Structural Steel Model Basics - CAESAR II - Help

CAESAR II Users Guide (2019 Service Pack 1)

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English
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CAESAR II
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CAESAR II Version
11.0 (2019)

Start the Structural Steel Modeler from the CAESAR II main window by opening a structural file, and then choosing Home > Input > Structural Input on the ribbon. The software opens the CAESAR II Structural Input dialog box.

Define the structural steel model

The CAESAR II Structural Input dialog box uses keywords to define parameters. If you are not familiar with the keyword input, refer to Structural Steel Input Examples.

The following example shows a structural steel model with two sections and multiple elements defined.

FIX 5 ALL - Fixes node 5, all degrees of freedom.

SECID=1,W10X49 - Defines properties for section #1 (a 20-inch wide flange of 49 pounds per foot).

EDIM 5 10 DY=12-0 - Defines a vertical element from 5 to 10.

Because many structures have a considerable degree of repeatability, there are various forms, options, and deviations for these commands to help you generate large structural models. The method of single element generation is well suited to the needs of most pipers.

Create new lines by selecting a keyword command from the Edit menu or from the toolbar. The most typically used commands are as follows:

EDim

Defines structural elements.

Fix

Defines structural anchors (ALL) or restraints.

Load

Defines concentrated forces.

Unif

Defines uniform loads.

SecId

Defines cross-section properties.

From the Edit menu, you can complete other frequently used functions, including:

Edit > Undo

Reverse the last action.

Edit > Copy Card

Copies an existing command. You must first select the command to copy.

Edit > Paste Card

Pastes a command in the model at the location specified from the Insert menu.

Edit > Delete Card

Deletes an existing command. You must first select the command to delete.

Certain commands set parameters that the software uses for all future element generations:

Default

Sets the default Section ID and Material ID.

Angle

Sets the default element orientation.

Beams, Braces, and Columns

Sets the default end connection type.

Before you start working with structural models in CAESAR II, you must specify the database for upon which the software bases the model.

Select the database for a structural steel model

The full AISC database with more than 900 cross-sectional shapes is available on a “per-member-name” basis. Additionally, you can define any arbitrary cross-sectional shapes.

  1. Open the CAESAR II Configuration Editor to select the proper database before starting the construction of a structural model.

  2. Click Database Definitions in the CAESAR II Configuration Editor, and then click Structural Database. Refer to Structural Databases for information on the structural databases available in the software.

  3. Click Save Save to save the configuration settings.

AISC database names should be typed exactly as shown in the AISC handbook with the exception that fractions should be represented as decimals to four decimal places. Input is case-sensitive. For example, the angle L6X3-1/2X1/2 would be entered L6X3.5X0.5000.

Member-end connection freedom is a concept used quite frequently in structural analysis that has no real parallel in piping work. Several of the structural examples contain free-end connection specifications (such as Column, Beam, and Brace), so you should study these examples for details.

Structural models may be run alone (singularly) or may be included in piping jobs.

Run the structural model without piping (singularly)

  1. Open the structural file.

  2. Click Home > Input > Structural Input .

  3. Enter the structural steel model.

  4. Click File > Save to exit the model.

  5. Click Yes.

    The software saves, error checks, and builds the CAESAR II modules automatically, and then opens the Model Generation Status dialog box.

  6. Click OK, and close the CAESAR II Structural Steel dialog box to return to the main menu.

  7. Click Analysis > Statics to start CAESAR II at the analysis level.

  8. Select the load cases you want to analyze.

    CAESAR II recommends the weight only (W) load case. If needed, create additional load cases to address other input loads or concentrated forces.

  9. Click Run Analysis to begin the analysis, and then click OK.

    When the analysis finishes, the software opens the Static Output Processor. You can also click O345868 Static Output to view or print output reports.

  10. Close the Static Output Processor.

If needed, click Analysis > AISC to open and independently run a Unity Check (stress evaluation) for the most heavily loaded elements, as defined by the American Institute of Steel Construction (AISC). Displacements, forces, and moments are available for each structural element.

Include the structural model in a piping job

Use caution when establishing steel node numbers. Common nodes with piping have the steel anchored to the corresponding pipe node. Usually, piping is connected to steel through restraints with connecting nodes (CNodes).

  1. Complete steps 1 through 6 from the previous section for running a structural model without piping.

  2. Click File > Open and select to open a piping input file.

  3. Edit the piping file to meet your requirements.

  4. Click Environment > Include Structural Input Files from the Classic Piping Input dialog box.

    The Include Structural Files dialog box displays.

  5. Click Browse to select the structural files to include in the piping job, and then click Open.

    SHARED Tip You can browse and select up to 10 structural input files.

  6. Click OK.

    The selected structural models display on the piping input model.

  7. Click Batch Run to begin error checking the model. After you resolve and eliminate any warnings and errors, you can run the entire model successfully.

    The software includes the structural elements in the model for the flexibility calculations. These elements appear as any other piping element, except that CAESAR II does not calculate stresses for structural elements.

You can use stand-alone AISC Code Check software to verify that forces and moments on standard structural shapes do not exceed the various allowable stress limits as defined by the American Institute of Steel Construction.