Section Profile

The profile defines the shape of the section.

Profile

There are three basic ways of defining this:

Catalogue – this gives the option to choose a section from the different categories in various section tables. This is intended for steel sections. For a catalogue section the profile description will always start CAT.

Standard shapes – for most concrete sections a standard section will be used. The required shape is chosen and the defining dimensions given to construct the section profile. For a standard shape the profile description will always start STD followed by a characters denoting the section shape, e.g. R for rectangular or CHS for a circular hollow section.

Geometric definition – for a section that cannot be selected from a catalogue or described by a standard shape there is an option to define the geometry more directly, either as a perimeter or as a series of line segments. The most commonly used of these is the perimeter option where the profile is defined by a series of (y,z) points. This option also allows standard bridge beams to be imported stored as perimeter sections. For a geometric section the profile will always start GEO.

Once the basic section is defined there are options to manipulate the basic definition by rotating, reflecting and translating the profile.

Reference point

By default the reference point is taken as the geometric centroid of the section. In some cases it is convenient to work with a different reference point. There are two options for modifying the reference point. The first uses the extremes of the section: top/bottom and left/right. If further adjustment s required an additional (y,z) offset can be specified directly

Tendon positions

Tendon positions are holes in the section are distinct from voids. A rectangular hollow section would be a section with a void. A tendon position hole is treated as a point area, so is only suitable for small or zero area holes (positions) such tendon positions in bridge beams.

Bridge beams

GSA has a database of precast concrete bridge beams. These are considered as a special case of perimeter sections. Rather than defining the perimeter directly the section is read from the database. In addition to the perimeter, the database holds the positions for tendons. These are also imported as point voids (holes with zero area). The user can then place tendons at the required positions in the section, based on the point voids.