Professor Theodosis Tassios was born in Kastoria. He received his Diploma in Civil Engineering from the National Technical University of Athens (1953) and continued his studies at the Center d’Etudes Superieures ITBTB in Paris for one year. He was awarded a PhD from NTUA in 1958. He was elected Lecturer at the NTUA (1958) and then Associate Professor (1964) and Professor (1969). He founded the Reinforced Concrete Laboratory of NTUA and directed it until 1997. He also taught at the Universities of Baghdad (1979), Shanghai (1982), Nanking (1985) and Pavia (1986) as well as the College International des Sciences de Construction Paris (1979-1989).
An outstanding figure in the scientific and professional life of the country, he taught thousands of engineers and published hundreds of scientific papers in the areas of Soil Mechanics, Concrete Technology and Ancient Greek Technology. He engaged with a wide range of scientific, technological and educational issues (European and national regulations, earthquake protection, protection of monuments, public works), but also with matters of Philosophy, Education, Language, Terminology and Society, as an author of opinion pieces in the daily and weekly press.
He is a founding member and President of many Greek scientific associations and a member of American and European associations, and served as President of RILEM (1977-78), CEB (1983-87) and Model Code 90 (1987-91), Advisor for the United Nations, and Expert for the European Community.
He has received several honors and awards. He is Honorary Professor of the University of Nanking (1985), Honorary Doctor of the University of Liege (1986), Fellow of the American Concrete Institute (1986), Honorary President of CEB (1988), Honorary Member of RILEM (1989), CIAS (1998), the Scientific Technical Chamber of Cyprus (1999), and CICOP (2001), Honorary Doctor of the Democritus University (2001), Member of the Academy of Sciences of Torino (2004), Honorary President of the Hellenic Philosophical Society (2004) and Honorary Member of the Hellenic Society of Terminology (2008). He has also been awarded the Medal of the City of Paris (1986).