Simplified Life Cycle Cost Estimation of Low-Rise Steel Buildings Using Fundamental Period

Round 1

Reviewer 1 Report

The study includes a set of analyses in order to compare the life-cycle cost (LCC) derived through the proposed method in the paper and non-linear THA, which is an interesting and innovative study. The details of this reviewer’s raised questions/comments are listed in the following. As a general suggestion, the quality of some produced Figures are not clear enough such that their details are not readable, and it is recommended to improve their quality (Figures 4 - 10).

1.      Page 4: The DeltaD and DeltaC parameters are introduced as the demand and capacity of the structure. What do these parameters exactly stand for? Please clarify.

2.      Page 4: As mentioned in the context as “all the parameters are adjusted to the most common mean values of building structures”. It is recommended to mention the assumed distribution of the parameters. Similarly, there is a raised comment on this sentence: that “the mean, the upper bound (mean + one standard deviation), and lower bound (mean - one standard deviation) of a variable are considered …”. The assumed distribution of LCC versus T should be clarified.

3.      Page 5: Please comment on accuracy of obtaining a and b while using the mean response spectrum? Also, these coefficients are based on regression over NLTHA. Please clarify.

4.      Figure 3: The schematic illustration of the LS and CP limit states in Fig. 3(b) is different from FEMA-356. Please make a clarification about your assumptions.

5.      Table 1: As seen in Table 1, there are some repeated records in each set of earthquake records (for example No.11 and No.21 or No.12 and No.30). It would be better to mention why these earthquake records are repeated.

6.      Figure 6:There is an interesting observation in Figure 6. which deserves adding additional discussion. It seems that increasing the fundamental period in a high-rise frame exponentially increases the LCC, while this phenomenon is minor in low-rise frames. It is recommended to add a discussion on this phenomenon.

7.      Figures 8, 9: Figures show the LCC curve versus T1, while variating different parameters in LCC estimation. As a result, there is a mean estimation model (in which all parameters are set as mean values), and each Figure should show the variation of LCC curve while imposing the STD of each parameters. This requires that in each Figure a Mean curve should be repeated and the Mean+STD and Mean-STD reveal the effect of each parameter. However, the mean models are not identical in different subfigures of Figures 8 and 9. It is advised to provide some explanation on this.

8.      Figure 10: Some explanation is needed for the purpose of producing Figure 10.

9.      Page 16, second bullet: It is obvious that the sensitivity of any assessed parameter at IO limit state is higher than those of CP. Therefore, this is not the specific concluding remark of this study.

10.  References: The following paper is recommended to be cited by the authors:

Mahdavi G, Nasrollahzadeh K, Hariri-Ardebili MA. Optimal FRP jacket placement in RC frame structures towards a resilient seismic design. Sustainability. 2019 Dec 7;11(24):6985.

 

Author Response

attached

Author Response File: Author Response.pdf

Reviewer 2 Report

Introduction

Please check the last sentence in paragraph 2

please check the last part of paragraph 5 and the early part of paragraph 6. I think it should be in the same paragraph.

Results and Discussion

1. The quality of the figure is really bad, please change it to high quality and attractive. figures 5, 6, 7, 8, 9, 10 11.

2. The quality of tables 3 and 4 should be improved.

Author Response

attached

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper investigated the simplified life cycle cost estimation of low-rise buildings using fundamental period. The outcome is interesting for readers. However, there are several aspects that need to be improved. The reviewer can only recommend for publication if the author satisfactorily address the following comments in the revised version.

1.     Why the equivalent single degree of freedom model was utilized since the real structures is multi degree of freedom? How to validate the use of this equivalent single degree of freedom model?

2.     The novelty of the study should be highlighted in the end of introduction section. How this study is different from the published study in literature?

3.     How the outcome of this study will benefit researchers and end users? This need to be highlighted.

4.     The authors should enrich the state of the art by referencing the following articles: 

https://doi.org/10.1007/s10518-018-0476-8

https://doi.org/10.1007/s10518-018-00523-x

https://doi.org/10.1016/ j.istruc.2020.05.002

https://doi.org/10.1016/j.jksues.2021.02.007

https://doi.org/10.1088/1757-899X/933/1/012034

https://doi.org/10.1088/1757-899X/1087/1/012022

5.     Revise the reference list according to journal format.

6.     Since there are too many notations and symbols used in this paper, please provide the list of notations and symbols at the beginning or the end of the paper.

7.     Figures 4–12 are blur, please replace with clear figures.

8.     Tables 3 and 4 are blur, please replace with clear tables.

9.     It is preferable to add a section "Recommendations" to indicate the authors' recommendations for future research and the possible of using this study result in real structures. Please also add the limitation of this study.

Author Response

attached

Author Response File: Author Response.pdf

Reviewer 4 Report

The work illustrates a simplified seismic life cycle cost (LCC) estimation procedure and its application to case studies. The research proposes the use of the average values of the main input variables of the structure, these are used to build a relationship between the fundamental period (T) and an average estimate of the LCC (LCCavg).

 

The authors focus on the analysis of steel structures, this should be well present in the title of the work otherwise the methodology seems to be applicable to all types of structures.

The very interesting work framed exhaustively from the bibliographic point of view but the low quality of the images and a more accurate description of the evaluations carried out and the results obtained for the case studies limit its understanding.

In the opinion of the reviewer why a planar analysis was chosen instead of a three-dimensional analysis, specify this choice and its effect on the results.

Why were the results presented in figure 6 (difficult to understand, low quality) referring to several floor configurations and then only those with 3 and 5 floors were treated?

In the figures, in addition to improving the quality, it is advisable to use the same full scale when comparing the same quantities for a better reading.

There appear to have been two different approaches to the recall of citations in the text that matched the one intended by the journal.

For the reviewer, the work is accepted but there is a need for a significant improvement in the part describing the results and analyzes carried out because in the current state they do not allow for an adequate reading.

Author Response

attached

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The paper can be published with present form

Reviewer 3 Report

The authors have revised the manuscript and solved my concerns.