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: Size Effect in Torsional Strength of Plain and Reinforced Concrete
Author(s): Kedar Kirane, Konjengbam Darunkumar Singh, and Zdenek P. Bažant
Publication: Structural Journal
Appears on pages(s): 1253-1262
Keywords: crack band model; microplane model; reinforced concrete; size effect; torsion
Abstract:As shown long ago, plain and longitudinally reinforced concrete beams without stirrups exhibit a significant size effect on torsional strength, which was thought to be of a type occurring after long, stable crack growth (called Type II). This paper shows, by experimentally calibrated finite element simulations, that: 1) longitudinally reinforced concrete beams with stirrups also exhibit a significant size effect; and 2) the size effect in beams both with and without stirrups is not of Type II but Type I, characterizing failure at macrocrack initiation. In the practical size range, Type I is deterministic and terminates with a horizontal, rather than inclined, asymptote. The simulations are based on microplane model M7, which was shown to match well all the types of uniaxial, biaxial, and triaxial tests with post-peak softening in tension and compression. The model is calibrated by simulating previous torsional size effect tests of plain concrete beams and of longitudinally reinforced beams without stirrups, as well as the tests of beams with stirrups having different reinforcement ratios and different aspect ratios. The fact that all these tests are fitted closely, in terms of not only the maximum loads but also the crack patterns, lends credence to the predictions of size effect in beams with stirrups.
Click here to become an online Journal subscriber