Performing steel design in Robot

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MARTHA HOLLOWELL ORCUTT: Performing steel design

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in robot--

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In this video, we will perform steel design

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for a selected group of bars on the roof.

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I'm working in robot structural analysis

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using the small Medical Center model that

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was linked from Revit.

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The easiest way to perform structural design and robot

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is to use a predefined screen layout steel aluminum design.

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In the standard toolbar, expand the layouts dropdown list

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and select steel design, and then steel aluminum design.

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This opens the definitions and calculation dialog boxes along

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with the structural model toolbar on the right.

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First I want to select the beams I want to modify

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and I'm going to choose the rafters on the roof

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of the lobby of the building.

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I want to edit the steel design parameters

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for the active design code of the predefined beam type.

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In the structure model toolbar, I'm

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selecting steel aluminum design member type.

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This opens a member type dialog box,

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where I can update the member definition parameters.

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I'm going to select the beam type

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and this opens the member definition parameters dialog

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box specifically for beams.

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I'm going to change the buckling parameters about the z axis

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to include the intermediary bracings that

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are not defined in this model.

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I'm clicking the button to bring up the buckling diagrams dialog

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box, where I'm selecting the internal bracing button.

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In the internal bracing dialog box,

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I'm defining manually the relative coordinates of three

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bracings along these beams.

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The coordinates are displayed in the graphical preview.

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After this modification, we would

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like to save the parameters.

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In the member definition dialog box, click Save.

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As you can see it's not possible to overwrite

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the predefined beam member definition.

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So I'll change the name to rafter 1 and then

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Save and Close the dialog box.

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You can see the rafter 1 type was added to the list.

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The selected bars are noted in the lines bars section.

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And selecting apply assigns a rafter 1 type

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to the selected bars.

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Will close that dialog box too.

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Now, we want to set up calculations for the same bars.

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I'm going to reselect the rafters.

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And in the calculations dialog box,

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we're going to activate member verification

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for the selected list to bars and then under limit states.

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I'm going to click the list beside the ultimate limit state

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option.

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This opens the load case selection dialog box.

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In the combinations tab, we can select

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all the ULS combinations.

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And click the two up arrows to apply it to the bars.

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Then under serviceability load states,

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I'm going to change the list for each type of load

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leaving only the combination of 15.

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Now you're ready to run calculations

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for member verification.

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This results in the list of verified members

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with a brief information on the status of calculations

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containing design combination ratio and member slenderness.

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Selecting specific members results

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and opening the window with more detailed information containing

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design forces and moments design code formulas and references.

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As the ratio for these members is close to 0.5,

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we need to search for a more efficient section.

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First-- we'll define a design group.

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In the definitions dialog box, I'm clicking on the Groups tab.

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When I click in the member list edit box,

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it applies the selected bars.

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Beside number, I'm going to click New and the number 1

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is applied.

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Under the name I'm going to click rafters and then click

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Save.

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Now I can search for the sections.

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Beside the member list, I click the sections button.

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In the selection of sections dialog box,

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I can choose from different bar shapes.

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If no specific bar shape is selected,

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robot will search for any of the W sections.

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I'm going to click OK to go with the default.

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Next, I'm going to run the calculations

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for group 1 defined before.

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In the calculations dialog box, click code group design

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and optimization.

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Then I'm going to click the Options button.

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And in the optimization dialog box,

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I'm going to select wait and click OK.

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In the code group design edit box, I'm going to type 1

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for the group defined earlier and click calculations.

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The displayed windows shows the optimum section

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with the blue exclamation sign.

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The optimum section is W 12 by 26

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while the original section in these bars is a W 21 by 44.

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The efficiency ratio for the optimum section

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is 99, an increase from 0.53.

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Click on the optimum section to review the results dialog box

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and then close it.

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Now let's click change all.

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This replaces the original section with the optimum one.

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An alert box reminds you that this automatically

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changes the status of results from available to out of date.

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And you can see this also up in the title bar.

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This is why it's necessary to rerun

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the calculations of the model.

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In the standard toolbar, click calculations.

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The model is regenerated after the update

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and then the finite element analysis is performed.

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The change of sections for bars can

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result in a different distribution of internal forces

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and moments in the model.

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So after recalculation, it's necessary to perform at least

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the code group verification for group 1.

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In the calculations dialog box, select code group verification

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type in 1 and click calculations.

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Notice that after the recalculation,

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the efficiency ratio has changed from 0.99 to 0.93.

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This is still acceptable.

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You are now ready to continue design and analysis

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on the model.