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Peer-Review Record

Seismic Damage Model of Bridge Piers Subjected to Biaxial Loading Considering the Impact of Energy Dissipation

Appl. Sci. 2019, 9(7), 1481; https://doi.org/10.3390/app9071481

by Shangshun Lin¹, Zhanghua Xia^2,* and Jian Xia²

Reviewer 1: Anonymous

Reviewer 2: Anonymous

Appl. Sci. 2019, 9(7), 1481; https://doi.org/10.3390/app9071481

Submission received: 15 February 2019 / Revised: 18 March 2019 / Accepted: 27 March 2019 / Published: 9 April 2019

(This article belongs to the Section Civil Engineering)

Round 1

Reviewer 1 Report

Authors present an exciting work on improvement of seismic damage model. They should be commended for the experimental works presented in the manuscript. They have improved the Usami model to create M-Usami model as well. The paper is well written and the content falls within the scope of the journal. My concern is: Could you please create finite element model as well to justify/calibrate the experimental data? It would be very interesting.

Furthermore, please type all equations like Eq. 4. Also, consider some typo errors.

Author Response

Reply: Thanks for your commendation on our work. This part of work focuses on the experimental study to improve the accuracy of Usami model. The large amount of testing data successfully justifies the new model. We believe this justification is sufficient, given that the FEA data can only be interpreted with certain assumptions. However, we are interested in developing a FEA model in future to conduct a parameter analysis for the further understanding of the damage mechanism and damage indices.

All the equations have been typed like Eq.4. The whole manuscript was also reviewed to remove any typo errors.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

Thank you very much for your efforts for conducting this experimental study and for publishing your results in this paper, “Seismic damage model of bridge piers subjected to biaxial loading considering the impact of energy dissipation”. In this paper, damage models for RC box piers are developed and verified using the experimental result from 14 specimens.

Strength:

The organization of the materials is good, and the manuscript does not need a comprehensive English editing. The experimental procedure is described very well and the results are well-documented. The paper and results are interesting for readers in bridge engineering, particularly from the seismic design perspectives.

Minor comments:

Since the damage patterns depends of the shape of the cross-sections, it would be better to provide some reasons and examples of bridges with the square/rectangular piers, and compare with the circular cases. Also, considering the scale of the tests, and to avoid misunderstanding, please provide a real-scale application of such piers.

The concrete materials preparation is not clearly described. What type of concrete have you used? Is that a HPC or UHPC? Could you please explain and verify with the codes on seismic design specifications for bridges, like AASHTO’s?

In the results section and the conclusion, you have stated: “the load displacement was small”. Please clarify what you mean by ‘load displacement’. Please find the other similar phrases and revise all. Another example is the phrase “loading displacement”; all the displacement are from the loadings.

Writing suggestions:

Line 094: “piers” à ‘the piers’

Line 096: “cross section” à ‘cross-section’

Line 108: “pier” à ‘the pier’

Line 173: “quantity” à ‘quantitative’

Line 192, 204, 416: “concrete surface” à ‘the concrete surface’

Line 233: “the Stage 2 and Stage 3” à ‘Stage 2 and Stage 3’

Line 249: “afterwards” à ‘afterward’

Line 286: “are then expressed” à ‘are expressed’

Line 314: “for the consideration” à ‘for consideration’

Line 386: “the higher energy dissipated” à ‘the higher the energy dissipated’

Line 397: “pseudo static” à ‘pseudo-static’

Regards,

Author Response

Minor comments:

Reply: There are many bridges with the square or rectangular piers in the world. For example, Maojing Bridge in Guizhou Province, China has rectangular piers with the maximum height of 113.1 m; Daxifeng Bridge in Fujian Province, China has rectangular piers with the maximum height of 83 m. Compared with circular piers, rectangular piers are generally used in long-span bridges. The cross-section of bridge piers is relatively large, and the slenderness ratio is relatively large. The deformation during earthquake is large, producing bending deformation damage and energy consumption. While, most of the circular piers are applied to small and medium-sized bridges, and the relative deformation is small, but the cumulative damage under earthquake could have a great influence on the mechanical properties of piers. This study focuses on the study of tall RC piers with rectangular piers, and the results could be potentially applied to those with circular piers. Future experiments on circular piers will be carried out.

Considering the scale of tests (1:14), the range of pier height is from 2.8*14 to 5.8*14, i.e., 39.2 m to 81.2 m. The real-scale application of such pier with rectangular cross-section can be the Huangsha No.1 Bridge in Fujian Province, China has rectangular piers with the maximum height of 60 m. There are also many other bridges with heights more than 40 m.

Reply: The normal-strength concrete with fine aggregates was cast to reach the design strength of C50 (50 MPa at 28 day-curing age). The water-cement ratio was 0.36. This was updated in text. Regarding the seismic design specifications for bridges, the current design methods are still not ready for designing hollow RC bridge piers subjected to multi-dimensional seismic excitations. Future work can be performed to improve the current design specifications for hollow RC bridge piers based on the understanding of this study.

Reply: The ‘load displacement’ and ‘loading displacement’ were changed to ‘displacement load’, which means the application of displacement to the pier.