.0 m + 3 × 105.0 m + 4 × 90.0 m + 80.0 m + 61.8 m.
The point of rest of movement in the longitudinal direction is in the middle of the bridge, where two pillars, each with a superstructure, are fixed.
execution
The eastern superstructure was constructed from the southern abutment over a length of 788 m using the incremental launching method in 33 cycles, the remaining 352 m on falsework . The western superstructure was built using the contact method due to the variable floor plan geometry consisting of a straight clothoid circle . This was done from both abutments with section lengths of 737 m and 551 m. The maximum cycle length was 26.3 m. Because of the large spans, auxiliary piers were necessary in the middle of the field. These were also made of reinforced concrete and built on piles. To create the second superstructure, these were shifted across.
literature
- Federal Ministry of Transport: Bridges and tunnels on federal highways 1998. Verkehrsblatt-Verlag, Dortmund (Germany), ISBN 3-89273-000-3 , 1998; Pp. 73-88.