Limit Carrying Capacity Calculation of Two-Way Slabs with Three Simply Supported Edges and One Clamped Edge under Fire

Round 1

Reviewer 1 Report

The manuscript presented fire-resistance experiment with reinforced concrete slabs with three simply supported edges and one clamped edge, and based on the test results, calculation formulas were introduced for limit carrying capacity of reinforced concrete two-way slabs with four different boundaries under fire considering the membrane effect under large deflection. The test set-up, test procedures, and test results are described in good details. The manuscript is well-organized and comprehensive, which lead to clear conclusions. The results of this study would be useful in fire-resistance engineering by predicting limit-carrying capacity more accurately when compared to the traditional methods.

The following comments are offered for the authors’ consideration.

1. In Introduction, it is not noted why particularly this reinforced concrete slab with three simply supported edges and one clamped edge was not studied so far. It is recommended to include the reason in this paper, so to justify the necessity of this particular research.
2. In the test program, two slabs were tested with the same parameter, but the test results slightly differ as expected by nature of uncertainty. Please provide the test conditions, if any, that made small change of the test results.
3. Table 2 is unorganized, and it needs clear layout for better understanding of readers. There is also lack of explanation on Table 2 in this manuscript.
4. The length of this manuscript is too long with too many figures. It is recommended to exclude 4.1 Plate balance method and 4.2 Energy method with many equations in the manuscript and insert into appendix. Or, authors could reduce waste of spaces by integrating the double graphs with Specimens CS1 and CS2 into single graph.

Author Response

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Reviewer 2 Report

The manuscript is good, and detailed. I have some comments.

1. English are good, some phrases may need improvement.
2. In literature review in introduction, publications by Yong Wang should be considered (they are exactly on the topic).
3. The reinforcement of the slab is unclear, please provide specific information.
4. I believe the called "burst" is spalling (explosive(?)), and the terminology is wrong (?), I believe useful can be 10.2749/101686614X13830790993041 for the discussion of the effect.
5. Although the manuscript includes very detailed analysis of the behaviour of slab in fire, it might be useful to explain the failure mechanisms in simple words and simple mechanics.
6. Also, I believe there was bowing effect (due to high difference of temperature between the two surfaces (exposed and not).
7. Although the paper is very detailed needs  more critical discussion and clear terminology. This is the main comment.

Author Response

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Reviewer 3 Report

The paper concerns capacity the calculation of two-way slabs with three simply supported edges and one clamped edge under fire. The authors analyzed the distribution of the temperature field of concrete and steel in the direction of the section thickness, deflection from the plane, deflections in the plane and the slab edge angle of the two-way concrete slab under fire conditions. The paper present extensive material from experimental test. The topic is interesting. Nevertheless, the paper is not acceptable as it stands.

Comments and suggestions are stated below.

1) The key question is: what is new in this study?

2) It was also difficult for me to determine the state of research against the background of world literature, as the vast majority of references are domestic (in Chinese). So how does this relate to the world's knowledge in this area?

3) There is no clearly defined aim of the research.

4) When delving into the content of the work, I got a little lost, because the authors presenting the results in a graphical form in legends used many markings that are not explained. Example: Fig. 18 in the legend we have ST5-1, ST5-2, ST6-1, ST5-2. In the text (line 239-240) the authors only described ST6-1 and ST6-2. This is the case in many places in the article. Please note that this study is intended to be of assistance to a wide range of scientists working on related topics. Perhaps it would be advisable to use a notation.

5) Second Section: Test overview - does not add relevant information to the article. The suggestion: should be redrafted in such a way as to provide a detailed description of the samples, their markings and the area and scope of the research. An example is e.g. the description of samples CS1 and CS2. It is not known how they differ. I concluded that the reinforcing bars are of different diameters. The authors skillfully provided a reference to the literature where their characteristics were described. Unfortunately, a local study, is not in a reputable research base.

6) Not very understandable sentence (line 252-253). It is not clear from the charts.

7) The discussion of the results obtained is superficial.

8) Other minor comments include: missing units (see Table 3), description in Figure 31a, section numbering, reference not consistent with the formula.

Author Response

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Round 2

Reviewer 2 Report

The revised manuscript is good. The only comment I have is that the used literature on concrete spalling used should be added in references. 

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Reviewer 3 Report

Dear Authors,

I would like to thank the authors for responding to my comments and clarifying the disputable issues.

In this form, I recommend the paper for further processing.

Author Response

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