Table Designing of Floor Joists

You can use span table design to estimate the structural strength of a simple floor framing. The program will compare the spans in the building model to the spans in the design table. The design results are based on the span comparison. The program will also create a model of the loaded area and check whether the table design limit load is exceeded.

You can use span table design in the following cases:

• The designed parts are frame joists under an even load (no point loads). End and side beams cannot be designed using table designing.
• The joists are one-span beams.

Table Design is an add-on feature of the Vertex BD software. The add-on feature includes the span table design mechanism but not the span tables themselves. Users must create the tables for the desired profile libraries.

Creating a span table for the cross sections of a profile library

You can create the span table as follows:

1. Select System Settings > Cross Section Libraries > Edit Cross Sections.
2. Select the desired profile library from the list.
3. Select the Edit Span Table function.

   

   The Span Table database view opens.

4. Add a row for each cross section in the database and fill in the cross section data.

   The cross section must be defined in the profile library. Enter the code defined for the cross section in the profile library in the Code field.

5. Click the To XML button.
6. Click the OK button. The program will save the database in XML format in the ../custom/setup/pcecalc/spantables folder. The name of the XML file is the same as the name of the profile library.

Note

• System Settings is available on the toolbar only if you are a system administrator.

Design code

You must then add the span table data to the XML file defining the design code, for example in file

../custom/setup/pcecalc/Example.xml.

Open the file in, for example, a text editor, and add a tag in the file for each span table of the profile library, for example:

<Library>lumber.xml
<Name>lumber</Name>
</Library>

Equations

The equations are defined in the ../custom/setup/pcecalc/SpanTableEquations.xml file. Editing the equations requires special expertise. Editing the equations is necessary, for example when you wish to use span table design on several-span beams.

Beam design

You can carry out the span table design of floor framing as follows:

1. Select Floor Joists, Roof Rafters > Member Design.
2. Select the design criteria in the dialog box.
3. Confirm by clicking OK. The program will add a load table to the floor plan.
4. Select the parts to be designed.
5. Select Confirm.
6. If problems occur during the design process, a list of error messages and warnings will be provided at the end. Such an error message might, for example, refer to a cross section not found in the span table. Close the list by clicking the OK button.

   The program will add calculation labels for the floor joists on layer 54.

If necessary, edit the framing based on the error messages and rerun the framing design. You can view the error messages and calculation results with the Design Results function.

Note

• The loads of floors above are not transferred to the designed joists.

Design results

You can view the design results as follows:

1. Select Floor Joists, Roof Rafters > Design Results. The Piece Calculation Results dialog box opens.
2. Select a part from the list in the dialog box and do one of the following:
   • Click the Results button.
   • Click the Stress Indices button.
   • Click the Detailed Output button.
   • Click the Print Select (Detailed) button.
3. You can view the error messages and warnings reported during the design process by selecting the Warnings and Errors tab of the dialog box.
4. Click OK to close the dialog box.

If necessary, edit the framing based on the results and rerun the framing design.

Floor Joists, Roof Rafters