Karl Girkmann studied civil engineering at the Vienna University of Technology and during the First World War, as an officer in the railroad regiment, was entrusted with the construction of new bridges. After the end of the war, Girkmann turned his attention to the construction of overhead power lines for hydroelectric power plants at AEG in Vienna. At Waagner-Biro A. G., he was involved in structural steel engineering and played a leading role in the steel skeleton construction of the tobacco factory in Linz.
From 1938 until his retirement in 1958, he was Full Professor of Engineering Mechanics at the Vienna University of Technology (also Rector in 1950/51) and during this time he wrote a fundamental work on the calculation and design of surface bearing structures, which was first published shortly after the Second World War.
With fundamental scientific works and publications on bridge construction, structural steel engineering, tank construction and many other branches of civil engineering, Girkmann is considered a leader in the development of civil engineering in the first half of the 20th century.