page_title: Lavr Proskouriakov
section_title: Life and career
hierarchical_section_title: Lavr Proskouriakov / Life and career
caption_attribution_description: English: The old rail bridge over the Yenisei river near Krasnoyarsk. A picture of the late 19th - early 20th centuries.
context_page_description: Lavr Dmitrievich Proskouriakov was one of the foremost authorities on bridge engineering and structural mechanics in the Russian empire and the early Soviet Union.
context_section_description: Lavr Proskouriakov was born on 18 August 1858, into a large peasant family. In 1884, he graduated from the Saint-Petersburg Institute of Railway Engineers and worked as a designer of bridges. Since 1887, he lectured at the same institute, and starting from 1896, Proskouriakov held the position of Full Professor at Moscow State University of Railway Engineering.
  Even the early Proskouriakov's projects for the bridges across the rivers Western Bug (1885) and Sula in the Ukrainian city of Romny (1887) attracted attention by their novelty and ingenuity. The drawings of those bridges were published by Professor L.F. Nikolai, the head of the bridge faculty at the Petersburg Institute of Railway Engineers, in his tutorial on bridge design for railway engineers.
  In the summer of 1895, Proskouriakov was sent abroad, according to the decision of the Institute academic council in order to take part in the International Railway Congress in London, as well as explore local mechanical laboratories and bridges. Besides London, he visited laboratories in Paris, Zurich, Munich, Vienna and Berlin, and then went to the United States in order to get acquainted with the biggest bridge structures and local mechanical laboratories.
  Proskouriakov was the first in Europe to reject then existing lattice bridge trusses with many vertical and diagonal members, which were extremely difficult for truss analysis. Instead, he designed a statically determinate triangular web truss with the minimum number of diagonals, which provided better distribution of stresses due to moving loads throughout a bridge structure.
  The research and practical activities of Lavr Proskouriakov were aimed at the elaboration of a perfect bridge structure, and he managed to achieve his goal: this was the noble 1,000 metres (3,300 ft) long railway bridge across the Yenisei near Krasnoyarsk that was built between 1896 and 1899. The superstructure system of the bridge was composed of six spans. The length of each span was 144.7 metres (475 ft), the height 21.64 metres (71.0 ft), the weight 900 tons. The piers were reinforced by starlings (cutwaters) pointing upstream, to break up ice that floats downstream during the annual spring thaw.
  When designing the bridge, Proskouriakov proposed a new original truss system. By using featheredge design for its upper chord (similar to Schwedler truss), Proskouriakov extended the height of the main trusses up to 21.64 metres (71.0 ft). The engineer also utilized the theory of influence lines for truss analysis that enabled more accurate calculation of internal forces in every member in a truss due to moving loads. Since then, the theory of influence lines for truss analysis has been used in engineering both in Russia and around the world. Incidentally, the Yenisei bridge was the first in Russia, during the construction of which the incremental launching method was applied for the first time.
  Thanks to its engineering and technical characteristics, the bridge was recognized as the longest in Russia and the second largest in Europe (the first one was in the Netherlands across the Lek River near Kuilenburg). Represented at the Exposition Universelle (1900), the Yenisei bridge's model received the Gold medal, while Proskouriakov himself went on to become one of the country's most prominent engineers. The bridge was subsequently approved by the UNESCO for inclusion in the World Heritage List.
  The Yenisei bridge opened up a new frontier for the Russian bridge engineering since. Proskouriakov's statically determinate trusses with subdivided panels and upward-angled upper chords were subsequently widely used by many other bridge engineers. For example, such a system (with a few changeups) was borrowed by Prof. Nikolai Belelyubsky in the design of the rail bridge across the Volga River near Sviyazhsk.
  Overall, Proskouriakov managed to elaborate the most suitable types of spans for a variety of bridges. He designed many unique multi-span bridges, including the bridges over Oka near Kashira (1897), Belev (1897) and Murom (1912), Vyatka on the Cherepovet
caption: The railway bridge over the Yenisei. A picture of the late 19th - early 20th centuries
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