Multi-Cell CIP Box Section Dialog Box
The Multi-Cell CIP Box Section dialog box allows you to define a typical box-girder cross section. To open this dialog box, open the Cross Section Layout dialog box by clicking the Cross Section button on the Geometry tab. Select the section you want to modify, and then click the Section button located in the grid.
Defining Exterior Girders
One of five available shapes defines each exterior girder and its dimensions, including thickness, slope factor, and radius of the corner. If any of the three dimensions (thickness, factor, and radius) is not applicable to a shape, then the field will be disabled.
- Select the exterior girder type from the drop-down list.
Setting Description Vertical The girder edge will be defined vertical. Slope The girder will edge will be sloped by defining the factor "f". Chamfer The girder will edge will vertical and the bottom corner will be chamfered by defining the distance "F". Vert Round The girder edge will be defined vertical and a rounded bottom corner of radius "r" will be defined. Slope Round The girder will edge will be sloped by defining the factor "f".and a rounded bottom corner of radius "r" will be defined. The distance "f" measures from the overhang length "l" to the PI of the rounded corner. None No exterior girder is present. - Enter the web thickness for the exterior girder in the Thickness (t) field.
- Enter the factor for the exterior girder in the Factor (f) field.
- Enter the radius for the exterior girder in the Radius (r) field.
Defining Section Properties
You can choose to specify the cross section properties instead of the calculated values. These properties include centriodal location, area, moment of inertia, and volume-to-surface ratio. To calculate the section properties, select Auto Calculate. To enable the manual input of section properties, select User Input and then complete the following fields:
| Setting | Description |
|---|---|
| CGz | Enter the center of gravity location along the z-axis. |
| Cgy | Enter the center of gravity location along the y-axis. |
| Area | Enter the area of the section. |
| Izz | Enter the moment of inertia of the section. |
| Vol/Area | Enter the volume-to-area ratio of the section. |
Defining Material Properties
You can define the basic material properties that are used in analysis, calculation of loss of prestress, and capacity of the section. Click the Material button to define the material properties of the section using the Concrete Material dialog box.
Defining Cross Section Parts
Parts of the basic geometric shapes can be added or removed from the section. This capability can be used to add to the thickness of a specific interior girder, to remove the concrete at the location of utilities, or for other similar applications. Click the Parts button to add additional cross section parts using the Multi-Cell CIP Box Parts dialog box. By selecting the Parts Only option, the cross section properties will be based on the parts only and will not include the properties of the box girder section.
Defining Superstructure Width and Depth
| Setting | Description |
|---|---|
| Width (w ) | Enter the overall width of the structure from Edge-of-Deck (EOD) to EOD. In addition to defining the size of the cross section, these fields are also used in the calculation of the Live Load Distribution Factors. |
| Depth (d) | Enter the overall depth of the structure from the top of the deck slab to the bottom of the soffit slab. |
Defining Slab Thickness
| Setting | Description |
|---|---|
| Top Thick (tt) | Enter the thickness of the deck (top) slab. |
| Bottom Thick (bt) | Enter the thickness of the soffit (bottom) slab. |
Defining Interior Girders
| Setting | Description |
|---|---|
| Number | Enter the number of interior guides. |
| Web Thick (tw) | Enter the web thickness to be used for all interior girders. |
Fillet
You can define the fillets with equal width and height to be added to the top or bottom of the girders. The size of the fillet is measured from the intersection of the face of the girder and the face of a slab as a vertical or horizontal dimension.
| Setting | Description |
|---|---|
| Top Fillet (tf): | Enter the horizontal/vertical delta for all top slab fillets. |
| Bottom Fillet (bf) | Enter the horizontal/vertical delta for all bottom slab fillets. |
Exterior Overhangs
Technical Discussion
Cross section dimensions are used to calculate the properties that are used in analysis. These include location of center of gravity (CG), area, bending moment of inertia about the horizontal axis, torsional moment of inertia, and volume-to-surface ratio. Shear deformation is ignored; therefore, shear area is not calculated. The volume-to-surface ratio is calculated based on the entire section, as the ratio of the area of the cross section to the outer perimeter of the section,Nomenclature
| Setting | Description |
|---|---|
| Area | The area of the section. (Section Properties) |
| Auto Calculate | Automatically calculate the section properties. (Section Properties) |
| Bottom Fillet (bf) | The horizontal/vertical delta for all bottom slab fillets in the section. (Fillet) |
| Bottom Thick (bt) | The thickness of the soffit (bottom) slab of the section. (Slab) |
| CGy | The center of gravity location along the y-axis. (Section Properties) |
| CGz | The center of gravity location along the x-axis. (Section Properties) |
| Chamfer | The girder will edge will vertical and the bottom corner will be chamfered by defining the distance "f". (Exterior Girders) |
| Depth (d) | The superstructure depth of the section, including overhangs. |
| Exterior Girders | The properties of the exterior girders. |
| Exterior Overhangs | The properties of the exterior overhangs. |
| f | The factor for the section's exterior girders. (Exterior Girders) |
| Fillet | The properties of the top and bottom fillets. |
| Interior Girders | The properties of the interior girders. |
| Izz | The moment of inertia of the section. (Section Properties) |
| Len (l) | The horizontal length of the section's exterior overhangs. (Exterior Overhangs) |
| Material | Define the material properties of the section using the Concrete Material dialog box. |
| Number | The number of interior girders in the section. (Interior Girders) |
| Parts | Define additional cross section parts using the Multi-Cell CIP Box Parts dialog box. |
| Parts Only | Ignore the cross section dimensions as if the section is made of the parts only. |
| r | The radius of the section's exterior girders. (Exterior Girders) |
| Section Properties | Automatically calculate or manually input the section properties. |
| Slab | The properties of the concrete slab. |
| Slope | The girder will edge will be sloped by defining the factor "f". (Exterior Girders) |
| Slope Round | The girder will edge will be sloped by defining the factor "f".and a rounded bottom corner of radius "r" will be defined. The distance "f" measures from the overhang length "l" to the PI of the rounded corner. (Exterior Girders) |
| t | The web thickness for the section's exterior girders. (Exterior Girders) |
| te | The exterior thickness of the section's exterior overhangs. (Exterior Overhangs) |
| ti | The interior thickness of the section's exterior overhangs. (Exterior Overhangs) |
| Top Fillet (tf) | The horizontal/vertical delta for all top slab fillets in the section. (Fillet) |
| Top Thick (tt) | The thickness of the deck (top) slab of the section. (Slab) |
| Type | The type of exterior girder used in the section. (Exterior Girders) |
| User Input | Manually input the section properties. (Section Properties) |
| Vert Round | The girder edge will be defined vertical and a rounded bottom corner of radius "r" will be defined. (Exterior Girders) |
| Vertical | The girder edge will be defined vertical. (Exterior Girders) |
| Vol/Area | The volume-to-area ratio of the section. (Section Properties) |
| Web Thick (tw) | The web thickness to be used for the section's interior girders. (Interior Girders) |
| Width (w) | The superstructure width of the section, including overhangs. |