Safety Concept for Textile-Reinforced Concrete Structures with Bending Load

Round 1

Reviewer 1 Report

Overall Comments:

The paper deals about the reliability of textile-reinforced concrete structures subjected to bending loads. The paper is well structured and has a clear outcome. The reviewer acknowledges the valuable contribution the authors made to the field of textile reinforcement. However, it has to be mentioned that the content is not new, as the present manuscript is a one by one translation of the paper published in Beton-und Stahlbetonbau previously. This practice might be ok in order to address different groups of readers, but at least a reference should be given to the previous manuscript to keep the transparency high and to avoid giving the impression that the content is new. This is the reason why I have chosen major revisions.

Furthermore I have following minor remarks on the content:

Editorial Comments:

The paper is translated from the original source. In some cases the translation is not very concise. See for example the last two sentences of the abstract or the first two sentences of the introduction. Better wording can be chosen and redundancy should be avoided. The reviewer suggests to carefully check the manuscript again in this context.

Page 2, line 47: ….for the determination of the reliability theory…. ? Please clarify, a theory cannot be determined

Page 2, line 62: In the context of the studies presented in this study…. Bad wording

Page 3, Table 2: Why is n2 listed in this table? It doesn’t give any additional information and is not related to the TRC-structure. Please also name n1 and n2 accordingly in the text (line 86 and 87)

Page 3, Eq. 3. Please define alpha_ed

Page 4, line 105/106: Can you provide more information on the chosen values of theta_E and theta_R?

Page 4, table 4: Define acronym LN in the table footer

Page 4, line 119: Explain alpha_t

Page 5, line 130: … is adopted… replace with …is applied…

Page 6, Table 5 and 6: table footer (distribution type) is not necessary as all the types have already been declared in the previous tables

Page 6, Table 6: Check parameters for errors. I guess line 3 and 4 is the young’s modulus and no the elongation, line 5 and 6 should be alpha_t

Page 6, line 146/147: It is referred to the equations as equation Eq. (X). Please delete the double mention.

Page 7, line 163: check references for errors.

Page 8, Figure 5: Flow chart – textile failure: ultimate is written as uktimate. Please correct it.

Section 5.3 to 5.5: Please provide more information on the used fabrics and boundary conditions in the respective studies. E.g. what was the effective depth in section 5.3 and which textile fabric was used in the calculation?

Page 11, line 236: space between ….to 3.8…

Please unify index of alpha_t. Sometimes it is written with capitalized t and sometimes not.

 

Technical Comments

Page 1, line 18/19: …This means that research on bending behavior is particularly necessary… A lot of research has already been conducted on the flexural behaviour of TRC-structures and the flexural response is well understood. Suggestion: delete sentence.

Page 1, line 31/32: Any limitations on the type of textile reinforcement? Is the partial safety factor suggested in this paper only valid for epoxy-impregnated textile or also for other textile fabrics?

Page 1, line 36-40: ….partial safety factor should also vary…. I guess it means that the partial safety factor is varied within the reliability calculation in order to achieve the desired reliability index? Please make the sentence more concise.

Section 5.4: Was any limited durability part of the investigation in this section, or was parameter alpha_t = 1.0?

Page 11, line 263-267: In the case of AR-glass textiles the value of beta does not reach the threshold value of 3.8 between a reinforcement ratio of 3-8 per mill. Please clarify this. Can you provide more information on the difference between AR-glass and carbon. As for high reinforcement ratios a concrete failure occurs, why is there a different target value of beta?

Page 13, line 300-302: In my understanding no appropriate safety level can be achieved for an effective depth of 15mm if the partial safety factor of gamma_c is 1.5. Please clarify the sentence.

Page 14, line 335: Neither the long-term durability factor alpha_t, nor the ratio of dead to live load has been part of the investigation described in this manuscript (or it was not mentioned). Please clarify this.

Author Response

Dear Reviewer,

Thank you very much for your comments.

You are completely right and we will mention, that this article is based on the paper in „Beton- und Stahlbeton“. It was not on purpose and a mistake, which will be corrected.

The article in German language addresses just few engineers. However, our aim is establish this new material. In this case, it is important to presents the results more than just the German engineers are.

We will include your comments and send you the new version within the next days.

Best regards

 

Sergej Rempel

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript presents an investigation on a design approach for carbon concrete members in bending, analysing in the detail the reliability approach and resulting levels. The topic is very intereting and pertinent to current scientific discussions. The methodology followed by the authors is also sound and leads to clear conclusions. On the basis of these considerations, the manuscript is suggested to be accepted for publication.

However, the manuscript presents a large number of inconsistencies on the explanations, presentation and english wording. These errors or unclear aspects shall be corrected before the paper is published. The most relevant aspects are listed below:

• General: Please clarify what is carbon concrete or Textile Reinforced concrete. Its use is not so general and deserves a small introiduction
• L57: "stability"? do the authors refer to "resistance"?
• Why is v_x in Table 1 blank? hall it be removed?
• L73-78: Unclear. Define what refers to actions and what to the resistance
• L77: The width seems definitely a very significant parameter on the resistance side (but neutral if considered in action and resistance side)
• L82: "The share"?
• L85: "For their turn"?
• Many symbols are not defined and completely unclear
  • alpha_ed in Eq.(3)?
  • Ground for alpha_eff = 0.85?
  • alpha_t? why is it different to aplha_eff? Ground for values? What is meant by "durability"?
  • alpha_cc?
  • theta_R and theta_E?
• In general, please replace "decisive" by "governing"
• L163: Reference missing
• L176-180: The results seem to be given for gamma_T = 1.5 and not for varying levels of gamma_T as claimed
• Section 5: Is gamma_C = 1.5?
• L191-198: Completely unclear: design, "tests"...? Please rewrite the paragraph and clarify its idea
• Section 5: It seems that Figure 8 refers to a small depth and Figure 9,10 to a large one. This is only understood after a detail observation of figure 12a-b. Please state thius clearly in the text as conclusions are completely different and the text is very difficult to understand!
• Figure 10: "Zielindex"?
• Figure 14: "und"?
• L341: "indices"?

 

 

Author Response

Dear Reviewer,

please see the attachement.

Regards

Sergej Rempel

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The comments of the review were considered conscientiously and the manuscript has been improved significantly, which is why I recommend to accept the paper in its present form.

One minor comment on P14,L311-313:

"If the effective depth d is 15 mm, to achieve an appropriate safety level, it is necessary to have partial safety factors of γT = 1.5 for the tensile strength of textile reinforcement and γC = 1.5 for the concrete compressive strength."

I would rather delete this sentence as it gives the impression that the required safety level in the case of d=15mm can be achieved by simply increasing the safety factor γT to 1.5, which is not the case in State B and C.