No abstract

No abstract

This paper examines the evidence for the one‐way shear model developed for the fib Model Code for Concrete Structures 2010 and provides examples of its application. For the design and analysis for shear, for members with and without shear reinforcement, the fib Model Code 2010 procedures have been developed from physical‐mechanical models that are based on observed behaviour at the meso‐scale level; they represent a significant advance over previous standardized empirical methods. In addition, an approach referred to as “level of approximation” (LoA) is incorporated where advanced models are simplified in a consistent and conservative way such that the designer can select the effort needed to justify their design. To illustrate the practical use of the models and the LoA approach, two examples are presented. The first is a deck slab of a cut‐and‐cover tunnel where design and possible refinements are discussed for a given configuration. The second is a prestressed concrete bridge girder, which is considered for the cases of design and for the analysis of an existing structure.

No abstract

Traditional shear design procedures for concrete structures rely on empirical equations derived from laboratory experiments and lack the type of adequate theory that forms the basis of flexural design. As shear resistance depends on so many variables and because laboratory tests do not cover the full practical range of parameters, empirical shear design equations can result in structures with inadequate shear strength. Recent failures of such structures have highlighted the need for shear design provisions solidly based on an adequate theory. This paper introduces such a theory and explains the simple design models derived from the theory, which include a strut-and-tie model for disturbed regions and a sectional model for flexural regions. These models form the basis of the shear provisions on the 2004 Canadian standard for the design of concrete structures. In the current paper, results from nine major experimental series are compared with predictions from the new shear provisions and with predictions from the shear provisions of the Eurocode and the American Concrete Institute code. It is demonstrated that the new shear design provisions are capable of predicting the shear strength of reinforced concrete members and prestressed concrete members with considerably greater reliability.