Mean Stress Effect in High-Frequency Mechanical Impact (HFMI)-Treated Steel Road Bridges
Round 1
Reviewer 1 Report
Thank you for your very interesting work. In my opinion your work is very important for the application and design consideration of HFMI-treatment on bridges in the future. The study contains extensive data and is strongly recommend for publication. Just some minor revision are needed:
Page 1, Line 23: I recommend to cite the IIW-guideline for HFMI-treatment after the first sentence “f steel weldments [4]”.
Page 1, Line 30: I would avoid the work “sharpness” please use “notch effect” instead.
Page 2, Line 45: The authors are encouraged to spend one or two sentences and explain why there is an influence of mean stress on the fatigue strength of HFMI-treated welded joints (relaxation of beneficial compressive residual stresses at high mean stresses).
Page 2: You mention a lot of studies on the R-ration influence of HFMI-treated welded joints. I would strongly recommend also mentioning this study: doi.org/10.1007/s40194-016-0400-2 and https://doi.org/10.1016/j.ijfatigue.2016.09.009
Page 3, Line 80: Could you spend 1- sentence to clarify how the measurement in Ref 10 are done? Strain-gauge for example?
Page 10, Line 186: “Heavier traffic generates cycles with a larger stress range but with lower 186 mean stress”. For my understanding: If heavier traffic occurs, does this not leads to higher mean stress because of a higher number of lorries at the same time on the bridge? Please check the meaning of this sentence.
Page 12, Line 223: Please right “accuracy” instead of "correctness".
Page 17, Line 223: Please right “capability” instead of "fitness"
Author Response
Please see the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
This paper presents a study on the mean stress effect on HFMI-treated weldments in steel road bridges. Traffic measurements in Sweden and Netherlands were used to validate previously-derived expressions derived from the authors' previous researches, the proposed design method was further validated by using four composite case-study bridges. It was also found that the mean stress effect was mainly influenced by the self-weight, while the variation of the mean stress due to traffic had a minor influence on the total mean stress effect. Furthermore, it was found that the mean stress effect could not be accurately or conservatively predicted using FLM3 or FLM4. The research done in this paper is systematic and comprehensive, practicability is strong, but part of the article is not expressed properly, and it is suggested to modify.
- The comparison of self-weight stress distribution of different bridges was not clear, it is suggested to fix the extreme value of vertical axis in Figure 6.
- Lin 190 mentioned that "the use of the proposed Φ—λHFMI curves can be extended to different countries even if the traffic volumes and intensities are different", it is suggested to give more explanation to this sentence.
- Lin 209 "t This is due to the fact that the local traffic……" is suggested to be " Figure 15 shows the fact that the local traffic……".
- As shown in Figure 17&18, the calculated λHFMI for the top flanges were more conservative than the bottom flanges by Equation 4 & 5, it is suggested to give an explanation.
- The format of Figure 2, 7, 8 & 9 were confusing, which needs to be modified.
- It is suggested to combine conclusion (1)&(2), (6)&(7).
- The number of references in recent years was too small. It is suggested to increase or update relevant references appropriately.
Author Response
Please see the attachment
Author Response File: Author Response.docx
