Failure Analysis of Steel Fiber-Reinforced Concrete T-Beams without Shear Stirrups

Inkyu Rhee

doi:10.3390/app12010411

Abstract

The shear failure of a reinforced concrete member is a sudden diagonal tension failure; flexible failure is gradual, associated with significant cracks, and leads to extensive sagging. Therefore, reinforced shear rebars are commonly used to ensure that flexible failure occurs before shear failure under extreme conditions. Extensive efforts are underway to replace conventional shear reinforcements with steel fibers. Here, a nonlinear analysis of a steel fiber-reinforced concrete T-beam was performed in order to estimate the maximum shear capacity with the aid of experimental test data. A continuum-damaged plasticity model and modified compression field theory were used for nonlinear analysis. Three 360 × 360-mm web elements were selected between the shear span; changes in the principal axis caused by crack development and propagation were traced. Changes in the crack angle according to the average strain of the bottom longitudinal reinforcement and the vertical strain of the web element were also determined. For verification, a strut-tie model was used to predict shear capacity. The experimental results and the finite element analyses were in good agreement.

Highlights

Shear stirrups are commonly used to ensure that flexible failure occurs before shear failure under extreme conditions
Despite many experiments [1,2,3] and interpretations [4,5,6,7,8] over the years, shear failure remains poorly understood; the design of shear force-bearing members continues to rely on formulae derived from experimental data
Web elements in a biaxial stress state rotate theofcrack angle as the averaged tensile strain of the bottom rebar increases, and the strain is released when of the principal axis tended to fall because the transverse strain ε gradually increased as the steel fiber-reinforced concrete (SFRC) beam failed abruptly

Summary

Introduction

Shear stirrups are commonly used to ensure that flexible failure occurs before shear failure under extreme conditions. Among the theories on various shear failures, the average behavior of web elements in the shear span (inclined cracking in terms of transverse strain, and longitudinal strain) was examined, and the change in the crack angle until major failure was traced. The angle of inclination critical, and (3) secondary shear-critical [Figure 7(a)] were selected for the sake of the modof the principal axis tended to fall because the transverse strain ε t gradually increased as ified theory. Web elements in a biaxial stress state rotate theofcrack angle as the averaged tensile strain of the bottom rebar increases, and the strain is released when of the principal axis tended to fall because the transverse strain ε gradually increased as the SFRC beam failed abruptly.

Results

Conclusion