Recent Approaches to Shear Design of Structural Concrete

Description

Design procedures proposed for regulatory standardsshould be safe, correct in concept, simple to understand, andshould not necessarily add to either design or construction costs. These procedures are most effective if they are basedon relatively simple conceptual models rather than oncomplex empirical equations.

This report introduces design engineers to some approaches for the shear design of one-way structural concrete members. Although the approachesexplained in the subsequent chapters of this report are rela-tively new, some of them have reached a sufficiently maturestate that they have been implemented in codes of practice.

This report builds upon the landmark state-of-the-art reportby the ASCE-ACI Committee 426 (1973), The Shear Strength of Reinforced Concrete Members, which review the large body of experimental work on shear and gave the background to many of the current American Concrete Insti-tute (ACI) shear design provisions. After reviewing the many different empirical equations for shear design, Committee 426 expressed in 1973 the hope that “the design regulations for shear strength can be integrated, simplified, and given a physical significance so that designers can approach unusual design problems in a rational manner.

”The purpose of this report is to answer that challenge and review some of the new design approaches that have evolved since 1973 (CEB 1978, 1982; Wal raven 1987; IABSE1991a,b; Regan 1993). Truss model approaches and related theories are discussed and the common basis for these new approaches are highlighted. These new procedures provide a unified, rational, and safe design framework for structural concrete under combined actions, including the effects ofaxial load, bending, torsion, and pre stressing.