An Experimental Study of the Hysteresis Model of the Kanchuang Frame Used in Chinese Traditional Timber Buildings of the Qing Dynasty

Round 1

Reviewer 1 Report

This paper’s aim is making a hysteresis model of Chinese traditional timber frame with masonry wall. I think that this experimental work is very interesting, but I don’t understand well the mechanical properties of wood and brick. And also, what do you want to get material properties from some element tests. So, I can’t accept this paper for this journal.

It is better than now, you focus on the experimental data and phenomenon.

 

1. Check them as followings,

P3L21 Infill walls of Chinese ancient timber architecture always considered nonstructural members. Really?

What wood spices are using target timber frame?

In this test, what wood spices do you use?

P7 Table 1 Is this right, the compressive strength of parallel to grain? This value is too small.

P9L19 shows no damage before 25mm deformation but P11L4 shows under 10mm elastic. Which is true?

How to use this hysteresis model to design of traditional timber frame with masonry?

Author Response

1. P3L21 Infill walls of Chinese ancient timber architecture always considered nonstructural members. Really?

Answer: Infill walls of Chinese ancient timber architecture always considered as nonstructural members in earlier researches. So, few researches have been done to study seismic performance of timber frames with infill walls. Emile et al. [29] studied the failure modes, stiffness, strength (including rate of degradation), and energy dissipation capacity of Chinese traditional mortise-tenon jointed beam-column frames with wood panel infill. Xie et al.[30] studied influence of wood infill walls on the seismic performance of Chinese traditional timber structure by shaking table tests. The test results show that natural frequencies, damping ratio and acceleration responses of the model with wood infill walls was greater than that without ones.

Details are shown in the 3^th paragraph of section 1.

2. What wood spices are using target timber frame?In this test, what wood spices do you use?

Answer: Pinus sylvestris var. mongolica, lime and Xiaotingni brick are selected to fabricate the specimen. Details are shown in the 1^th paragraph of section 2.2.

3. P7 Table 1 Is this right, the compressive strength of parallel to grain? This value is too small.

Answer: Sorry for the typo. We revised the mistake. The compressive strength of parallel to grain in the table is 46.21Mpa.

4. P9L19 shows no damage before 25mm deformation but P11L4 shows under 10mm elastic. Which is true?

Answer: Before 10mm (drift angle is 1/160) cycles, no obvious damage was observed. Details are shown in the 1^th paragraph of 2.4.

Before 25mm (drift angle is 3/32) cycles, no obvious damage occurred in the timber components and no penetrating crack formed on the masonry wall. Details are shown in the 1^th paragraph of 3.2.

5. How to use this hysteresis model to design of traditional timber frame with masonry?

Answer: This study aims to provide useful reference for seismic evaluation and preservation of cultural heritage. It references for dynamic analyses of the traditional timber structure under dynamic loads. The whole experimental and analytical study were conducted on a scaled specimen not a full-scaled one. Whether this hysteretic model could apply on other frames of different dimensions or not need further study and discussion. In the further study, seismic and hysteretic behaviours of more timber frames with different types infilled walls from an ancient timber building would be studied. Details are shown in the last paragraph of section 6.

Author Response File: Author Response.pdf

Reviewer 2 Report

Reviewer’s comments

This manuscript presents a physical test on the wall of a traditional timber building. An analytical model was established basing on the test result. The specimen represented most of the details of the real case. The test data and numerical could provide valuable information for the conversation of historical buildings. A few comments are provided as below:

 

1. A hysteric model of the wall was established basing on the test. For a wall with different dimensions, can the model be applied? The strength of the wall should come from the resistances of wood frame and masonry wall. How to consider their contribution?
2. Does the wall sustain vertical load in the test? Would it be important parameter that would affect the result?
3. Author should provide more information about the test observations. The damage should be noted with the corresponding loading amplitude. The displacement would be better to be presented as a drift angle. In addition, these damages might cause some changes on the hysteretic loop. They are not mentioned in the article.
4. In section 2.4, cracks in wood frame or masonry were not distinguished in the description. They represents different meanings. The description should be more specific and clear. And, how does author define collapse of the specimen? It would be better to provide a photo of the final status (collapse) of the specimen.
5. The test used a pin connection for the column base. What is the situation in real case? It is put on the floor or fixed by dowels?
6. Fig. 13 is one of the important figures in the manuscript. The resolution, details and dimensions of the specimen should be clear.
7. Fig. 6 is not clear. The number is too small. Fig. 8 and Fig. 9 is unnecessary. These are fundamental and common tests. Fig. 10 does not show how the load added on the specimen. It would be better to have the fixtures figure.
8. Fig. 12 is less important. It would be useful to have the informations such as: what kind of wood was used in the test, and what are the dimensions of the specimens.
9.  The test used cyclic displacement control method. It would be better to know the corresponding drift angles of the displacement amplitudes.

Comments for author File: Comments.pdf

Author Response

Dear the Reviewer,

Thank you very much for your attention and  invaluable comments on our manuscript.

We have carefully considered your constructive suggestions, and revised the manuscript accordingly. I am submitting the revised version for your further consideration for publication. Attached with the manuscript is a copy of the responses to the reviewers. Please see the attachment.

Thank you again and look forward to hearing from you soon.

 

Best regards

Yours sincerely

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper investigated the mechanical properties of a Kanchuang frame used in Chinese traditional timber buildings of Qing Dynasty by cyclic loadings. By analysing its load-displacement hysteretic behaviours, a theoretical model was built, and it was consistent with the experimental curve. The conclusion of this paper is contributory to the seismic study of the ancient Chinese timber buildings. However, the manuscript needs carefully revised according to following comments:

• Section 1: More literatures should be reviewed in the restoring fore model of the ancient Chinese timber frames. Clarify why the restoring fore model of the ancient Chinese timber frames is significant to be studied in this paper through comparisons with others.
• Section 1: How typical is the Kanchuang frame? How can this study outcome contribute to the seismic evaluation theory of the common ancient Chinese timber buildings?
• Section 2.1: The specimen is fabricated in a 1:2 scale. Have the authors considered the size effect? What solutions are used for reducing the size effect in the further analysis and the hysteretic model building?
• Section 2.1: High-resolution pictures should replace Figures 6 and 7.
• Section 2.2: Give an introduction why the material tests were carried out?
• Section 2.2: Why only Young's modulus of masonry is showing?
• Section 2.2: Clarify the testing protocols of testing mortar, wall bricks and masonry even though the standards were cited.
• Sections 2.2: It is quite messy in the presentations of the tested results of the mortar, the wall bricks and the masonry. Tabulate these data.
• Section 2.2: It should be ‘elastic modulus’ rather than ‘Modulus of elastic’ in Table 1.
• Section 2.4: The failure positions are explained in a blur. Point out each failure mode in Figure 16 in which position of Figure 15.
• Section 3.1: Where is the specific displacement in the load-displacement hysteretic curve from?
• Section 3.1: Explain what the stiffening trend is. Why is there a stiffening trend with increasing displacement? From reviewer’s view, the timber and the masonry structure are degrading.
• Section 3.2: Why is the strength degradation in the positive loading not obvious during 30mm-65mm cycles? This should be explained with the failure modes.
• Sections 3.1 and 3.2: Have the authors compare the results with other research results? There should be more discussions.
• Section 5: Because there are only three cycles have been tested at each displacement level, how about the hysteretic behaviours of the fourth and fifth cycles? Would the hysteretic behaviours be stabilised or not? Would the pinching be continuing developing? As we know, there are repetitive cycles at a displacement in an earthquake.
• Section 6: How does this model be used for seismic evaluation from a whole structural view? Namely, think big of the application of the model in future studies. Discussions should be supplemented.
• Whole paper: English writing should be improved by proofreading by a native speaker.

 

 

 

Comments for author File: Comments.pdf

Author Response

Dear the Reviewer,

Thank you very much for your attention and  invaluable comments on our manuscript.

We have carefully considered your constructive suggestions, and revised the manuscript accordingly. I am submitting the revised version for your further consideration for publication. Attached with the manuscript is a copy of the responses to the reviewers. Please see the attachment.

Thank you again and look forward to hearing from you soon.

 

Best regards

Yours sincerely

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Reviewer’s comments

Most of the comments and questions were answered. Some addition explanations would make the sentences more clear and readable.

1. The description of damage observation is not clear. The crack occurred on the masonry wall or on the timber frame? Damage patterns shown in Fig. 13 should occur at different loading amplitudes. The damages with respect to the occurring amplitudes and figures would help readers to understand the failure sequence. The small photos in Fig. 13 might be attached with numbers and be referred in the damage description of section 2.2.
2. In Fig. 14, the responses of over 65mm amplitudes should be majorly contributed by the timber frame since the masonry wall had failed. However, the strength tended to have larger value in the negative direction. What makes it unsymmetrical? Does it related to the loading sequence?

Author Response

Dear the Reviewer,

 

Thank you very much for your attention and  invaluable comments on our manuscript.

 

We have carefully considered your  constructive suggestions, and revised the manuscript accordingly. I am submitting the revised version for your further consideration for publication. Attachment is a copy of response.Please see the attachment.

 

Thank you again and look forward to hearing from you soon.

 

Best regards

Yours sincerely

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments for author File: Comments.pdf

Author Response

Dear the Reviewer,

 

Thank you very much for your attention and  invaluable comments on our manuscript.

 

We have carefully considered your  constructive suggestions, and revised the manuscript accordingly. I am submitting the revised version for your further consideration for publication. Attachment is a copy of response.Please see the attachment.

 

Thank you again and look forward to hearing from you soon.

 

Best regards

Yours sincerely

Author Response File: Author Response.pdf

Round 3

Reviewer 3 Report

I am satisfied with the current version of the manuscript. However, I found some discussions in the 'Response to reviewers' have not added into the manuscript. I hope the discussions in the manuscript would be supplemented.

Author Response

Dear the Reviewer，

Thank you very much for your invaluable comments on our manuscript.

We added the missing disscussions in the 'Response to reviewers'   into the manuscript.

Here are the details.

15) The answer for this question is an escape. Why three cycles were chosen should be clarified in detail. Would the pinching be continuing developing? Discussions should be supplemented in terms of the material properties, the structural performances or other research.

Response: We supplemented the discussions in the 1th paragraph of section and cited reference [49].

Details:

“This study focus on how to established the hysteresis model of Kanchuang frame. Therefore, this paper laid special stress on hysteretic behaviours of the test model were analyzed. Structural performances of Kanchuang frame， such as stiffness degradation, energy dissipation and so forth, were discussed reference [49].

Reference [49] Huan JH, Guo XD, Ma DH, et al. Seismic performance and damage evaluation of Kanchuang frame of ancient architecture [J]. Journal of Civil and Environmental Engineering, 2022, 44(2), 129-137.

 

16) I don’t think the authors have answered my question. How the outcomes in this study can be applied further is particularly important. Clarify in detail

Response: We supplemented the discussions in the last paragraph of section 1 to clarify how the outcomes in this study can be applied further.

Details:

“Finite element analysis is a frequently used way to analysis the seismic performance of timber structures. In order to get a correct and accurate calculation result, a model as similar with the prototype as possible. However, timber structure is quite different from the RC structure. And an ancient timber building always consist of different kind of materials. There are a lot of contact areas and small gaps between different components, which is difficult to simulate by finite element analysis software. Even though a model with all of the contacts, mechanical properties and material properties considered was established, the calculation results probably not convergent. And the calculation process can be very complicate. It takes a lot of time to get the calculation results by finite element analysis. The whole structure can be divided into different units. If the researches knew the units’ hysteretic model, rigidity and strength, the analysis model can be considered as an ensemble of different simplified units. In this way contact analysis in the finite element calculation can be avoided, which could improve the computational efficiency. Moreover, a correct hysteretic model is also very important to nonlinear seismic analysis. A simplified calculation model that can presents mechanical properties of the structure for nonlinear seismic analysis need to be established. If researchers don’t know the mechanical properties of the units, the calculation model would be very complex. With the hysteretic model of the structure known, the structure or the units can be simplified as mass elements or shell elements. The calculation model could be simpler than before. Nonlinear seismic analysis methods, such as Newmark-β, can be applied to calculate the seismic responses of the structure.”

Please see the attachment. 

Thank you again .

 

Best regards

Yours sincerely

Author Response File: Author Response.pdf