Stößenseebrücke

About

The Stößenseebrücke is a steel truss bridge over the Stößensee and the Havelchaussee in the Berlin district of Spandau. The listed bridge from 1908 to 1909 is part of Heerstraße (federal highway 2/5) and connects the Spandau district of Wilhelmstadt with the Westend district of Charlottenburg-Wilmersdorf. The biggest technical and financial problem during the construction of the Heerstraße was bridging the Havel lowland, which includes the Stößensee, an old arm of the Havel. From several options, including an additional 250-meter-long bridge over the Scharfe Lanke, the planners opted for a route that could manage with two bridges – over the Havel and the Stößensee. With regard to the variants of the Stößensee bridge, the "small" solution with a dam embankment and a bridge around 100 meters long was chosen instead of a bridge over the entire lake. The bridge consists of a system of cantilever girders with connected towing girders and has a span of around 50 meters. It was designed by civil engineer Karl Bernhard.

Together with the Frey Bridge 800 meters to the west, which crosses the Havel, which was canalized in this area in 1880/1881, the Stößensee Bridge spans the waters of the Havel lowlands. The Stößensee is a bulge of old Havel arms, the remains of which are preserved in the area of the Tiefwerder Wiesen with the Faulen See, the Hohlen Weg and the main ditch. The eastern shore of Stößensee rises towards Grunewald, the western shore towards Pichelswerder – both part of the north-western foothills of the Teltow Plateau, which borders the Havel to the west. The original soft-ice glacial Rinnsee lake, or the later Havel branch, had dug into the edge of the plateau, so that the bridge height of around 25 meters, which is unusual for Berlin conditions, had to be built. For landscape planning reasons and to save costs and avoid having to bridge the entire 350-meter-long Stößensee, the Stößensee was filled in with a dam from the Pichelswerder and divided in two except for a channel that was kept open. Beyond the division of the lake, the embankment and the bridge connected the former island of Pichelswerder to the western land and turned the Werder into today's peninsula.

Part of the Döberitzer Heerstraße, Bauherr

The bridge was part of the overall Döberitzer Heerstraße project, which was built between 1903 and 1911 as an extension of Kaiserdamm as a direct link from Berlin Palace via the towns of Charlottenburg and Spandau, which were independent until their incorporation into Greater Berlin in 1920, to the Döberitz military training area. The east–west road comprises today's streets Unter den Linden, Straße des 17. Juni, Bismarckstraße, Kaiserdamm, Heerstraße and, after the Berlin city limits, Hamburger Chaussee in Dallgow-Döberitz. The road, built for military reasons, was public from the outset and opened up the western Grunewald forest and Pichelswerder for Berlin excursion traffic.

At the time of construction, the site of the bridge belonged to the Grunewald-Forst estate district (partly merged into the Heerstraße estate district in 1914) in the district of Teltow. While the military, finance and forestry treasury as well as Berlin, Charlottenburg, Spandau, the district of Teltow, the district of Osthavelland and some municipalities were financially involved in the overall project, the Stößensee Bridge was largely financed by the forestry treasury, which the Berlin Monument Database lists as the bridge's builder.

The otherwise dead straight east–west axis of the entire street makes a single bend and turns slightly to the northwest at Scholzplatz. The route supposedly drawn by Kaiser Wilhelm II using a ruler could not be adhered to for cost reasons, which were due to the difficulties of bridging the Havel lowlands. The dead straight continuation would not only have required bridging the Havel and Stößensee, but also the Scharfe Lanke. A 250-metre-long bridge would have had to be built here. The costs for this variant were estimated at 16.9 million marks, ten million of which were accounted for by the Scharfe Lanke bridge alone. A slimmed-down version with embankments in all the waterways touched and shorter bridges would still have cost 11.2 million marks. The chosen variant with the slightly bent route left the Scharfe Lanke to the south untouched. Although the road, which simply continued straight ahead after the bend, reached the Döberitz military training area at a different point than planned, the deviation seemed justifiable to everyone involved in view of the significantly reduced costs and other advantages. The Stößensee Bridge including the dam and the Frey Bridge cost a comparatively low 2.54 million marks. The Stößensee Bridge accounted for 850,000 marks and the dam for 550,000 marks.

Both the planners involved in the road construction and the bridge engineers endeavored to make the impact on nature as gentle as possible and to affect the landscape as little as possible. According to Adolf Frey, the decision in favor of the small Stößensee bridge with the dam instead of a large bridge over the entire lake was made for landscape planning reasons, after the senior civil engineer Hoßrat had made sketches showing the effects of the variants on the landscape. According to these sketches, a "dam, if it was built in the style of the adjacent banks with foreshore and planted accordingly, seemed to have less of an impact on the landscape than a [large] bridge." Excavated material from the army road and from the widening of a nearby valley was used for the dam, which was around 350 meters long and 125 meters wide.

The above information comes from articles published in 1911 by the bridge designer Karl Bernhard and the head of Heerstraße construction, the Charlottenburg Privy and Chief Building Councillor Adolf Frey (the neighboring Frey Bridge, which until then had been called the Havel Bridge, was named after Frey in 1913). There appear to have been problems with the construction of the dam that the two parties involved in the project did not mention. The morning edition of the Berliner Tageblatt reported on March 1, 1907:

"Fifty meters of dam sunk. The construction of the Döberitzer Heeresstraße seems to have found an unfathomable opponent in the Stößensee. The gravel embankment built in this swampy recess of the Havel had already sunk repeatedly."

Four years after the dam was completed, the local politician, historian and local historian Ernst Friedel noted that the planners might have opted for a longer bridge if they had known about the problems and the actual costs of backfilling:

"They were thoroughly mistaken about the subsoil conditions of this ancient, rotten and overgrown lake. If one had known that solid ground could only be found at the enormous depth of 35 meters, and that the burdened embankment on both sides had been constantly rising for months before one could stop and tame the escape of the pressed up mud masses with pile and fascine works, one might have preferred a longer bridge as cheaper."

In total, the embankment required around one million m³ of soil. The digested sludge masses were mixed with water to form a flowing slurry and pushed through hoses into the northern, silted-up part of the lake.

Project sketch by Karl Bernhard for bridging the Stößensee without a dam and with a straight continuation of the Heerstraße. Pichelswerder on the left, Rupenhorn on the right, where the road would have met the Stößensee in this variant.

The bridge was part of the overall Döberitzer Heerstraße project, which was built between 1903 and 1911 as an extension of Kaiserdamm as a direct link from Berlin Palace via the towns of Charlottenburg and Spandau, which were independent until their incorporation into Greater Berlin in 1920, to the Döberitz military training area. The east–west road comprises today's streets Unter den Linden, Straße des 17. Juni, Bismarckstraße, Kaiserdamm, Heerstraße and, after the Berlin city limits, Hamburger Chaussee in Dallgow-Döberitz. The road, built for military reasons, was public from the outset and opened up the western Grunewald forest and Pichelswerder for Berlin excursion traffic.

At the time of construction, the site of the bridge belonged to the Grunewald-Forst estate district (partly merged into the Heerstraße estate district in 1914) in the district of Teltow. While the military, finance and forestry treasury as well as Berlin, Charlottenburg, Spandau, the district of Teltow, the district of Osthavelland and some municipalities were financially involved in the overall project, the Stößensee Bridge was largely financed by the forestry treasury, which the Berlin Monument Database lists as the bridge's builder.

The otherwise dead straight east–west axis of the entire street makes a single bend and turns slightly to the northwest at Scholzplatz. The route supposedly drawn by Kaiser Wilhelm II using a ruler could not be adhered to for cost reasons, which were due to the difficulties of bridging the Havel lowlands. The dead straight continuation would not only have required bridging the Havel and Stößensee, but also the Scharfe Lanke. A 250-metre-long bridge would have had to be built here. The costs for this variant were estimated at 16.9 million marks, ten million of which were accounted for by the Scharfe Lanke bridge alone. A slimmed-down version with embankments in all the waterways touched and shorter bridges would still have cost 11.2 million marks. The chosen variant with the slightly bent route left the Scharfe Lanke to the south untouched. Although the road, which simply continued straight ahead after the bend, reached the Döberitz military training area at a different point than planned, the deviation seemed justifiable to everyone involved in view of the significantly reduced costs and other advantages. The Stößensee Bridge including the dam and the Frey Bridge cost a comparatively low 2.54 million marks. The Stößensee Bridge accounted for 850,000 marks and the dam for 550,000 marks.

Both the planners involved in the road construction and the bridge engineers endeavored to make the impact on nature as gentle as possible and to affect the landscape as little as possible. According to Adolf Frey, the decision in favor of the small Stößensee bridge with the dam instead of a large bridge over the entire lake was made for landscape planning reasons, after the senior civil engineer Hoßrat had made sketches showing the effects of the variants on the landscape. According to these sketches, a "dam, if it was built in the style of the adjacent banks with foreshore and planted accordingly, seemed to have less of an impact on the landscape than a [large] bridge." Excavated material from the army road and from the widening of a nearby valley was used for the dam, which was around 350 meters long and 125 meters wide.

The above information comes from articles published in 1911 by the bridge designer Karl Bernhard and the head of Heerstraße construction, the Charlottenburg Privy and Chief Building Councillor Adolf Frey (the neighboring Frey Bridge, which until then had been called the Havel Bridge, was named after Frey in 1913). There appear to have been problems with the construction of the dam that the two parties involved in the project did not mention. The morning edition of the Berliner Tageblatt reported on March 1, 1907:

"Fifty meters of dam sunk. The construction of the Döberitzer Heeresstraße seems to have found an unfathomable opponent in the Stößensee. The gravel embankment built in this swampy recess of the Havel had already sunk repeatedly."

Four years after the dam was completed, the local politician, historian and local historian Ernst Friedel noted that the planners might have opted for a longer bridge if they had known about the problems and the actual costs of backfilling: