International Concrete Abstracts Portal

Sixty percent of the nation's highly toxic and radioactive mixed wastes are stored at Hanford in 177 deteriorating underground storage tanks. To close or remove these storage tanks from service and place them in a condition that is protective of human health and the environment, the tanks must be physically stabilized to prevent subsidence once wastes have been retrieved. Remaining residual liquid waste in the tanks that cannot be removed must be solidified and the solid wastes encapsulated to meet the Nuclear Regulatory Commission, Department of Energy, Environmental Protection Agency, and the State of Washington requirements. The Department of Energy has developed cementitious flowable concretes to restrict access and provide chemical stabilization for radionuclides. Formulation, laboratory, and field testing for application at Hanford began with flowable, self-leveling structural and non-structural fills. A slump flow equal to or greater than 610 mm, 0% bleed water, and 0.1% (by volume) shrinkage measurements were key parameters guiding reformulation efforts that resulted in highly flowable, self-consolidating concretes that met Hanford 241-C Tank closure short- and long-term regulatory and engineering performance requirements.

Deep beams are common elements in concrete structures such as bridges, water tanks, and parking garages, which are usually exposed to harsh environments. To mitigate corrosion-induced damage in these structures, steel reinforcement is replaced by fiber-reinforced polymers (FRPs). Several attempts have been made during the last decade to introduce empirical models to estimate the shear strength of FRP-reinforced concrete (RC) deep beams. In this study, the applicability of these models to predict the capacity of simply supported deep beams with and without web reinforcement was assessed. Test results of 54 FRP-RC, 24 steel-fiber-reinforced concrete (FRC), and 7 FRP-FRC deep beams were used to evaluate the available models. In addition, a proposed model to predict the shear strength of FRPFRC deep beams was introduced. The model was calibrated against experiments conducted previously by the authors on FRP-FRC deep beams under gravity load. The model could predict the ultimate capacity with a mean experimental-to-predicted value of 1.04 and a standard deviation of 0.14.

The purpose of this symposium and special publication is to recognize and honor Professor Amin Ghali’s outstanding long-term dedication to the concrete industry. Dr. Ghali obtained his B.Sc. and M.Sc. degrees in Civil Engineering from Cairo University, Cairo, Egypt, respectively in 1950 and 1954, his Ph.D. from Leeds University, England in 1957. He spent ten years in engineering practice before joining at the University of Calgary, AB, Canada as a professor in 1966. Dr. Ghali has developed the revolutionary, multi-patented and globally used, headed-stud shear reinforcement systems for concrete flat slabs; he has been a consultant for a number of major international structures, including offshore structures, multi-story buildings, bridges, and tanks. Dr. Ghali authored over 300 papers and eight patents. In 15 editions and 6 translations, his books include: Structural Analysis Fundamentals (2022), Structural Analysis: A Unified Classical and Matrix Approach (2017), Circular Storage Tanks and Silos (2014), and Concrete Structures: Stresses and Deformations (2012). Professor Ghali has served the industry in many ways, including his role as a voting member of ACI Committee 435, Deflection of Concrete Building Structures, 343, Concrete Bridge Design, and 421, Design of Reinforced Concrete Slabs. Jointly with associates at University of Calgary, his research on punching shear design and control of long-term deflection enables design of affordable concrete floors. Dr. Ghali served as expert, providing technical testimony, for a number of complicated engineering cases. Dr. Ghali received a number of teaching and research excellence awards over his long career, and was elected a Fellow of ACI, ASCE, CSCE, and CAE; in 2017, he received the Top 7 Over 70 Award for his outstanding continued research and engineering contributions. The papers found in this SP publication encompass a broad overview on the important issues related to punching shear resistance and sustainable serviceability of flat plates from both a theoretical and design perspectives. These papers formed the basis of presentations made at the Amin Ghali Symposium on Design of Structural Concrete Slabs for Safety Against Punching and Excessive Deflection held at the ACI Fall 2020 Virtual Convention, on October 25, 2020. Twelve presentations were made in two sessions by those who have worked closely with Dr. Ghali in his areas of interest. The SP includes nine papers on design of concrete floors for punching and for serviceability. The sessions were sponsored by ACI Committee 421, Design of Reinforced Concrete Slabs. All papers in this publication were reviewed by at least two recognized experts in accordance with ACI review procedures. Special thanks are extended to all who helped to make the two technical sessions and accompanying publication a success.

Publication of the first edition of ACI 376 in 2011 has standardized the design and construction of precast, prestressed concrete walls with a sliding base for full-containment liquefied natural gas (LNG) tanks. This article describes the unique challenges encountered during design and construction of concrete foundation and outer wall for an LNG tank in Fairbanks, AK.

Two liquefied natural gas (LNG) storage tanks, 33 m (108 ft) high with 93 m (305 ft) internal diameter, were recently constructed in Darwin, Northern Territory, Australia. The article discusses the material design and its verification by routine testing, with a focus on durability performance, for the concrete used in the LNG tanks.