Title: Design Approach for Flexural Strength of Reinforced Ultra- High-Performance Concrete Members Considering Size Effect

Author(s): Fei Peng, Weijian Yi, and Zhi Fang

Publication: Structural Journal

Volume: 119

Issue: 1

Appears on pages(s): 281-294

Keywords: design equations; flexural strength; moment-curvature; size effect; ultra-high-performance concrete (UHPC)

DOI: 10.14359/51734140

Date: 1/1/2022

Abstract:
A new simplified method considering size effect was proposed to calculate the flexural strength of reinforced ultra-high performance concrete (UHPC) members in this paper. First, an iterative numerical procedure was developed to predict the moment-curvature behavior of reinforced UHPC sections. Based on the developed procedure and available experimental results, the performance of three constitutive models for UHPC under tension was evaluated. It was found that the size-dependent stress-strain model could provide accurate and consistent predictions of the flexural strength of reinforced UHPC members, while the size-independent model overestimated the flexural strength of largescale members. A parametric study was then conducted to evaluate the contribution of fibers and the size effect. An equivalent rectangular stress block was proposed to simplify the tensile stress distribution of UHPC. On this basis, a simplified yet rational design approach for predicting flexural strength was proposed based on a regression analysis of parametric analysis results. Finally, the accuracy of the proposed approach was verified based on the available experimental results of 117 reinforced UHPC members.