Built up box formed by four angle sections– bbfa

This is a section frequently adopted for the modelling of box formed by four angle sections steel profiles.

Materials and Dimensions

Only one material (steel) needs to be defined.

The required dimensions are as follows:

• Flange width. The default value is 0.15 m
• Flange thickness. The default value is 0.01 m
• Flange to Flange distance. The default value is 0.02 m

Note: Users may use a built up box formed by four angle sections to model the retrofitting of a RC rectangular member with longitudinally-oriented steel or FRP layers applied on the two opposite sides of the section. To do this, first create a material model featuring the properties of the retrofitting material and then use a built up box formed by four angle sections element that equals that of the original element's section, flange thickness dimensions corresponding to the thickness of the retrofitting layer, and connect this new retrofitting element to the same nodes to which the existing element is connected to.