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This is a joint meeting with the Institution of Structural Engineers History Study Group

The “Vierendeel” type bridge takes its name from the Belgian professor Arthur Vierendeel, who patented the principle in 1895 and intensively promoted it as a replacement for the truss bridge. From the outset, Vierendeel envisaged this type of bridge being used for railway bridges. That said, the very first railway bridge of this type was not built in Belgium until 1922. Then, on the initiative of one of Vierendeel’s former students, it was used for some forty spans on the BCK railway line in the Congo in the 1920s. Finally, in the 1930s, the national railway company adopted the Vierendeel type for the construction of a number of long-span bridges in Belgium. The Mechelen bridge mentioned above is part of this series.

At the same time, the Vierendeel bridge type was also adopted en masse for the construction of around forty road bridges over the future Albert Canal, currently under construction. But unlike the rail bridges, which were always riveted, the road bridges were built using the new and little-experienced technique of arc welding. This led to the famous accident in March 1938, when the Hasselt welded bridge collapsed into the Albert Canal.

Professor Bernard Espion has studied the history of these welded Vierendeel road bridges and their importance in the history of brittle fracture in various publications. However, he has never reported on the history of the Vierendeel rail bridges which, to his knowledge, were only used in Congo and Belgium. There are a large number of them in the Congo that are almost 100 years old, and a few more in Belgium.

The history of these Vierendeel rail bridges will be the subject of Professor Bernard Espion‘s presentation, along with a few lessons drawn from the very recent expert examination of this bridge in Mechelen concerning the properties of the steel used at the time in Belgium.

About the Speaker

Professor Bernard Espion graduated in Civil Engineering from the Polytechnical School of the University of Brussels (Université Libre de Bruxelles, ULB) in 1979. He earned his doctoral degree in 1986 with a dissertation on the Numerical modelling and analysis of the nonlinear and time-dependent behaviour of concrete structures.

Between 2000 and 2021, Professor Espion was the Director of the Laboratory for testing Materials and Structures, a laboratory with origins in 1924. He taught courses on Structural Analysis and Design of Steel and Concrete Structures. Since 2021, he has been Professor Emeritus from the University of Brussels (ULB) where he has spent his whole scientific and academic career in the Department of Civil Engineering.

Professor Espion’s themes of research from 1980 to 2006 were mainly in structural concrete and concrete technology. He acquired an extensive experience of testing of materials and structures and in situ stress analysis of bridges.

Since 2002, his research interests have mostly been in Construction History and Conservation of heritage engineering structures, specializing in the history of Construction in Belgium (19th-20th Centuries), with emphasis on concrete and steel structures, construction materials, biographies of engineers, bridges, thin concrete shells and lightweight cable roof structures.