Part 1 – Problem 08: The definition of existing structure is unclear. When replacing flexible with rigid diaphragms, does existing structure include only the first 10 stories, or all stories on the existing structure with the addition?
For this question, change the diaphragms from flexible to rigid for all the levels from the bottom floor up to the 10th floor (roof of the existing structure). Keep the diaphragms of the extension (11th floor to roof level of the addition) flexible. You are asked to compare mode shapes of this configuration to mode […]
Part 1 – Problem 09: When applying density to our model in deliverable 3, we accidently applied as weight per unit volume rather than mass. However when changing this value, our model yields very low displacements and forces. We would like to confirm that the 8 pcf value is in fact weight per unit volume for our final model and analysis
The 8 pcf value is the weight per unit volume for the balsa wood members. This is similar to mass per unit volume but expressed as a specific weight rather than a density. Make sure that in addition to this self weight of the balsa wood members, you apply a dead load of 1.44 psf […]
Part 1 – Problem 10: If we make changes to our addition from what we submitted in Deliverable 2, what should we use for the D/C checks in Part 1-1? (1) The deliverable 2 addition plus existing structure OR (2) The addition that we’re currently working on, plus the existing structure but not including the retrofit of the existing structure
Because this was not clear in the instructions and the question and response were posted very close to the submission deadline, either of the above checks will be acceptable. However, we would prefer option (2) as a more direct comparison between the unretrofitted and retrofitted conditions.
Part 1 – Problem 11: Our final construction drawing shows every member in a single line and then states the thickness of each type of member in notes. When we calculate the weight of our design, can we still subtract out the weight of the overlapping connections to make it actually accurate? Or will you guys not account this reduction due to connections? We found that subtracting out the redundant volumes for connections can potentially make a 5% difference, which can mean getting a penalty or not.
For the sake of simplicity, we would prefer that this reduction due to overlapping connections is not taken into account when determining the weight of the structure. Also, consider that if you’re measuring lengths of members from centerline to centerline of perpendicular members, the overlapping member volume on the inside corner of the connection would […]
Part 1 – Problem 01: the Design Guide notes that “rentable floor area may only be within the continuous perimeter beams of the floor” (page 5). When calculating the total rentable utilized floor area of the structure, do we calculate the area from the centerline of the perimeter beams of the floor or from the inner edge of the perimeter beams of the floor?
We would like you to use centerlines of perimeter beams when determining the total rentable floor area of the structure.