Structural Model
- jcallahan
- Tony Sun
- Tim Kostka
Restraints
All restraints above the bottom most restraint are assumed be unrestrained in the vertical (Y) direction.
Header | Description |
|---|---|
Add Foundation Connection | The user may select between pinned, fixed, vertical roller, or nothing for the bottom most node. Typically the bottom connection for a precast panel is modeled as a pin (fixed against translation but not rotation). |
Add Floor Tie | While you could add a floor tie in the restraint table, using this option flags this restraint as the ‘floor restraint’. This exposes additional options for when the floor tie is cast. |
ID | Incremented number assigned to the restraint for identification in the model. |
Elevation | Height or vertical position of the restraint. |
Type | Restrained: This restraint acts as a pinned-roller, except when it is the bottom most restraint when it will act as a pinned-pinned. Spring: This restraint will act as a translational spring. When selected, a corresponding stiffness must be entered. |
Releases
Can add moment releases at this section. These are often used to model joints between two panels.
Header | Description |
|---|---|
ID | Incremented number assigned to the release for identification in the model. |
Elevation | Height or vertical position of the release. |
Concentrated Loads
Concentrated loads support vertical, lateral, and point moments. These are all entered into the same loading grid. Positive vertical loads are downward, positive lateral loads are towards the interior of the member.
Header | Description |
|---|---|
ID | Incremented number assigned to the load for identification in the model. |
Elevation | Vertical elevation of the load, measured from the bottom of the panel stack. |
Ecc. | Horizontal eccentricity of the load measured from the specified face of the panel, defined in the loading options. For a load applied at the centerline of a panel input a negative eccentricity. |
Dead | Dead load component of this load. |
Live | Live load component of this load. |
Roof | Roof load is used for the R / S / Lr portion of the load combinations. One cannot input both rain and snow individually but must input the controlling case. |
Pressure / Suction | Two values exist for wind, pressure and suction both represent two different load cases. The program checks all pressure loads together and all suction loads together. |
Seismic | Seismic load component of this load. |
Wind Loads
Wind loads are divided between pressure and suction. Suction is applied toward the exterior of the panel, and pressure is applied toward the interior of the panel.
Header | Description |
|---|---|
ID | Incremented number assigned to the load for identification in the model. |
Start from Bottom | Starting location of the wind load, measured from the bottom of the panel. |
End from Top | Ending location of the wind load, measured from the top of the panel. |
Type | Indicates which loads are treated as pressure or suction. |
Start Magnitude | Starting magnitude at the bottom of the wind load. Note that this load should always be input as a positive value. |
End Magnitude | Ending magnitude at the top of the wind load. Note that this load should always be input as a positive value. |
Seismic Loads
Seismic loads can be added to the member. This represents a % of the dead load on the member. The inputs are as follows:
Header | Description |
|---|---|
Zone Location(s) | Full Height: A single zone running the full height of the member. By Story: Multiple zones are added to the panel. One zone will be added between each restraint. |
Apply multipliers to | Dead Load + Self Weight: Multiplier will be added to self weight and all super imposed dead loads. Self Weight: Multiplier will be added to self weight only. |
Start of Zone (x/L) | Read only variable for the start of the zone as a relative location (0 - 1) |
End of Zone (x/L) | Read only variable for the end of the zone as a relative location (0 - 1) |
Load Options
Header | Description |
|---|---|
Pattern live load for flexure | An option to control whether the analysis should automatically pattern live loads. More information on live load patterning can be found on the following page: Load Patterning |
Floor tie installation time | After Internal Grade: Floor tie will be added in after the internal grade has applied it’s loading After all Soil Load: Floor tie will be added in after internal and external grade has applied it’s loading Before all Loading: Floor tie will be added in before any load is applied. |
Self weight eccentricity | Eccentricity to be applied to the self weight. Will create a distributed moment as a self weight. |
Eccentricity measured from | Determines if the loading eccentricity is measured from the interior face (positive towards interior), from the exterior (positive towards exterior) or the panel’s CG (positive towards exterior). For sandwich panels (only), Eriksson Wall needs some additional information to properly locate the concentrated loads horizontally. This option is used in conjunction with the Sandwich Panel Loading Datum option on the Design Criteria tab which allows the program to calculate where the CG of the sandwich panel is located. To emulate v1 of Eriksson Wall, use ‘Inside Face’. |
Temperature Loads
Allows the input of the exterior and interior temperature. This gradient will be applied as a strain gradient through the thickness. If a beam-spring model is being used it will be applied as two axial strains instead.
αT, Coefficient of thermal expansion. For design, 6×10-6/in./in./°F is frequently used for normal weight concrete. Because the thermal coefficient for steel is approximately 6×10-6 in./in./°F, the addition of steel reinforcement does not significantly affect the concrete coefficient.
Soil Loads
Header | Description |
|---|---|
External Grade | External ground level measured from the bottom of the panel, i.e., the point at which the surcharge load is applied vertically. |
External Surcharge | Surcharge loading applied to the exterior face. This value is converted to a horizontal load by use of the lateral pressure coefficient input on the Design Criteria page, and will only be included in the analysis if the external grade is greater than zero. |
Internal Grade | Internal ground level measured from the bottom of the panel, i.e., the elevation at which the surcharge load is applied vertically. |
Internal Surcharge | Surcharge loading applied to the interior face. This value is converted to a horizontal load by use of the lateral pressure coefficient input on the Design Criteria page, and will only be included in the analysis if the internal FF is greater than zero. |
Additional Self Weight
This load is typically used to model an architectural feature, such as brick facia. The load also contains an input for where it is located relative to the top and bottom of the panel. Only 1 additional self weight entry can be added.
Design Strips
Single Member
Design Strips can be used to define the pieces of the member which will be used to resist the loads. When structural segments are used as a single member, the entire element is used when computing the applied loads. But only the area defined in the input is used to resist those loads. Below is an example of a wall where structural segments may be defined to ensure accurate analysis results.
The inputs for defining structural segments are defined on the structural model tab. Any number of segments can be defined and they are assumed to be full thickness and full length. Any reinforcement that falls outside of a structural segment will not be included in the analysis.
Input | Description |
|---|---|
Label | A unique identifier that will be used to view results for this segment |
Left Distance | The distance from the left edge of the wall panel to the start of the segment |
Width | The width of the segment |
Right Distance | The distance from the right edge of the wall panel to the start of the segment |
Input Method | Since only two of the above options are needed, this tells us which two are being input, and which is being computed based on the total width of the wall panel |
One Member Per Strip
A design strip analysis may also be used to create a design where multiple design strips are run independently (i.e. each strip is treated as its own member). This option will show a new selection box in the output summaries in which any design strip can be selected by its label and the results can be viewed.
The Load Division Method option is available if the design strip is run as its own member, this allows for the selection of the division of loads method. The options are:
Input | Description |
|---|---|
Tributary Area | This option divides loads based on the area of each design strip. The larger the strip area the more load is applied |
Relative Stiffness | This option divides loads based on the EI of each section. The larger the strips EI the more load is applied |
Both Tributary Area and Relative Stiffness | This option combines both area and relative stiffness as E*I*A. This larger the EIA value the more load is applied |