Use this option to define member type parameters for the Polish steel code PN90-03200.
There are two ways to access this option.
- Click the New Bar Type option located in the Bar Type dialog
- Click the Parameters button located in the Definition dialog.
The following dialog displays:
The bar type field displays the name of the selected bar type (enter the name of the defined bar type). The Buckling with respect to axis Y or Z, fields displays the length of the bar for the appropriate plane.
There are two ways of defining this length.
- Select the Real option, the entered value is interpreted as the length
- Select the Coefficient option, the value is interpreted as the coefficient by which the actual length should be multiplied to get the correct value. For instance, entering the value 0.25 means that the appropriate length is equal to 1/4 of the actual length.
Choose the Coefficient option to define simultaneous members of differing actual lengths whose additional supports are, for example, equally spaced. If the set parameters are to be maintained as a category, it is necessary to enter the length. Introducing the value 1.0 guarantees that each member defined with the help of the category as Ly will have its actual length accepted.
In the Buckling Length Coefficient field, the actual length of the member (or, the sum of the component element lengths) is automatically entered in the appropriate fields. The buckling length coefficients of a member are defined in both directions.
The buckling length coefficient depends on the end-support conditions of a bar nodes in the buckling plane. The buckling length is also defined in the Buckling Patterns dialog, which is opened by clicking the icon representing the selected bar buckling model type. After selecting a typical scheme, the coefficient value is accepted or calculated automatically.
The icons in the dialog are divided into two groups:
- The first group contains typical (code) methods of member support and the corresponding buckling coefficient values.
- The second group contains icons for calculating the buckling coefficient for multi-story frames. The colors of the icons signify appropriately: red (A) - calculations for movable frames, blue (B) - for fixed frames.
Buckling is considered during calculations if a compression force operates in a member, even if it is small in comparison to the other internal forces. A separate analysis is not performed that would determine whether buckling effects should be ignored. To eliminate buckling effects from calculations, click the last icon.
Select the Annealed sections option to include the heat treatment operation (annealing) in the steel parameters. For such steel, verification at certain stages of code calculations proceeds differently than for regular steel. Thus, it is necessary to indicate it before calculations. If the option is selected, then steel used in calculations will be considered as heat-treated steel.
In the Lateral Buckling Parameter field you can select the following options used during the verification of the lateral buckling for the member: lateral buckling type, load level and the lateral buckling length coefficient. Clicking the appropriate icon opens the dialog for the definition of corresponding parameters.
The Lateral Buckling Type option defines the corresponding code lateral buckling parameters depending on the static pattern of the member. As required by code, one of the patterns included in the code must be accepted. Patterns in the shape of icons mirror the appropriate items from the code. The last icon represents the resignation from including lateral buckling effects during calculations.
The Load type option defines the load scheme of an analyzed beam. As required by code, when calculating code coefficients (concerned with buckling, lateral buckling), it is necessary to determine the character of loads acting on a member in both or one plane of the member section axis.
To accurately describe lateral buckling conditions, the level of load application has to be included. The ordinate height of load application is defined in the member section axis system. Assuming that lateral buckling will occur when loading the member in the XZ plane, only one coordinate is entered. It is a relative value from the <-1.0,1.0> interval. If the load is applied at a characteristic section point - upper flange, lower, etc. then, the coordinate value is entered automatically once an appropriate icon is selected.
To calculate lateral buckling for a bar, you must provide the distance between sections blocked against twisting (lateral buckling length). It is necessary to distinguish two buckling lengths (for the upper and for the lower flange) as it is possible to attach the upper and lower flanges separately, which results in the appearance of different load cases of compression forces. The value of the coefficient by which the base bar length should be multiplied to obtain the lateral buckling length must be provided. The length IZ is taken as the base length. The coefficient value is entered directly or by selecting the icon representing typical attachment case for which the coefficient is automatically chosen.
It is also possible to select an instability curve included in calculations of the lateral buckling coefficient Fi_L; as specified in section 4.5.4, choose one of the following two curves: the curve 'a0' (a default one) and the curve 'a'.
The Lateral buckling parameters field includes an option for selection of a method of supporting member ends for torsion (fixed or pinned member ends).
At the bottom of the dialog there are edit fields used to define the coefficients A1, A2, B (C1,C2) for calculation of the critical moment Mcr; the option allowing automatic selection of values of these coefficients is activated by default. If the user-defined option is selected, then coefficients defined in Table Z1-2 are determined manually.
Click the More button to open an additional dialog. You can then define the remaining member type parameters described in the code, such as: load type (Beta coefficient), section parameters.
Click the Complex section button to open the Complex Section dialog where parameters of complex members are defined.
Click the Service button to open an additional dialog. You can then define the parameters of bar type (limit displacements, initial deflection).
When checking the critical conditions for the correct calculations, it is necessary to define the character of the bending moment diagram - appropriately in the Y and Z plane of the section. The Beta coefficient value is required in the calculations. There are four ways to define the character of moment diagrams and member attachments considered by the code.
Click the Add button to add a bar type - with defined name and parameters - to the list of predefined steel bar types.