After his education at the University of Graz, with emphasis on structural engineering (Prof. Sattler) and ground engineering (Prof. Veder, inventor of slurry walls and contractor for the World Trade Center in New York), Gerhard Sauer worked as an Assistant and Lector at the University of Karlsruhe. He worked with Prof. Mueller, the founder of the science 'rock mechanics' and was an early exponent of the New Austrian Tunneling Method (NATM), which was developed in the 1950's and 1960's. He was involved in the first application of NATM in soft ground in an urban environment (Frankfurt, 1970) and played a major role in researching and further developing this construction method.
The findings of numerous field observations, model tests and numerical analyses are described in his dissertation 'Stress Rearrangement and Surface Settlement during Tunneling in Shallow Ground (Karlsruhe, 1976).'
In 1979, he established the 'Büro Dr. Sauer' in Salzburg, and started to develop value engineering designs based on the high cost effectiveness of NATM compared to conventional construction methods. In 1984, after several productive years in Austria, Germany and other European countries he expanded operations by opening new offices in Washington, DC and London. The Washington office or (the 'Dr. Gerhard Sauer Corporation') was one of the first Austrian consultant firms to design NATM tunnels in the United States. First employing NATM with subway stations and running tunnels for the Washington Area Metropolitan Transit Authority (WMATA). The London office, ('Dr. Gerhard Sauer Company, Ltd.') was formed as NATM was starting to make its way into the United Kingdom's expanding tunneling market.
In the following years, the Dr. Sauer Group successfully completed more than 250 Tunneling projects all over the world.