Fritz Leonhardt and Wolfhart Andrä continue their co-operation in Stuttgart.

Following the planning of the Rhine Bridge Cologne-Deutz, the first slender steel box girder bridge with 184 m main span, fundamental developments and inventions in the field of prestressed concrete take place.

In connection with the planning of bridges across the Mosel, Elz, Donau and Neckar the prestressing system Baur Leonhardt (concentrated cables) and later the Leoba AK-system (Leonhardt Baur, single tendons with special wedge anchorages) are developed. This scientific work on prestressed concrete led to the book "Prestressed Concrete, Design and Construction" by Prof. Leonhardt, an internationally recognized standard text on the subject.

With the founding of the independent consulting firm Leonhardt, Andrä und Partner GmbH the era of incrementally launched bridges, cable-stayed bridges, large-span bridges for the new railway lines in Germany, cable net structures and tent-like roofs, universities, administration buildings and hospitals starts.

The most prominent example of a cable-net structure is the Olympic-Roof in Munich. At the same time the roof of the Swimming Hall "Sechslingspforte" at Hamburg is built as one of the largest shell structures of its kind in the world.
In a design competition for a bridge across the Strait of Messina the largest cable-stayed bridge up to now with a main span of 1300 m is designed and awarded one of the first prizes.
The two cable-stayed bridges Zárate Brazo Largo are the first cable-stayed bridges with an aerodynamically shaped cross-section for road and railway traffic.
The Oberkassel Bridge in Düsseldorf is the "youngest" member of the so-called Düsseldorf Bridge family consisting of the Kniebridge and the Theordor-Heuss Bridge. Lateral shifting was done on Neopot-Teflon sliding bearings.
The cable-stayed bridge across the Columbia River between Pasco and Kennewick with a bridge deck of prestressed concrete is the first of a series of bridges with superstructures of concrete and steel in the United States, e. g. East-Huntington Bridge, Burlington Bridge, Baytown Bridge and the design of the Sunshine-Skyway Bridge.

Involvement in the area of structural planning of valley bridges for the German Federal Railway (DB). This work consists of approximately 100 structural drawings proposed to become part of the German Railway codes and approximately 30 booklets clarifying the planning stages of valley bridges for future German railways. Much of this work may be used in the future for the serviceability of roadway bridges as well. Among these projects are the Main Bridge Gemünden (concrete frame bridge with 135 m main span), Main Bridge Veitshöchheim (concrete box girder bridge with 162 m main span) - the superstructure was included in the Guinness Book of Record as the longest incrementally launched bridge.
Intensive research for composite girders under negative moments contribute decisively to the development of steel composite bridges without prestressing of the top slab over the piers. With haunched girders and a concrete bottom chord at the piers increased span lengths have been achieved, e.g. a main span of 208 m for the railway bridge across the river Main at Nantenbach and a main span of 214 m for the highway-railway bridge across the river Caroni in Venezuela. At both bridges the perfobond rib was used for the first time. Over the last decade the firm has also become active in the field of bridge maintenance, reconstruction and repair without interruption of traffic.

During the construction of towers upwinds have been noticed in the tower shafts and the idea of a thermal upwind or solar chimney power plant was born. A pilot plant has been financed by the Federal Ministry for Research and Technology and built at Manzanares, Spain, in order to collect design data.

In the structural design of high-rise buildings the development of flat slabs has been successful as the problems of punching failure were solved by the development of shear stud rails. This construction method has proved to be economic especially for large jointless structures with up to 200 m length, e. g. for the Post Office Ministry in Bonn, the IBM administration center in Ehningen, the BASF central engineering building in Ludwigshafen or the Daimler-Benz AG head office in Stuttgart.
Synergy effects between the construction of bridges, tunnels and high-rise structures facilitate the realization of a multi-story residence over a highway in Berlin-Wilmersdorf (Schlangenbader Street) or of a desulforisation and washing plant for a thermal power plant in Stuttgart.
The perfobond rib, a very effective connection between steel and concrete with high ultimate capacity, was used for the construction of the Caroni Bridge for the first time.

After the German reunification new offices have been founded in Berlin, Dresden, Erfurt and Leipzig.

The successful co-operation of now 175 employees from all parts of the reunified Germany is reflected in nearly all new bridges across the Elbe, in large-scale projects in Berlin, especially in the conversion of the Reichstag Building as seat of the German Parliament in Berlin.
The range of projects stretches from construction engineering e.g. for the site excavation of the Lehrter Railway Station, the Subway Station Mendelssohn-Bartholdy-Park, the construction pit of the A + T building above the sub- and underground railway at the Potsdamer Platz, refurbishment of the former Narva factory (Oberbaum City) in a difficult urban situation to attractive steel-glass structures for the administration building of the Landesbank Baden-Württemberg (former Landesgiro-kasse) in Stuttgart, the CDU Head Office at Berlin or for the Transparent Factory of the Volkswagen AG in Dresden.
A contribution to future production of energy is the design of the Institute for nuclear fusion research of the Max Planck Institute in Greifswald.
Hospitals in Heidelberg and Tübingen, university buildings in Magdeburg, the Zeppelin Museum in Friedrichshafen and the Museum of Fine Arts in Leipzig, the New Theatre in Erfurt, the REMU Business center in Munich (in joint venture with Boll and Partner), the Office building for the IKB, Bank of German Industry, in Düsseldorf and the SMS DEMAG administration office in Düsseldorf, tunnel and galleries for the bypass road of federal road B 30 at Ravensburg and in Ertingen, or the new highway bridge with double composite action and corrugated steel webs across the Altwipfergrund stand for all the projects in Germany.

Abroad there are still large cable-stayed bridges in design and under construction, e. g. in Argentina, Finland, Norway, Sweden, Korea and Hong Kong.
Other remarkable bridges abroad are the Galata Bridge in Istanbul, a bascule bridge with the largest surface worldwide, the La Cartuja Bridge designed for the Expo 92 in Sevilla, a continuous steel beam with an orthotropic plate, a single haunch and noticeable slenderness, opened for traffic only 12 months after the award of the contract.
Like in bridge design structural creativity has been applied to develop the design of the Millennium Tower in Portsmouth.
To manage the extensive tasks of the checking and supervision of bridges as part of the high-speed railway line in Taiwan the Taipeh Office has been established.

The traditional development of prestressing methods continues with the Leoba Carbodur system. Anchorage and jacking devices have been developed to prestress carbon fibre strips on the surface of reinforced or prestressed concrete, steel or timber structures. This method was first applied for the Gomadingen Bridge.
High technical qualification, flexibility, enthusiasm for the work, ability of teamwork and sense of responsibility in accordance with the legacy of Fritz Leonhardt and his partners distinguish the employees today and for the future.