Review of

M.J.P. Tol, T. Waiboer, J.J. Weeland, 2023 Shell Structures, report for course CT3280 Shell Roofs, Delft University of Technology, Department of Civil Engineering and Geosciences, 2024, online: phoogenboom.nl/B&B_schaal_report_11.pdf

by dr.ir. P.C.J. Hoogenboom, Delft, 8 January 2024

 1. Complete report. Excellent report structure. Few typing errors. Handed in on time (8 Jan. 2024).

 2. Include "Course CT3280 Shell Roofs", "Delft University" and "Department of Civil Engineering and Geosciences" on the title pages. I would not put student numbers on the cover; most readers do not need this information.

 3. This is not a good summery. The first sentence is a definition, which is just boring. The second sentence states the aim of the report but it is hidden in an uninteresting comment about lab reservation. The third sentence is about tools and supervision, which better fits in the Preface. A good summery is interesting for other Delft students: What was the problem? What was the objective? How was it obtained? What is the main conclusion? For example, start with: "Shell structures can be used for covering large spaces. Beautiful and efficient shell roofs have been realised al over the world. However, ... The challenge is to ..." 

 4. The introduction starts with the things that will be done. This is not good. The introduction should start with a problem or an opportunity. The things that have been done (approach) come after the research question.

 5. The introduction includes research questions, which is good. (A research question is equivalent to "aim", "goal", "objective".) The research questions must be answered in the conclusions, however, only the last two are answered.

 6. The design process is described clearly. Another problem with triangles is that each needs a different size, otherwise you get a flat structure.

 7. I cannot find the dimensions of the slats in the report. Readers need to know this to be able to reproduce your experiment.

 8. Beautiful Rhino perspective. The drawing is clear, though there are several extra lines that I do not understand. The dimensions are accurate in 1/10 mm which is more accurate than can be built. The height of the model is not on the drawing.

 9. Good photos and drawings of the construction process. Excellent description.

10. Accurate description of the wood test. The wood broke suddenly ... but in compression, usually it fails plastically. The fibres are crushed but still carry much of the load. Compare this to a glass jar which fails brittle in an "explosion" of pieces.

11. Very good load distribution. Perfectly statically determined.

12. Beautiful SCIA model. The connection to the foundation is fixed. Was is glued? If not, a hinged connection might have agreed better with how it was built.

13. The stress check is realistic. I should have done a compression test perpendicular to the fibres for you.

14. The stress check could have been done by hand too: stress is load over foundation area.

15. Realistic buckling check. But a knockdown factor should have been applied.

16. Excellent scale up to the large structure. Correct calculations.

17. Honest discussion.

18. Interesting clear conclusions and a positive ending. Very good.