Part 1 – Problem 10: The deliverable states that we should report the maximum axial, bending and shear forces that are undergone by individual members. Does this mean that for each TH we need to check each member in our balsa wood numeric model in SAP2000 and report the maximum? Is this what individual members refer to?
Yes, but only members with the highest axial, bending, and shear forces must be reported. This should be easily obtainable by viewing member force diagrams or output tables from the software. Note that in question 3, we are asking for the highest forces, but in question 5, the highest stresses will also depend on cross-sectional […]
Part 1 – Problem 05: For inter-story drift ratio calculation for SAP users (since I believe ETABS has this already calculated), is there a location of preference to make these calculations? This question could also be reframed as reassurance that the diaphragm is still assumed to be flexible (and therefore not rigid nor semi-rigid as ASCE 7-16’s third drift calculation criterion dictates).
The best approximation may be to select the nodes at/closest to the Center of Gravity. This is one way of calculating the Center of Gravity:
Part 1 – Problem 06: For this part, do you want us to run the full time history analysis? Or should we input the time histories and tell SAP to analyze the data using a response spectrum analysis?
The full time history analysis should be run for each ground motion.
Part 1 – Problem 07: For the design checks in Question 5 Part 1, which grade should we use when determining the size factor in NDS Table 4A for member capacity?
You may assume a dimension lumber grade of No.1 for the purpose of determining the size factor.
Part 2 – Problem 03: Is our addition (and future retrofit, including all bracing, etc.) restricted to a set footprint/the footprint of the existing structure?
Please refer to “2021 SDC Structural Design Guide” for all the details regarding the extension building geometry, member sizes and spacing requirements.