Which structural framing systems and materials are most commonly used in the United States for residences? For office buildings?
Office buildings: Steel and Concrete
Residential Buildings: Wood framing
◦ What factors explain why those dominate?
For residences wood has been used historically because it is less expensive and lumber is plentiful.
For offices, steel is easy to install and extends over long distances without columns. For concrete it is less expensive, adaptable to change, and can withstand office loads.
◦ Why did you choose your system, and what did it cost you?
I chose a mix of concrete and timber columns and joists because I've worked roofing before, so I know homes are usually made of wood. I used wood for all floors above the ground floor to first floor. However, I made the ground floor concrete since I have glass curtain walls, and I feel concrete looks better with them than wood. There's also a patio, and I usually see patios made of concrete rather than wood. The concrete gave me the aesthetic I wanted but costs more compared to wood.
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?
Maintains separate files that are easier to manage, enables many teams to work simultaneously, and changes in the linked model can carry over to the host model automatically.
◦ What errors does linking make possible that a single model would not?
Components across models cannot be combined or tidied. Conflicting project standards can lead models to become out of sync and dimensions and annotations that are dependent on linked model components could turn unusable after link updates or replacements.
◦ Why is getting shared coordinates right at the start so much cheaper than fixing it later?
If coordinate systems are not correct in the beginning, every clash report and dimension in the whole model will be inaccurate. Fixing coordinates later involves rework at the source model, possibly costing several days compared to seconds if you just do it right from the start.
Not every clash is a problem.
◦ On what basis did you classify a clash as an issue versus not an issue?
I determined clash as an issue when there was physical overlap. For example, structural and architectural models intersecting, like a column in the corner of a stairwell because the stairs sit in the building corner where the columns start. I determined a clash as not an issue when the problem stemmed from transferring the model from forma to revit incorrectly, so the clash isn't real. I didn't fix it in model coordination, even though it still technically shows as a clash.
◦ Who should have authority to close a clash on a real project?
The person accountable for the impacted model closes the clash, not the person who fixed it
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?