Lavr Dmitrievich Proskouriakov (18 August 1858, the village of Borisovka, Voronezh Governorate – 14 September 1926, Moscow) was one of the foremost authorities on bridge engineering and structural mechanics in the Russian empire and the early Soviet Union. Life and career 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 began his career 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 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 by the decision of the Institute academic council for taking part in the International Railway Congress in London and exploring local mechanical laboratories and bridges. Besides London, he visited laboratories in Paris, Zurich, Munich, Vienna and Berlin and then went to the United States for getting acquainted with the biggest bridges and local mechanical laboratories. Proskouriakov was the first in Europe, who rejected the widespread lattice girder design of trusses with many vertical and diagonal members that were extremely difficult for truss analysis. Instead, he designed a statically determinate triangular web truss with a minimum number of diagonals that provided a better distribution of the effects of moving loads on bridge structures. The research and practical activities of Lavr Proskouriakov were aimed at creating the perfect truss superstructure, and he eventually achieved this goal: it was the noble long railway bridge across the Yenisei near Krasnoyarsk that was built in the period between 1896 and 1899. The truss superstructure was composed of six spans. The length of each span was , the height , 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 groundbreaking truss system. By using the camelback truss design for its upper chord (similar to Schwedler truss), Proskouriakov extended the height of the