Which structural framing systems and materials are most commonly used in the United States for residences? For office buildings?
◦ What factors explain why those dominate?
Light frame wood framing is most common for residential buildings in the US. This is because it is cheapest and has the lowest embodied carbon.
Steel is most commonly used for office buildings in the US because of its high strength-to-weight ratio, which allows for taller, lighter structures with longer spans to prevent columns from interrupting open spaces. It also allows for quick construction because the steel sections are manufactured off-site.
◦ Why did you choose your system, and what did it cost you?
The ground level of my building is a concrete framing system. This provides a strong foundation for the floors above, but concrete is carbon intensive.
I chose to use Glulam beams and columns for the upper floors because my building is too tall for the wood framing system. I would have preferred the wood framing system, since glulam is much more expensive and is higher in embodied carbon, but I had already established a building that is too tall. In future years, this should be mentioned in week one.
You sized members by judgment rather than analysis.
◦ What did you base your first guess on?
I based my first guesses on standard engineering practices for buildings of a similar use and size.
◦ Why is it safer to guess large and shrink than to guess small and grow?
In guessing larger, we are assuming a worst-case design, which limits the need for a redesign since sizes would be decreasing.
◦ At what point in a real project does the engineer take over from the guess?
Once the framing plan is laid out and the building use is determined, the structural engineer can compute the loading demands on each member and determine the appropriate sizes.
Not every clash is a problem.
◦ On what basis did you classify a clash as an issue versus not an issue?
I determined if a clash was an issue based on whether it posed a significant impact on the construction of the building. For example, a wall blocking the stairs posed a significant issue, but a wall/column intersection did not since those elements should intersect anyway.
◦ Who should have authority to close a clash on a real project?
I think an engineer with a PE should be consulted before closing a clash. The decision should not be made by one single person, and everyone on the team should be in agreement before a decision is made.