Energy-Based Evaluation on Soil–Structure-Interaction-Related Damping of Inelastic Bridge Pier Structure Subjected to Pulse-like Velocity Ground Motion

Round 1

Reviewer 1 Report

This manuscript focuses on the evaluation on soil-structure-interaction-related damping of inelastic bridge pier structure using the energy method. This has reference significance for further clarifying the disaster mechanism of bridge piers under strong earthquakes. The topic is generally interesting and suitable for Sustainability; however, there are major issues that require thorough revision and improvements:

1.       How is the constitutive relationship between concrete and steel considered in this paper? Please provide additional explanations.

2.       In the article, contents such as structural dynamic characteristics analysis and Fourier transform of structural response should be added in Section 3. It is necessary to investigate whether or not the SSI interaction can induce the natural vibration of structures under different seismic actions, with or without SSI interaction.

3.       Please complete the information on h_s, d_s, pier column stiffness, and superstructure related parameters in Figure 8.

4.       Based on the conclusions of this paper, when the SFS system is subjected to near fault earthquakes, the SSI effect is suppressed; What help does the author think this will have for the future seismic design of structures?

5.       Please explain whether different types of soil, the buried depth and size of foundations, etc. will have an impact on the conclusions of this article.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

This paper proposed a procedure of using the energy method to evaluate the SSI-related damping effects on responses of bridge pier structures. Through the IIRF method, the frequency-dependent SSI function was transferred into the time domain to formulate the motion equation of the bridge pier SSI-based SFS inelastic system. An implementation study was conducted based on a previous experimental study to compare the response variance between distinct input earthquake recordings. The paper gives a significant contribution to the subject area. I suggest that the paper be published with the correction of the cited literature. In particular, to add references of a more recent date.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

 

This study aimed to develop a procedure for evaluating the SSI-related damping effect, through an energy perspective, on responses of bridge pier structures. This evaluation procedure first constructs a soil-foundation-superstructure (SFS) system by expanding an inelastic SDOF system to include a frequency-dependent SSI model via the discrete-time infinite impulse response filter (IIRF) technique. Then, based on the motion equations of the SSI-based SFS system, the energy equations were formulated to distinguish distinct energy quantities in a quantitative manner, particularly the SSI-related energy. The SSI-related damping ratio (SSIDR) was also introduced herein. An implementation study was conducted not only to demonstrate the proposed evaluation procedure, but also to compare the response variance between distinct input earthquake recordings. In general, the authors make efforts to present their work and the paper is well written, and a few questions are requested in the following comments to be duly handled.

1. For the Introduction section, the authors make the literature review of the SSI and damping systems, which is a good work. The reviewer suggests to focus more on the short comings of the existing references. Meanwhile, the reviewer suggests to add some literature review of the damping systems, see 10.1016/j.jobe.2022.104904; 10.1016/j.strusafe.2023.102330;

2. In the 2. Methodology, the authors show the principle of Soil-Foundation-Superstructure System and SSI. The reviewer suggests to add a simple flow chart of the equation steps and analysis steps, which will be a better choice for the readers.

3. In the 3 Implementation Study of the bridge pier system, how to simplify the system into the SDOF and how to verify with the MDOF? Maybe some words are needed.

4. In the SSI assessment and structural response evaluation, how to determine or select the pulse-like velocity ground motion? Is it from the database or via the earthquake model for generation?

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

The paper evaluates the damping effect in a bridge pier system under earthquake loading considering soil-structure interaction. The analytical formulations and numerical simulation results are shown for a simple SDOF system. Even though the results are interesting, the paper lacks novel contributions. The energy-based evaluation of bridge pier systems considering soil-structure interactions has been studied for a long time. The article fails to demonstrate original research contribution, hence in its current form, the paper is recommended as not suitable for publication.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The reviewer recommends the manuscript be accepted for publication due to the satisfactory responses to the previous comments.