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SAFI Sample Projects

Design of a Steel Structure

SAFI Quality Software Inc.3393, chemin Sainte-FoySte-Foy, Quebec, G1X 1S7Canada

Contact: Rachik Elmaraghy, P.Eng., M.A.Sc.

Tel.: 1-418-654-94541-800-810-9454

Fax: 1-418-653-9475

Internet Site: http://www.safi.comE-mail: [email protected]

Design of a Steel StructureDescriptionThis example describes the edition and analysis of a small two-storey building. The verification ofthe elements resistance is also presented at the end of the document.

The height of the storeys is 3.6 meters. The spacing of the columns is 7.5 meters between axes A,B, C and D. The spacing of the columns between axes 1, 2, 3 and 4 is 6.0 meters. The first floorspans on three bays only (from axis 1 through axis 3).

Creating the project1. To create a new file when SAFI is already running, use the New command from the File

menu.2. Select the folder in which to save the file and enter the name of that file. Then, click on the

Save button.3. The General Options dialog box is automatically displayed. You may adjust the general

parameters of the project. These parameters can also be modified later. For this example,select 3D in the Analysis mode section.

Design of a Steel Structure 2

Creating the geometryEditing the construction linesThe first thing to do when creating a new model is to define the grids according to the requirementsof the model.

To define the working grid, select the Grid Options command from the View menu or click on the button from the Edition toolbar.

SAFI allows to use multiple edition grids at the same time. To make a grid visible on screen andallow to use this grid for the edition of the geometry, check the Show this grid option box for thedesired grid.


Modify the parameters of the grid according to the requirements of the actual model. First, changethe plane of the grid to obtain a horizontal grid (plane X-Z). Change the name of the grid to Base.As described earlier, the columns along the X direction are evenly spaced at 7500 mm so click onthe Create regular lines button in the Lines along axis "x" section, specify the spacing at 7500mm in the Spacing field and set the Number of divisions to 3 (which will give three divisions andthus four lines). Repeat this operation for the lines in the Z direction (the spacing is 7000 mm andthe number of divisions is 3).

The new grid is not in the same plane as the original one. Click on the Top View button ( ) fromthe Camera toolbar (Top View command from the View Camera menu). Notice that the globalaxes are displayed in the bottom left corner of the screen. The Y axis should now head out of thescreen.

To adjust the size and position of the model to the dimensions of the screen, use the Fit to Screencommand ( ) from the Camera toolbar (Fit to Screen command from the View Cameramenu).


Editing the geometryWhen the grid is properly defined, the geometry may be quickly created. The model may be createdin different ways depending on your preferences and work methods. The easiest way is to use thegraphical edition commands along with the grids. The model may also be created using tables. Notethat the grid is not required when editing the geometry by means of tables. The grid is yet a goodlocating system.

Step 1: Creating the joints at the baseIn a 3D building model, it is better to position the joint corresponding to the base of the columnsfirst.

Activate the Add ( ) command from the Edit Joint menu (this command is also accessiblefrom the Edition toolbar).

Using this command, it is possible to create joints one at a time by clicking at the intersection of thegrid lines. It is also possible to create an array of joints on an area of the grid. To create an array ofjoint, press the left button of the mouse (keep it pressed) at a point located outside the bottom left


corner of the grid and drag a window up to the top right corner of the grid. Release the mousebutton to create the array of joints. A joint will be created at each intersections of the grid lines.


Step 2: Creating the columnsClick on the Isometric View ( ) button from the Camera toolbar to view the model in 3D. Then,adjust the size and position of the display with the Fit to Screen command.( ). Select the jointsof the base by using the Select All command from the Edit Selection menu. This command isalso accessible from the Edition toolbar ( ).

Open the Extrude dialog box from the Edit Operations sub-menu (this command can also befound from the Edition toolbar ). Fill the dialog box as shown below and click on the Extrudebutton from this dialog box. The result should look like the image below.


Step 3: Creating the beams of the first floorTo ease the edition, it is better to display only the joints of the first floor (Y=3600 mm). First, clickon the Front View ( ) button from the Camera toolbar. To keep only the joints of the first floorvisible, select them by using the Select by Window command from the Edition toolbar and theactivate the View/Hide command ( ) from the Camera toolbar. At this point, only the joints ofthe first floor should be visible as shown on the image below. When a joint is selected, it is drawnas a large blue point. Selected members are drawn as a thick line.

To create the beams of first floor, you may create the links between the joints one at a time or createthem in one operation in the same way the base joints were created. To create the members all atonce, you must first adjust the elevation of the grid to Y = 3600 mm.

To modify the elevation of the grid, click on the button from the Edition toolbar. Change the Ycoordinate of the grid as shown below, click on the Set button and then on the Close button.

The grid should now be positioned at the same level than the visible joints. Activate the Top View( ) command from the Camera toolbar to view the model from the top. Activate the Addcommand from the Edit Member menu (this command is also accessible from the Edition


toolbar ). Create the members by dragging a window around the joints to connect them. Forexample, drag a window around the joints located on line 1 (one) between lines A and D to connectnodes A1 and B1, nodes B1 and C1 and finally nodes C1 and D1. Repeat the same procedure tocreate the remaining beams.

Activate the isometric view ( ) and deactivate the mask by clicking on the View/Hide command. The structure should now look like the image below.


Step 4: Creating the beams of the second floorBy repeating the method described above, you can quickly create the beams of the second floor.Select the joints of the second floor and hide the rest of the structure. Move the grid at Y=7200 mmand create the members.

The image below shows the beams of the second floor once created.

Activate the isometric view ( ) and deactivate the mask by clicking on the View/Hide command. The structure should now look like the image below.


Step 5: Creating the floorsThe floors in this example will be simulated by a slab supported by joists. SAFI allows for threetype of surfaces (two way slabs, one way slabs, and slab with joists) which can have three or foursides.

Using the technique described in step 3, keep only the members of the first floor visible. Then, usethe top view to ease the edition of the floors.

To create a floor, use the Add ( ) command from the Edit Surface sub-menu (this commandis also accessible from the Edition toolbar). To create a floor, simply click on the four joints thatwill define the four corners of the floor. Remember that the loads acting on the floors will bedistributed on the members located on the perimeter of the surface. Thus, to distribute the loads onall the members of the first floor, three surfaces are required. Click consecutively on the jointslocated at A3, B3, B1, A1 to create the first floor. The order in which the joints are selected willdetermine the connectivity of the floor which has an influence on the layout of the trusses. Thesurfaces can be edited, when required, by the Edit Surface ( ) command from the Edit Surface sub-menu.

When the first surface is created, a dialog box is opened allowing you to define the defaultparameters of the load surfaces. To define the surface as a slab with trusses, adjust the values of thedialog box as shown below.


From the same dialog box, you may activate the diaphragm effect generated by the steel deckand/or slab. To activate the diaphragm, click on the Diaphragm tab.


The stiffness of the diaphragm may be approximated by determining an equivalent plate thickness.Click on the button to define a plate element. Complete the information of the plate as shownbelow and click on the OK button.

Back in the diaphragm tab, complete the information for the diaphragm as shown below and clickon the OK button.

The first surface is now completely defined. As it is the first surface created in the model, theparameters of this surface will be used as the default parameters for the new surfaces created. Tocreate the other surfaces of the first floor, click on the four joints of the second and third surface.The result of these operations are shown in the image below.


Use the same approach to define the surfaces at the roof level. After deactivating the View/Hidecommand, select the beams of the roof and reactivate the View/Hide command. Before creating thesurfaces, modify the default parameters of the surfaces by using the Default parameters commandfrom the Edit Surface sub-menu.


Change the default number of trusses to 11 and click OK. Once this is done, add the surfaces asshown below.

The image below shows the structure as it should be when all the floors are defined.

Step 6: Creating the wallsWhile floors can be defined to distribute pressure loads to the surrounding beams and simulate thediaphragm effect of slab and/or steel deck, wall may be defined to distribute the wind loads actingon the wall surface to the columns of the building. SAFI does not make a distinction between wallsand floors, load surfaces are all treated the same way without considerations for their orientation.

The walls may be created with the same method used to create the floors (see step 5). Unlike thefloors for which the diaphragm effect is considered, the walls will be used only to distribute thewind loads, their plane stiffness will not be considered. To lateral stability of the building will be

Surface A1, A2, D2, D1




provided later by means of bracings. The wind loads will be transferred only to the columns, thesurfaces will thus need to be defined as one way surfaces.

To modify the default parameters of the surfaces, use the Default parameters ( ) command fromthe Edit Surface sub-menu. Change the Surface Type to One Way Distribution. Click on theDiaphragm tab and deactivate the diaphragm effect (uncheck the Enable Diaphragm option).Click OK when this is done. Finally, add the surfaces on the walls. The image below shows onwhich wall to add the surfaces.

Step 7: Creating the vertical bracingsTo ease the creation of the bracings, it is better to hide a portion of the structure. From a top view,select the members of the perimeter of the building. To make a selection in multiple steps, holddown the SHIFT key while selecting.


Activate the View/Hide command, and switch back to an isometric view. To create the bracings,use the Add command ( ) from the Edit Member sub-menu.

The bracings should be created on the outer faces of the building as shown below.

Assigning support conditionsTo assign support conditions are other attributes such as section shapes, loads, imposeddisplacements, etc., you must first select the elements of the model to which you want to assignthese attributes. Here, the support conditions will be assigned to all the joints located at the base ofthe columns.

First, display the model from the front by using the Front View ( ) command from the Cameratoolbar. Then, select the joints at the base of the columns using the Select by Window command from the Edition toolbar. Press the left button of the mouse, make a window around thebase joints and release the mouse button to select the joints.

When the base joints are selected, the support conditions may be assigned to them. Activate theJoint Attributes command from the Edit Joint sub-menu or click on the Joint Attributes


button ( ) from the Edition toolbar. From the dialog box displayed, specify the supportconditions as shown below.

In addition to restraining the movement along the X, Y et Z axes, the rotation around the vertical Yaxis must also be restrained in order to prevent the columns from rotating around their longitudinalaxis. Click OK when this is done.

A symbol representing the support conditions defined should appear on the selected joints.

Assigning member properties (sections, end releases, ...)For this example, we will assign three different section shapes from the CISC database. One sectionto the columns (HSS152x152x6.4), one section for the beams (W360x45) and one section for thebracings (L127x127x6.4). We will see later in this chapter how to verify the resistance and how tooptimize the sections according to the requirements of a given design code.


From a front view, select the beams of the first floor and the beams of the roof.

Then, activate the Member Attributes command from the Edit Member sub-menu or click onthe Member Attributes button ( ) from the Edition toolbar.

For the moment, no section is defined in the current model. To define a standard section, click onthe button above the section list. In the menu that appears, select the Section Librariescommand.


The dialog box displayed allows to add a standard section or any section stored in a user definedlibrary to the current model. The default material (STEEL) is a G40.21M-350W steel. This materialmay be modified at any time using the Materials command from the Tables menu. Select aW360x45, in the Section name list and then click on the Add button and the Close button. Back inthe Member Attributes dialog box, select this section in the section list.

The beams will be considered hinged according to their strong axis (MZ) and their weak axis (MY)at both ends (node I and node j). Check the four corresponding option boxes.


Make sure the Change Section Shape option is checked and click OK to assign these parameters tothe selected beams. The button above the section list displays the dimensions and properties ofthe selected section shape in the list.

To assign the section to the bracings, you must first select them by using the Select by Windowcommand. To simplify this task, you may hide a portion of the structure as described in step 7.

Press the SHIFT key on the keyboard to make the selection of the bracing in multiple steps. TheCTRL key allows to add or remove a member to the selection while the SHIFT key always add tothe current selection. While maintaining the SHIFT key pressed, successively click on each memberof the bracings. When you have selected all bracings, assign a L127x127x6.4 by the using theMember Attributes command as shown above. Also assign hinges at both ends of these members.

To assign the HSS152x152x6.4 to the columns, you must first select them. To quickly select thecolumns, you may use the Special Selection command ( ) from the Edit Selection sub-menu.In this dialog box, select Y Dir. in the Direction list, and click on the Select button. When this isdone, click on the Close button.

Once again by using the Member Attributes command, assign a HSS152x152x6.4 section to thecolumns. Note that no hinges are defined for the columns of the building.

Assigning loadsStep 1: Creating the basic loadsThe basic loads are families of loads acting on the structure. The different basic load types aretypically the dead loads, the live loads, the snow loads, the wind loads, etc.

To edit the basic loads, activate the Basic Loads command from the Tables menu. Fill this dialogbox as shown below and click OK.


All loads added to a given basic load will have the same factor for a given load combination (seenext step). Note that new basic loads may be added at any time.

Step 2: Creating the load combinationsThe load combinations are used to factor the various loads defined. For the current example, wewill create two load combinations.

1. 1.25 Dead + 1.5 Live + 1.5 Snow2. 1.25 Dead + 1.05 Live + 1.05 Snow + 1.05 Wind

Select the Load Combinations command ( ) from the Tables menu. For the moment, no loadcombination is defined. To create a load combination, click on the button in the upper rightcorner of the dialog box. Enter the factor associated with each basic load in the table. To rename aload combination, double-click on the tab label or use the button. Click a second time on the button to create a second load combination and specify the corresponding factors.


Step 3: Adding the dead loadsIn this example, the dead loads are composed of loads of two natures.


The first load added to the model is the gravity load which takes into account the self weight ofeach element of the model. To define this load, select the Gravity Load command from the Tables

General Loads sub-menu. To define the gravity load, first select 1 - Dead in the Basic Load listand specify the direction of the gravity (-1.0 along the Y axis). The image above shows this dialogbox filled with the correct information.

The second dead load is a pressure load of -2.5 kPa (2.5 kN/m2) applied to the floors. To define thisload, first select the floors of the building.

Then, click on the Surface Loads command from the Edit Loads menu. This command is alsoaccessible from the Assign Loads( ) command of the Edition toolbar.

Each tab of this dialog box is divided into two parts. The upper part is common to all tabs, it allowsto select the basic load into which the loads will be added. This part also contains shortcuts to thebasic loads, load combinations and load tables dialog boxes. The second part of the dialog boxallows to specify the various parameters required to properly define a load.


Click on the Pressure tab to display the input data for the surface loads and the select 1 - Dead inthe Basic Load list. Fill the data as shown below and click on the Add button to assign this load tothe selected surfaces. The pressure is defined negative to indicate that the pressure is acting alongthe negative Y direction (downward). The pressure P1 is constant on the whole surface.

Click on the Close button. The pressure load just defined should be visible on screen.

Step 4: Creating the live, snow and wind loadsSelect the Graphic Options command from the View menu. In this dialog box, click on the Loadstab and uncheck the dead load (Dead) in the Basic Load list. This will allow to validate the newloads more easily as they are added to the model.


Select the surfaces on the first floor to add a live pressure load of -4.8 kN/m2. Then, on the SurfaceLoads command from the Edit Loads menu. Fill the information as described below (payattention to the basic load selected), click on Add and then click on Close.


Select the members of the second floor (roof) to add a snow load of -3.2 kN/m2. Then, on theSurface Loads command from the Edit Loads menu. Fill the information as shown below (payattention to the basic load selected), click on Add and then click on Close.

Finally, select the surfaces located along the A axis (left wall) to define a wind pressure of 1.1kN/m2 along the X direction. Then, on the Surface Loads command from the Edit Loads menu.Fill the information as shown below (pay attention to the basic load selected), click on Add andthen click on Close.


Verifying the input dataBefore executing the analysis of the model, it is of good practice to perform a quick verification ofthe input data. SAFI has multiple tools to verify and help to correct the model. One of these tools isthe Verify Input Data command ( ) from the Analysis menu. This command verifies simpleinstabilities, double or orphan joints, missing member attributes, etc.

Running the analysisWe are now ready to run the analysis of the structure. All analysis, verification and designcommands are located at the same place to ease the analysis operations. To display the analysisdialog box, use the Run command from the Analysis menu. This command can also be found onthe Main toolbar ( ).


The analysis and design options available depend on the modules installed on your computer. Torun the static analysis, select static linear in the list Analysis list and click on the Run button.

Verifying the resultsOnce the structure is analyzed, you need to verify that the results are correct and that theycorrespond to what you expected.

The post-processing commands are available from the Analysis menu or from the Results barwhich can be displayed using the View/Hide results bar command ( ) from the Analysis menu.


The Results bar contains six sections (Analysis, Frequencies, Dynamic, etc.)containing three to four buttons each. Each section allows to view the results for aspecific type of analysis. The button allows to define the results which will beshown for the entire structure (or the visible part if the View/Hide Selection commandis activated). The checkbox at the left of this button allows to toggle the display ofthese results on and off.

The button allows to view the numerical results in tables. Some filters may beapplied to these results to reduce the quantity of data displayed and ease theirinterpretation. When this button is clicked, a menu showing the available results isdisplayed.

The button allows to view the results by means of charts along with the numericalvalues. These charts may be customized, printed or transferred to other applications.When this button is clicked, a menu showing the available results is displayed. Onlythe results which can be plotted are available here.

In the current example, the static analysis has been made. Thus, the results areavailable only for the commands of the Analysis section of the results bar. The button allows to define which results of the static analysis should be presentedgraphically.

Let's start by displaying the internal deformations of the members. Click on the button from theAnalysis section of the Results toolbar to open the static analysis results dialog box.


In this dialog box, check the Internal option located in the Deformations section and click OK.Then, check the option box at the left of button. You should see the internal deformations onthe screen corresponding to the first load combination.

It may be difficult to view the results when the entire structure is visible. Many operations can bemade to ease the visualization of the results.

You may use the Rotate command from the Camera toolbar to change the angle of view of thestructure. To ease the use of this command, click on the right button of the mouse to display thecontextual menu for this command. In this menu, select the Restrain to Y Screen Axis command.This option allows to rotate the view of the structure around the screen vertical axis only.

You may also use the various commands from the Graphic Options dialog box (found in the Viewmenu). The Visualization tab allow to display or hide any type of element of the structure. TheText tab allows to specify if the numerical values of the displayed results are visible or hidden.(Joint Text Results and Member Text Results). The Text Properties tab allows to change the sizeand the position of the texts as well as the font.

The Scale tab allows to enlarge or reduce the drawing scale of the results curves (Axial, Shear,Torsion, Bending, Stresses, Displacements, etc.). For example, a displacement scale of 10 mm/mmeans that a displacement of 10 mm will be displayed on screen as 1 m. In this particular case, thereal scale is 1000 mm/m. In most cases, this scale is not practical as the displacements appear toosmall on the screen. For this example, a value of 50 mm/m gives interesting results.

Finally, it is possible to hide a part of the structure by using the View/Hide command ( ) inconjunction with the selection commands.


To view the results for the second load combination, click on the Combinations command in thelower part of the Results bar. Check the load combination for which you want to view the resultsand click OK.

It is also possible to view the numerical results for the entire structure or a part of the structurethrough tables. Click on the button in the Analysis section of the Results bar. When thebutton is clicked, a menu is displayed allowing to select which type of results to view.

Choose Joint Displacements in this menu. When the command is activated, you are allowed todefine some filters to apply to these results which will reduce the amount of data displayed.


Select All structure in the Elements list and All Load Combinations in the Load Combinationslist. Then, click on OK to display the joint displacements for all joints and all load combinations.

Certain analysis results may be viewed through charts. Click on the button in the Analysissection of the Results bar. When this button is clicked, a menu is displayed which allows to selectthe type of results to display.


Select the Internal Forces command from this menu. Once this command is activated, click on amember of the structure. The internal forces in the selected member will be displayed in a dialogbox. In the Diagram list, select Moment Z to view the distribution of the bending momentaccording to the strong axis for the load combination selected in the Load Combination list.

When the mouse pointer is moved over the chart, the numerical results corresponding to thisposition on the beam are highlighted in the table. The buttons in the left part of the dialog box allowto customize the charts, to print the table, to print the chart or to copy the chart to the clipboard foruse with other applications such as a word processor.

Printing the reportAfter the analysis is performed and the validation of the results is made, the analysis report may beprinted. The report generator allows to customize the data to print in the report. To open the reportgenerator, use the Generate Report command ( ) from the Analysis menu. This command isalso accessible from the Main toolbar.


The report generator is made of a certain number of tabs depending on the modules installed: theModel tab for the input data, the Analysis tab for the analysis results and seven other tabs for theinput data and results of the design modules.

The first tab (Model) contains two parts. The upper part is a tree list of the data that can be includedor excluded from the report by checking or unchecking the appropriate branches. The et markers allow to expand or collapse a branch of the list. If a base branch is unchecked, all itemscontained in that branch will be automatically excluded from the report.

The lower part of this tab allow to specify a range of elements, load combinations, basic load andtime (for seismic and/or dynamic analysis) which will be used to determine which data to print inthe report.

The Analysis tab (and all other tabs) is made of a tree list only. This list works the same way as thetree list in the Model tab.

When the desired options are selected, click on the Generate button. At this time, you areprompted to provide a name for the report file. It is also possible to specify the report format. Fourreport formats are available: SAFI Report (default), Microsoft Excel™ Worksheet, MicrosoftAccess™ database and ASCII file (unformatted text). Enter a file name and click on Save.

When the report is generated, it is automatically displayed. The SAFI Report contains a table ofcontent which allows to quickly access individual tables. It is also possible to open a full section of


the report by selecting the All item in the list (All Analysis Results for example). The image belowshows a preview of the analysis report for the current example.

Assigning steel parametersDesign codeThe various design codes handled by SAFI have all their own characteristics. Thus, it is importantto select the design code which will be used to make the verification of the limit states beforespecifying any parameters required by that code. For example, the Canadian and American codesuse only one bending coefficient (w2 or Cb) while the European code uses three coefficients (c1, c2and c3). The program will allow you to specify only the parameters required by the selected code.Activate the Parameters command from the Applications Steel sub-menu or the Codescommand from the Analysis menu. In the Steel tab of this dialog box, select theCAN/CSA-S16-01code.


Effective area in tension of the bracingsThe steel module of SAFI can make the verification of the tensile resistance of the structuralelements subjected to tensile forces. By default, the program considers that the effective area intension of a section is equal to the gross area of the section. To perform an accurate verification ofthe members in tension, it is necessary to specify the net area of the members which take intoaccount the area reduction due to the bolts holes and/or connection plates.

In the current example, the effective area will be specified for the members of the bracings. Selectthese members by using the selection by window command (Select command from the Edition Selection sub-menu). To ease the selection of these members, you may use the Overlapping Areaoption which allows to select elements inside a window and also the elements crossing that window(Selection Options command from the Edit menu). Note that the members may be selected inmultiple steps by using the CTRL and SHIFT keys which allows to add and remove members to thecurrent selection.

When all the bracings are selected, activate the Member Attributes command from the Edit Member sub-menu. The dialog box opened contains at least two tabs (e.g. the General tab and theSteel tab). Click on the Steel tab to access the parameters of the steel module.


At the bottom of the dialog box, specify a ratio of 0.75 (75%) as the ratio of the gross area.(Change Net Area in Tension field). The effective area in tension will be taken as the gross areamultiplied by this ratio. Click OK when done.


Flexural buckling supportThe steel module of SAFI can make the verification of the bending and compression-bendingresistance and stability of the structural elements subjected to bending moments. By default, theprogram considers that the members are supported against flexural buckling at their two ends andthat for the top flange (positive moment) and at the bottom flange (negative moment).

In the current example, it is reasonable to consider that the beams to which the trusses are attachedare supported at their top flange at each connection with the trusses. As the spacing of the trusses isdifferent at the first floor than at the roof, the operation must be made in two steps.

First, select the members of the first floor to which the trusses are attached using the selection bywindow command (Select command from the Edit Selection sub-menu).


Beams of the first floor with intermediate lateral supports

When the beams of the first floor are selected, activate the Member Attributes command from theEdit Member sub-menu. The Steel tab of this dialog box should already be active. If it is not,click on it to activate it.

In the Change Top Flange Support area, select Discontinuous in the Lateral Support Type listand specify a length of 2000 mm between the supports in the Unbraced Length field. This lengthcorresponds to the spacing of the trusses of the first floor.


Click on OK when done. Repeat the same operation for the beams of the roof. The unbraced lengthfor these beams should be 1875 mm. This length corresponds to the spacing of the trusses at theroof level.

Beams of the roof with intermediate lateral supports

We will also consider that the floor and roof slab provides a continuous lateral support to the topflange of the outer beams parallel to the trusses. The two following images shows the beams towhich continuous lateral supports will be assigned.

Beams of the first floor (mezzanine) with continuous lateral supports


Beams of the second floor (roof) with continuous lateral supports

Select these beams and activate the Member Attributes command from the Edit Member sub-menu. In the Steel tab, specify the parameters as shown below.


DesignThe program has some tools to determine the optimal section shapes for each member of thestructure. However, for practical reasons, it is often better to optimize the section shapes for groupsof elements instead of each element separately. In addition, to allow for the numericalcomputations, a continuous column or beam must be cut at the intersection with other elements ofthe structure. Thus, a continuous beam will be modeled by a certain number of member which can'tlogically be optimized separately (a continuous beam is made of only one section shape). In thiscase the concept of groups is mandatory.

Design groupsTo create a group of members, you must first select the members of that group using the variousselection commands and save that group using the Define Group command of the Edit Selection sub-menu. The only parameter required to define the group is a name allowing tosubsequently refer to that group.

Let's first create a group for the bracings. By using the selection commands, select the members ofthe bracings as shown below. Note that the members may be selected in multiple steps by using theCTRL and SHIFT keys which allows to add and remove members to the current selection.

When the bracings are selected, activate the Define Group command from the Edit Selectionsub-menu. When the command is activated, a dialog box is displayed allowing you to assign aname to the group of members selected.


Type Bracings in the Selection Group Name and click on the OK button. The member group isnow saved and may be recovered at any time using the Fetch Group command of the Edit Selection sub-menu. Repeat this process for the other groups of members presented below.

Inner beams of the mezzanine (group Mezzanine (inside))

Outer beams of the mezzanine (group Mezzanine (outside))


Other beams of the mezzanine (group Mezzanine (others))

Inner beams of the roof (group Roof (inside).)


Outer beams of the roof (group Roof (outside))

Other beams of the roof (group Roof (others))


Columns (group Columns)

OptimizationWhen the design groups are created, the optimization of the section shapes can be made. Activatethe Design command from the Applications Steel sub-menu.


In the upper part of the dialog box, check the Auto Assign Sections option. This option allows toautomatically assign the optimized sections to the members of the groups. It is thus possible, bydisabling this option, to optimize the sections of the model without losing control on the model. Ifthis option is not enabled, the sections may be manually assigned using the Assign button found inthe design summary at the right of the dialog box. For this example, we will consider that theselected section shapes are suitable. Also check the Force Convergence option which forces theoptimization module to repeat the optimization cycles until the full convergence is reached.

In the Group Name list, select the Mezzanine (inside) group which contains the inner beams of themezzanine. Select 1 - STEEL in the Material list, CISC in the Section Library list and W in theSection Type list (a W section in the CISC database corresponds to an IPE in the Europeandatabase).

Click on the button in the upper right part of the dialog box to create a new tab which will beused to specify the optimization parameters for the Mezzanine (outside) group. When a tab is added,you have the possibility to copy the parameters of the current tab in the new one. Click Yes to copythe current tab in the new one. All the parameters are copied except the design group. In this newtab, select the Mezzanine (outside) in the Group Name list. Repeat this procedure for the otherbeam groups.


Finally, create a tab for the columns (group Columns) and select a HS (square) section type. Forthis example, the bracings will not be optimized.


When all groups are defined, click on the Optimize button to launch the optimization of thestructure.

After the optimization is made, click on the View Report button to display a summary report of theselected selections. This report also presents, at the end, the total weight of the structure includingthe members that have not been optimized (in the present case, the bracings).

Click on OK to close the optimization module dialog box.

Verification of the limit statesThe optimization performs, at each cycle, the verification of all limit states in order to select thebest section shape. However, the results of these verifications are not stored. Thus, it is necessary toexecute the analysis with the steel verification to obtain the numerical values of these limit states.Activate the Verification command from the Applications Steel sub-menu. This commandquickly performs the analysis using predefined options. When the command is activated, you areprompted to save the file. Click Yes to save the model and run the analysis.

Results and reportThe results of the limit states verification may be consulted in three different ways, each havingspecific uses. The results can be first presented for the whole structure (or the visible part if the


View/Hide Selection command from the View menu is active) by the means of color charts. Thismethod is useful to have a rough estimate of the limit states for each member of the model and tospot the critical areas. It is also possible to view the numerical results of the limit states throughtables. This method is convenient to quickly obtain the numerical values of each limit states for thewhole or part of the structure. These tables also present the main analysis results used to computethe limit states. These two methods are fast and require a low amount of manipulations. However,they present the results of the last analysis only and do not allow to store the results in a permanentmanner. The analysis reports, as though longer to generate, allow to keep permanent copies of thesteel verification results in different file formats (SAFI Report, Excel Worksheet, etc.).

Global resultsTo display the results of the limit states computations directly on the members of the structure, usethe Options command from the Analysis Global Curves Steel sub-menu. In the dialog box,select the type of results you want to see and click OK. To display these results, activate theDisplay command from the Analysis Global Curves Steel sub-menu.

These results may be viewed for one or several load combinations. When more than one loadcombination is selected, the results displayed correspond to the maximum for these loadcombinations. To specify the load combinations for which to display the results, use theCombinations command from the Analysis Global Curves sub-menu.


Select all load combinations and click on the OK button.

To view the results for only a part of the structure, select the members for which you want to seethe results and activate the View/Hide Selection command from the View menu.

Maximum limit states (Roof) Maximum limit states (Mezzanine)

Maximum limit states (Columns)


Numerical resultsTo consult the numerical values of the limit states, use the command in the Analysis NumericalResults Steel which corresponds to the type of results you want.

When one of these command is activated, a dialog box allowing to filter the content of the table isopened.

It is possible to display the results for the whole structure or only for the selected members of themodel (Elements list). It is also possible to view the results for a specific load combination or forall load combinations (Load Combinations list). If a certain filter is grayed in the filter dialog box,it means that this filter is not applicable to the type of results requested.


Limit States Summary for some members of the model

Analysis reportTo store the limit states results in an external file, it is required to generate a report. To do so, usethe Generate Report command from the Analysis menu. When the command is activated, thereport manager is opened.

This dialog box contains a certain number of tabs depending on the modules installed on yourcomputer. For this example (and for the design of steel structures in general), only the Model,Analysis and Steel tabs are useful. In each of these tabs, select the parts you want to see in thereport. It is possible, here also, to generate the report for the whole or a part of the model by usingthe edition field (which allow to specify a range of elements or a range of load combinations) and


the Selection Groups list which allow to print the report for the currently selected elements orpredefined groups (including the design groups).

Example of steel verification report

safi sample projectssafi.com/pdf/design of a steel structure.pdf · design of a steel structure 2...

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