Title: Design UHPC Structure with High Deformation Capacity

Author(s): Shao

Publication: Web Session

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Date: 10/17/2021

Abstract:
Compared to conventional concrete, UHPC materials exhibit higher tensile ductility on the material level due to its fiber reinforcement. However, recent studies reveal that reinforced UHPC (R/UHPC) beams may show fewer failure warning signs and lower deformation capacity than reinforced concrete. To guarantee the reliability and performance of UHPC structure, it is necessary to understand the causes of low structural ductility in some R/UHPC beams. This presentation reports the results of a large-scale experimental and numerical program, which characterize the failure mechanism of R/UHPC beams. The experimental program tested R/UHPC beams with different fiber volumes (0.5%, 1.0%, and 2.0%), reinforcing ratios (0.96% and 2.10%), and commercial UHPC materials (Ductal and UP-F). The numerical program validates and expands the knowledge from the experimental program by simulating R/UHPC beams with different UHPC tensile properties, reinforcing ratios, and steel properties. Results reveal that two flexural failure paths exist for R/UHPC flexural members: failure after crack localization or failure after gradual strain hardening of longitudinal reinforcing steel. These two failure paths represent distinct failure mechanisms and ductility ranges. Based on the results of the experimental and numerical program, a simple method is proposed and validated to help design UHPC structure with high deformation capacity. This study provides insights into the selection of appropriate UHPC material properties and the development of future UHPC structures.