Theodor Kristen

This article covers the civil engineer. For people with the similar family name "Kirsten" see Theodor Kirsten .

Theodor Maximilian August Kristen (born June 11, 1888 in Paderborn ; † December 7, 1976 in Braunschweig ) was a German civil engineer and from 1938 head of the " Air Protection Seminar" at the Institute for Structural Air Protection at the Technical University of Braunschweig, founded in 1937.

education

Kristen studied civil engineering at the Technical University in Hanover from 1908 to 1914 . From 1914 to 1918 he did his military service in the First World War . He then worked in a reinforced concrete company in Paderborn, as Regierungsbauführer in the railway department in Kassel and was since 1921 a research assistant to Robert Otzen , where he in 1924 with the contribution to the question of the favorable impact of finely ground blast furnace slag on the strength of cement mortar doctorate . In 1926 Kristen worked as a chief engineer in the civil engineering laboratory of the road construction research center at the Technical University of Hanover. In 1931 his habilitation took place on the subject of new scientific findings in the field of modern concrete research . Kristen then accepted a teaching position at the Technical University of Berlin and the position as head of department at the State Materials Testing Office (MPA) in Berlin-Dahlem .

In 1937 Kristen was appointed full professor to the chair for “Building Materials Science and Reinforced Concrete Construction” in the Architecture Department at the Carolo-Wilhelmina (TH Braunschweig) and was appointed director of the “Department for Materials Testing” at the Institute for Building Materials Science. Among other things, he carried out material checks during the construction of the automobile plant near Fallersleben , later the Volkswagen plant in Wolfsburg . He then succeeded Diedrich Dieckmann at the “Institute for Structural Air Protection” and headed the “Air Protection Seminar” there from the autumn semester 1938/1939 to 1945. He was then suspended from duty until 1947.

research

Kristen devoted himself to the study of binders, mortar, concrete, building noise protection and the examination of components in the event of a fire attack. Until the end of his active activity, he was particularly concerned with researching the use of lime as a binding agent , which made important new knowledge available to the lime industry. He was also responsible for the creation of model rules, according to which the different constructions or mixtures of concrete could be tested cost-effectively. He contributed to the creation of the bunker models on a scale of 1: 5, which were used for test purposes in the Querumer Forest .

Kristen campaigned for research on reinforced concrete bunkers. Therefore, in 1939, the institute was given a suitable site in the Querumer Forest, on which test blasting and fire tests could be carried out on the concrete models. There were also tests on original-size structures at the Bergen military training area in the Lüneburg Heath . In these tests, a design for protective structures was to be determined that offered the best possible protection with minimal use of material. The tests showed that the arrangement of the steel inserts within the concrete had an effect on the absorption of the explosion energy and was able to reduce it by means of plastic deformations to such an extent that it was avoided in the interior space. The construction of the Braunschweig reinforcement , which was prescribed for all new air-raid shelter systems from July 1941, was based on this. By arranging more steel mats in the area close to the interior than to the outside, a high level of resistance to bomb hits was achieved and only the relatively small amount of steel of 30 kg / m³ had to be used. The most effective possible composition of the concrete used was also one of his research tasks.

As a result, Kristen has contributed to the construction of many effective air raid shelters to protect the civilian population, so that, for example, only a relatively few people lost their lives due to the around 40 bomb attacks on the city of Braunschweig. In 1959, Karl Kordina succeeded Kristen at the "Institute for Building Materials Science and Materials Testing", as it was called after the two institutes for Building Materials Science and Air Protection were merged.

Commitment and honors

Kristen was a member of a variety of professional, scientific associations and was:

• Founding member of the “ Braunschweigische Wissenschaftliche Gesellschaft ” and at the same time a full member of the “Class for Building Sciences ”.
• Founder and member of the “Prussian and Reich Expert Committee for New Building Materials and Types”. Contributions to the further development of the standards and guidelines, for example the new version of the building lime standards (DIN 1060) .
• In 1953 he was awarded the Great Cross of Merit of the Federal Republic of Germany.
• From 1955 to 1957 director of the Lower Saxony Materials Testing Office (NMPA).
• Dean of the Faculty of Construction and Head of the Department of Architecture.
• In 1961 he was awarded an honorary doctorate by the TH Hannover .
• October 1, 1964 became councilor of the city of Braunschweig and head of the construction committee.
• 1974 50th (golden) doctorate anniversary.
• On December 7, 1976, he was awarded the " Heinrich Henne Medal " for his special services to preventive structural fire protection by the Association for the Promotion of German Fire Protection .

Fonts (selection)

• Contribution to the question of the favorable influence of finely ground blast furnace slag on the strength of cement mortar. (= Dissertation, University of Hanover) Hanover 1925, OCLC 720888396 .
• New scientific findings in the field of modern concrete research. (= Habilitation thesis, University of Hanover). 1931.
• with Martin Hermann, Bernhard Wedler: Fire tests with loaded reinforced concrete components (and stone iron ceilings). In: German Committee for Reinforced Concrete. Part 1: blankets. Ernst, Berlin 1938, OCLC 250334855 .
• with K. Ehrenberg: The development of the protective reinforcement of defense structures, especially LS structures made of reinforced concrete. In: Messages from the Institute for Structural Air Protection at the Technical University of Braunschweig. Braunschweig 1944 ( ibmb.tu-braunschweig.de , PDF).
• with Adolf Meyer: Steam-hardened aerated concrete in residential construction. In: Treatises of the Braunschweigische Wissenschaftlichen Gesellschaft. Volume 5, Friedr. Vieweg & Sohn, Braunschweig 1953, pp. 132–140. ( tu-braunschweig.de , PDF).
• with G. Blunk, Wolfgang Westhoff: Investigations of building materials for fire resistance. Braunschweig 1954, OCLC 258711307 .
• with Hans Werner Müller, Roman Palazy: Sound effects of floating screed on different ceiling constructions. Braunschweig 1957, OCLC 258173908 .
• with Wilhelm Krämer, Johannes Gottschalk: Investigations of exterior walls made of aerated concrete for moisture content and thermal insulation on buildings in Braunschweig and Hamburg. Braunschweig 1956, OCLC 258706554 .
• with H.−J. Wierig: Fire tests on ceilings made of prefabricated parts. In: Report from the Institute for Building Materials Science and Testing of the Technical University of Braunschweig. Braunschweig 1959, OCLC 258710877 .

literature

• Rainer Maaß: Kristen, Theodor Maximilian August. In: Horst-Rüdiger Jarck , Günter Scheel (ed.): Braunschweigisches Biographisches Lexikon - 19th and 20th centuries . Hahnsche Buchhandlung, Hannover 1996, ISBN 3-7752-5838-8 , p. 349 .
• Werner Piepenburg: Theodor Kristen - 80 years. (Mr. o. Prof. emer. Dr.-Ing. E. h. Dr.-Ing.habil. Theodor Kristen on his 80th birthday June 11, 1968) Inst. For building materials, solid construction and fire protection, Braunschweig 1968, OCLC 255092046 .
• Klaus Stiglat: Civil engineers and their work. Ernst & Sohn, Berlin 2004, ISBN 3-433-01665-8 , p. 231.

Web links

• Literature by and about Theodor Kristen in the catalog of the German National Library
• Karl Kordina : Theodor Kristen (PDF, obituary tu-braunschweig.de )
• Publications and reports Professor Kristen (1926–1976) ibmb.tu-braunschweig.de

Individual evidence

1. ↑ Kristen, Theodor ( memento of October 17, 2013 in the Internet Archive ) (PDF; 513 kB) on digisrv-1.biblio.etc.tu-bs.de, accessed on October 17, 2013.
2. ^ The development of material testing at the TH Braunschweig in the 1920s and 1930s ( memento from December 29, 2014 in the Internet Archive ) on mpa.tu-bs.de, accessed on October 16, 2013.
3. ↑ ^{a b c} history on ibmb.tu-braunschweig.de, accessed on May 22, 2017.
4. ↑ ^{a b c} Rainer Maaß: Kristen, Theodor Maximilian August. In: Horst-Rüdiger Jarck , Günter Scheel (ed.): Braunschweigisches Biographisches Lexikon - 19th and 20th centuries . Hahnsche Buchhandlung, Hannover 1996, ISBN 3-7752-5838-8 , p. 349 .
5. ^ History of the MPA Braunschweig ( Memento from December 29, 2014 in the Internet Archive ) on mpa.tu-bs.de, accessed on October 16, 2013.
6. ↑ 1976 Kristen, Theodor, Prof., Dr.-Ing. on vfdb.de, accessed on October 17, 2013.