Partially encased composite I-section - pecs

This is a section frequently adopted for the modelling of composite columns.

Materials and Dimensions

Four different materials can be defined; longitudinal reinforcement, transverse reinforcement, steel profile, concrete.

The required dimensions are as follows:

• Flange width. The default value is 0.2 m
• Flange thickness. The default value is 0.015 m
• Web height. The default value is 0.25 m
• Web thickness. The default value is 0.02 m
• Unconfined concrete thickness. The default value is 0.01 m

Reinforcement

Longitudinal reinforcement bars can be defined in two different ways

1. by editing the reinforcement pattern;
2. by entering the respective area and sectional coordinates (the latter being defined in the local coordinate system of the section).

Further, the transverse reinforcement may be specified, in terms of the stirrups' diameters and legs, as well as the distance between them.

Note: A parabolic curve has been assumed to represent the boundary between fully and partially confined concrete areas. Its depth may be conservatively estimated as 20% of the profile's flange width. More rigorous estimation procedures, however, can be found in the work of Mirza [1989] or Elnashai and Elghazouli [1993], amongst others.