SAMPLE BUILDING DESIGN
Type 6 press enter
`Enter X offset': Type 0 press enter
`Enter Y offset': Type -1.0 press enter
`Enter Z offset' : Type 0 press enter.
The column is located 0.6 meter down to node no. 6.
This way you have located all the columns. This is nothing but specifying the boundary conditions at nodes. When a column is located, it means that the vertical displacement (in Z axis) at the specified node is zero.
as a simple support. To provide fixity at these nodes, you should follow following steps.
Click `Support' option from menu bar.
STRUDS displays the screen showing the floor plan and right hand side menu items vertically arranged.
Presently the boundary group defined is BG1 only which denotes columns at (W - zero)the specified nodes. You can specify any type of boundary group and attach it to the required node.
From the floor plan geometry it can be seen that at nodes 16 17 and 21, we need to provide fixity about Y axis i.e. rotation about Y axis is restrained (Ry = 0).
Click the option `Define Group'.
STRUDS displays a window with different fields to click to define a group. You are defining group no. 2 for nodes 16, 17 and 21.
Click the box of `Y - Rotation'.
Select node 16, 17 and 21 by mouse.
Click ‘Close’ button by mouse.
Now you have drawn the floor plan, located the columns and specified the support conditions wherever required.
{X-1.4} Creating And Attaching Sections to Beams
The next step is to provide the sections to the beams.Select ‘Property’ from menu bar.
Point to ‘Create’.
Point to ‘Section’ and click the mouse.
A Window appears on the screen, which has a number of fields and buttons.
Click ‘New’ by mouse or pressing ‘Alt+N’ from Keyboard.
Click the dropdown icon at the ‘Section Types’ pull down menu.
Select ‘Rectangular’.
STRUDS displays two fields for width and depth of the ‘Sec1’.
Type ‘230’ in the field in front of b.
Press ‘Tab’ key from keyboard or click mouse in the next field.
Type ‘450’ in the field.
Select ‘Save’ button Select ‘New’
Again select ‘Rectangular’ from the pull down menu.
Type ‘150’ in the field of b Type ‘380’ in the next field Select ‘Save’
This way you have defined three rectangular sections Sec1, Sec2 and Sec3 which you can provide to any of the beams in the floor plan. Please note that Sec3 is a hidden beam section or dummy
not act as a beam. In such case we need to provide a hidden beam or dummy beam section at such elements.
Select ‘Property’ from menu bar.
Point to ‘Attach’
Point to ‘Section’ and click mouse.
A small window appears on the screen with a pull down menu and menu buttons to allow you to attach the defined sections to the beams.
Select ‘Sec3’ from the pull down menu.
Select ‘Locate’ button
A box type cursor appears on the screen.
Select element numbers 21,23 and 24 by clicking the cursor along these elements.
Select ‘Sec1’ from pull down menu.
Click ‘Grid’ button.
Again the box type cursor appears on the screen.
When you use the option ‘Grid’ and click it along any element, that element and all other elements in line with this element will have the chosen section attached.
Select element No. 4,10,27 & 1 by clicking the mouse along these elements.
Select ‘Sec2’ from the pull down menu.
Click ‘Rest’ button.
All the remaining elements, which do not have any section, are attached with sec2 by this
Select ‘close’ button.
This way you have specified the section sizes for all the elements in the floor plan. It should be noted that you must have specified the section for all the elements in the floor plan before proceeding to analysis.
{X-1.5} Creating and Attaching Walls
In STRUDS you can attach the walls on beams as per your requirement. STRUDS will automatically calculate the weight of walls on beams as UDL as per the physical attributes provided by you. Now to generate walls follow following procedure
Select ‘Create’ from menu bar.
Select ‘wall’ from the menu.
A window with fields and buttons appears on the screen.
Click ‘New’ button.
In the field for ‘Name’ type W1 In the field for thickness type 0.23 In the field for height type 3
From the pull down menu select ‘BRK’.
‘BRK’ stands for brick masonry. The density of brick masonry 19 kn/m3 is automatically taken by the program. If you want to change the density, you can simply click in the field and overwrite new value of density.
Select ‘Define’ button from the window.
Select ‘New’ button.
Select ‘New’ button.
In the field of Name type (w3).
In the field of thickness type ‘100’
In the field for height type 1.0 M
Select ‘Define’ button from the window.
This way you have defined three walls W1,W2 &W3 of brick masonry and thickness 230 mm,100mm and 100 mm respectively.
Click ‘Close’.
Select ‘Property’ from menu bar.
Select ‘Attach’
Select ‘Wall’ and click the mouse.
A small window appears on the screen. You can use the various options in this window to attach the defined walls to the elements in the floor plan.
The flag for Consider Element section is always true by default i.e. while attaching a wall to an element, the program will automatically, deduct the depth of the beam from the wall height while calculating the wall load on that element. If you do not want to deduct the depth of beam section from wall height, you can do so by clicking the box of consider element section.
Select ‘W1’ from the pull down menu.
Select ‘Grid’ button from the window.
Select elements 1,4,10 and 27 by clicking the box type cursor along these elements.
Select ‘W2’ from the pull down menu.
Select ‘Grid’ button from the window.
Select element numbers 2,3,7,15 and 13 by clicking the box type cursor along these elements.
All the elements in line of these elements are attached with wall W2.
Select ‘Curve’ button from the window.
Select the curved element by clicking the box type cursor along it.
Select ‘Close’ button from the window.
Select ‘Display’ from menu bar.
Select ‘Entities’.
A window is displayed on the screen with several fields and small boxes to On/Off the flag. You can put On/Off the display of any of the entities listed in this dialog box by clicking the small box before these entities.
Select the box for ‘Wall’ by clicking mouse Select ‘OK’ button.
The program on screen displays the walls attached to corresponding elements.
Select ‘Floor’ from menu bar.
Select ‘Generate Wall Loads’ from the drop-down menu.
Once you use this option, STRUDS automatically calculates the wall load on corresponding elements.
STRUDS displays a message ‘Wall load generation is completed’
Click ‘OK’
{X-1.6} Creating and Attaching External Loads
In case you want to provide any extra load on the elements; for example, in this plan the circular slab is defined by a curved beam. There physically is no slab enclosed by this curved beam.
Here as we want to attach the load of the slab on curved beam, we can do the same by following procedure.
Select ‘Property’ from menu bar.
Select ‘Create’.
Select ‘Load’.
Select ‘Elemental Loads’ & click the mouse.
A Window appears on the screen with a pull down menu and few buttons.
Select ‘New’ button
Select ‘Full UDL’ from the pull down menu Type 3 in the field in front of W : (which denotes the value of uniformly distributed load on the elements.)
Click ‘save’ button.
Select ‘Close’ button.
Select ‘Property’.
Select ‘Attach’.
Select ‘Loads’.
Select ‘G1’ from the pull down menu Select ‘curve’ button from the window.
Select the curved element by taking box cursor anywhere along the curved element and clicking the mouse.
Select ‘Close’ button.
Now you have defined the complete typical floor of the sample building.
{X-1.7} Saving Floor Plan
Select ‘Floppy’ option from the menubar.
Select ‘Save’.
A dialog-box appears on the screen.
Type `sample’ in the field for ‘File Name’.
Select ‘Strudwin’ folder and select ‘Data’ folder in it.
Select ‘Save’ button
Select ‘Floor’ option from the menu.
Select ‘Pre-Analysis Enquiry’ option.
STRUDS displays ‘Pre-Analysis Information dialog box’
Note that the three list boxes should be empty. Otherwise do the necessary corrections.
Click ‘OK’
Select ‘Floor’ option from the menu.
Select ‘Analysis files’ option.
Select ‘All levels’ option.
Click ‘Save’ button.
Select ‘Floor’ option from the menu.
Select ‘Close’ option.
Now this window will disappear. And the first window of PreProcessor will reappear on the screen.
{X-1.8} Copying the Floor Plans
In STRUDS once you define a floor plan, you can copy it for other floors. Then you can select any floor and make changes in that floor as per your requirement.
Select ‘Floor Plan’ from the menu.
Select ‘copy’.
A window appears on screen having a series of fields which allows you to copy the floor plan from one floor to other floor.
The Source Floor No. is 1
By default the Destination Floor No. is ‘New’.
Click the dropdown arrow of the Destination Floor No.
Select 2
Click ‘OK’ button of the dialog box.
The floor plan of Floor 1 is copied at ‘Floor No.2’.
Click ‘OK’ button of the dialog box.
The floor plan from Floor 1 is copied at ‘Floor 3’.
In this way copy the Floor 1 to ‘Floor 4’ and ‘Floor 5’
{X-1.9} Editing The Floor Plans
We can now change the data in any particular floor by selecting and editing that floor level.
Select ‘Floor Plan’.
Select ‘Set’.
Select ‘1’ from the pull down menu.
Select ‘OK’ button.
The floor plan at bottom most level or level1 is displayed on the screen. Let us assume that this
‘Sample’ building has plinth beams at first level. Which means that there are no slabs in this plan (or) the load of slabs in this plan is not transferred on the beams. In other words, the beams are designed only for their self weight and imposed loads like wall load. To accomplish this, follow the below procedure.
Select ‘Property’ from menu bar.
Select ‘Load’.
Select ‘Slab-Beam Loads’.
A window displaying a small box to on/off flag is displayed.
By default the flag for ‘Compute Loading from slab to beam automatically’ is always on.
Click the check box by mouse to put the flag ‘off’.
Select ‘Close’ button.
Now in this particular floor plan, STRUDS will not consider the loads from slab to elements.
Delete the slabs S7 and S8 by moving cursor on these slabs and clicking the left button of mouse.
STRUDS gives a warning message
Click the ‘OK’ button for both slabs S7 & S8.
Now to delete the curved element Select ‘Edit’
Select ‘Delete’
Select ‘Element’
Select any element in the curved beam by moving cursor along them and clicking the mouse.
As there is no sunk at the last slab as being a terrace follow the next steps.
Select 'Edit' from menu bar.
Select 'One Slab' option.
Select the Slab 'S4' by clicking on it with box cursor.
STRUDS will display the 'Slab Property' window.
Click 'Sunk Depth' box from the Sunk Slab option and enter ' 0.0' Click ' Material Density ' box from the Sunk Slab option and enter ' 0.0' Click 'OK' button.
Select 'Edit' from menu bar.
Select 'One Slab' option.
Select the Slab 'S5' by clicking on it with box cursor.
STRUDS will display the 'Slab Property' window.
Click 'Sunk Depth' box from the Sunk Slab option and enter ' 0.0' Click ' Material Density ' box from the Sunk Slab option and enter ' 0.0' Click 'OK' button.
Select ‘Property’ from menu bar Select ‘Create’
Select ‘Section’
Select ‘New’ button
Select ‘Rectangular’ from the pull down menu. Type ‘230’ in the field of b Type ‘380’ in the field of d.
Select ‘Save’ button.
You have created a new beam section Select ‘Close’ button
Select ‘Property’ from the menu bar.
Select ‘Attach’
Select ‘Section’
Select ‘Sec4’ from the pull-down menu Select ‘All’.
STRUDS gives a warning message.
Select ‘Yes to All’ button from the message box.
Now the new section Sec4 is attached to all the elements. The program overwrites the previously attached sections.
The building file is saved by using this option.
Select ‘Floor’ from menu bar.
Select ‘Change Floor’ option.
STRUDS displays 'SELECT FLOOR 'window.
Select 'Floor 5'
Select ‘Slab’.
Select slab S1 by moving the cursor on this slab and clicking mouse.
STRUDS displays warning message Click ‘OK’
Select ‘Edit’ from menu bar.
Select ‘Delete’.
Select ‘Column’ & click the mouse.
Select column no. 1 by the cursor and clicking the mouse.
Select ‘Edit’ from menu bar.
Select ‘Delete’.
Select ‘Node’ & click the mouse.
Select Node No. 1 by the cursor and clicking the mouse.
As there is no sunk at the last slab as being a terrace follow the next steps.
Select 'Edit' from menu bar.
Select 'One Slab' option.
Select the Slab 'S4' by clicking on it with box cursor.
STRUDS will display the 'Slab Property' window.
Select 'Edit' from menu bar.
Select 'One Slab' option.
Select the Slab 'S5' by clicking on it with box cursor.
STRUDS will display the 'Slab Property' window.
Click 'Sunk Depth' box from the Sunk Slab option and enter ' 0.0' Click ' Material Density ' box from the Sunk Slab option and enter ' 0.0' Click 'OK' button.
Considering there is parapet wall on fifth slab we have to detach the wall load from it and then to attach the parapet wall load.
Select ‘Property’ from menu bar.
Select ‘detach’.
Select ‘Wall’ & click by mouse.
A window is displayed on the screen
Select ‘All’ from ' Select Wall ' from the menu.
Select ‘All’ from ' Select Elements ' from the menu.
Select ' Detach from selected element ' STRUDS displays the following window
Select 'Wall' sub-option.
STRUDS will display 'Attach Loading Wall' window.
Select 'Wall 3' from the dropdown bar.
Click 'Locate' button.
Select the elements 1,3,23,24,26,31,14,16,17 and 2,9,19,22,21,20 by using the box cursor.
Click 'Curve' button.
Select any element of the curved beam and click on it with the box cursor.
Click 'Close' button of 'Attach Loading Wall' window.
Select ‘Floor’ from menu bar.
Select 'Generate Wall Loads'
STRUDS displays a message ‘Wall load generation is completed’
Click ‘OK’
Select ‘Close Floor’ option.
This way you have created all the five floor plans for sample building.
Now the main window of PreProcessor will reappear on the screen.
{X-1.10} Setting Column sizes and Orientation of Columns
Select ‘Column’ option from menu bar.Select ‘Set Parameters’ option.
STRUDS displays ‘Set Column Dimensions’ dialog box.
Select the `Increment' option given below the Column sizes title. The other fields below this are activated.
The default increment is 75mm. Which means that after every floor the from top, the depth of column is taken as 230 + 75 = 305mm, 305 + 75 =380mm etc. So the column sizes shall be 230 x230, 230 x 305, 230 x 380...from top to bottom. Similarly you can specify the parameters and STRUDS will take column sizes accordingly.
Select `Close' button.
Select `Column' - `Generate' option.
STRUDS takes the sizes of columns as the parameters specified by you.
Select `Column' Select `Orient' option.
STRUDS displays a new screen with a menu bar and some buttons and icons at the right hand side. You can use these options to specify the orientation of column. You can also change the sizes of any column. The icons at the top right are to specify the flushing of column with respect to beams.
Suppose you want to change the orientation of a column -Select `-Select Column' button.
Select the column by cursor.
That column is displayed on screen in an enlarged manner.
Select `Rotate' option
by clicking the icons at top right.
Select `Shape & Size' button.
STRUDS displays a small window. You can select any column by using the drop down list menu of column group.
Select `Column Sizes' button.
STRUDS displays the floor wise sizes of selected column. The basic parameters as specified in
`Column' -`Set Parameters' option are also available at bottom. You can change these parameters for this column. Or you can select the floor and overwrite the sizes in the fields provided for width and depth for that floor. For example
Select floor no. 1 by double clicking the mouse.
Overwrite 750 in the field provided for depth.(optional) Select `Save' button.
STRUDS automatically computes the sizes for remaining floors.
Select `Save' button.
Select `Close' button.
Select `Close' button.
Select `Close' button.
Select ‘Floor plan’ from menu bar.
Select ‘Analysis Files’.
Select ‘All’.
STRUDS displays a window where you can specify the directory in which you want to store these analysis files.
Select ‘Save’ button.
Select 'Building' from menu bar Select 'Exit'
STRUDS displays a message box
Click 'Yes' button.
Now the main window of STRUDS will appear on the screen.
{X-2} Analyzing the Building Structure
In STRUDS, the building can be idealized as Plane Grids, Plane Frames or Space Frame.
By defining the floor plans per floor, you have specified the floor grids for each floor. You can now analyze and design this sample building by following three methods.
1. PLANE GRID METHOD - In this method the beams shall be designed as continuos beams with end supports as simple supports and the intermediate supports as continuos supports.
The columns and footings will be designed for axial load only. Slabs will be designed as panels.
Many consultants for low-rise buildings adopt this method with simple grid like floor plans.
2. PLANE FRAME METHOD - STRUDS automatically generates the plane frames in X and Y direction and analyses them in one stroke. The analysis results are automatically taken to design. The stiffness of columns is also taken into account in the analysis. Beams are designed as continuos beams with fixity at end supports. Columns will be designed for axial load and moments in X and Y directions. Footing shall also be designed for biaxial bending. Also in this method STRUDS can automatically generate horizontal loads like Wind Load and Earthquake Loads on the frames as per the basic parameters provided by the user.
This method is used by most of the consultants for multistoried building where analysis
3. SPACE FRAME METHOD - STRUDS automatically generates and analyses the space frame. The results are then automatically taken to design module for design. The stiffness of columns is taken into account for analysis. Beams are designed as continuos beams with fixity at end supports. Columns will be designed for axial load and moments in X and Y directions.
Footing shall also be designed for biaxial bending. Also in this method STRUDS can automatically generate horizontal loads like Wind Load and Earthquake Loads on the frames as per the basic parameters provided by the user.
This is the most accurate and desirable method for analysis and design. This method is difficult to adopt for manual calculations, but is most suitable for computer aided design.