Study on Elastic Global Shear Buckling of Curved Girders with Corrugated Steel Webs: Theoretical Analysis and FE Modelling

Round 1

Reviewer 1 Report

This work presents a research on the global elastic shear buckling strength of plane curved corrugated steel webs in prestressed concrete girder bridges with corrugated steel webs. The problem has been analyzed both through an analytical approach and finite element analyses, developed taking into account different geometries and configurations. The paper is well written and clear. There are few typos that can be fixed during the proof-reading on the manuscript. 

Few minor comments:

at page 4, Line 118: correct the symbol for the Poisson ratio;

at page 8, Line 243: no reliability analysis has been carried out. I would like to suggest to change the word as "accuracy";

Figure 4: it should be changed (it is the same of Figure 2, not representing the finite element model); 

Figure 11 and 15: their quality can be improved, especially the sub-box that can is fairly visible.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Good paper. I suggest the authors continue the research also with experimental tests in order to definitely prove the theoretical relations provided in the paper. 

Author Response

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Reviewer 3 Report

The paper is on a relevant topic, and generally well written.

Few suggestions and recommendations are provided, to enhance some last aspects or improve the presentation of results.

figure 1: it would be beneficial for the reader to show (adding for example an arrow or some labels) the position of corrugated steel webs in the real strutcture

figure 2: when multiple plots are presented, labels (a), (b) etc should be defined and properly described in the caption

Eq.19: three different expressions are grouped. It would be good to have different numbers for each one of them (or 19a, 19b, 19c)

figure 4 is not the FE model, revise it

section 6.2: the mesh size and pattern should be shown,in an additional figure

figure 5 should include also an axonometric view, to allow a global vision of the deformed shape

figure 5: legend values and meaning of colours are missing

figure 5: boundaries and loads should be properly defined, to facilitate the readability and understanding of the figure content

table 4 (and comments in the text): it would be beneficial to mention in the text not only the mean ratio of comparisons (and COV) but adding also max & min values

figure 11: the meaning and goal of the "box" detail is not clear, please clarify

figure 15: the meaning and goal of the "box" detail is not clear, please clarify

tables 7 or 8 should be removed, or at least condensed.

general comment: the paper presents an original model and approach, that seems able to provide suitable results for the structural components object of analysis. In place of the real system, a shear buckling formulation is proposed for the corresponding equivalent, orthotropic shell element. This general approach is not at all new for structural engineering applications, while it's new its application to the systems presented in the paper. The manuscript should mention some few examples of literature, where classical buckling models have been proposed and reformulated/adapted to allow for reliable but simplified calculations of (even complex) real structures. Recent interesting examples can be found in the literature, for example, for timber walls and others. Some recommendations are listed here below, then the authors are free to add further documents to this list:

(1) https://www.sciencedirect.com/science/article/pii/S0141029617340890?via%3Dihub

(2) https://www.sciencedirect.com/science/article/pii/S0141029614006385

Author Response

Thank you for your comments on this manuscript. Please see the authors' response in the uploaded word document.

Author Response File: Author Response.pdf

Reviewer 4 Report

This paper presents theatrical and numerical investigations on the performance of curved girders with corrugated steel webs. Some comments are listed as follows. In general, literature needs to be enhanced to make the novelty and significance more clearly and with some other questions related to modelling and presentation of the content.

 

1. There is no sufficient literature on curved bridge girder with steel webs. What has been done (i.e. existing approaches) and what is new in this paper compared with the others ( particularly the advantages of the developed model)?

 

2. Line 85, Punching shear is more critical than static shear on the failure of a bridge. Please restate this.

 

3. Line 168, assumption of ‘continuous, homogenous, orthotropic...’ and later in Fig. 3 the in theoretical work, the CSW was equivalent to a flat orthotropic shell elements.  In fact the performance of a corrugated element along a corrugated web is not same due to the geometric difference, please justify this assumption.

 

4. Line 275, No Fig shows the labelled edges (i.e. AD and BC) Please add.

 

5. There are only validations of theoretical results using FEM, but no benchmark for FEM results.

 

6. Any parametric studies/comparisons of the results presented in sections 6.4 and 6.5? Are they part of theoretical study and why they come after the numerical part?

 

7. The angles marked on Fig.6 are not clear (i.e. α1, α2)

 

8. When conducting FEM, please explain the selection of mesh size.

 

9. How has the composite action between steel and concrete been quantified in theoretical and numerical work, please explain.

Author Response

Thank you for your comments on this manuscript. Please see the authors' response in the uploaded word document.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The paper presents an original model and approach, that seems able to provide suitable results for the structural components object of analysis. In place of the real system, a shear buckling formulation is proposed for the corresponding equivalent, orthotropic shell element. 

Most of the previous suggestions have been taken into account.

Few of them / some further corrections are required, however, before publication.

The proposed general approach is not at all new for structural engineering applications, while it's new its application to the systems presented in the paper. For this reason, the manuscript should mention some few examples of literature, where classical buckling models have been proposed and reformulated/adapted to allow for reliable but simplified calculations of (even complex) real structures. Recent interesting examples can be found in the literature, for example, for timber walls and others. The following recommendations are given and should be mentioned as recent examples:

(1) https://www.sciencedirect.com/science/article/pii/S0141029617340890?via%3Dihub

(2)

https://www.sciencedirect.com/science/article/pii/S0141029614006385

Then, for sure, the authors are free to add/select further literature documents that could be suitable for the introduction.

In this manner, the paper content will be properly emphasised, with a direct link to existing context.

Author Response

Thank you for providing valuable documents for the authors. The articles on buckling analysis of timber walls and other composite structures you recommended show an interesting field of application research. We have benefited a lot from these excellent research. The authors have added these two articles [R1 and R2] to the Introduction and References of the revised manuscript. Please see the revised manuscript. Thanks again for your useful comments on this paper.

[R1] Bedon C.; Fragiacomo M. Numerical and analytical assessment of the buckling behaviour of Blockhaus log-walls under in-plane compression. Eng. Struct. 2015, 82, 134-150.

[R2] Bedon C.; Amadio C. Buckling analysis and design proposal for 2-side supported double Insulated Glass Units (IGUs) in compression. Eng. Struct. 2018, 168, 23-34.

Reviewer 4 Report

manuscript is in an acceptable form. 

Author Response

Thank you for taking your valuable time to review the revised manuscript, and thank you very much for your valuable comments on this manuscript.