To Professor Dr. Bruno Thfirlimann on his 60th Birthday

This issue has been published to celebrate the 60th birthday of one of the outstanding structural engineers, researchers and teachers of our time, Dr Bruno Tht~rlimann, Professor at the Swiss Federal Institute of Technology, Zurich, Switzerland.

The first 12 years of his career were spent in the USA, during which time the present writer first came to know him. The two have never lost contact since then, to the latter's great pleasure, since Prof. ThtMimann is not only a great engineer but he and his wife Susi are warm, friendly and alive people whose friendship one values as a pleasure and a privilege. Professor Thiirli- mann's most varied career and contributions will be briefly sketched below.

He arrived in the United States in 1948 to take a position as research assistant at Lehigh Uni- versity, Bethlehem, Pennsylvania. This was then, and still is, one of the major structural research centres in the USA. There he received his PhD degree in 1950 and then spent about two years as Research Associate in the Graduate Division of Applied Mathematics, Brown University, Providence, Rhode Island. In 1952 he joined the Faculty of Lehigh University as Research Professor in Civil Engineering. He remained there for eight years during which time he was active in doing and directing very extensive and important research on various aspects of steel struc- tures. In 1960 his ahna mater, the Swiss Federal Institute of Technology, offered him the position of Professor of Structural Engineering, which he accepted. Since then he has directed very important and widespread research activity at the ETH, primarily in the fields of reinforced and prestressed concrete, in contrast to his previous concentration on steel structures.

After his return to Switzerland, he received three Awards from the American Society of Civil Engineers, the Research Prize (1960), the Norman Medal (1963) and the Moisseiff Award (1964). In 1977 he was elected President of the International Association for Bridge and Structural Engineering (IABSE, in German IVBH), in which important post he still continues. During his presidency the Associa- tion has been revitalized in many important respects. In 1978 he was elected to the National Academy of Engin- eering, regarded in the USA as a very exclusive distinction. He received this honour not as a 'foreign associate' but as a regular American member, having maintained dual citizen- ship (Swiss and American) ever since his long stay there.

Throughout his career, Prof. Thi;~rlimann has not limited himself to academe. He has been an influential consultant on many unusual and interesting structures, including the CN-Tower in Toronto, Canada, and another tower in Basel,

Switzerland; the Youth Welfare Centre in Riad. Saudi Arabia; the Texas Commerce Plaza in Houston, USA, and the famous Hancock Tower, Boston, USA, where his contribution was decisive in stabilizing this excessively flexible structure which was not usable until far reaching changes had been made in the completed building, including increased rigidity and stabilization by specially provided masses. Apart from buildings he was also consultant on important bridge structures, such as that in Ruppoldingen, Switzerland, and the Gateway Bridge in Brisbane. Australia.

It is impossible to present in any detail the contents of his more than 80 publications. For this reason, only the most impor- tant of Prof. Thtirlinmnn's interests will be mentioned, to give some impression of the scope o1" his research activities.

His early interest at Lehigh University, and later in Switzerland, was in plastic design and analysis methods, chiefly in steel but also in reinforced concrete, methods which have since become standard design equipment. He did pioneer- ing research, in connection with colleagues, in the inelastic buckling of steel meinbers, particularly the influence of residual stresses on the buckling loads of steel columns. His very extensive research with his countryman K. Basler on the various aspects of the strength of plate girders has basically affected the design methods of this impor- tant class of members.

In reinforced concrete, he was again active in the area of inelastic

effects, such as in plastic design methods, in creep-buckling of columns, in the plastic performance of two-span con- tinuous beams, etc. An area of continuing intensive research was the strength of beams and slabs under various com- binations of simultaneous shear, torsion and bending, t'or reinforced as well as for prestressed concrete. Another useful area of investigation was that of partially prestressed beams.

His interests, however, are not limited to purely tech- nical matters, as evidenced by his wideranging activity as president of IABSE. Specifically, one may cite just a presentation at a tall buildings conference: 'Tall Buildings, yes or no, Technical Progress, a Curse or a Blessing'?'

In closing this sketchy overview of a remarkable career, may 1 express my best wishes to Bruno Thhrlinmnn for many more years as satisfying and remarkable as those which led up to his 60th birthday.

George Winter

2 Eng. Struct., 1983, Vol. 5, January