Mülmisch valley bridge

Coordinates: 51 ° 10 ′ 16 ″  N , 9 ° 32 ′ 39 ″  E

Mülmisch valley bridge
Convicted	High- speed line from Hanover to Würzburg
Subjugated	Mülmisch and u. a. L  3228
place	Melsungen
construction	Prestressed concrete - box girder bridge
overall length	870 m
width	14 m
Longest span	116 m
Construction height	5.3 m
height	74 m
start of building	1986
completion	1988
location

The Mülmischtalbrücke in the north Hessian Schwalm-Eder-Kreis is an approximately 870 m long and a maximum of 74 m high, double-track railway overpass on the high-speed line Hanover – Würzburg at a distance of 161.7 km. The reinforced concrete - girder bridge was built between 1986 and 1988th

The costs are given as 36.2 million DM.

Geographical location

The bridge is just under 2 km east of Körle and spans the valley of the Fulda tributary Mülmisch with the Körler Straße and Melsunger Straße ( Landesstraße  3228), which lead from Unter- Empfershausen to Körle and into the Fulda valley there.

Substructures

The abutments and pillars are founded on red sandstone with large bored piles . The piles have a maximum length of 33 m and 1.5 m in diameter. As a rule, 12 piles are arranged under pile head plates with the dimensions 11.2 m × 11.2 m × 2.3 m. In the bridge there is an arched A-frame with a span of 116 m, which corresponds to twice the span of the normal fields. Due to the geology, the A-frame is outside the middle of the bridge. This is the fixed point of the bridge and in particular transfers the longitudinal forces due to braking from the longitudinally coupled superstructure into the subsoil. The A- frame has a hollow cross-section made of reinforced concrete and, together with the two adjacent pillars, is each founded on a pile head foundation. This foundation with the dimensions 20.95 m × 17.2 m × 3.0 m is supported by 30 piles.

The rectangular reinforced concrete pillars with a maximum height of 68 m have a hollow box cross-section with a wall thickness of 35 cm. In contrast to the other bridges on the route with sloping pillar corners, these are designed with emphasized reinforced pillar corners and a curved shape at the pillar head. The minimum external dimension below the pier heads is 5.3 m × 3.2 m. From there the supports widen with a 60: 1 tightening in both directions downwards.

superstructure

Cross section of the superstructure

The superstructure consists of a chain of 15 single-span girders . This enables individual bridge segments to be replaced later. The cross-sectional shape is a single-cell reinforced concrete box with inclined webs, prestressed in the longitudinal direction . In addition, the deck is prestressed in the transverse direction. With a superstructure width of 14 m, the spans are uniformly 58 m. The constant construction height of 5.3 m (1/11 of the span) is relatively high due to the required rigidity to limit deflection. Expansion joints with rail extensions are available at the bridge ends.

history

In the planning phase, the bridge was in planning section 13 in the middle section of the route.

The Kassel road construction authority was entrusted with the supervision of the construction.

draft

The Mülmisch valley bridge was created according to a special design by the engineering office Harries and Kinkel. The administrative draft did not provide for an A-frame, but an additional pillar, which required a complex deep foundation in lignite deposits. With two fixed points on the abutments, only a large rail extension was necessary in the middle of the bridge, but the associated pillar and foundation had to be made considerably stiffer than the remaining piers.

The modeling of the columns was also a special suggestion. This required additional work compared to the specified pillar geometry, but this could be compensated for by savings in the required reinforcing steel . In addition, the slimmer pillars and the other design elements resulted in an improved structural appearance. The later built Pfieffetalbrücke was built with analogue modeled pillars by the same Wetzlar construction company.

execution

The A-frame was on a wooden shoring shuttered . The 6.5 m wide scaffolding consisted of five rows of logs , one behind the other, made of round timbers , which were connected with square timbers and steel wind pan straps . The scaffolding was braced in the transverse direction. Six carpenters built a total of 750 spruce trunks over a period of five months for the scaffolding . The 116 m long scaffolding of the largest wooden scaffolding that was built worldwide after the Second World War. The approximately 600 t of wood was extracted in north Hesse windbreak areas. In the final state, the construction supported around 3,200 t of concrete. Compared to conventional steel scaffolding, in connection with the neighboring Pfieffetal bridge, around 200,000 D-Marks could have been saved.

The superstructure was concreted field by field with a feed scaffold every two weeks. The scaffolding consisted of a prestressed concrete trough with a protruding nose that was demolished after the bridge was completed.

literature

• Ernst Rudolph: Railway on new paths . Hestra Verlag Darmstadt, 1989. ISBN 3-7771-0216-4 .
• H. Harries, H. Petri, HG Reinke: The Mülmisch and Pfieffe valley bridge . In: Der Bauingenieur 64 (1989), pages 549-558.

Web links

Commons : Mülmischtalbrücke  - collection of images, videos and audio files

Individual evidence

1. ↑ ^{a b} Joachim Naumann, Günter Moll: Road and Rail . In: Die Bundesbahn , 9/1988, pp. 885–892.
2. ↑ Bundesbahndirektion Frankfurt (M), project group NBS Frankfurt am Main of the Bahnbauzentrale (publisher): New lines Hanover-Würzburg from Kassel to Fulda, Cologne - Rhine / Main in the directorate area . Leporello with 12 pages (10x21 cm), Frankfurt am Main, no year (approx. 1984).
3. ↑ The high-speed age is approaching . In: Die Bahn informs , ZDB -ID 2003143-9 , issue 1/1989, pp. 4-8.
4. ↑ The renaissance of wooden scaffolding . In: Die Bahn informs , ZDB -ID 2003143-9 , issue 3/1988, pp. 10-11.