Stiffening Statements

The stiffening statements are maybe the most complicated ones, therefore this paragraph contains a survey about how they are related to each other. The details about their use can be found in relation with each individual statement.

Some basic facts and conditions:

• A bracket may be stiffened along its free edge and/or in its interior.

• Stiffening along the edge can take place via

  • a) a folded (bent) flange,

  • b) a stiffener welded parallel to the free edge at a short distance,

  • c) a flange (face plate) welded against the free edge.

• Any way of stiffening the free edge may be combined with additional stiffeners in the "interior" of the bracket.

• If there are several stiffeners on a bracket they are all supposed to be parallel.

Except for folded flanges the stiffening of a bracket means that profiles are welded to the bracket. A set of profiles (types, dimensions) available for the bracket stiffeners can be defined in a PROFILE statement. Many independent such sets may be defined, for example, to be used in different brackets.

The PATTERN statement specifies the location of the stiffeners on a bracket. Each pattern is valid when a bracket has a certain number of stiffeners. For certain brackets the number of required stiffeners may increase as the bracket size grows. This means that there must be a number of patterns set up for such a bracket, each valid in case of a certain number of stiffeners, for example, one pattern when there is one stiffener, another when there are two, The position of bracket stiffeners in the interior are normally supposed to be depending on the depth of the bracket.

In addition the PATTERN statement specifies how the profile dimensions should be selected from the profiles available in a certain profile set, selected for the current bracket. Normally the profile section is supposed to be compared to a tenth of the profile length times the bracket thickness. Suppose that the profile length is L and the bracket thickness t. Let A = L*t/10. Then the profile should be selected whose cross section area is comparable to A (times a factor which is normally close to 1). Further details will be found in relation with the PATTERN statement.

The STIFFENER statement specifies the stiffener pattern to select as a function of the bracket size, specifies the profile set to be used and also the endcuts of the stiffeners (which are all supposed to have the same endcut). The FACE_PLATE statement is used in a similar way for welded flanges.

The different statement types will be specified in subsequent paragraphs of their own in this document in the logical order, which is the order in which they are presented above.