Helong Huang

Journal Entry For
Module 9 - Share Your Design
ACC Folder Link
https://acc.autodesk.com/docs/files/projects/6db2c3ca-7a2c-4f34-96a1-8a8189c7754d?folderUrn=urn%3Aadsk.wipprod%3Afs.folder%3Aco.hv6V3aeUR4-CVu0trwc5RA&viewModel=detail&moduleId=folders
Link to Student
Helong Huang
  • CostMoment Introduction
    • CostMoment is a great tool for receiving early design feedbacks (Cost) in designing Steel Moment Resisting Frame (SMRF). By varying design variables, such as grid spacing, story height, number of stories, and frame total length, the tool provides early feedbacks in structural element’s total cost and weight with the lightest elements (cheapest) that are able to resist the seismic loads.
  • Teaser Images
    • Steel Frame
    • This steel frame can be changed by varying:
      • Story Heights
      • Number of Stories
      • Total Frame Length
      • Grid Spacing/Bay Length
      • Seismic Loads
        • image
    • Total Cost and Weight
    • They are calculated by summing the weights from all members in the model and multiply it by an arbitrary unit price per pound. In here, the unit price is 10 dollars per pound.
      • image
  • Record Video Demo

https://stanford.zoom.us/rec/play/A5FB4lS_iM3s1wQ2AgbPUHA4n_dJFUnyQzr7k6puDNxeJHc6Ljq8EkkvtG_8L6eYOvbmFR4wSL6i5DI.q_QX-aUBaIh8uE5E Password: ^?hr?Y78

In the video, I discussed how this tool may benefit structural engineers, architects, and construction manager. Also, how the imputs are impacting the outputs are mentioned. In general, the element size is related to all the varying inputs. For example, longer grid spacing results in larger elements as well as more cost.

Due to 2 minutes time constraint, I didn’t mention that the frame total length has to be integer multiiple of grid spacing so that the beams won’t punch through columns in Revit.

Seismic loads are assumed to be uniform on each story with uniform beam and column sections.

For simplicity, I only check stiffness (Drift Ratio) which controls in most cases.

All element information is from AISC Database Excel file. I created two more spreadsheets one for W14 and one for W21. Only W14 columns are available for columns and only W21 beams are available for beams. I chose W14 for columns because W14 is the best shape to counter buckling, and W21 for beams because it provided enough clear heights for architects.

The process of calculating lightest elements may return NULL which means none of the available elements can satisfy the demand.

For example, If I increase the number of stories to 10 from 5, the base shear will be doubled causing higher required strong axis moment of inertia (Ix). The required Ix might be too large for any sizes of columns or beams to satisfy.

In this case, it indicates that the Moment Resisting Frame design is not good enough or not even applicable. Another lateral system might be applied or changing the dimensions (grid spacing, story height, number of stories) is necessary.