In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Become an ACI Member
Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
American Concrete Institute
38800 Country Club Dr.
Farmington Hills, MI
Feedback via Email
Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: Review of Basic Assumptions for the
Author(s): K.-H. Reineck
Publication: Special Publication
Appears on pages(s): 367-384
Keywords: codes; concrete ties; concrete contribution; crack friction; shear design; structural concrete; truss model.
Abstract:There are two basic assumptions for the shear force Vc in ACI 318-02: 1) Vc
is the shear force at cracking; and 2) Vc is the same for members with and without shear reinforcement. By reviewing tests, it is shown that neither assumption is valid. Therefore, different terms have to be defined for the concrete contribution Vct of the shear capacity for members without shear reinforcement and Vc for members with stirrups. The size effect has to be considered for Vct for members without shear reinforcement, but plays a minor role for Vc for members with stirrups.
Chapter 4, "Truss model versus Vc-term" shows that there is a clear relationship between the angle q of the inclined struts and a Vc-term. A more realistic model for the state of stress in the web, however, is described by the "truss model with crack friction," where the crack angle is different from the strut angle or angle of principal compression. There, the term Vc has a clear mechanical meaning as the vertical component Vf of friction forces along the inclined crack. In the web, an inclined biaxial tension-compression-field exists, so that the usual truss model is superimposed with a truss model with inclined concrete ties. Because the crack angles are considered, the shear design for prestressed concrete beams leads to a lower value for the angle q and less amount of stirrups than that for reinforced concrete beams.
Click here to become an online Journal subscriber