Kevin O’Marah

Link to Design Journal
Journal Entry For
Module 8 - Share Your Design
Created By
Kevin O'Marah
Property
Related to 120C/220C Students - Spring 2022 (1) (Related to Design Journal Entries | Winter 2022 (Linked Student))

Share your new tool in a way that allows others to download and easily use it.

Your complete submission should include:

  • The Dynamo or Grasshopper scripts and all the supporting nodes needed to run your tool.
  • Documentation for how to use your tool. It should include:
    • A brief overview of what your tools does (to help users decide whether to download it and give it a try). Think of a “ReadMe” file for software.
    • My tool is for the preliminary design process of steel moment frames in a rectangular steel building. This tool will help speed up the initial part design process by calculating deflection, base shear, and overturning moment using approximate equations to give a designer a sense of whether or not their design meets all the sufficient criteria. This tool would be used before spending a lot of time creating a more complex model in Sap 2000 or etabs to conduct a more detailed analysis. My tool also places the selected elements in a Revit file which can be helpful to communicate your design to you clients.
    • A catchy name (or acronym) for your tool
    • Steel Moment Frame Seismic Design Aid
    • A teaser image that shows typical results, i.e. what users should expect to get as an output
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    • A link to a recorded video demo (2 minutes max) in which you demonstrate how a user would interact with and benefit from using your parametric design tool.
    • Please be certain to share your video with a PUBLIC link that will allow anyone with the link to view it:

    • If you use Zoom to record your video, download the recording to an MP4 file or Copy the shareable link from the Canvas interface.
    • If you save an MP4 file to Google Drive or One Drive, be sure to set the permission to Allow Anyone with Link to View.
    • If you use YouTube to host your video, set the Visibility to Unlisted, then paste the link into your Notion posting using the “/Video” command.
    • Be sure to test your video link to confirm that the visibility / permission settings will allow others to view it.

      Here are the inputs for the building geometry width is in the y-direction, length in the x-direction, and height in the z. Make sure your building is longer than it is wide because the later forces are being applied in this direction. For the beams, you can use either number of divisions or max spacing. U direction corresponds to the x and v corresponds to the y. To toggle between the two you can use the boolean node set to true for the number of divisions and false for max spacing.

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      Here you can select the steel sections used for this tool and to be placed in Revit. Direction one corresponds to x direction and direction 2 corresponds to the y direction.

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      The logic to model the geometry in Dynamo follows the same logic as example 8.3.A. Using the geometry input a cuboid and boundary box are created. Then the first floor is created and panelized. The floor is then translated and this process is repeated for all floors.

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      Here the structural elements are placed on the lines for their corresponding locations the volumes are taken from Revit and the total weight is computed.

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      Here the section properties of the columns are calculated assuming a nominal depth of W14 sections (which is pretty typical). If another section for the columns is desired and equivalent PLF should be input to get the same section properties. These sections are calculated using the linear relationship between the section pounds per linear foot and the respective property.

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      Here are the inputs for the response spectrum, the live load at each floor for, and the R/Cd reduction and amplification factors. For these values, the user should consult ASCE 7 hazard tool for spectrum details and ASCE 7 ch. 12 for R 7 Cd and ASCE 7 for minimum live loads for the structure.

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      Using the two-period spectrum we approximate the accelerations in g’s based on the fundamental period calculated with the ASCE equation from chapter 10.

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Here we calculate the total live load and the force distribution factor. The loads need to be concentrated at the top for buildings with higher periods so an exponential value between 1 and 2 is calculated for the equivalent later load method.

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The seismic force per floor is calculated by mutiplying the total weight times acceleration and reducing by R. These are then summed up for the total seismic force at the base and the distribution factors or Cv are calculated to compute the equivalent load at each floor.

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Using an approximate method we can approximate the deflections when the loads are applied to half the building. Due to symmetry, they will be the same on both sides. It assumed that only the outer frames are lateral resisting and the internal frames are for gravity loads. The capacity is calculated by comparing the overturning moment to the flexural capacity of the columns at the base. Assuming only 85% of the flexural capacity is available due to axial loads and a safety factor of 0.9.

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Here are the outputs of the tool deflections are given in inches, moments are given in kip inches and forces are given in kips. The lists give the value at the top floor first and the bottom floor last. So roof displacement is at the top of the deflection list and base shear is at the bottom of the shear list.

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