Limcon is normally supplied configured for one of the following design codes: ANSI/AISC 360-05 (ASD & LRFD) CSA-S16-01 BS 5950 : 2000 EN 1993 : 2005 (EC3) AS 4100 / NZS 3404 Each connection design model is essentially defined by the cited reference but the relevant provisions of the configured design code take precedence where any difference occurs. The design code can only be changed when Limcon has been supplied validated for more than one design code. When Limcon is validated for ANSI/AISC 360-05 you may choose either ASD or LRFD. >Configure > General command permits the country and the section library to be changed. The country determines which steel grades may be used for plate components and the section library determines availability of steel sections and their grades.
Print Output
The report for an MEPC is shown below. The first page of this report shows dimensions and design actions and the second page shows results of all checks performed. You may supply a 1200 x 200 pixel bitmap in order to print your company logo at the top of each page.
Limcon Window
The Limcon window is a multi-cell view with the main menu and toolbar at the top. Each connection in the current job is shown in miniature as a thumbnail in a cell. A data tip appears when the cursor passes over a cell containing a connection. Double-clicking on a thumbnail displays a dialog box (see below) for editing the connection data. Right-clicking on a thumbnail displays a menu offering commands to show the connection at full size, edit, copy, or print the connection.
Connection Dialog Box
The main menu is the principal command interface. Each main menu item gives access to a drop-down menu of commands. In general, each toolbar button corresponds to a menu item. Double-clicking on a thumbnail or selecting a command on the Connections menu displays a dialog box for the particular connection. From this dialog box you may check or design a connection.
A detail window on the left of the dialog box shows the current configuration of the connection. The parameters defining the connection are shown in boxes on the right and an adjacent Edit or "…" button permits editing of any of the enclosed parameters. The output window at the bottom of the dialog box displays the most recent results of a check or design operation.
The Go button and the adjacent Check and Design option buttons initiate the selected check or design operation. Clicking the View button displays a virtual reality view of the connection. The Print button prints a report containing a detail diagram and the current results, while the DXF button creates an AutoCAD format drawing exchange file containing a detail of the current connection.
The check operation reports the capacity of the current connection configuration for all failure modes specified in the connection model. The design function uses an iterative method, changing some connection parameters, in an attempt to achieve an optimum connection configuration for the design load. Some connection parameters (e.g. bolt diameter) are not changed during design. The connection parameters that may change during design are displayed in red when design mode is selected.
Virtual Reality
Clicking the View button in a connection dialog box displays a new window containing a virtual reality view of the connection. This view is not available on displays with less than 16-bit color. Initially, the connection is shown rotating in the window. You may drag the mouse to rotate the view to any convenient orientation and zoom by pressing the PageUp / Page Down or + / - keys. Keyboard arrow keys also rotate the view. The pop-up menu shown appears when you right-click in the window. On this you may select an option so that dragging the mouse pans the display instead of rotating it. You may also select various fixed views, including a plan and elevation.
Limcon Configuration
The File > Configure > General command allows you to set the default library file, edit library files, set text size, and set OpenGL parameters. Configuration settings are saved from run to run, for each user.
Analysis Methods for Splices & Moment Connections
The distribution of forces between the flanges and web in BSPL, WSPL, BMEP, HBEP, and WBC connections is determined by the analysis method set with the File > Configure > General command. There are three different methods - these are elastic, plastic, and simplified analysis methods.
The elastic method is recommended in Ref. 4 and the AASHTO 1999 Interim. Plastic analysis gives a more rational force distribution when the factored loads are sufficient to cause yield. Other analysis methods may then produce flange forces that exceed the capacity of the flange. The elastic method is the default for checking to AS 4100. The simplified method is a traditional approach in which the flange plates are assumed to resist all the moment and axial force while the web plates resist the shear (and the resulting eccentricity moment). Choosing the simplified method gives designs with stronger flange plates and weaker web plates. It is the default method when Limcon is configured for BS 5950 or AISC LRFD.
All three analysis methods give safe, lower bound, designs but the simplified method leads to more yielding and redistribution of forces as the connection conforms to the applied loading.
Section Library Manager
After you have selected a destination library Microstran's Section Library Manager displays the dialog box shown above. There is a tree view of the destination library on the right while all available library source files are shown on the left. Each library may be expanded to show the section categories and each of these may be expanded to show the sections contained in the category. You may select any library, category, or section on the left and click the arrow button to send it to the destination library on the right.
Double-clicking a section on the right will display a section property dialog box in which you may alter any value.
I SECTION PROPERTY DIALOG BOX
During the compilation of the output library source file the properties of all sections are checked and a warning is displayed for each value that differs by more than 1% from the check value. This is a powerful tool in eliminating errors in section libraries.
