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: Critical Assessment of ACI 318 Eq. (18-3)
for Prestressing Steel Stress at Ultimate Flexure
Author(s): Ravi K. Devalupura and Maher K. Tadros
Publication: Structural Journal
Appears on pages(s): 538-554
Keywords: flexural strength; prestressed concrete; prestressing steels; stan-dards;
strain compatibility methods; stress relaxation; stress-strain relation-ships;
Abstract:An attempt is made by the authors to explore the background and feasibility of Eq. (18-3) of the ACI Code 318-89. Advantages and disadvantages of the equation are discussed in detail, and results of laboratory testing conducted by the authors on 270-ksi low-relaxation strands for the Precast/Prestressed Concrete Institute also are included. A lower-bound curve based on 56 actual stress-strain curves is compared with other prediction methods, and an alternative approach for calculating prestressing steel stress at ultimate flexure is proposed. Recommendations are made to revise some of the existing Building Code and Commentary sections. Two design examples are presented to show the versatality of the iterative strain-compatibility method and to show the invalidity of Eq. (18-3) for use in some practical cases.
Click here to become an online Journal subscriber