Crosses Obvodny Canal Designer Nikolai Belelyubsky | Total length 983.5 m (3,227 ft) Opened 1897 | |
Locale St. Petersburg, Russian Federation No. of spans 9 х 109.25 m (358.4 ft) | ||
The American bridge (it was also referred to as The Howe Bridges, or Nikolaev railway bridge until December 31, 2008) — is essentially a group of railway bridges that connect the Bezymyannyi island (St. Petersburg) to the left bank of the Neva River via the Obvodny Canal, and provide links between the Central and Nevsky districts of the city of Saint Petersburg.
Contents
History
The wooden bridges of the same design as now were constructed over the period 1840-1850 during the construction of the Nikolayevskaya Railway. The main construction works were supervised by the prominent American railroad engineer George W. Whistler to a design by William Howe, an American bridge builder and inventor.
The essence of the construction project was that the bridge's spans were expected to be a truss system of bracing wood design constricted by cross iron bars (this was the very novelty). Due to the presence of the metal parts, the bridge structure became much stronger without substantial increases in overall weight.
The William Howe's system was theoretically checked and then improved by the Russian engineer Dmitrii Juravsky, who was an executive assistant to George W. Whistler during the construction of the railway line. Juravsky performed structural analyses and tests on physical models of Howe trusses from 1843 to 1848, and executed studies of the effect of posttension in Howe trusses. He published two books "About Bridges of the Howe System" in 1855 and 1856.
Juravsky was able to prove that the closer to a bridge's pillars, the greater the strain on the vertical tension bars and diagonal braces. So, he proposed to make the truss members of varying thickness depending on a specific location. His ideas were endorsed by Whistler, and then used in the construction of other rail bridges on this line. As the road was built in the forward direction, it was necessary to build 278 artificial structures.
Metal bridges
The bridge across the Obvodny Canal that was built by George W.Whistler using the Howe-Zhuravsky system had served well for about 30 years. However, in 1869, the decision was made to replace the wooden bridges with new metal span structures. The design works for the new bridge were carried out by or under the supervision and direction of Nikolai Belelyubsky, a famous Russian civil engineer. In his work, Belelyubsky proved himself to be a talented scientist and practitioner. Belelyubsky systematized all existing structures of metal trusses and on this basis he developed typified designs for bridges.
Despite the constructive scheme of the wooden bridge was changed, the new metal structure resembled the former truss of the Howe-Zhuravsky system. Similar to its wooden predecessor, new metal bridge had also a double-track structure.
As a result, the station of Saint-Petersburg (Major yard) experienced steady progress, passenger numbers and cargo handled by the terminal increased rapidly alongside the expansion of rolling stock. Due to shortage of space on the left bank of the Obvodny Canal, there was a need to build a new train maintenance depot on the right one, as well as to construct new crossings.
In 1906, a single-track American bridge number 2 was erected on the downstream side along the existing metal bridge, which became number 1 in a consequence. And in 1911, a double-track rail bridge with the letter "B" was added to the existing "Americans".
In 1913, a double-track bridge with the letter "E" was erected, and in 1916 this engineering composition was complemented with one more bridge of the letter "A", which resembled the railway bridge in Tsarskoye Selo across the Obvodny Canal on the railroad track at the Vitebsky railway station.
Name and numbering
Since the construction completed, the first bridge has come to be known as “American“ for its design. Later, after the other bridges were opened for traffic, this name passed to them.
All five bridges started to be described as "Nikolaev railway bridge" in the official register of the urban environment objects names (according to the former names of the Moscow Station and Oktyabrskaya Railway (or October Railway).
However, on 31 December 2008, the bridges were upgraded to 'The American Bridge' by a resolution of the Government of St. Petersburg. The Government's decision was motivated by the fact that "it was referred to as “American“ since it was built."
From the West to the East
Renovation
Since 2006, the October Railway has been carrying out renovation works on the bridge. The total reconstruction costs ran to 4.5 billion rubles, for an overall work of 39 months.
The renovation aims to address the following:
1. to rebuild or modernize the bridges on a routine basis;
2. to integrate the bridges in the high-speed railway line St. Petersburg - Moscow;
3. to transfer technical areas of the railway outside the city's limits to develop the vacated territories.
The renovation works have been carried out by "Mostostroy-6".
On 23 November 2007, a duplicate of the bridge with the letter "A" was opened for traffic (it is located further west of it). Now it carries the first and third main lines to Moscow. By design, the old bridge with the letter "A" was to be completely demolished, while a new one was to be erected on its site to a design by the institute "Lengiprotrans". The spans of 101.5 meters-long should be rested on just two pillars, while the former structure had six ones and was 25 meters shorter. The other American bridges were expected to be exactly the same. For their construction, metal arched trusses were expected to be used.
By the end of 2007, one of those crossings was almost completely built. For its construction, a two-story building was demolished that had been used as a remote control post of all traffic signals and arrows in the station St. Petersburg (Mayjor yard). It was expected that the new crossing would play a role of the old bridge with the letter "B", as just as its construction would have been completed by the end of that year.
However, in April 2008, the completion date was redefined, because of the lack of coherence between Russian Railways and municipality, and due to the inconsistency of the reconstruction works on the Ligovsky Prospect. The new dates were set as follows: in early May, static and dynamic tests were to be held on the bridge by passing locomotives. The load testing took place on 6 May 2008, whereupon the bridge was opened for shunting rail traffic.