Creep and Shrinkage

Abstract

Hubert Rusch, the senior author of this volume, who died in 1979, was one of the great international figures in the field of reinforced concrete. He combined outstanding professional achievements in design, research and teaching with a warm outgoing personality. Aided by his knowledge of five languages, this combination made him a most effective leader in international organizations and led to many personal-professional friendships in a variety of countries.As a practicing engineer, both in Germany and in Argentina, he was responsible for the design and, often, construction of exceptional concrete structures such as large shell roofs, domes, aircraft hangars, industrial plants, harbor structures, and precast and prestressed concrete systems. His distinguished academic career began in 1948 when he accepted a professorship in concrete construction at his Alma Mater, the Technische Universitiit Munchen. In his additional related capacity as director of the Materials Testing Institute, which he greatly enlarged and modernized, he conducted and supervised research on a large scale. This resulted in important basic contributions in such areas as the structural performance of concrete, creep, shrinkage, crack formation, inelastic flexural theory, concrete quality control, limit design, and safety theory based on probabilistic reasoning, to mention only the most important ones.His far-reaching international impact was based not only on these engineering achievements, but also very much on his multilinguality and, particularly, on the ease and warmth with which he established and maintained close personal relationships. When the European Concrete Committee (CEB) began its work in 1953, he immediately became one of its leading members as a Founding Vice President, later its President, and finally its Honorary President. In these capacities, he helped guide the CEB in the creation of its internationally important Model Code, and also established close liaison between the CEB and the American Concrete Institute.Among his international connections, those with the United States were particularly close. For one year he was Distinguished Visiting Professor at Cornell v vi Dedication University, and later held a similar appointment at the University of Texas in Austin. At both institutions his interaction with colleagues and students was immediate, close, productive, and often long lasting.His multifarious activities and his 130 publications, including books translated into several languages, brought him many honors and distinctions in Germany and elsewhere. Of these, only those bestowed on him in the United States will be mentioned here: He was elected Foreign Associate of the National Academy of Engineering, an Honorary Member of the American Concrete Institute, which also conferred on him its Wason Medal and Alfred Lindau Award, and he received the Longstreth Medal of the Benjamin Franklin Institute in Philadelphia.This great man enjoyed life in many of its aspects, in his closeness to his family, in his love for nature, music...

Shear Strength of Reinforced Concrete Beams: Concrete Volumetric Change Effects

“…To date, many studies have been published on internal stress, shrinkage cracking, crack control, and flexural stiffness change (Rüsch et al 1983;Bischoff 2001;Sakata and Shimomura 2004;Tanimura et al 2005;Sato et al 2007;Gribniak 2008). Furthermore, some studies on structural strength have been published.…”

Experimental investigation on the reversibility of concrete creep under repeating loads

“…The recoverable part of creep is often referred to as the delayed elastic strain e cr.d (t)-a consequence of the interaction between predominantly viscous cement paste and predominantly elastic aggregates [15]. The major share of the creep strain is irreversible and often referred to as the flow e cr.f (t).…”

“…Groups of researchers in Europe [14][15][16][17] and in the United States [18] have made successful efforts to experimentally investigate and describe concrete creep under variable stresses. However, keeping in mind that their aim was to check the principle of superposition and not to simulate the real variations of the working loads (which are repeatable in nature), they have created stepwise stress histories (e.g.…”

Veränderung der Steifigkeit und des Dehnungsverhaltens von Normalbeton bei zyklischer Druckschwellbeanspruchung mit Ruhephasen

“…In den Serien 4 und 5 (Regime II) betrugen analog dazu die Reduktionen der bezogenen Längsdehnung nach 20 Minuten im Mittel 1,4 % (Serie 4) und nach zwei Stunden 2,7 % (Serie 5). Dieses Verhalten wird bereits von Rüsch, Jungwirth und Hilsdorf auf das verzögert elastische Verhalten des Betons zurückgeführt [10].…”