Title: Design and Detailing Guidelines for Axially Loaded UHPC Columns

Author(s): Milana Cimesa and Mohamed A. Moustafa

Publication: Structural Journal

Volume:

Issue:

Appears on pages(s):

Keywords: axial columns, structural-scale columns, circular columns, square and rectangular columns, lateral reinforcement ratio (r_t), spacing-to-longitudinal reinforcing bar diameter ratio (s/d_b), confinement effect, strengt

DOI: 10.14359/51742143

Date: 7/31/2024

Abstract:
With a well-thought packing theory for sand, fine aggregates, cement, a water-to-cement ratio lower than 0.2, and steel fibers, UHPC achieves remarkable mechanical properties. Despite UHPC's superior mechanical properties compared to conventional concrete, its utilization remains limited, especially in structural applications, due to factors such as high cost, lack of design standards and guidelines, and inadequate correlation between material properties and structural behavior. By compiling and synthesizing the behavior of 70 structural- or full-scale axial UHPC columns, this research provides a new set of generalized design and detailing guidelines for axial UHPC columns. The study first uses the assembled database to assess and revisit the current ACI 318 axial strength design factors for applicability for UHPC. Next, the behavior trends are carefully analyzed to provide detailed recommendations for proper transverse reinforcement (ρ_t volume), spacing-to-longitudinal rebar diameter ratio (s/d_b) where s represents the centerline-to-centerline spacing between transverse reinforcement, and UHPC steel fiber ratio for best use of confinement.