Steel Deck

Use the Structural Geometry and Properties for Steel Deck form to define a steel floor system.

Note: This form also displays when the Edit menu > Add to Model From Templates > 3D Structure command is used and the Steel Deck button is clicked on the Add to Model - 3D Structure form.

Overhangs
- Along X Direction -- Left Edge Distance and Right Edge Distance edit boxes. Use the defaults or specify positive values greater than or equal to zero for the distance from the perimeter grid line (Grid Plan) to the edge of the slab/deck in the X direction.
- Along Y Direction -- Top Edge Distance and Bottom Edge Distance edit boxes. Use the defaults or specify positive values greater than or equal to zero for the distance from the perimeter grid line to the edge of the slab/deck in the Y direction.
Secondary Beams. Secondary beams (infill) do not frame into columns. By default, moment is released at the ends of all secondary steel beams; that is, they are pinned.
- Secondary Beams check box. When this check box is unchecked, no secondary beams (infill) are included in the model.

When this check box is checked, secondary infill beams will be included in the model. Provide input in the following areas to specify the alignment and the number of secondary beams:

- - Direction drop-down list. Use this drop-down list to specify that the span of the beams is parallel to the X or the Y axis.
  - Max Spacing option and edit box or Number option and edit box. Use one of these options to specify the number of secondary beams.

If the Max Spacing option is selected, the program determines how many beams fit in a bay based on the length specified in the edit box.

If the Number option is selected, use the edit box to specify the number of secondary beams to be spaced equally between the primary beams.

Moment Frame Type options. Choose an option to specify how moment is applied to the frame:
- None option. Moment is released at all beam to column connections; that is, these connections are pinned.
- Perimeter option. Moment is not released at beam-to-column connections for perimeter columns. Moment is released at beam-to-column connections for all interior columns. In other words, beam-column connections at perimeter columns are moment resistant and at interior columns they are pinned.
- Intersecting option. Moment is not released at any beam-to-column connections; that is, all beam-to-column connections are fully moment resisting.
- Special Moment Beams check box. When this check box is checked, click the Specify Type button to access the Special Moments Beam form. After one of the special moment beam options has been selected on that form, ETABS creates a special, nonprismatic analysis section for the beam. That special section is used internally only in the analysis model, not in the object-based model. In addition ETABS adds several special output stations to the beams so that forces are reported at relevant locations in the beam.
Structural System Properties - Use the drop-down lists in this area to select a frame section property for the columns and beams in the model, and to select a deck section property for the deck/floor. Alternatively, click the button to the right of the drop-down lists to display the Frame Properties form or the New Deck/Slab Section form, which has options that can be used to display the Deck Properties form or the Slab Properties form that can be used to add a new property definition to the model file.
- Lateral Column drop-down list. Select a frame section property for the columns where the beam-to-column connections are fully moment resisting.
- Lateral Beam drop-down list. Select a frame section property for the beams where the beam-to-column connections are fully moment resisting.
- Gravity Column drop-down list. Select a frame section property for the columns where the beam-to-column connections are pinned, that is, not fully moment resisting.
- Gravity Beam drop-down list. Select a frame section property for the beams where the beam-to-column connections are pinned, that is, not fully moment resisting.
- Secondary Beam drop-down list. Select a frame section property for all secondary beams.
- Deck/Floor drop-down list. Select a deck section property for the deck/floor.
Load drop-down lists and edit boxes. Use the drop-down lists and edit boxes in this area to specify dead and live load patterns on the model.
- Dead Load Pattern drop-down list and Dead Load (Additional) edit box. When accessing this form to begin a model, the default Dead load pattern is the only option. Use the Dead Load (Additional) edit box to define uniformly distributed dead load in addition to the self-weight of the structure. The self-weight of the structure is determined by multiplying the weight per unit volume of each object that has structural properties times the volume of the object. The weight per unit volume is specified in the material properties.

- Live Load Pattern drop-down list and Live Load edit box. When accessing this form to begin a model, the default Live load pattern is the only option. Use the Live Load edit box to define additional uniformly distributed live load.

TIP: If the Initialize from Existing .edb File option was selected on the Model Initialization form when the File menu > New Model command was used to begin the model, and if load patterns other than dead and live (e.g., snow, wind, wave) were created for the "existing .edb file" selected as the basis for creating the current model file, additional load patterns will be available in the Dead Load Pattern or Live Load Pattern drop-down lists.

Restraints at Bottom options. Use these options to specify the type of restraint at the bottom of all columns.
- None option. Specify no restraints (supports) at the bottom of all columns.
- Pinned option. Specify pinned restraints (UX, UY and UZ restrained and RX, RY and RZ free) at the bottom of all columns.
- Fixed option. Specify fixed restraints (UX, UY, UZ, RX, RY and RZ restrained) at the bottom of all columns.

Floor Diaphragm Rigidity check box. Choose rigid, semi-rigid, or no diaphragm. Both rigid and semi-rigid diaphragms also can be assigned to floor members during the modeling process. The rigid and semi-rigid options affect only the analysis of the model. If the rigid option is selected, a fully rigid diaphragm is assumed. If the semi-rigid option is selected, the in-plane rigidity of the diaphragm comes from the stiffness of the floor member that is part of the diaphragm.

Access the Structural Geometry and Properties for Steel Deck form as follows:

Click the File menu > New Model command to access the Model Initialization form and initialize a new model.
When the New Model Quick Templates form displays, specify the grid dimensions and story level, and the click the Steel Deck button.
Click the OK button.