Sustainable Design of Circular Reinforced Concrete Column Sections via Multi-Objective Optimization
Round 1
Reviewer 1 Report
Suggest rewriting the conclusion and clearly providing some conclusions related to carbon dioxide as well as conclusions for design optimization.
Normal
Author Response
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Author Response.pdf
Reviewer 2 Report
The manuscript presents an optimization-based approach for the sustainable design of circular reinforced concrete columns. A Genetic Algorithm (GA) implemented in MATLAB was used to minimize cost and carbon dioxide emissions considering both, single and multi-objective optimization. Design examples for various combinations of axial force and bending moment are presented.
The manuscript addresses an interesting topic. It is well organized and well written with only a few typos and minor grammatical mistakes. The reviewer does not suggest publishing the manuscript in the present format. It can be stated that it represents a contribution about the sustainable design of circular reinforced concrete columns, but it needs a major revision. Some revisions and improvements should be made before the manuscript is suitable to publish in this journal.
General comments:
1) Considering that the sustainability concept involves cost, environmental impact and social impact, the title should be changed to better express what is presented in the manuscript. The reviewer suggests “Sustainable design of circular…” or “Environmental and economical design of circular…”.
2) It should be referred in the Introduction that the proposed optimization model was developed in MATLAB.
3) Introduction, Lines 82 to 92 – The authors present the features and advantages of a genetic algorithm to justify its use in the proposed method. The disadvantages should be also referred, even if they are not relevant for the proposed method.
4) In Section 2.2, the authors present the constraints considered in the optimization problem and refer minimum reinforcement area. Please clarify why the maximum reinforcement areas was not considered as a constraint. Concerning this issue, in Table 4 the optimized design for NEd = 1000 kN and MEd = 1000 kNm exceeds the maximum reinforcement area of 0.04 Ac prescribed in Eurocode 2. Furthermore, values well above 0.02 Ac poses difficulties in the execution of reinforced concrete members. Please comment and/or clarify.
5) Figure 2 – The variable “s” is not defined. It is worth adding the concrete stress values.
6) Section 2.2, Line 175 – Please rephrase to clarify this sentence.
7) Equation 9 – “c_con” is only defined later in Table 1. Please correct.
8) Line 155 – Please rephrase to correct the statement “The neutral axis is the point…”.
9) Line 157 – Please rephrase because the sentence is not accurate. The location of the neutral axis depends on the strain diagram.
10) The reviewer suggests replacing “decision variables” by “design variables”.
11) Section 2.3 – Please provide more information aiming to clarify the meaning of “high quality solutions”.
12) Genetic algorithm is a stochastic population-based optimization algorithm. Therefore, different runs of the algorithm may lead to different optimized solutions. Nothing is referred in the manuscript concerning this topic. The authors should discuss this topic in the manuscript and how this feature affects the results obtained.
13) A figure depicting the evolution of the fitness function throughout the generations is missing. This is an important result to show the convergence of the optimization algorithm.
14) Captions of Figures 4 to 9 – Please correct “reinforced circular” by “reinforced concrete circular”.
15) Line 394 – Please replace “A complete optimization model” by “An optimization model” because the proposed model does not include everything about the design of reinforced concrete circular columns.
16) Line 397 – Please rephrase to improve the accuracy of the statement and, therefore, clarifying the meaning of “This exact optimization model…”.
Specific comments:
17) Abstract, Line 8 – Please replace “cross sections” by “cross-sections”.
18) Abstract, Line 8 – Please replace “Eurocode” by “Eurocode 2” or “Eurocodes”.
19) Keywords – The reviewer suggests removing the first keyword and adding the following keywords: reinforced concrete columns; circular cross-section; cost; CO2 emissions.
20) Introduction – Concerning the second and third sentences, it is worth adding some information about the steel reinforcement area, from which depends the columns N-M resistance.
21) Introduction, Lines 28 to 30 – Please replace “pair of axial load and bending moment… on N-M graph” by “pair of axial load (N) and bending moment (M)… on a N-M graph”.
22) Introduction, Line 32 – Please replace “are not” by “is not”.
23) Introduction, Lines 36 to 38 – It is worth adding references for each optimization method referred.
24) Introduction, Line 42 – Please replace “optimal dimensions” by “optimal cross-sectional dimensions”.
25) Introduction, Line 51 – Please replace “reinforced concrete structures” by “reinforced concrete frames”.
26) Introduction, Line 66 – Please replace “deals with” by “concerns”.
27) Introduction, Line 76 – Please replace “propose” by “proposed”.
28) Introduction, Lines 80 and 81 – Please rephrase to avoid repeating “reinforced concrete circular columns”.
29) Introduction, Lines 82 and 83 – Please correct, using “In this paper, a genetic algorithm is used to solve a multi-objective optimization problem…”.
30) Please rephrase the last sentence of the Introduction because it repeats the last sentence of the Abstract.
31) Section 2 – It is suggested to move the first sentence to the end of the Introduction aiming to explain the approach adopted for accomplish the main objectives of the work.
32) Lines 109 to 111 – Please correct using the terms “design value of the applied axial load”, “design value of the applied bending moment”, “characteristic value of the compressive strength of concrete” and “characteristic value of the tensile strength of steel”.
33) Line 115 – Please replace “objective function” by “objective functions”.
34) Line 122 – Please correct “determined by with number” by “determined by the number”.
35) Line 151 – Please replace “dimensioning” by “design”.
36) Lines 152 and 153 – Please rephrase. Suggestion: “Both objective functions aim to minimize the amount of concrete and steel reinforcement, however, the circular reinforced concrete cross-section must be able to resist…”.
37) Lines 171 and 172 – Please correct using “… design axial resistance NRd of the cross-section is presented in Equations (7-50)”.
38) Line 187 – Please correct “in therefore” by “is therefore”.
39) Line 277 – Please replace “above” by “previously”.
40) Line 291 – Please replace “reinforced concrete structure” by “reinforced concrete member”.
41) Line 394 – Please replace “reinforced concrete cross sections” by “reinforced concrete circular columns”.
42) Line 394 – Please replace “The discrete variables are used for the accurate design…” by “Discrete variables are used for the practical design…”.
43) Line 395 – Please replace “to obtain solutions” by “to solve the optimization problem”.
Please see the previous comments.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The article mainly studies a complete optimization model for reinforced concrete cross sections based on the Euro-code standard, It has a certain degree of innovation, but there are still the following issues that need to be modified before the article is accepted for publication, recommended as a reviewer for publication after major repairs:
1. The abstract and introduction of the article need to further emphasize the research significance of this article, so that readers can better find the focus of the article's research;
2. The author's research conclusion needs to be further simplified and reduced, highlighting the more meaningful conclusions of the article;
3. The article needs to add more references related to the content of the article, such as:Jianxing Chen, Lei Zhou, Zheming Zhu, Leijun Ma, Meng Wang, Ze Deng. Crack propagation analysis and mechanical properties of basalt fiber reinforced cement composites with changing fiber surface characteristics;Jianxing Chen, Zheming Zhu, Lei Zhou, Jinping Zhuang, Meng Wang, Leijun Ma. Study on mechanical properties of (1 % PVA fiber +1 % Steel fiber) PS-ECC under the coupling effects of elevated temperature and dynamic loads. Structural Concrete. 2023,24:4126-4144.
4. The English language issue of the article needs further improvement to promote the improvement of the English proficiency of the article;
5. There are also a large number of language spelling errors and Syntax error in the article. It is suggested that the author carefully check and correct them.
The article mainly studies a complete optimization model for reinforced concrete cross sections based on the Euro-code standard, It has a certain degree of innovation, but there are still the following issues that need to be modified before the article is accepted for publication, recommended as a reviewer for publication after major repairs:
1. The abstract and introduction of the article need to further emphasize the research significance of this article, so that readers can better find the focus of the article's research;
2. The author's research conclusion needs to be further simplified and reduced, highlighting the more meaningful conclusions of the article;
3. The article needs to add more references related to the content of the article, such as:Jianxing Chen, Lei Zhou, Zheming Zhu, Leijun Ma, Meng Wang, Ze Deng. Crack propagation analysis and mechanical properties of basalt fiber reinforced cement composites with changing fiber surface characteristics;Jianxing Chen, Zheming Zhu, Lei Zhou, Jinping Zhuang, Meng Wang, Leijun Ma. Study on mechanical properties of (1 % PVA fiber +1 % Steel fiber) PS-ECC under the coupling effects of elevated temperature and dynamic loads. Structural Concrete. 2023,24:4126-4144.
4. The English language issue of the article needs further improvement to promote the improvement of the English proficiency of the article;
5. There are also a large number of language spelling errors and Syntax error in the article. It is suggested that the author carefully check and correct them.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Meet requirements
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
The authors addressed all the reviewer’s comments and the overall quality of the manuscript was improved. However, before the manuscript is ready for publication, an additional revision should be made concerning the following issues:
1) Title – Please replace “reinforced-concrete” by “reinforced concrete”.
2) Line 199 – Please rephrase to clarify the sentence “In proposed model to each rebar ID is assigned and the exact location”.
3) Comment 18 of the previous revision – Abstract, Line 8 – Please replace “Eurocode standards” by “Eurocode 2 standard” or “Eurocodes”.
4) Comment 19 of the previous revision – Keywords – The reviewer suggests removing the first keyword and adding the following keywords: reinforced concrete columns; circular cross-section; cost; CO2 emissions.
Please see the previous comments.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Papers can be accepted
Papers can be accepted
Author Response
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Author Response File: Author Response.docx
