A variety of different structures are looked at on the site and can be accessed via the beginner, intermediate or advanced tabs, in tutorials aimed at different levels of engineering experience.
Beginner tutorials assume a level of knowledge equivalent to students starting an undergraduate degree in civil engineering or a similar qualification and this level is built on through the intermediate and advanced tutorials.
The tutorials consist of text with diagrams and accompanying videos. Although the videos cover the same concepts as the text they have a slightly different approach. You can choose to look at both text and videos or focus on one format depending on which you find most useful.
There are also quizzes which test your understanding of the concepts covered in the tutorials. Quizzes are accessible to everyone but detailed feedback is only available for Civil Engineering students at the University of Sheffield. Sorry! There's too many of you otherwise.
You can also find a toolbox link that covers useful concepts in structural analysis that aren't related to any specific structure but are good for everyone to be aware of.