An Output-Only, Energy-Based, Damage Detection Method Using the Trend Lines of the Structural Acceleration Response

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

Your paper is interesting and the topic presented follows current trends. The article, however, has some faults. Furthermore, some editing is required.

1.      The title- use one convention or use capital letters for wording or use sentence-style wording. Currently, you are mixing both styles.

2.      The article is mostly clearly written and easy to follow.

3.      The authors give relevant references which are linked to their study. However, the number of connections and especially evaluation in the introduction is limited and does not fully present the state of the art of the field. Many of the references, for some aspects of the literature review, are connected mainly to Chinese authors and few others as multiple references to the same ones. Consider having a broader look at worldwide research. Some possibilities are mentioned below.

4.       The abstract is well written introducing the basic overview of the paper. It is also written in a way that even a person not familiar with the topic can understand what the authors are proposing in their research. The reviewer would suggest putting some emphasis on novelty, which in its current form is not pointed out in the abstract.  

5.      The introduction requires some improvements. The purpose of the introduction is to present the problem of the article and clearly present the overview of the state of the art in case of the topic and presented later and methods. Some problems noticed:

a.       First paragraph- there are some definite statements with no connection to the literature.

b.      second paragraph- there are some not entirely correct statements, or some elements are missing. The authors mention some measurement techniques, e.g. using accelerometers. One problem is that the authors consider this as a cheap method which is not really true for professionals, especially seismic accelerometers. If you mention one kind of equipment, you should also mention others, maybe more expensive but more accurate ones like. E.g. geophones e.g. DOI: 10.1016/j.nima.2023.168495.

c.       In the last paragraph, the aim and scope are presented. However, the novelty is not presented strongly enough (in the scope of state-of-art evaluation). This part is not fully easy to follow so please rethink better organization of presenting your aim, scope and novelty.

6.      Chapter 3 some comments:

a.       No specific data on accelerometer parameters especially sensitivity which is essential as authors evaluate signals close to the background noise.

b.      Tables- just a tiny editing problem with align style. In the case of description if aligned to one of the sides would look much better.

7.      Results comments: the results are mostly well presented. Some small edits may be required at the later editorial stage.

8.      Conclusions are acceptable. However, an emphasis on novelty would be profitable.  

Conclusions

The article has the potential to be interesting but after corrections to some problems found. Some additional state-of-the-art analysis of testing techniques has to be incorporated in the introduction.

 

Author Response

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Reviewer 2 Report

Comments and Suggestions for Authors

The paper titled “An Output-Only Energy-based damage detection method using  the trend lines of structural acceleration response” is an original contribution, which completely corresponds to the scope of the MDPI Journal “Buildings”. An output-only SGF-based damage  detection method in which there is no need to determine and monitor the dynamic modal  properties to locate and quantify the structural damage, was developed and tested on the model of five-storey framework building.  The following comments should be addressed to made the description of the results were obtained clearer for understanding: 

1. Chapter 1 “Introduction” should be completed by the short explanations, why the developed new energy-based DI enables to locate the structural damages more acсuretely. Information regarding the choice of the model for the experiment ( model of five-storey framework) also should be added. 

2. Chapter 3 “Experimental model and numerical simulation of a five floor building” should be supplied by the following information:

- Cross-sections of all horizontal and vertical members with its geometric parameters.

- Detailed information regarding solution of structural joints (details with it geometric parameters).

 - Positions, in which the accelerometers were placed, should be indicated at the Figure 2. 

3. An output-only SGF-based damage detection method, which enables to locate the structural damage more accurately, due to the using of a new energy-based ID, was mentioned as a main result of the current study. This method should be done clearer for understanding by the presenting an algorithm with detailed description of all the stages should be realized. 

4. Table 2 should be supplied by the additional textual explanations in the Chapter 3. The following questions should be answered:

 - What means certain percent of stiffness reduction of the column? Is it relating to the certain damaged section or zone or to the whole length of the member?

 - Positions of the damaged zones.

 - How the considered 21 scenarios of the building’s framework damages related to situations which can took place in practice?

 - Why the damages of structural joints which are very often observed in the case of seismic actions, were not taken in to account?   

5. Explanations, how the information, obtained by the developed damage detection method, can be used in case of surveying the real damaged structure, should be provided also.

Author Response

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Reviewer 3 Report

Comments and Suggestions for Authors

The paper studies the dynamic performance of structural systems using an output-only energy-based damage detection method relying on trend lines of structural acceleration responses to determine damage localization based on an adjusted Savitzky-Golay filter.

There are a handful of studies about the dynamic performance of buildings using damage detection and system identification techniques. However, a new aspect of this study could be exploring the application of an adjusted Savitzky-Golay filter to formulate an output-only damage detection method.

The study relies upon both experiments and numerical simulations, I think this is the main strength of the study, causing the research to stand out compared to similar studies.

The author may want to discuss in section 3 any probable effects of scaling down an actual building in the test.

Authors may want to touch on the code compliance levels of the case study buildings described in Table 1.

The damage type differs for different structural systems, i.e., shear wall, bracing, and moment frame. In this study, it seems that the focus is moment frame systems. However, I wonder if the authors would like to discuss whether their approach is valid for any structural system.

Damage is predicted using a demand parameter called TRENDI defined using energy concepts. It would be great if authors could compare the damage assessment using this damage measure versus more common damage measures like story drifts.

It seems that the proposed approach, similar to many other works in the field of structural damage detection, quantifies damage at the story levels. However, it might be more useful for engineers if the damage can be quantified at a component level in order to have a grasp of loss caused by incurred damages. My question for authors in this regard is if the proposed approach can be tweaked to predict damages at the component level rather than the story level.

Authors may want to include a paragraph to address practical aspects of their study for design engineers.

I could not find out what type of excitation is used to study the response reported in Fig. 5 and damage patterns. Authors may need to explain this aspect of the study further.

I think the conclusion section could be slightly expanded. Authors may want to discuss future studies to develop the proposed approach further.

References are adequate.

Author Response

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