Fritz Leonhardt

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Fritz Leonhardt
Born(1909-07-12)12 July 1909
Stuttgart, Germany
Died 30 December 1999(1999-12-30) (aged 90)
Nationality German
Education Stuttgart University
Purdue University.
Occupation Engineer
Engineering career
Discipline Structural engineer
Institutions Institution of Structural Engineers
Practice name Leonhardt und Andrä
Projects Cologne-Rodenkirchen Bridge
Stuttgart Television Tower
Awards Werner von Siemens Ring
Honorary Medal Emil Mörsch
Freyssinet Medal of the FIP
IStructE Gold Medal
Award of Merit in Structural Engineering

Fritz Leonhardt (12 July 1909 – 30 December 1999) was a German structural engineer who made major contributions to 20th-century bridge engineering, especially in the development of cable-stayed bridges. His book Bridges: Aesthetics and Design is well known throughout the bridge engineering community.

Structural engineers analyze, design, plan, and research structural components and structural systems to achieve design goals and ensure the safety and comfort of users or occupants. Their work takes account mainly of safety, technical, economic and environmental concerns, but they may also consider aesthetic and social factors.

Cable-stayed bridge type of bridge

A cable-stayed bridge has one or more towers, from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern or a series of parallel lines. This is in contrast to the modern suspension bridge, where the cables supporting the deck are suspended vertically from the main cable, anchored at both ends of the bridge and running between the towers. The cable-stayed bridge is optimal for spans longer than cantilever bridges and shorter than suspension bridges. This is the range within which cantilever bridges would rapidly grow heavier, and suspension bridge cabling would be more costly.



Born in Stuttgart in 1909, Leonhardt studied at Stuttgart University and Purdue University. In 1934 he joined the German Highway Administration, working with Paul Bonatz amongst others. He was appointed at the remarkably young age of 28 as the Chief Engineer for the Cologne-Rodenkirchen Bridge.

Stuttgart Place in Baden-Württemberg, Germany

Stuttgart is the capital and largest city of the German state of Baden-Württemberg. Stuttgart is located on the Neckar river in a fertile valley known locally as the "Stuttgart Cauldron." It lies an hour from the Swabian Jura and the Black Forest. Its urban area has a population of 609,219, making it the sixth largest city in Germany. 2.7 million people live in the city's administrative region and another 5.3 million people in its metropolitan area, making it the fourth largest metropolitan area in Germany. The city and metropolitan area are consistently ranked among the top 20 European metropolitan areas by GDP; Mercer listed Stuttgart as 21st on its 2015 list of cities by quality of living, innovation agency 2thinknow ranked the city 24th globally out of 442 cities and the Globalization and World Cities Research Network ranked the city as a Beta-status world city in their 2014 survey.

Purdue University public research university in West Lafayette, Indiana, United States

Purdue University is a public research university in West Lafayette, Indiana, and the flagship campus of the Purdue University system. The university was founded in 1869 after Lafayette businessman John Purdue donated land and money to establish a college of science, technology, and agriculture in his name. The first classes were held on September 16, 1874, with six instructors and 39 students.

Paul Bonatz German architect

Paul Bonatz was a German architect, member of the Stuttgart School and professor at the technical university in that city during part of World War II and from 1954 until his death. He worked in many styles, but most often in a simplified neo-Romanesque, and designed important public buildings both in the Weimar Republic and under the Third Reich, including major bridges for the new autobahns. In 1943 he designed several buildings in Turkey, returning to Stuttgart in 1954.

In 1954 he formed the consulting firm Leonhardt und Andrä, and from 1958 to 1974 taught the design of reinforced concrete and prestressed concrete at Stuttgart University. He was President of the University from 1967 to 1969.

Reinforced concrete composite building material

Reinforced concrete (RC) (also called reinforced cement concrete or RCC) is a composite material in which concrete's relatively low tensile strength and ductility are counteracted by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel reinforcing bars (rebar) and is usually embedded passively in the concrete before the concrete sets. Reinforcing schemes are generally designed to resist tensile stresses in particular regions of the concrete that might cause unacceptable cracking and/or structural failure. Modern reinforced concrete can contain varied reinforcing materials made of steel, polymers or alternate composite material in conjunction with rebar or not. Reinforced concrete may also be permanently stressed, so as to improve the behaviour of the final structure under working loads. In the United States, the most common methods of doing this are known as pre-tensioning and post-tensioning.

Prestressed concrete form of concrete used in construction

Prestressed concrete is a form of concrete used in construction that while under construction is substantially "prestressed" (compressed) in the areas that will be subjected to tensile forces while in service to strengthen it against these forces.

He received Honorary Doctorates from six universities, honorary membership of several important engineering universities, and won a number of prizes including the Werner von Siemens Ring, the Honorary Medal Emil Mörsch, the Freyssinet Medal of the FIP, and the Gold Medal of the Institution of Structural Engineers. In 1988, he was awarded an Honorary Degree (Doctor of Science) by the University of Bath. [1]

The Werner von Siemens Ring is one of the highest awards for technical sciences in Germany.

Institution of Structural Engineers professional body for structural engineering based in the United Kingdom

The Institution of Structural Engineers is a professional body for structural engineering based in the United Kingdom. It has 27,000 members operating in 105 countries. The Institution provides professional accreditation for structural engineers. It publishes a monthly magazine, The Structural Engineer. The institution also has a research journal titled Structures,published by Elsevier, Inc.

University of Bath university in England

The University of Bath is a public university located in Bath, Somerset, United Kingdom. It received its royal charter in 1966, along with a number of other institutions following the Robbins Report. Like the University of Bristol and University of the West of England, Bath can trace its roots to the Merchant Venturers' Technical College, established in Bristol as a school in 1595 by the Society of Merchant Venturers. The university's main campus is located on Claverton Down, a site overlooking the city of Bath, and was purpose-built, constructed from 1964 in the modernist style of the time.

Throughout his career, Leonhardt was as dedicated to research as to design, and his major contributions to bridge engineering technology included:

Caroní River river in Venezuela

The Caroni River is the second most important river of Venezuela, the second in flow, and one of the longest, 952 kilometres (592 mi) from the Tepui Kukenan, where it originates with the same name Kukenan, up to its confluence with the River Orinoco to which it belongs. The name "Caroni" is applied starting from the confluence of the Kukenan with the Yuruani, at 182 kilometres (113 mi) from the source of the Kukenan and 770 kilometres (480 mi) from its discharge in the Orinoco. The meeting takes place in the south of Venezuela, in Bolivar State, being the most important tributary of the Orinoco, mostly because of the high discharge rate. The higher basin of the Caroni is situated in the Gran Sabana close to the border with Brazil.

Ciudad Guayana Place in Venezuela

Ciudad Guayana is a city in Bolívar State, Venezuela. It stretches 40 kilometers along the south bank of the Orinoco river, at the point where it is joined by its main tributary, the Caroní river. The Caroni crosses the city south-north and divides it on its two main halves: the old town of San Félix in the east, and the new town of Puerto Ordaz in the west. The city was officially founded in 1961 by the unification of this two former settlements, but the history of San Félix goes back to its foundation in 1724. Within the city limits are located the site of Cachamay Falls and Llovizna Falls. There are three bridges across the Caroni and the second crossing over the Orinoco, the Orinoquia Bridge, was inaugurated in the city in 2006. With approximately one million people, it is Venezuela's fastest-growing city due to its important iron, steel, aluminium and hydroelectric industries. Ciudad Guayana is one of Venezuela's five most important ports, since most goods produced in the industry-rich Bolívar state are shipped through it, as ocean-going vessels can sail to it from the Atlantic Ocean up the Orinoco river.

Orthotropic deck

An orthotropic bridge or orthotropic deck is one whose deck typically comprises a structural steel deck plate stiffened either longitudinally or transversely, or in both directions. This allows the deck both to directly bear vehicular loads and to contribute to the bridge structure's overall load-bearing behaviour. The orthotropic deck may be integral with or supported on a grid of deck framing members such as floor beams and girders.

Major works

First modern TV Tower in Stuttgart Fernsehturm stuttgart.jpg
First modern TV Tower in Stuttgart

His major structures include the Cologne-Rodenkirchen Bridge, Stuttgart Television Tower, Hamburg's Alster-Schwimmhalle and various cable-stayed bridges in Düsseldorf.

Cologne Rodenkirchen Bridge

The Cologne Rodenkirchen Bridge is a steel suspension bridge over the Rhine located in Cologne, Germany. Completed in 1954, it has a main span of 378 metres. It was named after the Cologne district of Rodenkirchen.

Alster-Schwimmhalle Swimming venue in Hamburg, Germany

The Alster-Schwimmhalle is one of Germany's larger aquatics centers, located in the Hamburg district of Hohenfelde. Opened in 1973, it has regularly hosted various national and international swimming competitions.

Düsseldorf Place in North Rhine-Westphalia, Germany

Düsseldorf is the capital and second-largest city of the most populous German federal state of North Rhine-Westphalia after Cologne, as well as the seventh-largest city in Germany. with a population of 617,280. At the confluence of the Rhine and its tributary Düssel, the city lies in the centre of both the Rhine-Ruhr and the Rhineland Metropolitan Regions with the Cologne Bonn region to its south and the Ruhr to its north. Most of the city lies on the right bank of the Rhine. The city is the largest in the German Low Franconian dialect area. "Dorf" meaning "village" in German, the "-dorf" suffix is unusual in the German-speaking area for a settlement of Düsseldorf's size.

He also worked on the design of several cable-stayed bridges abroad, including the Pasco-Kennewick bridge (1978) in the U.S., and the Helgeland Bridge (1981) in Norway.

Fritz Leonhardt Prize

This prize was established in 1999 on the 90th anniversary of Leonhardt's birth, to recognise outstanding achievements in structural engineering. The first prize was awarded to Michel Virlogeux. [3] Subsequent winners have included Jörg Schlaich (2002), René Walter (2005), and William F. Baker (engineer) (2009). [4]



  1. "Honorary Graduates 1989 to present". University of Bath . Retrieved 18 February 2012.
  2. Troyano, Leonardo Fernandez: "Bridge Engineering: A Global Perspective", Thomas Telford Publishing, 2003
  3. Saul, Reiner et al.: "Eminent Structural Engineer: Fritz Leonhardt (1909-1999)", Structural Engineering International 1/2007
  4. "William F. Baker Awarded Fritz Leonhardt Prize For Achievement In Structural Engineering" Archived 2009-09-21 at the Wayback Machine .. 2009-07-09. Retrieved on 2009-07-14

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