Punching of Structural Concrete Slabs


Book Description

Punching is considered to be one of the most difficult problems in structural concrete design and mechanical models or theoretical analyses were developed rather late in the history of concrete research attempts. This fib Bulletin reviews the development of design models and theoretical analyses since the CEB Bulletin 168 Punching Shear in Reinforced Concrete - State-of-the-Art Report published in 1985. The role of the concrete tensile strength was specially addressed. In this respect the present bulletin is also following-up the CEB Bulletin 237 Concrete Tension and Size Effects - Utilisation of concrete tension in structural concrete design and relevance of size effect - Contributions from CEB Task Group 2.7 published in 1997. Apart from new theoretical developments a comprehensive databank for comparisons with experimental evidence is included. About 400 punching tests were critically reviewed and evaluated in a consistent manner. This is thought to be the first step towards a generally agreed selection of reliable tests. The evident value of such a data bank is illustrated by comparisons carried out between the data and some of the analytical proposals as well as empirical code formulas. List of contents : (1) Introduction, (2) Code equations, (3) Mechanical models for punching, (4) New developments for mechanical models, (5) Numerical investigations, (7) Comparison of mechanical models and test results of slabs without shear reinforcement, (8) Comparison of code rules and tests of flat slabs without shear reinforcement, (9) Comparison of codes, models and tests of flat slabs with shear reinforcement, (10) Experimental investigations, (11) Summary and conclusions, References, Appendices : (I) Databank on slabs without shear reinforcement, (II) Databank on slabs with shear reinforcement, (III) Comparison of test data with code rules, (IV) Comparison of test data with selected models, (V) Notations.




Punching shear of structural concrete slabs


Book Description

fib Bulletin 81 reports the latest information available to researchers and practitioners on the analysis, design and experimental evidence of punching shear of structural concrete slabs. It follows previous efforts by the International Federation for Structural Concrete (fib) and its predecessor the Euro-International Committee for Concrete (CEB), through CEB Bulletin 168, Punching Shear in Reinforced Concrete (1985) and fibBulletin 12, Punching of structural concrete slabs (2001), and an international symposium sponsored by the punching shear subcommittee of ACI Committee 445 (Shear and Torsion) and held in Kansas City, Mo., USA, in 2005. This bulletin contains 18 papers that were presented in three sessions as part of an international symposium held in Philadelphia, Pa., USA, on October 25, 2016. The symposium was co-organized by the punching shear sub-committee of ACI 445 and by fib Working Party 2.2.3 (Punching and Shear in Slabs) with the objectives of not only disseminating information on this important design subject but also promoting harmonization among the various design theories and treatment of key aspects of punching shear design. The papers are organized in the same order they were presented in the symposium. The symposium honored Professor Emeritus Neil M. Hawkins (University of Illinois at Urbana-Champaign, USA), whose contributions through the years in the field of punching shear of structural concrete slabs have been paramount. The papers cover key aspects related to punching shear of structural concrete slabs under different loading conditions, the study of size effect on punching capacity of slabs, the effect of slab reinforcement ratio on the response and failure mode of slabs, without and with shear reinforcement, and its implications for the design and formulation in codes of practice, an examination of different analytical tools to predict the punching shear response of slabs, the study of the post-punching response of concrete slabs, the evaluation of design provisions in modern codes based on recent experimental evidence and new punching shear theories, and an overview of the combined efforts undertaken jointly by ACI 445 and fib WP 2.2.3 to generate test result databanks for the evaluation and calibration of punching shear design recommendations in North American and international codes of practice.










Reinforced Concrete Slabs


Book Description

Unter "bewehrtem Beton" versteht man eine Kombination von Beton mit anderen, verstärkenden Materialien (meist Stahl). Aus Stahlbetonplatten werden nicht nur Häuser gebaut, sondern auch Straßen und Mauern. Bauingenieure müssen die Merkmale und Einsatzfelder dieser Werkstoffe kennen und Belastungsgrenzen abschätzen. Dieses Buch, das einzige seiner Art, dient Praktikern und Studenten der Bautechnik als kompetenter Begleiter. (01/00)




Fibre Reinforced Concrete: Improvements and Innovations II


Book Description

This volume highlights the latest advances, innovations, and applications in the field of fibre-reinforced concrete (FRC), as presented by scientists and engineers at the RILEM-fib X International Symposium on Fibre Reinforced Concrete (BEFIB), held in Valencia, Spain, on September 20-22, 2021. It discusses a diverse range of topics concerning FRC: technological aspects, nanotechnologies related with FRC, mechanical properties, long-term properties, analytical and numerical models, structural design, codes and standards, quality control, case studies, Textile-Reinforced Concrete, Geopolymers and UHPFRC. After the symposium postponement in 2020, this new volume concludes the publication of the research works and knowledge of FRC in the frame of BEFIB from 2020 to 2021 with the successful celebration of the hybrid symposium BEFIB 2021. The contributions present traditional and new ideas that will open novel research directions and foster multidisciplinary collaboration between different specialists.




Effect of Fibers on the Punching Shear Strength of Reinforced Concrete Slabs


Book Description

This study summarizes experimental results of the punching shear behavior of reinforced concrete slab-column connections containing fiber reinforcement. Fiber reinforcement is particularly attractive and beneficial for concrete, especially where shear stresses are involved. Tests are reported on simply supported slab specimens loaded through a stub column to study the effect of several parameters, namely, type, volume, fraction, and aspect ratio of fibers. The experimental tests on reinforced concrete slabs showed that fiber reinforcement can contribute significantly to the enhancement of punching shear strength and ductility of concrete structural members. This increase is function of the fiber volume and fiber type. A simple empirical relationship describing the effect of steel fibers on the punching shear strength of slab-column connections is derived based on the results of this test and other experimental results reported in technical literature.







Two-way Shear Strength of Reinforced Concrete Slab-column Connections


Book Description

To assess the two-way shear resistance, or punching shear strength, of reinforced concrete slabs, code provisions fitted from experimental data are typically employed. The experimental data forming the bases of these provisions have generally consisted of isolated slab-column connection tests that seek to represent the negative moment region of a flat plate slab. This research is focused on exploring the variation in the punching performance of slab-column connections when the typical testing conditions used to investigate isolated slab specimen are varied in a manner that produces alternative sectional loading conditions within the column connection region. To accomplish this, an innovative testing apparatus is introduced that permits alternative combinations of slab bending moment to out-of-plane shear force ratios to be applied to the slab-column connection. Results are presented from an experimental program conducted at the Ferguson Structural Engineering Laboratory (FSEL) of The University of Texas at Austin and an analysis is presented comparing the results from the tests with estimations made from current standards, the Critical Crack Shear Theory (CSCT), and also from numerical models. The data obtained from the experimental program are used to scrutinize current design and analysis procedures, and to shed light on the significance of the sectional loading conditions in the light of flat plate connection shear resisting performance.