-->PONE-D-25-27560-->-->Characteristics of a new UT-Type Prefabricated Joint for Rectangular Steel Tubes under Combined Axial-Moment Loading-->-->PLOS ONE

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #2: Yes

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Reviewer #1: A comprehensive study on the static and hysteretic behavior of a new type of Prefabricated beam-column joint (UT-type) is presented in the manuscript entitled “Characteristics of a new UT-Type Prefabricated Joint for Rectangular Steel Tubes under Combined Axial-Moment Loading”, in order to promote the practical application of the joint, a simplified trilinear restoring force model is proposed. The quality of the paper is good, but some parts need to be improved:

1. Joint Construction and Assembly Method: The technological explanation in Section 2 regarding the assembly of the UT-type joint components, particularly the bolt tube and the threaded sleeve, requires clearer and more detailed elaboration.

2. Experimental Methodology: he justification for omitting the 0.2μ and 0.6μ failure modes in Section 3.1 remains incomplete. To address this gap, the text should clarify that "Results for μ=0.2/0.6 are omitted here due to similar failure patterns but included in Table 3 for quantitative comparison." This addition would provide readers with a clear rationale for the selective data presentation while ensuring all critical information remains accessible in the supplementary data tables. 3 for quantitative comparison."

3.Abstract Structure: The novelty and key quantitative findings of the study are not prominently highlighted. To improve clarity, the abstract should explicitly state: *"We propose a UT-type prefabricated joint featuring adjustable sleeves (tolerance: ±5 mm) and energy-dissipating segments. Tests reveal axial tension increases initial stiffness by 42.6% (μ=0.4), while compression reduces yield moment by 24.5%. The validated trilinear model predicts hysteresis with <10% error."* This revision ensures the innovation and critical results are immediately apparent to readers.

4. Figures & Tables (Moderate Revisions for Readability & Rigor):Some tables in the article are missing units, such as table 7 and Table 8; Some figures (e.g., Figs. 6–7) would benefit from clearer labeling and more informative captions to help readers better understand the observed failure modes.

5.Improve readability and adherence to academic writing standards, please revise passive voice constructions to active voice (e.g., change "It was observed that..." to "We observed..." in lines 78 and 112) for greater directness and clarity, as recommended by most style guides. Additionally, correct unit spacing format (e.g., "3.7mm" should be written as "3.7 mm" in Table 2) to follow standard SI unit conventions and maintain consistency throughout the manuscript. These modifications will enhance both the precision and professionalism of the text.

6. Nomenclature Consistency: The current manuscript alternates between the terms "energy-dissipating" (line 45) and "energy-consuming" (line 12), which may cause confusion. For standardization and compliance with ASTM terminology, all instances should be unified under the preferred term "energy-dissipating". This correction ensures technical precision and maintains consistency with established industry standards throughout the paper.

7. The following research works regarding the prefabricated beam-column joints and related structures can be reviewed and are suggested for possible reference:

(1) Modeling of force- displacement behavior of post- tensioned self-centering concrete connections. Engineering Structures, 2019, 198: 109538.

(2) Probabilistic analysis on time-dependent mechanical behavior of posttensioned self-centering concrete connections. Engineering Structures, 2020, 218, 110856.

(3) Influence of connection properties on seismic performance of post-tensioned self-centering concrete frames, Journal of Building Engineering, 2022, 46, 103761.

Reviewer #2: The manuscript presents an investigation into the UT-type prefabricated beam-column joint, combining experimental testing (static and cyclic loading) with finite element simulations to analyze its mechanical behavior under axial force-bending moment coupling. The inclusion of both numerical and experimental work is a strong foundation, and the experimental program—particularly the cyclic loading tests—provides valuable insights into energy dissipation and failure modes, which are critical for engineering applications. The proposed trilinear restoring force model adds practical value by offering a design-oriented tool. However, several fundamental issues regarding clarity of objectives, novelty of the joint design, and technical rigor require major revisions to strengthen the study's contribution to the field.

A A critical gap in the manuscript is the lack of clarity on whether the UT-joint represents a new design innovation or an adaptation of existing prefabricated connections.

B The research objectives are not explicitly articulated, leading to a disjointed narrative between the problem statement, methodology, and findings. While the study explores mechanical behavior and proposes a restoring force model, the overarching goals—such as improving seismic performance of prefabricated structures, addressing constructability challenges, or enhancing design codes—are not clearly defined.

C The writing of the manuscript requires substantial improvement. The language is often unclear, and the sentences are poorly structured, making it difficult for readers to follow the arguments. The authors should pay more attention to grammar, punctuation, and sentence construction.

D Format and grammar Issues requiring correction:

1. The abbreviation UT-Type is never defined.

2 The reference style should be consistent. References mix author-year and numeric citation formats. If the reference number is used, there is no need to include year. And usually, the last name is used when referring.

3 Some paragraphs are too short and only have one sentence (I.e. Line 66, 73). Please combine to improve the flow.

4 No unit in Figure 4

5 Line showed Eq. (3), where is Eq. (1) and (2)

6 The format of tables should be consistent (i.e. Line space, space between number and unit)

7 Ensure all technical symbols are italicized throughout the manuscript.

8 What is the arrows in Table 3 represent for?

9 Line 96 is not a new sentence; there is no need of the indentation and uppercase of W.

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Reviewer #1: No

Reviewer #2: No

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Characteristics of a new UT-Type Prefabricated Joint for Rectangular Steel Tubes under Combined Axial-Moment Loading

PONE-D-25-27560R1

Dear Dr. zailin Yang,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Kind regards,

Dajiang Geng

Academic Editor

PLOS ONE

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