Finite Element Analysis of Pre-Stressed Ultra High-Performance Concrete (UHPC) Girders

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1)     What’s the highlight of the paper, what is the key point of FEA to simulate UHPC compared with ordinary concrete beams, which point can be referred to other girders, please state them in the abstract part or in the conclusion part.

2)     L20, full name of abbreviations “CDP” should be given the first time it appears.

3)     L64-65,” none of the previous FE studies on UHPC structural elements have compared their results with full-scale experimental tests.” Please refer to more references because it is not the first time the authors carried out the FEA study for UHPC.

4)     L140，“their v positions”,is it a typo error?

5)     L146-156,how is the FE model meshed? How many elements are there in the FE model?

6)     L185-194,the parameters are suggested to be illustrated in terms of figures or equations.

7)     L195, how the CDP parameters were determined based on extensive sensitive analysis?

8)     L254,how Figure 9 was obtained ,was it from a test or from a reference.

9)     Since the steel pre-stressing strand are simulated using truss elements (L153), and they are embedded in the UHPC(L278),where the concrete acts as the host, how the model simulates the slip of steel and concrete after the cracking.

10)  L344-346,what kind of equipment is used to obtained the Test-stress since most experiments use strain gauges.

11)  L404-405,why there is no descent stage in FEM, whereas experiment has.

12)  L420, the experiment is carried out in form of static test, why there is dynamic load interactions?

13)  L429, why there is a descent stage curve after 0.005 of strain in the experiment- bottom of the section, but the FEM does not show it.

14)  L443,what does “Damage T” mean.

Comments for author File: Comments.docx

Comments on the Quality of English Language

The quality of English Language is good

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In the manuscript, the authors present a numerical study on the flexural strength of UHPC prestressed girder. The numerical model was developed based on Abaqus. Some revisions should be made before considering the possibility of publication.

1. Explanations for alpha factor (0.85, in the compressive strain model) and gama factor (in the tensile strain model) should be given with physical insights.

2. As the strain model is used to describe the tensile response of the concrete, mesh-sensitivity and element sizes should be considered. Explanations about the choice of element sizes in Tables 1 and 2 should be given.

3. Some comments should be given to explain the divergences between experimental and numerical results shown in Figs. 14 and 15.

4. More details should be given to assess the failure criteria in the numerical models (e.g. location and appearance of first crack, first yielding of strains). Are those failure similar to those observed in the test (location of strain gauge and crack profile).

5. Fig. 16 should be compare to experimental result.

2. Some typos are found locally (e.g. line 140, line 216, etc)

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I think the authors have answered my questions and  can be published

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have revised the manuscript according to the reviewer's comments. The manuscript can be accepted in the current form.