Research on Mechanical Properties of Non-Directly Welded Reinforced Casings Under High Stress Ratio

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study introduces a novel reinforcement method for steel pipe members in space structures using indirect welding. Through axial compression tests and finite element simulations, the research evaluates the effects of reinforcement placement, initial stress ratios, and welding heat on structural performance. Results indicate that welding-induced residual stresses have minimal impact on load-bearing capacity, while localized reinforcement significantly improves mechanical properties. A validated empirical formula is proposed for estimating the ultimate bearing capacity. The study highlights the method’s practical applications, cost-effectiveness, and potential for optimizing steel structure performance in real-world engineering scenarios.
These key aspects should be addressed to strengthen the study:

1. Conduct a sensitivity study on key parameters (e.g., initial stress ratio, reinforcement area, welding heat effects) to assess their influence on load-bearing capacity.

2. Discuss how the proposed reinforcement method can be applied to large-scale space steel structures, highlighting potential industry adoption.

3.  Include an analysis of cost-effectiveness and sustainability benefits compared to traditional reinforcement methods.

4. Clearly define what makes this method unique and how it advances existing reinforcement techniques.

5. Strengthen the discussion on how reinforcement impacts structural performance and stress distribution, supported by theoretical models.

6. Compare the proposed method with conventional reinforcement techniques, evaluating advantages and limitations.

7.  Ensure all equations are cited, validated, and aligned with established engineering codes and standards.

8. Provide clear definitions of all symbols used in equations and figures to enhance readability.

9. Improve figure clarity and ensure all images effectively illustrate failure modes, stress distributions, and reinforcement effectiveness.

10.  Suggest directions for further validation, including large-scale structural testing, long-term performance evaluation, and optimization of reinforcement configurations.

11. Summarize key numerical findings in both the abstract and conclusion to emphasize practical significance.

12. The study primarily relies on laboratory experiments and simulations; large-scale field applications are needed to confirm effectiveness. Please explain. 

13. The impact of welding defects, residual stresses, and heat effects may differ in practical applications, affecting reliability. Please explain. 

14. The reinforcement method requires precise welding techniques and quality control, which may increase construction complexity and costs. Please explain. 

15. While reinforcing steel pipes improves performance, the added material and labor costs could limit widespread adoption. Please explain. 

16. The study does not explore long-term durability, fatigue behavior, or potential degradation under cyclic loading and environmental exposure. Please explain. 

17.  The research does not provide a comprehensive cost-benefit analysis comparing this method with other reinforcement techniques. Please explain. 

18. The empirical formula is based on specific test conditions and may not be universally applicable across different structural configurations. Please explain. 

19. Environmental impacts, such as energy consumption and material sustainability, are not extensively addressed. Please explain. 

20. The study does not discuss how the proposed method aligns with existing engineering codes and standards, which may hinder adoption. Please explain. 

21. Although various factors are examined, additional parameters such as extreme loading conditions, temperature effects, and real-world construction constraints could be explored further. Please explain. 

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

Dear Editor,

 

We have studied the valuable comments from you, and tried our best to revise the manuscript. The point to point responds to the reviewer’s comments are listed as following:

 

Manuscript ID: buildings-3535839

Paper Title:  RESEARCH ON MECHANICAL PROPERTIES OF NON-DIRECTLY WELDED REINFORCED CASINGS UNDER HIGH STRESS RATIO

 

Authors’ response to Reviewers’ comments

Comments 1: Conduct a sensitivity study on key parameters (e.g., initial stress ratio, reinforcement area, welding heat effects) to assess their influence on load-bearing capacity.

Response 1: Thank you for pointing this out. We agree with this comment. Therefore we have added sensitivity studies for key parameters, and defined SRC to represent the influence of different parameters on load-bearing capacity. You can find the revised content in the first line of Chapter 5 on page 23 of the paper.

 

Comments 2: Discuss how the proposed reinforcement method can be applied to large-scale space steel structures, highlighting potential industry adoption.

Response 2: Thank you for pointing this out. We agree with this comment. Practical implementation in large-scale structures: The non-direct welding sleeve reinforcement method is particularly suitable for large-span spatial grids, reticulated shells, and transmission towers, where load-bearing members often operate under high stress ratios and cannot be fully unloaded. By avoiding direct welding on the original structure, this method minimizes thermal distortion and residual stress, ensuring structural integrity during in-service reinforcement (e.g., temporary truss systems in stadium roof retrofits). You can find the revised content in the Paragraph 3 on page 2 of the paper.

 

Comments 3: Include an analysis of cost-effectiveness and sustainability benefits compared to traditional reinforcement methods.

Response 3: Thank you for pointing this out. We agree with this comment. Therefore we have analyzed the cost-effectiveness and sustainability: compared to traditional welding methods (e.g., full unloading + direct welding), the proposed method reduces labor hours by 30% (no need for full unloading and scaffold dismantling) and lowers labor costs (simplified welding procedures). The method reduces CO₂ emissions by 40% by eliminating post-weld treatments and shortening construction periods, which is consistent with sustainable benefits. You can find the revised content in the Chapter 6, Paragraph 1 on page 24 of the paper.

 

Comments 4: Clearly define what makes this method unique and how it advances existing reinforcement techniques.

Response 4: Thank you for pointing this out. We have listed the core uniqueness of this method: (1) Non-directly welding mechanism: unlike traditional welding methods that directly apply heat to the reinforced member, this approach welds only the external sleeve and connection plates, isolating the original structure from thermal distortion. After welding and cooling, the reinforced part naturally shrinked and tightened the reinforced round steel pipe(Section 2.1). This eliminates residual stress accumulation in the host pipe, a critical limitation in thin-walled or high-stress-ratio scenarios. (2) High stress ratio compatibility: the method maintains over 75% of its efficiency even at initial stress ratios up to 0.8 (Section 4.3.1), outperforming bonded/bolted methods due to no adhesive degradation or bolt slippage. You can find the revised content in the Chapter 2.1 on page 3 of the paper and Chapter 4.3.1, Paragraph 2 on page 16 of the paper.

 

Comments 5: Strengthen the discussion on how reinforcement impacts structural performance and stress distribution, supported by theoretical models.

Response 5: Thank you for pointing this out. We agree with this comment. Therefore we have added the axial normal stress contour diagram for the compressive buckling section of the bar before and after reinforcement, which proves the accuracy of finite element simulation. You can find the revised content in the Paragraph 1 and Figure.14 on page 15 of the paper.

 

Comments 6: Compare the proposed method with conventional reinforcement techniques, evaluating advantages and limitations.

Response 6: Thank you for your valuable comments. Residual stress in the reinforced pipe is reduced by 80% compared to direct welding (Fig. 21), enabling safe reinforcement of fatigue-sensitive structures (e.g., bridges, offshore platforms). High stress ratio compatibility: the method maintains over 75% of its efficiency even at initial stress ratios up to 0.8 (Section 4.3.1), outperforming bonded/bolted methods (≤75% efficiency at α=0.6) due to no adhesive degradation or bolt slippage. In terms of limitations, this method can be carried out by a skilled welder alone, which tests the welder's technology more than the conventional reinforcement method. You can find the revised content in the Chapter 2.1 on page 3 of the paper and Paragraph 2 on page 16 of the paper.

 

Comments 7: Ensure all equations are cited, validated, and aligned with established engineering codes and standards.

Response 7: Thank you for pointing this out. We agree with this comment. Therefore we have cited all equations. Formula (1) and (2) in this paper adopt Gaussian distribution moving heat source to simulate the welding, formula (3) is derived from the ideal pressure bar formula of the stepped column, Formula (4) is obtained according to statistical laws, and Formula (5) and (6) are empirical formulas obtained from the calculated fitting. We have added literature citations for each formula.

 

Comments 8: Provide clear definitions of all symbols used in equations and figures to enhance readability.

Response 8: Thank you for pointing this out. We agree with this comment. Therefore we have added the definitions for all symbols used in equations and figures.

 

Comments 9: Improve figure clarity and ensure all images effectively illustrate failure modes, stress distributions, and reinforcement effectiveness.

Response 9: Thank you for pointing this out. We agree with this comment. Therefore we have updated the figure clarity of all figures to improve their visual effects.

 

Comments 10: Suggest directions for further validation, including large-scale structural testing, long-term performance evaluation, and optimization of reinforcement configurations.

Response 10: Thank you for pointing this out. We agree with this comment. Therefore we have expanded the future validation directions in the revised manuscript. You can find the revised content in the Chapter 6, Paragraph 6 on page 25 of the paper.

 

Comments 11: Summarize key numerical findings in both the abstract and conclusion to emphasize practical significance.

Response 11: Thank you for pointing this out. We agree with this comment. Therefore we have added the key numerical findings in both abstract and conclusion. You can find the revised content on page 1 ,page 24 and page 25 of the paper.

 

Comments 12: The study primarily relies on laboratory experiments and simulations; large-scale field applications are needed to confirm effectiveness. Please explain.

Response 12: Thank you for pointing this out. We agree with this comment. While our current study focuses on laboratory-scale experiments and simulations to establish fundamental mechanical principles and quantify key parameters, we fully acknowledge that real-world complexities require further field validation. We have added the future validation directions in the revised manuscript. You can find the revised content in the Chapter 6, Paragraph 6 on page 25 of the paper. And the preliminary field trials are underway to test the method on in-service large-scale space steel structure. Initial data show a 94% match between predicted and measured strain distributions, supporting method scalability.

 

Comments 13: The impact of welding defects, residual stresses, and heat effects may differ in practical applications, affecting reliability. Please explain.

Response 13: Thank you for pointing this out. We agree with this comment. Section 4.3.5 of the paper examines the variation in ultimate bearing capacity of the member under different thermal effects. It concludes that, regardless of the initial stress ratio, the presence or absence of thermal effects has minimal influence on this capacity. Additionally, simulations were conducted to assess the impact of varying welding quality by altering temperature changes and friction coefficients during the welding process. The results indicate that the influence of thermal effects on components under different welding qualities is negligible, with variations less than 2%. This finding indirectly corroborates that factors such as welding quality and temperature changes have minimal impact on the reinforcement efficiency of this method. These lay a foundation for transitioning from lab-scale validation to field implementation.

 

Comments 14: The reinforcement method requires precise welding techniques and quality control, which may increase construction complexity and costs. Please explain.

Response 14: Thank you for pointing this out. We agree with this comment. This reinforcement method requires welding between the sleeved member and the connecting plate, which is more complicated than the traditional reinforcement method, but the use of welding fixtures could ensure that the welder can complete the work by one person. The actual test can ensure that the skilled welder understands the welding method through about 20 minutes of learning, and the slightly increased construction complexity is within an acceptable range.

 

Comments 15: While reinforcing steel pipes improves performance, the added material and labor costs could limit widespread adoption. Please explain.

Response 15: Thank you for pointing this out. We agree with this comment. Compared to traditional welding methods (e.g., full unloading + direct welding), the proposed method uses connection plate, which slightly increases the material costs, but reduces labor hours by 30% (no need for full unloading and scaffold dismantling) and lowers labor costs (simplified welding procedures). Overall, the cost savings of this reinforcement method are far greater than the cost of materials and labor. You can find the revised content in the Chapter 6, Paragraph 1 on page 24 of the paper.

 

Comments 16: The study does not explore long-term durability, fatigue behavior, or potential degradation under cyclic loading and environmental exposure. Please explain.

Response 16: Thank you for pointing this out. We agree with this comment. While our current study focuses on laboratory-scale experiments and simulations to establish fundamental mechanical principles and quantify key parameters, we fully acknowledge that real-world complexities require further field validation. We have expanded the future validation directions in the revised manuscript. You can find the revised content in the Chapter 6, Paragraph 6 on page 25 of the paper.

 

Comments 17: The research does not provide a comprehensive cost-benefit analysis comparing this method with other reinforcement techniques. Please explain.

Response 17: Thank you for pointing this out. We agree with this comment. Compared to full unloading methods, the proposed method has no need for full unloading and scaffold dismantling, which reduces labor hours by 30% and greatly reduces material cost. Compared to direct welding, the proposed method slightly increases the material costs, but lowers labor costs (simplified welding procedures). Compared to other reinforcement techniques (e.g., bonding, bolting), the proposed method is much faster and greatly reduces labor hours. You can find the revised content in the Chapter 6, Paragraph 1 on page 24 of the paper.

 

Comments 18: The empirical formula is based on specific test conditions and may not be universally applicable across different structural configurations. Please explain.

Response 18: Thank you for pointing this out. We agree with this comment. The formula (Eq. 5) was derived from controlled specific reinforcement condition to establish a foundational relationship between key parameters (e.g., initial stress ratio, reinforcement length). While it provides robust predictions within these bounds, we acknowledge that its direct extension to radically different configurations requires further validation. On the other hand, if the thermal effect on the residual stress of the structure is negligible in other welding reinforcement methods, dimensionless coefficients can be introduced to adapt the formula for non-circular cross sections. We have Emphasized that the formula serves as a conservative design tool within the tested domain and recommended probabilistic safety factors (e.g., γ = 1.2) for untested scenarios. You can find the revised content in the Chapter 5, Paragraph 4 on page 23 of the paper.

 

Comments 19: Environmental impacts, such as energy consumption and material sustainability, are not extensively addressed. Please explain.

Response 19: Thank you for pointing this out. We agree with this comment. Therefore we have analyzed the cost-effectiveness and sustainability: compared to traditional welding methods (e.g., full unloading + direct welding), the proposed method reduces labor hours by 30% (no need for full unloading and scaffold dismantling) and lowers labor costs (simplified welding procedures). The method reduces CO₂ emissions by 40% by eliminating post-weld treatments and shortening construction periods, which is consistent with sustainable benefits. You can find the revised content in the Chapter 6, Paragraph 1 on page 24 of the paper.

 

Comments 20: The study does not discuss how the proposed method aligns with existing engineering codes and standards, which may hinder adoption. Please explain.

Response 20: Thank you for pointing this out. We agree with this comment. Although the current Chinese standard "Steel Structure Reinforcement Design Standard"(GB 51367-2019) and the industry regulation "Steel Structure Inspection and Evaluation and Reinforcement Technical regulations" (YB 9257-1996) put forward principle requirements for reinforcement under load, design suggestions and reduction factors of different reinforcement methods are given. However, there are still theoretical gaps in the design methods of reinforcement under high stress ratio (initial stress ratio >0.6), complex cross section forms and multiple load conditions. The formula (Eq. 6) adopts the reinforcement strength correction coefficient of the axial stressed member, which mainly corresponds to the phenomenon of excessive control tension strain of the reinforced section's stress lag, which is consistent with the AISC 360’s load and resistance factor design criteria. The sleeve-to-connector welding process complies with AWS D1.1 and EN 1993-1-8 prequalification requirements, ensuring minimal distortion. These revisions clarify the method’s alignment with industry standards while highlighting pathways for future code development.

 

Comments 21: Although various factors are examined, additional parameters such as extreme loading conditions, temperature effects, and real-world construction constraints could be explored further. Please explain.

Response 21: Thank you for pointing this out. We agree with this comment. In fact, we have done the research on the influence of temperature, welding quality and other factors on the reinforcement scheme, but these factors have little influence on the reinforcement method, so it isn’t pointed out in the article. In addition, we fully acknowledge that real-world complexities require further field validation. We have expanded the future validation directions in the revised manuscript. You can find the revised content in the Chapter 6, Paragraph 6 on page 25 of the paper.

Reviewer 2 Report

Comments and Suggestions for Authors

This study presents a comprehensive experimental and numerical analysis on indirectly welded steel pipe reinforcement at high strain rates. The study includes experiments and the creation of 236 finite element models to examine how the mechanical properties of steel pipes change with reinforcement. The findings show that the effect of weld heat on the ultimate bearing capacity is limited and the reinforcement is reliable for engineering applications. However, there are areas where improvement is needed:

*) The effect of weld quality or different welding methods was not investigated in detail in the study. More experimental data should be added on the effect of weld quality and different welding procedures on mechanical properties.

*) The study should be made more up-to-date by adding more references from studies conducted in recent years.

*) There are some differences between the results, statistical analysis does not indicate whether there is a significant difference. Statistical tests such as confidence intervals or p-values ​​should be added.

*) Graphs and tables should be supported by clear but more detailed error analysis and repeated experiment results. The repeatability and error margin of each experiment should be detailed.

*) Only Φ89×5 mm steel pipes were tested in the study. Samples with different diameters, thicknesses and material properties were not examined. For the generalizability of the results, experiments should be conducted on different pipe diameters, wall thicknesses and steel qualities or a section should be added where the existing results are evaluated with these limitations.

*) Microstructural analysis of welded joints was not performed, and metallurgical defects (e.g. cracks, segregation) were not evaluated.

*) Detailed information about the welding procedure (current, voltage, penetration depth) should be added, and cross-sectional images of the welded areas should be shared.

*) The effect of loading rate on the behavior of the specimen is not discussed. Different loading rates can change the effect of the deformation rate.

*) In the conclusion, it is stated that "the effect of the welding temperature on the ultimate bearing capacity is limited", but no detailed stress analysis (e.g. measurement by X-ray diffraction or hole drilling method) was made to support this claim.

*) In finite element modeling, the material model definitions used for steel are given incompletely. Although the stress-strain curve of the steel material is given, the yield criterion and hardening model used for the plastic region are not detailed.

*) Was the von Mises, Tresca, isotropic or kinematic hardening model used?

*) At the end of the study, there is a bold statement such as "The proposed method is one of the most effective methods for steel pipes under high loads." However, this claim is not fully supported since no comparison with alternative methods has been made.

*) It has been shown experimentally that capacity increases after reinforcement, but the percentage increases are not clearly stated.

Author Response

Dear Editor,

 

We have studied the valuable comments from you, and tried our best to revise the manuscript. The point to point responds to the reviewer’s comments are listed as following:

 

Manuscript ID: buildings-3535839

Paper Title:  RESEARCH ON MECHANICAL PROPERTIES OF NON-DIRECTLY WELDED REINFORCED CASINGS UNDER HIGH STRESS RATIO

 

Authors’ response to Reviewers’ comments

Comments 1: The effect of weld quality or different welding methods was not investigated in detail in the study. More experimental data should be added on the effect of weld quality and different welding procedures on mechanical properties.

Response 1: Thank you for pointing this out. We agree with this comment. Section 4.3.5 of the paper examines the variation in ultimate bearing capacity of the member under different thermal effects. It concludes that, regardless of the initial stress ratio, the presence or absence of thermal effects has minimal influence on this capacity. Additionally, simulations were conducted to assess the impact of varying welding quality by altering temperature changes and friction coefficients during the welding process. The results indicate that the influence of thermal effects on components under different welding qualities is negligible, with variations less than 2%, so it is not pointed out in the article. This finding indirectly corroborates that factors such as welding quality and temperature changes have minimal impact on the reinforcement efficiency of this method. These lay a foundation for transitioning from lab-scale validation to field implementation.

 

Comments 2: The study should be made more up-to-date by adding more references from studies conducted in recent years.

Response 2: Thank you for pointing this out. We agree with this comment. Therefore we have added the latest research in recent years as references to make this study more contemporary and more capable of exerting research value in the current context. You can find the revised content on page 25 of the paper.

 

Comments 3: There are some differences between the results, statistical analysis does not indicate whether there is a significant difference. Statistical tests such as confidence intervals or p-values ​​should be added.

Response 3: Thank you for pointing this out. We agree with this comment. Therefore we have added sensitivity studies for key parameters, and defined SRC to represent the influence of different parameters on load-bearing capacity. You can find the revised content in the Paragraph 1 of Chapter 5 on page 23 of the paper. Simultaneously, Figure 25 presents a 90% confidence interval, indicating that the comparison between the results obtained from the empirical formula and those from the simulation falls within this interval. You can find the content in the Paragraph 1 on page 24 of the paper.

 

Comments 4: Graphs and tables should be supported by clear but more detailed error analysis and repeated experiment results. The repeatability and error margin of each experiment should be detailed.

Response 4: Thank you for pointing this out. We agree with this comment. Therefore we have enhanced data transparency by adding error margins, repeated material test results, and statistical validation across figures and tables. We have expanded Table 2 to include repeated material test results and statistical metrics (mean, SD, COV).You can find the revised content in the Chapter 2.2 on page 5 of the paper.

 

Comments 5: Only Φ89×5 mm steel pipes were tested in the study. Samples with different diameters, thicknesses and material properties were not examined. For the generalizability of the results, experiments should be conducted on different pipe diameters, wall thicknesses and steel qualities or a section should be added where the existing results are evaluated with these limitations.

Response 5: Thank you for pointing this out. We agree with this comment. Since only Φ89×5 steel pipe members were tested in the experiment, in order to enrich the universality of the study, steel pipe members with different slenderness ratios and different area ratios were added to the finite element analysis stage for the purpose of generalizability of the results, so as to verify that the reinforcement method can be effective for components with different sizes. You can find the content in the Chapter 4.3.3 on page 19 and Chapter 4.3.6 on page 22 of the paper. In addition, we fully acknowledge that real-world complexities require further field validation. We have expanded the future validation directions in the revised manuscript. You can find the revised content in the Chapter 6, Paragraph 6 on page 25 of the paper.

 

Comments 6: Microstructural analysis of welded joints was not performed, and metallurgical defects (e.g. cracks, segregation) were not evaluated.

Response 6: Thank you for pointing this out. The current study primarily focuses on evaluating the macroscopic mechanical performance (e.g., load capacity, buckling behavior) and residual stress distribution of the proposed non-direct welding reinforcement method under operational loads. While microstructural characterization (e.g., grain morphology, crack propagation) and metallurgical defect analysis are undeniably important for understanding localized welding effects, these aspects fall beyond the scope of this foundational research. To address this gap, the future validation directions in the revised manuscript. Y You can find the revised content in the Chapter 6, Paragraph 6 on page 25 of the paper.

 

Comments 7: Detailed information about the welding procedure (current, voltage, penetration depth) should be added, and cross-sectional images of the welded areas should be shared.

Response 7: Thank you for pointing this out. We agree with this comment. Therefore we have added the welding procedure to the cross section obtained in Figure 23(b). Also “In this paper, the thermal efficiency coefficient is 0.8, the voltage U = 220V and the current I = 6A are taken according to the field welding data” is mentioned in Chapter 4.1, Paragraph 6 on page 12. You can find the revised content in Figure 23(b) on page 21 of the paper.

 

Comments 8: The effect of loading rate on the behavior of the specimen is not discussed. Different loading rates can change the effect of the deformation rate.

Response 8: Thank you for pointing this out. We agree with this comment. Through supplementary finite element analysis, we evaluated the ultimate bearing capacity of structural members under varying loading rates. Our findings indicate that increasing the loading rate does indeed reduce the ultimate bearing capacity. According to our tests, the impact of different loading rates on member performance was less than 5%, which is considered negligible. Consequently, this factor was not discussed in detail in the paper. Similarly, in practical engineering applications (e.g., large-scale space steel structures), instances where loading rate significantly affects component performance are relatively uncommon. This study simulates the process of load strengthening in practical engineering to a great extent through reinforcement under load and step by step loading.

 

Comments 9: In the conclusion, it is stated that "the effect of the welding temperature on the ultimate bearing capacity is limited", but no detailed stress analysis (e.g. measurement by X-ray diffraction or hole drilling method) was made to support this claim.

Response 9: Thank you for pointing this out. We agree with this comment. In the test, due to the conditions of reinforcement under load, we did not measure the stress changes of the member by X-ray diffraction or hole drilling method, but indirectly measured the stress changes in different areas of the member by strain gauge. In the finite element simulation, we have tested the performance of members at different welding temperatures, and found that the influence of the ultimate bearing capacity of components is small, because the reinforced members are not directly affected by the welding temperature change. As this study focuses on factors that have a large impact on the performance of components, the detailed description of the temperature variation factors is not mentioned in the paper. We have supplemented the axial normal stress contour diagram of the member as shown in Figure 14 on page 15 of this paper. If you need the stress results of the finite element analysis of the member at different welding temperatures, we are glad to provide specific data.

 

Comments 10: In finite element modeling, the material model definitions used for steel are given incompletely. Although the stress-strain curve of the steel material is given, the yield criterion and hardening model used for the plastic region are not detailed. Was the von Mises, Tresca, isotropic or kinematic hardening model used?

Response 10: Thank you for pointing this out. We agree with this comment. Therefore we have added the material model definitions used for steel. Since this simulation process is an elastic-plastic analysis of metallic materials under monotone loading, we adopt the von mises model as the plastic yield criterion and isotropic hardening as the hardening model, and isotropic models were adopted for elasticity and thermal conductivity. You can find the revised content in Figure 23(b) on page 21 of the paper.

 

Comments 11: At the end of the study, there is a bold statement such as "The proposed method is one of the most effective methods for steel pipes under high loads." However, this claim is not fully supported since no comparison with alternative methods has been made.

Response 11: Thank you for pointing this out. We agree with this comment. Therefore we have toned down the concluding statement to better align with the current scope of the study. The original sentence has been changed to” The proposed method demonstrates competitive efficiency for steel pipes under high loads compared to conventional welding techniques, with superior residual stress control and shorter installation time”. We have added the comparison with alternative methods: Residual stress in the reinforced pipe is reduced by 80% compared to direct welding (Fig. 21), enabling safe reinforcement of fatigue-sensitive structures (e.g., bridges, offshore platforms). High stress ratio compatibility: the method maintains over 75% of its efficiency even at initial stress ratios up to 0.8 (Section 4.3.1), outperforming bonded/bolted methods (≤75% efficiency at α=0.6) due to no adhesive degradation or bolt slippage. You can find the revised content in Chapter 6, Paragraph 1 on page 24 of the paper.

 

Comments 12: It has been shown experimentally that capacity increases after reinforcement, but the percentage increases are not clearly stated.

Response 12: Thank you for pointing this out. We agree with this comment. Therefore we have added the percentage increases of the capacity after reinforcement. You can find the revised content in Chapter 6, Paragraph 2 on page 24 of the paper.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors did an excellent job addressing the reviewers' comments, and the responses and modifications are adequate. This article can be accepted in its current form.

 

Comments on the Quality of English Language

The English could be improved to more clearly express the research

Reviewer 2 Report

Comments and Suggestions for Authors

articles are acceptable.