Matthias Koenen
Matthias Koenen (1848 – 1924) is considered to be the „spiritual father“ of reinforced concrete construction in Germany. After his studies at the Berlin Bauakademie (academy of construction), later named Technical University Berlin-Charlottenburg, from 1868 – 1872, he was first employed as a governmental foreman (Regierungsbauführer) by the railway administration and afterwards by the water engineering administration. In 1879, he passed the second state examination and was appointed governmental construction manager. Koenen worked as a civil engineer and quickly acquired a good reputation as an outstanding design and structural engineer. He imparted his knowledge in lectures and early publications.
In 1884, the construction administration entrusted him with the site management for the structural work for the new Reichstag building in Berlin. During this job he made the acquaintance of G. A. Wayss who, after completion of the construction works on July 1, 1888, employed him as technical director in his company Wayss & Cie. On November 20, 1886 Koenen already published the calculation of reinforced slabs in the Centralblatt der Bauverwaltung (central newspaper of the construction administration) – the first theoretical essay about how reinforced concrete works ever to be published in Germany -, whereas he attributed the taking up of tensile forces to the reinforced bars, he erroneously attributed the neutral axis to the middle of the slab. This rough simplification he corrected in his essay in 1902: „Grundzüge für die statische Berechnung der Beton- und Eisenbetonbauten“ (Outlines of structural calculation of concrete and reinforced concrete structures).
In winter 1886/87, Koenen managed the Berlin tests of Conrad Freytag and G. A. Wayss on behalf of the building inspectorate and is considered to be the real author of the Monier brochure. Considering his employment as a civil servant, he signed only the chapter about „Theorie einiger wichtiger Konstruktionen nach System Monier, Metallgerippe mit Cementumhüllung“ (Theory of some important constructions according to the Monier system, Reinforcement with cement cladding) with his name.
After the restless Wayss left the company in 1893, Mattias Koenen took over the management of the company for more than 30 years, which henceforth was named Beton- und Monierbau AG. He made an important contribution to the development and the rapid distribution of reinforced concrete construction in Germany. In his essay „Wie kann die Anwendung des Eisenbetonbaus in der Eisenbahnverwaltung wesentlich gefördert werden?“ (How can the application of reinforced concrete construction be significantly promoted in railway administration) which was published in 1907, one can find an early proposal for prestressed concrete construction.