button to the right of the drop-down lists to display the Frame Properties form or the Slab Properties form and add a new property definition to the model file.Use the Structural Geometry and Properties for Two Way or Ribbed Slab form to define a one-way ribbed concrete floor slab system or a concrete flat slab floor system with beams interconnecting all of the columns. No drop panels are included in this template. Note that the connections between the elements are modeled as fully moment resistant, as one would typically expect for a concrete structure.
Note: This form also displays when the Edit menu > Add to Model From Templates > 3D Structure command is used and the Two Way or Ribbed Slab 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 to the edge of the slab/deck in the X direction (i.e., left and right edges).
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 (i.e., top and bottom edges).
Ribs check box. As indicated above, when this check box is check, the form has options to specify a ribbed slab; when it is unchecked, the options specify a two-way slab. The program automatically specifies rib spacing for the ribbed slab, and rib spacing and direction for the two-way slab initial slab property. Rib spacing and direction can be modified using the Slab Property Data form.
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.
Structural System Properties drop-down lists. Use the drop-down lists in this area to select frame section properties for the columns, beams, and ribs, and to select a slab section property for the slab. The property definitions can be modified during the modeling process, if necessary.
Column drop-down list. Select a frame section property for all columns in the model.
For a Ribbed Slab:
Beams drop-down list. Select a frame section property for all beams (girders) in the model. These span perpendicular to the slab ribs (joists).
Ribs drop-down list. Select a frame section property for all one way slab ribs in the model.
For a Two-Way Slab:
Beam X drop-down list. Select a frame section property for all beams in the model that span in a direction parallel to the X-axis.
Beam Y drop-down list. Select a frame section property for all beams in the model that span in a direction parallel to the Y-axis.
Slab drop-down list. Select a slab section property for the floor slab.
Click the button to the right of the drop-down lists to display the Frame Properties form or the Slab Properties form and add a new property definition to the model file.
Load drop-down lists and edit boxes. Use the drop-down lists and edit boxes in this area to specify dead and live loads 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 case 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.
Floor Diaphragm Rigidity check box. Choose rigid, semi-rigid, or no diaphragm. Both rigid and semi-rigid diaphragms also can be assigned to slab/deck 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 slab/deck member that is part of the diaphragm.
Access the Structural Geometry and Properties for Two Way or Ribbed Slab 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 Two Way or Ribbed Slab button.
Click the OK button.