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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.
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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: High-Strength Concrete Columns Confined with Spirals
Author(s): Lonnie A. Marvel and Riyadh A. Hindi
Publication: Special Publication
Appears on pages(s): 1-14
Keywords: axial loading; cross spirals; ductility; concrete, high-strength; spiral reinforcement.
Abstract:This paper experimentally investigates the behavior of high-strength reinforced concrete columns confined using a new cross spiral confinement technique. The new cross spiral confinement technique uses two opposing spirals to confine circular concrete columns enhancing their strength and ductility, and increasing spiral spacing to facilitate the flow of fresh concrete. The new confinement arrangement is experimentally evaluated and compared to the conventional single spiral confinement arrangement. Twenty-one circular high-strength reinforced concrete columns with four different spiral spacings and longitudinal reinforcement ratios were tested under monotonic axial loading. Seven specimens utilized the conventional single spiral confinement, used as control specimens, while the remaining specimens utilized the new cross spiral arrangement. The new arrangement enables an increase in spiral spacing while maintaining the same volumetric confinement ratio as the conventional. Alternatively, doubling the volumetric confinement ratio without violating ACI 318-081 requirement for minimum spiral spacing. The study showed that the new cross spiral arrangement with the same volumetric confinement ratio as the conventional spiral obtained similar ultimate stress values while it attained about a twenty percent increase in ultimate displacement. The cross spiral confinement using twice the volumetric confinement ratio greatly outperformed the conventional spiral in all aspects.
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