Which structural framing systems and materials are most commonly used in the United States for residences? For office buildings?
Residential buildings commonly use wood framing, especially for houses and low-rise apartments. Office buildings typically use steel or reinforced concrete frames.
◦ What factors explain why those dominate?
Wood is relatively affordable and easy to construct for smaller buildings. Steel and concrete are more suitable for larger spans, heavier loads, and taller buildings.
◦ Why did you choose your system, and what did it cost you?
I chose a concrete podium for the first three floors and timber framing for the upper five floors. This gives the building a strong base while keeping the upper structure lighter. However, combining two systems made the connections and structural layout more complicated, especially at the transition between concrete and timber.
You sized members by judgment rather than analysis.
◦ What did you base your first guess on?
◦ Why is it safer to guess large and shrink than to guess small and grow?
◦ At what point in a real project does the engineer take over from the guess?
Design teams link and share models rather than working in one file.
◦ What are the advantages of linking?
Each discipline can work on its own model without changing other teams' work. It also makes coordination easier since everyone can update their models separately.
◦ What errors does linking make possible that a single model would not?
Models can be misaligned, use different coordinates, or show outdated information if they are not updated properly.
◦ Why is getting shared coordinates right at the start so much cheaper than fixing it later?
If the coordinates are wrong, structural elements may not align with the architectural model. Fixing this later could mean adjusting many elements and repeating the clash checks, which takes much more time.
Not every clash is a problem.
◦ On what basis did you classify a clash as an issue versus not an issue?
I classified a clash as an issue if it could affect the building layout or require changes to either model, such as a beam interfering with an opening. Expected overlaps between architectural and structural elements were considered not an issue.
◦ Who should have authority to close a clash on a real project?
The responsible architect or engineer should review and resolve the clash, while the BIM coordinator can track and verify that it has been addressed.
Your beam depths just constrained next week's ductwork.
◦ Where in your building is the ceiling plenum now tightest?
◦ What would you give up to get it back?
◦ Should the structural engineer have consulted the mechanical engineer before setting spans?