Multiaxial Fatigue Assessment for the Hanger Deck Connection of a High-Speed Steel-Truss-Arch Railway Bridge
Round 1
Reviewer 1 Report
Please see attached review report.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
The authors have dealt with a well-established theory of fatigue damage in engineering infrastructures and applied this to a real-life case study of a bridge and making valid lifetime predictions.
The paper is well structured, with appropriate literature that sets an adequate background for the problem addressed. A lot of the literature citings are rather dated and that is a reflection of the fact that the problem of fatigue is agelong. I would prefer if this section can be improved with more recent citations.
Abstract:
It is well structured addressing the rationale and methods well set out. However, the results and context need to be improved.
Line16-18
"An actual project, i.e., the Dashengguan Yangtze River High-speed Railway Bridge in Nanjing was introduced to assess the fatigue damage as well as the fatigue life by using the recommended method."
This needs to be rephrased, as it gives the impression that the rail service was introduced as part of the fatigue study! I assume the authors intend to say:
"The methodology was applied to real-life strain data from a High-speed Railway Bridge from which an assessment of fatigue damage and predicted fatigue life was estimated."
Line 26 - 28: Not clear and need to be rephrased
"With the increase in the total traffic flow and composition ratio of ... 10%, the fatigue life is much smaller than the design life cycle of the bridge."
The above is meant to be a summary of the results and it is a bit nebulous and needs to be reconstructed. My understanding is the authors intend to indicate that if freighting is taken into consideration, the fatigue damage will increase rapidly, and for the case 10% of proportion traffic as freighting, the actual fatigue life is estimated to be shorter than the design life.
Introduction
Line 39 Remove unknown character in
"...vibration ().
Multiaxial Fatigue Assessment Method
Line 86: Put "Stress - No of Cycles" before S-N
Line 139 Remove unknown character in "... damage reaches 1.0 ()."
Multiscale Numerical Model
After line 196:
Figure 3 not labelled and titled. Should be "Figure 3: Two-level FE model of the High-Speed Railway Bridge"
Line 218: "As shown in the figure" should be "It is shown that"
Line 242: Missing reference in: "... to a similar steel material[x]"
Influence of Multiple Factors on the Multiaxial Fatigue Life
Line 285 -287. Need to rephrase for clarity:
"Even though the ratio of freight trains is only 10%, the fatigue life is reduced from 138 to 73 286 years, which is only 53% of that of 0%."
Conclusions
Line 310 - 311: Rephrase "As the amount of the freight train traffic is only 10%, the fatigue life is as low as 73 years under the condition of an annual growth rate 311 of traffic flow of 10%." It could read better as:
If the proportion of freight train traffic is 10%, the fatigue life can drop to as low as 73 years.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The Paper is focused on a theoretical and numerical study of the multiaxial fatigue assessment for deck connection of steel arch bridge. An interestic fatogue approach has been applied to a real case study. The paper is well-presented and interesting. However some improvements are nedded:
1) Some typos have been found along the text, see as an example line 39. Please read carefully and with more attention all the text.
2) To thicken the introduction some comments about the difference between low-cycle and high-cycle fatigue assessment should be inserted. Low-cycle fatigue is really interesting in case of earthquake. See as an example papers: Bernuzzi et al., dx.doi.org/1016/j.tws.2017.03.002; dx.doi.org/10.1016/j.tws.2016.09.010
3) Please add more references to the Miner rule theory presenting also the typical fatigue graph associated with this rule.
4) Figures 1 and 2 should improved, they re not clear. Especially the flow-chart in Figure 1 should be better presented
5) Justify with more clear senteces the choose of the material properties
6) Why the modes are called order ? make no sense. Togheter with the comparison in term of eigenvalue also a comparison in term of eigenvectors is necessary.
7) How the experimental modes have been obtained ? which procedure have been followed. Please explain better this point
8) Please enphatise the difference bwteen your proposal and the one described within the code. In the conclusion or in the last chapter it could be useful to have a practical proposal to improve the actual fatigue design rules.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have revised the manuscript properly. It can now be accepted for publication.
Author Response
Thans for your recognition
Reviewer 3 Report
The paper has been improved by following all the suggestion. The new flow-chart (figure 1) is really good. Authors did an accurate work on the manuscript. No more revisions are necessary.
Please pay attention: seems that all text is shifted on the right part of the manuscript while the figures are in "full page" mode. There is the need of an uniform pagination.
Author Response
Thanks for your recognization, and the postion of the figures are revised in the newly uploaded manuscript.
