Plate girder design - detailed design
To extend the coverage of plate girder design previously given in the Plate girder behaviour and design parts 1 and 2 lectures. To include the design of transverse web stiffeners and end posts and consideration of patch loading. To outline design procedures for longitudinally stiffened girders and for girders with large web openings.
The detailed design of particular elements of plate girders is considered in this lecture. The structural action of web panels, designed as described in earlier lectures, imposes stringent requirements on adjacent boundary elements. This lecture considers the design of transverse web stiffeners and end posts according to Eurocode 3  and also considers the particular problems caused by patch loading. Two other aspects of design, the design of longitudinally stiffened girders and girders with large web openings, are also discussed.
The two previous lectures on plate girders, Plate girder behaviour and design part 1 and Plate girder behaviour and design part 2, concentrated on the main aspects of the structural behaviour upon which the design principles are based and outlined the design approach proposed in Eurocode 3 .
This lecture seeks to complete the discussion of plate girder design by considering further aspects of detailed design. For example, the development of post-buckling action in a web plate, assumed in the previous lectures, can only occur when the elements at the boundary of that web plate are able to provide an adequate anchorage for the tension field forces developed within the plate. This lecture will consider the design of these boundary elements. These elements may be in the form of intermediate transverse stiffeners or end posts.
Girders may be subjected to high loads in localised regions away from stiffener positions, creating a possibility that crippling of the web plate may occur. An example of this occurs in crane gantry girders subjected to a vertical loading which travels along the flange. The effects of such 'patch loading' must be carefully taken into account in design. This aspect is very thoroughly covered in Eurocode 3 . This lecture outlines the relevant design principles.
Two other important aspects of plate girder design are the treatment of girders with longitudinal web stiffeners and of girders with large openings in the web plates. Openings are frequently required, particularly in building construction, to allow access for service ducts, etc. However, this option is not covered in Part 1.5 of Eurocode 3 . This lecture discusses good practice in relation to the two situations.Read more