PERSPECTIVES: A MIXED ASSESSMENT
5.2. Towards a next step in the ratchet fusion?
Used to create mat boundary, meshing and specify analysis and design parameters to analyze and design mat slab. Mat module uses finite element analysis technique for accurate results. The modeling of mat foundations is done through physical modeling.
Note: Rectangular Mat foundation jobs can also be created quickly using theMat Foundation Modeling wizard.
The Mat foundation Job group contains following groups:
Group Name Description
Default Prop-erties
Opens the Default Prop-erties form in the Data Input pane, which is used to define default physical model object properties.
Physical Beam table
Opens the Physical Beam table in the Data Input pane, which is used to add beams to a mat foundation for additional stiffness and load transfer.
Pile Layout Pile Position table
Opens the Pile Position table in the Data Input pane, which is used to input pile locations by coor-dinates.
Rectangular Pile Arrange-ment Wizard (Parametric)
Opens the Rectangular Pile Arrangement parametric form in the data input pane, which is used to create rectangular pile lay-Project Info group items
Group Name Description out by
spec-ifying arrange-ment
parameters.
Circular Pile Arrangement Wizard (Par-ametric)
Opens the Cir-cular Pile Arrangement parametric form in the data input pane, which is used to create circular pile layout by specifying arrangement parameters.
Group Name Description
Opens the Using Polyline form in the Data Input pane, which is used to create irregularly shaped Region form in the Data Input pane, which is used to create rectangular regions.
Add meshing regions >
Circular
Opens the Circular Region form in the Data Input pane, which is used to create circular regions.
Add meshing regions > Reg-ular Polygon
Opens the Regular Polygon Region form in the Data Input pane, which is to create regular shaped con-vex polygonal region.
Meshing Setup Opens the Meshing Setup form in the Data Input pane, which is used to organize meshing regions to define finite element boundaries and to generate meshes.
Analysis Prop-erties
Slab Thickness Opens the Slab Thickness form in the Data Input pane, which is used to change the element thick-ness for the plate elements in a mesh.
Soil Properties Opens the Soil Properties form in the Data Input pane, which is used to
change and assign soil prop-erties for the design of mat foundations.
Group Name Description Pile Spring Opens thePile
Spring Def-inition tablein the Data Input pane, which is used to edit the pile spring con-stant values for all the piles present in the current job.
Group Name Description Mat slab
anal-ysis/ design options
Analyze Initiates the analysis of the current mat foundation job using the STAAD.Pro engine. An analyze/design confirmation dialog opens to verify you wish to pro-ceed.
Output View Options
Opens the Output View Options form in the Data Input pane, which is used to control the display of dif-ferent sets of output.
Moment Envel-ope Generation
Opens the Moment Envel-ope Generation form in the Data Input pane, which is used to choose longitudinal reinforcement directions and a generate moment envelope.
Design Param-eters
Opens the Design Param-eters formin the Data Input pane, which is used to input design parameters, design current panel and review design results.
Reinforcing Zon-ing
Opens the Reinforcing Zon-ing formin the Data Input pane, which is used to . Cut slab by a
line
Opens the Cut Slab by a Line form in the Data Input pane, which is used to draw a stress diagram along a specified section line and then design slab along that line.
Moment Capac-ity Check
Opens the Moment Capac-ity Check form in the Data Input pane, which is used to check the capacity of existing mat slab.
Group Name Description which is used to review design steps, analysis results and load values.
Mesh Generation
As Mat foundation module is based on FEA analysis, program needs to generate plate elements. STAAD.foundation has automatic mesh generation tools and it can generate both quadrilateral and triangular mesh for any shape and size.
Mesh regions are used to create mat boundaries, holes, control regions etc.
Note: Any shape of pedestal can be generated using control regions.
Although pedestal reinforcement (vertical reinforcement) for mat foundation is not reported by the program.
Delete a mat region
If the mat region has been defined as a boundary, hole, or control region, you must first delete this definition from the Meshing Setup form.
1. Click the Select Mat Boundary/Region tool in the Select toolbar.
Hint: Mat Regions can be selected using the default pointer, but this tool limits the selection to only boundaries or regions, reducing the likelihood of accidental deletions of other model elements.
2. Click anywhere along the boundary edge of the region you wish to delete.
The regions is highlighted in red.
3. Click the Delete tool in the Standard toolbar.
or
Press the [Delete] key.
4. Click Yes.
Warning: This action may not be undone.
Slab Design
Slab design of a mat foundation is performed using the following Main Navigation pane entries:
l Moment Envelope Generation
l Design Parameters
l Reinforcing Zoning
Note: Punching shear is checked automatically and reported in the Calculation Sheet. One way shear is not checked by the program.
Default Properties form (Mat Foundation) Used to define default physical model object properties.
The STAAD.foundation mat foundation module is based on physical modeling environment. So, whenever a physical entity is created, properties associated with that entity will also be created. For example if we create a mat boundary, properties like slab thickness and soil properties will also be created and associated to the newly created boundary automatically. While creating these properties STAAD.foundation takes advantage of default properties setup options.
Opens when Mat Foundation Job > Default Properties is selected in the Main Navigator pane.
Slab analysis thickness
This thickness will be used during the slab FEA analysis. This parameter can have its own unit. This property is especially useful if we you want to simulate pedestal etc. for stiffness analysis but use the actual slab
thickness for design. This can also be used to input uncracked thickness for analysis.
Slab design thickness
This thickness will be used during slab design. This parameter can have its own unit. This property is especially useful if we you want to simulate pedestal etc. for stiffness analysis but use the actual slab thickness for design. This can also be used to input cracked thickness for slab design.
Subgrade modulus
Subgrade modulus is a soil property available from geotechnical report.
Program uses this value to calculate spring stiffness under each support node by multiplying this value with the nodal tributary area.
Beam sectional property
This property will be used to define cross sectional property of the physical beams added to mat foundation. Current version of the program can only have rectangular property.
Pile spring values
If the mat is supported by piles you need to create pile layout by adding
piles to mat foundation. Program uses pile as spring support for analysis. So, program needs to know spring constant for those pile supports. Ky represents vertical spring constant. Kx and Kz represent lateral spring constants for respecting X and Z direction.
Physical beam table (Mat Foundation)
Used to add beams to a mat foundation for additional stiffness and load transfer.
These are referred to as "Physical" beams because you provide model input as they would physically be constructed. The program will internally decompose these physical beams in analytical entities for the model. Physical beams are created between two support nodes. As you enter two support nodes a physical beam will be created and the default beam sectional property as set inDefault Properties form is assigned. Those values can be edited as required.
Opens when Mat Foundation Job > Physical Beam table is selected in the Main Navigator pane.
Note: The input unit for cross sectional property is displayed in the column heading. The length unit can be changed by selecting the Set Input/Output Units tool in theStandard toolbar.
After adding a beam the beam will be displayed in main view area.
Pile Position table (Mat Foundation)
Used to add piles by specifying their (x,y,z) coordinates. As many piles as needed can be added to a mat foundation job. Whenever a new pile is created, the program will automatically create default spring values for that pile.
Newly created pile will be displayed in graphics view.
Opens when Mat Foundation Job > Pile Layout > Pile Position table is selected in the Main Navigator pane.
Hint: When pasting pile position data from an external source (such as a spreadsheet file), the piles can be arranged according to the pile group to simplify pile properties assignment.
Rectangular Pile Arrangement Parametric form (Mat Foun-dation)
Used to create rectangular pile layout by specifying arrangement parameters.
Unit
Select the length Unit for used for pile row and column spacing.
Number of Rows
Specify the number of rows (piles in a line in the X direction) in the pile arrangement.
Number of Columns
Specify the number of columns (piles in a line in the Y direction) in the pile arrangement.
Row Spacing
Minimum spacing between two piles in the same row, in the selected length Unit.
Column Spacing
Minimum spacing between two piles in the same column, in the selected length Unit.
Pile Table
By default program will create symmetric pile arrangement from the above input.
Select either Row Spacing or Column Spacing to display in the table. The first column represents either the Row or Column number and the second column displays the spacing between that row/column and the next.
Origin X / Y / Z
Generated pile coordinates will be in local coordinate system where first pile is at 0,0,0 position. You need to move pile group to the right loca-tion by inputting Origin X, Origin Y and Origin Z.
Apply
Transfers pile layout to graphics and add to the current mat foundation job. Please do remember to input appropriate origin coordinates to move the whole pile group to the right position.
Circular Pile Arrangement Parametric form (Mat Foun-dation)
Used to create circular pile layout.
Opens when Mat Foundation Job > Pile Layout > is selected in the Main Navigator pane.
Unit
Select the length Unit for used for pile spacing.
Number of Piles
Total number of piles in pile group.
Number of Circular layers
Number of concentric circular pile layers.
Pile Spacing
Minimum spacing between two piles, in the selected length Unit.
Pile Table
Displays the spacing values used between concentric pile layers. Each row represents a layer number and the number of piles within that layer.
The program will try to evenly divide the total Number of Piles to all the layers. Edit these fields to redistribute the piles.
Center Piles
Select this option to add a pile at the center of the circle (coordinate 0,0,0). If you check this box program will automatically add an extra piles to the total count of number of piles.
By default program will create symmetric pile arrangement from the above input. It will attempt to place equal number of piles to all layers. It will create an additional layer for the remainder of piles. User can change the default setup by editing the layers table as shown below.
Origin X / Y / Z
Generated pile coordinates will be in local coordinate system where center of the circle is at 0,0,0 position. You need to move pile group to the right location by inputting Origin X, Origin Y and Origin Z.
Apply
Transfers pile layout to graphics and add to the current mat foundation job. Please do remember to input appropriate origin coordinates to move the whole pile group to the right position.
Add Meshing Region > Using Polyline form (Mat Foun-dation)
Used to create irregularly shaped regions, which can be used to represent slab edges in the Meshing Setup.
Opens when Mat Foundation job > Mesh Generation > Add Meshing Region >
Using Polyline is selected.
Note: Polyline regions may be drawn in graphically using the Mat Boundary by Polyline tool, found in the Select toolbar.
No. of Boundary Points
The number of vertices in the polyline boundary.
Generate Table
Populates the table with a number of rows equal to the No. of Boundary Points specified.
Unit
Select a unit of length for all coordinates in the table.
Polyline coordinates table
Each row represents a polyline vertex. The X,Y, and Z coordinates for each poly line vertex. Note that coordinates should be specified in a clockwise or counterclockwise direction to prevent the polyline from crossing itself (which will in turn produce an error during meshing).
Add Region
Creates a meshing region in the job. The new region will be displayed in a light blue outline in the View window.
Create a mesh region using the polyline vertex coordinates
1. Select Mat Foundation job > Mesh Generation > Add Meshing Region >
Using Polyline in the Main Navigation pane.
2. Specify the No. of Boundary Points (polyline vertices).
3. Click the Generate Table button.
The table is populated with a number of rows equal to the number of boundary points specified.
4. Specify a unit of length to be used for coordinate values.
5. Enter the coordinate values in the Polyline vertex coordinates table.
Note: Data in the table can be pasted from Microsoft Excel.
6. Click the Add Region button.
The boundary region is added in the View window.
Draw a mesh region using the Polyline tool
1. Click the Mat Boundary by Polyline tool in the Select toolbar.
The mouse pointer changes to the Polyline tool pointer.
2. Click the first vertex of the polygon.
A line is "rubber banded" to the initial point from your mouse pointer.
This indicates the potential new region edge for the subsequent point. At times, this will also jump to key points (such as supports) to ensure they are enclosed. Clicked points will override this behavior.
3. Click, in sequence, on the points on the grid going in either a clockwise or a counter-clockwise order.
Hint: Only linear or radial grid points may be selected.
4. Once you have clicked on all the points that define the boundary of your slab, return to your starting point or right-click.
Add Meshing Region > Add Rectangular Region form (Mat Foundation)
Used to create rectangular regions, which can be used to represent slab edges in the Meshing Setup.
Opens when Mat Foundation job > Mesh Generation > Add Meshing Region >
Add Rectangular Region is selected.
Note: Rectangular regions may be drawn in graphically using the Create Rectangular Mat Boundary tool, found in the Select toolbar.
Note: Rectangular Mat foundation jobs can also be created quickly using the Mat Foundation Modeling wizard.
Unit
Select a unit of length for all coordinates and lengths.
X / Z Coordinate at Top left corner Specify coordinates for X
1,Z
1, which is the top-left corner of the rectangle when viewed in plan (View From Top in the Trans Rotate toolbar). This locates the rectangular region in plan.
Length / Width
Specify the length (rectangle dimension parallel to the X axis) and width (rectangle dimension parallel to the Z axis) to define the size of the rectangular region.
Y Level
Specify an elevation (Y coordinate for all points in the rectangular region).
Add Region
Creates a meshing region in the job. The new region will be displayed in a light blue outline in the View window.
Create a rectangular mesh region parametrically
1. Select Mat Foundation job > Mesh Generation > Add Meshing Region >
Add Rectangular Region in the Main Navigation pane.
2. Specify a unit of length to be used for coordinate and length values.
3. Specify X
1 and Z
1 coordinates of the top left corner (in plan).
4. Specify a Length and Width of the rectangular region.
5. Specify an elevation of the rectangular region.
Hint: This is typically left as zero for most jobs.
6. Click the Add Region button.
The boundary region is added in the View window.
Draw a rectangular mesh region
1. Click the Create Rectangular Mat Boundary tool in the Select toolbar.
The mouse pointer changes to the Rectangle tool pointer.
2. Click the first vertex of the rectangle and hold the left mouse button down.
A rectangle is "rubber banded" to the initial point from your mouse pointer. This indicates the potential new region edge for the subsequent point.
Hint: Only linear or radial grid points may be selected.
3. Drag the mouse diagonally to the furthest corner of the rectangle.
4. Release the mouse button over the second point.
Add Meshing Region > Circular Boundary form (Mat Foun-dation)
Used to create circular regions, which can be used to represent slab edges in the Meshing Setup.
Opens when Mat Foundation job > Mesh Generation > Add Meshing Region
> Add Circular Region is selected.
Note: Circular regions may be drawn in graphically using the Create Circular Mat Boundary tool, found in theSelect toolbar.
Unit
Select a unit of length for all coordinates and lengths.
X / Z Coordinate at center
Specify coordinates for X,Z, which is the center of the circular region when viewed in plan (View From Top in the Trans Rotate toolbar). This locates the circular region in plan.
Radius
Specify the radius to define the size of the circular region.
Y Level
Specify an elevation (Y coordinate for all points in the circular region).
Add Region
Creates a meshing region in the job. The new region will be displayed in a light blue outline in the View window.
Create a circular mesh region parametrically
1. Select Mat Foundation job > Mesh Generation > Add Meshing Region >
Add Circular Region in the Main Navigation pane.
2. Specify a unit of length to be used for coordinate and length values.
3. Specify the X and Z coordinates of the center (in plan).
4. Specify a radius of the circular region.
5. Specify an elevation of the circular region.
Hint: This is typically left as zero for most jobs.
6. Click the Add Region button.
The boundary region is added in the View window.
Draw a circular mesh region
1. Click the Create Circular Mat Boundary tool in the Select toolbar.
The mouse pointer changes to the Circle tool pointer.
2. Click the center of the circle and hold the left mouse button down.
A circle is "rubber banded" to the initial point from your mouse pointer.
This indicates the potential new region edge for the subsequent point.
Hint: Only linear or radial grid points may be selected.
3. Drag the mouse to a grid point to define the edge of the circle.
4. Release the mouse button over the second point.
Add Meshing Region > Regular Polygon form (Mat Foun-dation)
Used to create regular shaped convex polygonal regions, which can be used to represent slab edges in the Meshing Setup.
Opens when Mat Foundation job > Mesh Generation > Add Meshing Region
> Regular Polygon is selected.
Center X / Y / Z
Specify coordinates for X and Z, which are the center of the polygon when
Specify coordinates for X and Z, which are the center of the polygon when