Fritz Leonhardt

from Wikipedia, the free encyclopedia
Schwedenbrücke , in the background the Urania (Vienna) is brightly lit

Fritz Leonhardt , actually Friedrich Christof Leonhardt, (born July 11, 1909 in Stuttgart ; † December 30, 1999 there ) was one of the most influential German civil engineers of the 20th century. He is the founder of the engineering office Leonhardt, Andrä und Partner in Stuttgart.

Life

Studies and years of apprenticeship in the USA

Leonhardt was the son of an architect. After graduating from high school in 1927 at the Dillmann-Realgymnasium (today Dillmann-Gymnasium ), he studied civil engineering at the Technical University of Stuttgart , where he graduated in 1931. His teachers included Emil Mörsch in solid construction and Hermann Maier-Leibnitz in steel construction. Leonhardt often consulted the Stuttgart Materials Testing Institute (MPA Stuttgart) under Otto Graf for tests . After completing his studies, which he graduated as the best of his year, he, like many of his fellow students, did not find a permanent position due to the global economic crisis (he was temporarily structural engineer at the Süddeutsche Hammerwerke in Bad Mergentheim) until he received the offer from the University of Stuttgart in 1932 To set up a study abroad program at Purdue University , where he studied with Solomon C. Hollister , with whom he kept good contacts, and toured North America and Mexico for half a year , where he visited important civil engineering works, especially bridges. With his uncle Otto Nissler, who was an engineer at the Bethlehem Steel Corporation , he got plans for the Golden Gate Bridge , which was currently under construction. He also visited the George Washington Bridge in New York , which was under construction , the first American bridge to exceed the 1,000-meter span mark, the construction manager Othmar H. Ammann received him personally and made the plans available to him. In October 1933 he returned to Germany and became a member of the SA in the same year . Job prospects as an engineer had by now after the takeover of the Nazis improved in Germany - earlier he had temporarily considered in the United States to stay.

Beginning of his career until the end of the Second World War

From 1934 to 1938 he was a bridge engineer at the Reichsautobahn- Gesellschaft. His mentor in bridge building was Karl Schaechterle , who had also studied in Stuttgart. With him he was involved in the construction of the large Sulzbachtal bridge near Denkendorf , the Danube bridge Leipheim and the Rohrbachtal bridge Stuttgart. Leonhardt also came into contact with the architect of the Reichsautobahn-Gesellschaft, Paul Bonatz , who examined the bridge designs architecturally. In 1939 he joined the NSDAP (No. 7266993). In 1938 Leonhardt did his doctorate under Emil Mörsch on the subject of the simplified calculation of double-sided support grids. In the same year Fritz Todt entrusted him with the project and construction management of the suspension bridge over the Rhine of the Reichsautobahn, the Rhine Bridge Cologne-Rodenkirchen , a prestige project of the Reichsautobahn. Many of the employees he brought into his team, such as Willi Baur and Wolfhardt Andrä , worked in his engineering office Leonhardt and Andrä after the Second World War . He made use of experiences from his time in the USA and was involved with it until the inauguration in 1941, as construction was delayed by the outbreak of war.

In 1939 he founded an engineering office in Munich that still exists today under the name Leonhardt, Andrä und Partner . His office was involved in the planning for a new "Great Axis" in Munich, including a new central station, for which he made initial calculations for a dome with a diameter of 245 m before the plans were discontinued due to the war and were never taken up again. In 1941 Wolfhart Andrä also worked in his office on the planning of an Øresund crossing with a suspension bridge with three 756 m long main spans. Leonhardt had founded the engineering office with the permission of Fritz Todt especially for the planning in Munich and gave up the direct construction management at the Rhine bridge in Rodenkirchen during this time. Leonhardt also provided drafts for other prestige projects of the National Socialists, for example (unasked) for the planned Elbhochbrücke in Hamburg - Altona , which should penetrate as a suspension bridge with a total length of 1,300 m in American dimensions, the Gauhochhaus, also in Altona (where he provided a curtain wall, the thus it would have been one of the first in Europe for high-rise buildings), and a suspension bridge in Linz . In Munich he worked closely with the general building officer Hermann Giesler . After Fritz Todt's death in 1942, Albert Speer became his successor and the situation changed. The construction activity was limited to war essentials and major civil projects were discontinued. From 1943 Leonhardt became the chief construction manager of the Organization Todt in Estonia (task force of the Organization Todt Russia- North ), where he was in charge of the construction of the Baltöl works. When the war situation turned there, he was briefly involved in the construction of the planned Führer headquarters, Projekt Riese im Eulengebirge , in 1944 , before he managed, thanks to his good contacts, to be transferred to Munich, where he headed research and development at the Todt Organization until the end of the war.

Career after the war

He became known for the construction of numerous bridges, high-rise buildings and television towers in reinforced and prestressed concrete construction. He got to know prestressed concrete during his time at the Todt Organization in Estonia through an essay by Eugène Freyssinet from 1941, to which he also traveled twice to France during the war. The spread of prestressed concrete in Germany after the war, for example in bridge construction, was favored by the lack of steel (the reconstruction of the Rhine bridge Cologne-Deutz from 1946 by Leonhardt was an exception, as he got the steel thanks to personal contact with the British Commander-in-Chief Bernard Montgomery ). Immediately after the end of the war he founded an engineering office and the first prestressed concrete bridge was built in 1948 in the Black Forest. The Stuttgart television tower he planned was the world's first reinforced concrete television tower, which became the prototype of many other such structures. Together with Wolfhardt Andrä , Leonhardt founded the engineering office Leonhardt und Andrä in 1953, which has been expanded to include partners since 1970 under the name Leonhardt, Andrä und Partner (LAP). From 1957 to 1974 Leonhardt was professor for solid construction at the TH Stuttgart, from 1967 to 1969 also rector. From 1966 to 1968 he was a board member of the Association of German Engineers (VDI). In 1961 Leonhardt founded the company RIB Software for computer programs in the construction industry with Volker Hahn (Züblin) and Friedrich Wilhelm Bornscheuer .

During this time he was significantly involved in the planning of the type towers required for the radio link network . His office created the structural planning for the tent roof of the Munich Olympic site and thus enabled the construction of the model designed by Günter Behnisch without any knowledge of the realization. Leonhardt can be seen as the main representative of the "Stuttgart School of Structural Engineering", which focuses on lightweight construction. In 1940 he published the article "Lightweight construction - a requirement of our time. Suggestions for building construction and bridge construction". With Willi Baur (1913–1978) he developed the incremental launching method in bridge construction. The north bridge ( Theodor Heuss Bridge ) in Düsseldorf, built in 1956, was one of the first cable-stayed bridges in the world and set new standards. His office then planned many more cable-stayed bridges around the world.

After his retirement, Jörg Schlaich became his successor on the chair.

His grave is in the forest cemetery in Stuttgart .

Honors

Fritz Leonhardt received numerous honors, including the Great Cross of Merit and six honorary doctorates. In 1973 he was awarded the Grashof Memorial Medal by the Association of German Engineers . In 1975 Leonhardt received the gold medal from the Institution of Structural Engineers . In 1981 he was awarded the Award of Merit in Structural Engineering from the International Association for Building Construction and Bridge Construction, and in 1989 he received the first Albert Caquot Prize . In 1982 Leonhardt became an honorary member of the Heidelberg Academy of Sciences . In 1998, a previously unnamed secondary school in the Degerloch district of Stuttgart was named after him.

The Fritz Leonhardt Prize , named after him, is awarded every three years to outstanding civil engineers, and in 2015 for the sixth time.

Buildings

TV tower Stuttgart

Fonts (selection)

Comprehensive list of publications in: Christiane Weber, 2011 , pp. 190–198.

  • with Karl Schaechterle: The design of the bridges. People and Reich, Berlin 1937.
  • Instructions for the simplified grid calculation: with help tables, formulas and examples. Ernst & Son , Berlin 1940.
  • with Karl Schaechterle: suspension bridges. 3 parts, Structural Engineering , Volume 19, 1941.
  • with Paul Bonatz: Bridges. Langewiesche, Königstein / Taunus 1960 (first: 1951).
  • Prestressed concrete for practice. Ernst & Sohn, Berlin 1955 (3rd edition: 1973).
  • Civil engineering - civil engineers shape the environment. Carl Habel, Darmstadt 1974.
  • The civil engineer and his duties. 2nd edition, Deutsche Verlags-Anstalt (DVA), Munich 1981 (first as civil engineering: civil engineers create the environment. Habel, Darmstadt 1974).
  • Lectures on solid construction:
    • Part 1 with Eduard Mönning: Basics of dimensioning in reinforced concrete construction. 3rd edition Springer, 1984.
    • Part 2 with Eduard Mönning: Special cases of dimensioning in reinforced concrete construction. 3rd edition, Springer, 1986.
    • Part 3 with Eduard Mönning: Basics of reinforcement in reinforced concrete construction. Springer, 1977.
    • Part 4: Proof of serviceability: crack restriction, changes in shape, redistribution of moments, etc. Fracture line theory in reinforced concrete construction. 2nd edition, Springer, 1978.
    • Part 5: Prestressed concrete. Springer, 1980.
    • Part 6: Basics of solid bridge construction. Springer, 1979.
  • On the basics of the aesthetics of buildings. Meeting reports Heidelberg Academy of Sciences , Heidelberg 1984, pp. 29–48.
  • Builder in a revolutionary time. Memories. DVA, Munich 1984.
  • with Erwin Heinle: Towers of all times - of all cultures. DVA, Munich 1988.
  • Bridges. Aesthetics and Design, 4th edition, DVA, Munich 1994.

Literature (selection)

Extensive bibliography in: Christiane Weber, 2011 , pp. 185–189.

  • Wilhelm Zellner: Fritz Leonhardt on his 90th birthday. Stahlbau , Volume 68, No. 7, special issue, 1999.
  • Fritz Leonhardt . In: Der Spiegel . No. 2 , 2000, pp. 190 ( online - January 10, 2000 , section died ). Quote: "In 1954 the son of an architect, who under Hitler drove the construction of the motorway in the Reich Ministry of Transport, built the first prestressed concrete tower in the world in his home town of Stuttgart and thus created the prototype of all telescopic asparagus."
  • Wilhelm Zellner: Fritz Leonhardt (1909–1999). A life as a civil engineer in society. VDI Gesellschaft Bautechnik, yearbook 2001, pp. 289–342.
  • Klaus Stiglat (Ed.): Civil engineers and their work. Ernst & Sohn, Berlin 2004 (with an interview by Stiglat with Leonhardt, also in Beton- und Stahlbetonbau , Volume 89, 1994, No. 7, pp. 181–188).
  • Reiner Saul , Holger Svensson , Hans-Peter Andrä: Eminent Structural Engineer: Dr. Fritz Leonhardt (1909-1999). Structural Engineering International 1/2007, pp. 94-96.
  • Joachim Kleinmanns and Christiane Weber (eds.): Fritz Leonhardt 1909–1999. The art of engineering. Edition Axel Menges , Fellbach 2009, ISBN 978-3-936681-28-4 (German, English).
  • Henryk Ditchen: The involvement of Stuttgart engineers in the planning and implementation of the Reichsautobahnen with special consideration of the networks of Fritz Leonhardt and Otto Graf. Dissertation University of Stuttgart , 2009. At the same time: Logos, Berlin 2009 (= Stuttgart contributions to the history of science and technology, Vol. 12), ISBN 978-3-8325-2226-1 ( complete table of contents (PDF) on the DNB website, accessed on June 26, 2019).
  • Christiane Weber: Fritz Leonhardt. "Lightweight construction, a requirement of our time, suggestions for building and bridge construction". For the introduction of structural principles in lightweight construction in the 1930s and 1940s. Materials on building research and building history 18, KIT Scientific Publishing, 2011. ( Full text online (PDF) .)
  • Karl-Eugen Kurrer : The History of the Theory of Structures. Searching for Equilibrium. Ernst & Sohn, Berlin 2018, pp. 606ff, 763ff, 770ff and 1022ff (biography), ISBN 978-3-433-03229-9 .

Web links

Commons : Fritz Leonhardt  - Collection of images, videos and audio files

Individual evidence

  1. ^ "Leonhardt, Friedrich (Fritz) Christof, civil engineer; * July 11th, 1909 Stuttgart, ev., † December 29th, 1999 Stuttgart ". In: Leonhardt's inventory in the Southwest German Archive for Architecture and Civil Engineering , 2017.
  2. ↑ Christiane Weber, 2011 , p. 37.
  3. ↑ a b Christiane Weber, 2011 , p. 87.
  4. ↑ Henryk Ditchen, 2009 in the investment Directory, p 478: . 20:16 copy of the Nazi Party membership card No. 7,266,993 by Fritz Leonhardt.
  5. ↑ Christiane Weber, 2011 , p. 71f.
  6. ↑ Klaus Stiglat: civil engineers and their work. Ernst & Sohn, Berlin 2004, ISBN 3-433-01665-8 , p. 39.
  7. ↑ Christiane Weber, 2011 , p. 117.
  8. ↑ Christiane Weber, 2011 , p. 163.
  9. ^ Marie-Luise Heuser , Wolfgang König : Tabular compilations on the history of the VDI . In: Karl-Heinz Ludwig (Ed.): Technology, Engineers and Society - History of the Association of German Engineers 1856–1981 . VDI-Verlag, Düsseldorf 1981, ISBN 3-18-400510-0 , p. 597 .
  10. ^ Annette Bögle and Karl-Eugen Kurrer: The structural composition of supporting structures with Jörg Schlaich . In: Concrete and reinforced concrete construction . 109th year, no. 11 . Ernst & Sohn, Berlin 2014, p. 830 ff .
  11. ^ Fritz Leonhardt: Lightweight construction - a requirement of our time. Suggestions for building construction and bridge construction . In: The construction technology . 18th year, No. 36/37 . Ernst & Sohn, Berlin 1940, p. 413-423 .
  12. ↑ Erik Raidt: Werner Sobek honored for his life's work . In: Stuttgarter Zeitung . No. 152 , July 6, 2015, p. 16 .
  13. ↑ Wilhelm Zellner, born in 1932, he was a partner with Leonhardt and Andrä.
personal data
SURNAME Leonhardt, Fritz
ALTERNATIVE NAMES Leonhardt, Friedrich Christof (real name)
BRIEF DESCRIPTION German civil engineer of bridges and television towers
DATE OF BIRTH July 11, 1909
PLACE OF BIRTH Stuttgart
DATE OF DEATH December 30, 1999
Place of death Stuttgart