Percent Composite
Inputs exist to set the percent composite value for stripping, transportation, erection, and in-place. The construction stage uses the same percent composite values are in-place. For each of these stages, the user can give a percent composite for deflections, stress calculations, and all strength checks.
For service checks, deflections and stresses, the percent composite is used by interpolating the section properties between fully composite and non-composite. The non-composite section used for all interpolation contains only the structural wythe and the non-structural wythe is not considered.
For strength checks the percent composite is used by interpolating between capacities by the defined percent composite. For example, for an 80% composite panel, the flexure capacity would be 80% of the way between the non-composite and fully composite flexure capacity. Because of this accurate parameters used in computing capacities are not known (such as neutral axis depth). The PM Diagram is also interpolated between the non-composite and fully composite case.
The following options are also selected by the user:
Option | Description |
|---|---|
Solid Zone Behavior | This controls how solid zones are to be handled in the analysis. If set to partially composite, all the concrete in the solid zone is considered top-in-form as it is considered part of the secondary pour. If set to fully composite the section will not use any interpolation for section properties or strength checks. |
Structural Wythe | The user can select whether the structural wythe should be the top in form wythe, the bottom in form wythe, or the stiffness wythe (defined as the elastic modulus times the moment of inertia). The structural wythe is used as the non composite wythe for all interpolations. |
Loading Datum | This input determines which section is used when computing the applied eccentricity of a given point load. The selected value will be used to compute the centroid of the section. |
Beam Spring
When beam spring is selected as the analysis method the program will design two precast members attached to each other by a series of shear springs. The output for this methodology will be split into two, one for each wythe. The horizontal shear connections would be placed in areas of high slip (given in the output) in order to efficiently transfer forces between wythes. For a simply supported panel the ends are typically the areas of highest slip but for indeterminate systems this location may be harder to determine. For these cases iterations may be required for design.
Connector Properties
Connector properties contain the data coming from the five layer shear test and a few user options. The connector properties can also be exported and imported from disk as they typically will remain constant depending on the manufacturer of the connector. These inputs are as follows:
Option | Description |
|---|---|
Reduction Factor | A reduction factor used to limit the amount of allowable slip allowed in either yield or ultimate. This is applied to both the allowable slip and the force limit in order to leave the stiffness of the spring unchanged. |
Force | The amount of force allowable for the yield / ultimate condition. |
Slip | The amount of slip (defined as the differential axial deflections between each wythe) allowed for the yield / ultimate condition. |
Slip Limit | Sets the allowable slip to either yield or ultimate for both service and ultimate checks. This will not change the analysis results but will produce an error if violated. |
Connector Locations
The locations of the horizontal shear connectors can be specified as a series of rows down the length of the member. The transverse location of a connector will not change the results. The connection locations can be defined using two different methodologies. The connector locations can also be imported and exported to disk.
Simple
The simple input method provides a series of uniformly spaced rows of shear connectors with a small amount of variance allowed near the ends to allow for more dense spacing. The options for this are as follows:
Option | Description |
|---|---|
First row location | The distance from the end and start of the member to the first row of connectors. These connectors are laid out from both the start and the end towards the center of the member. |
Typical quantity per row | The typical quantity of connectors per row. |
Row spacing | Distance between the rows of connectors. |
Row quantity | Determines of the connectors should fill the entire precast member, or only provide the specified number of rows. |
Addition connectors in… | Can provide an additional connectors in both the 1st, 2nd, and 3rd rows from each end. |
Convert to detailed | If clicked, the input methodology will be changed to detailed and the grid of connector locations will be automatically filled out to contain the connectors from the simple input method. |
Detailed
The detailed input method provides a grid of connector entries. Each entry defines a number of rows and columns of connectors positioned on the member. Each entry has the following options:
Option | Description |
|---|---|
Rows | The number of rows of horizontal shear connectors |
Columns | The number of columns of horizontal shear connectors |
Transverse Method | Determines which two of the transverse position inputs are enabled |
Left Distance | Defines the distance from the left edge of the panel to the nearest connector |
Width | Defines the distance from the left most connector to the right most connector |
Right Distance | Defines the distance from the right edge of the panel to the nearest connector |
Longitudinal Method | Determines which two of the longitudinal position inputs are enabled |
Bottom Distance | Defines the distance from the bottom edge of the panel to the nearest connector |
Length | Defines the distance from the bottom most connector to the top most connector |
Top Distance | Defines the distance from the top edge of the panel to the nearest connector |
Yield / Ultimate Multiplier | A multiplier used to scale the amount of allowable slip allowed in either yield or ultimate. This is applied to both the allowable slip and the force limit in order to leave the stiffness of the spring unchanged. |
Solid Zones
The beam spring model will always splint forces between the two wythes, even when a solid zone (such as an end block) is connecting them. In the figure below, the two wythes are connected by rigid links connecting the centroid of each wythe. Options exist to connect all of the solid zones, none of the solid zones, or only the end blocks. Typically by just having end blocks, the slip in the panel goes near zero rendering other connectors meaningless for shear transfer.