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

Round 1

Reviewer 1 Report

Compliments for the excellent work done numerically and analytically to the author. The author needs to clarify just a few aspects of his excellent work. 
Section Introduction: Generally, in the introductory section, no equations are provided but the state of the art in the literature is reported and consequently the purpose of the article.
Page 4, line 2: What does D25 mean?
Page 4 "The angles of the three major inclined cracks increased with time.....": The author is invited to explain what "increased with time" means.
Page 5 "The Drucker-Prager Cap model....": The author is asked to justify the choice of model. Also in the literature the structural behavior of reinforced concrete can be described by Concrete Damage Plasticity as reported in (https://doi.org/10.1016/j.jobe.2021.103047), please add this in the reference. 
Page 5 "The yield strengths of the rebars and stirrups....": The author decided to model the bars with the linear-hardening mode model, but needs to provide better information on the ultimate value and deformations at yield and failure.
Figure 4C is unreadable;
Figure 8 is unreadable;
Figure 13a is unreadable;

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The author carried out nonlinear analysis of a steel fibre-reinforced concrete T-beam to evaluate the effect of steel fibres on their shear behaviour. He used the modified compression field theory for nonlinear analysis. The software was capable to predict the crack angle according to the average strain of the bottom longitudinal reinforcement. The author verified the shear capacity numerical results by comparing with experimental results from literature and the strut-tie model.

The author needs to adjust the writing format (second, third, and fourth paragraphs in the introduction are too long), spelling and language corrections. The subtitle "Results" need to be Results and Discussion. This section can be revised by adding some comparisons to enrich the obtained results. The conclusions are currently written as a one big paragraph while it is better to write the conclusions as separate short paragraphs showing the main findings. The references need to be updated by adding recent 2021 references.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

General report and comments:

• The numerical study is being submitted, so its relevance should be mentioned in the abstract, first and the last paragraph of the introduction section.
• The literature survey in the introduction chapter should be supplemented and extended.
• “Despite many experiments and interpretations over the years, … [1]” The reference was added to publication over 50 years ago. Please add a few present references.
• Page 2. The Authors indicated, that: “Many shear experiments have shown that a single diagonal tension crack in a member web immediately extends across the entire depth of the member; the member separates into two pieces and thus fails.” Please refer to proper citations.
• The introduction should define the purpose of the work and its significance. It is a lack of this information in the Introduction chapter. Therefore, the exact novelty of this research study described is not clear. Please give an extended description of the performed investigation.
• Figure 5b. The figure was published in [6]. Please verify copyright. Were new information were included?
• Page 5. The parameters of the Drucker-Prager Cap model used in calculations should be given directly.
• Page 5. The parameters of the linear-hardening model used in calculations should be given directly.
• Please explain in detail what interactions were applied between the three-dimensional continuum element and a 3D truss element (interaction between rebars and concrete) in numerical analysis. Why the rebars aren't also modelled by the 3D volume elements?
• Generally, at least three experiments are required to calibrate the Cap model: a hydrostatic compression test (an oedometer test is also acceptable) and either two triaxial compression tests or one triaxial compression test and one uniaxial compression test (more than two tests are recommended for a more accurate calibration). Please supplement the information about the calibration.
• Page 6. Please supplement proper citations to Figures and equations. What is new in this equation and Figure 3 in comparison with Abaqus documentation?
• Figure 4c. The numerical results correlation with the laboratory tests is not clear. Please explain in detail the difference and reason for the differences.
• Page 7. Please indicate new elements of performed analysis. The indicated parameters R, pa, pb are described in ABAQUS documentation. The standard options in the calculations were used.
• Page 7. The references to the Eligehausen model should be given.
• Page 7. Please describe in detail which options and models were used in the final calculations.
• Page 8. Result chapter. The chapter name should be verified. In the chapter, the numerical results are given.
• Figure 6. The presented numerical results were performed by Authors or other researchers. The description is not clear.
• Figure 6. The resolution and quality should be increased.
• Figure 8. The description in the text is laconic. Please verify and supplement the description.
• Page 16. The discussion of the results should be verified and supplemented.
• Figure 14. It is not clearly described in the text which results is given by the authors.
• A greater effort should be done in the conclusion chapter. The authors should directly indicate the exact novelty of this research study. The conclusions should indicate (underlined) directly the new science of this manuscript to the community.
• We performed nonlinearly… we compared model… We combined a continuum… We also monitored. Please rebuild and correct a form of sentences.
• Summarizing the conclusions using bullet points would certainly emphasize the significance of the outcomes.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The manuscript can be published in the present form

Reviewer 3 Report

Accept in present form.