Finite Element Modelling of Bolt Shear Connections in Prefabricated Steel Lightweight Aggregate–Concrete Composite Beams
Round 1
Reviewer 1 Report
The manuscript deals with an interesting topic related to the behaviour of the lightweight concrete-steel shear connection constructed by bolts. The manuscript consists of the development of a shear connection numerical model by the ABAQUS software. The numerical model is calibrated with the results of existing pushout experimental tests from the literature and the effects of the concrete strength, concrete density, bolt diameter, and bolt tensile strength are investigated through a parametric study. From the obtained results and results from the literature, empirical design formula for bolt connection shear strength is proposed.
Besides to novelty and necessity of the presented study, there are some aspects which should be improved in the manuscript. The title should be revised in order to be clear. For example, what is the meaning of the word “prefabricated” when this word is not mentioned in the manuscript at all? Bolt or bolted shear connection? It must be clearly stated in the abstract and the manuscript that experimental push out test results was taken from literature and not part of the presented research. In addition, the type and parameters of provided analyses in Abaqus software were not mentioned and discussed. The influence of mesh sensitivity is provided in section 3.3. show the only influence of bolt mesh density. The influence of other parts’ mesh density in the numerical model is not presented and discussed. The ductility aspects of analysed bolts were not discussed. For example, in some standards for composite structures, there are restrictions on the tensile strength of shear studs.
Specific comments:
L93: Figure 1 a) Presented solution in Figure 1a) does not correspond to the prefabricated solution.
L97: “…bar cages. “ – rebar?
L132: “The material stress-strain relationship of bolt connection…” – for bolt connection or for a bolt? It is not clear. In addition, the adopted equivalent stress, strain, and yield strain are not provided after the equation (3). Only bolt tensile strength is provided in Table 2.
L145: What is the reason for bolts prestressing?
L104 and L148: Figures 2, 3 and 4: From the presented figures it is not clear how the bolts were modelled, through the concrete slab or not?
L240: “The shear behaviour of the bolt connection embedded in steel-lightweight aggregate concrete composite beams (SLACCBs) was predicted based on the verified FE modelling shown above.” – The sentence should be simplified to: “The shear behaviour of bolt connection embedded in LAC slab….” The composite beams are not investigated in the paper, just the shear connection!
L328: Figure 17b) The influence of bolt tensile strength is presented only with one concrete strength. The conclusions could be different for other concrete strengths.
L334: The meaning of m and h should be given.
L352: Figure 18: What is the reason for not presenting equations from (4) to (9) in increasing order?
L362: Figure 19: The uncertainty of equation (10) should also be presented in contrast to the results from the literature as was the case for equations (4) to (9) in Figure 18.
L364-365- See General comments related to the manuscript title and comment L240.
L367: “…with the existing push-off test results.” - with the existing push-off test results from the literature.
L381: The conclusion No. 4 is expected if the only concrete density is changed as a parameter.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article addresses an important and very interesting topic of the finite element modelling of bolt shear connection in prefabricated steel-lightweight aggregate concrete composite beams, which is appreciated. The study includes of the numerical research. In this paper the tridimensional non-linear FE modelling considered the geometric and material nonlinearities was presented, calibrated and verified against the push-off tests initially. Subsequently, the basic shear performance of bolted connections embedded in SLACCBs was investigated and compared with NC slabs by utilizing the verified FE modelling. Besides, the effects of several key variables, including the concrete strength, concrete density, bolt diameter, and bolt tensile strength on the shear behaviour of the bolted connection, were explored by extensive parametric studies. Finally, some design recommendations were proposed to evaluate the per bolt connection shear strength. The Reviewer has some concerns regarding the conclusions and references. In addition, the English language is good but some sentence should be more clear (too long). Please check the text of Native Speaker. In opinion of Reviewer this paper should be subjected to minor revision.
Other comments:
- What is the next step of your research? Please add.
- References should be improved. Please add a few papers about similar research and please add some international papers (not only Researchers from China).
And the end I hope that my comments will be helpful for the authors.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
