Josiah Quincy Upper School | 900 Washington Street | Chinatown

I don't understand the cross-bracing showing through the windows. It can't be decorative or a poor excuse for creating open interior spaces, or is someone expecting a serious earthquake?
 
Life Coach Mike said:
I don't understand the cross-bracing showing through the windows. It can't be decorative or a poor excuse for creating open interior spaces, or is someone expecting a serious earthquake?
Click to expand...
The structural engineer for this actually popped up on Reddit several months ago to answer that exact question - but in short it's because the gym and auditorium are both cantilevered and significant open volumes underneath everything else. Evidently those trusses actually act like a bridge and are holding up the cantilevered volumes and spans.

Hey everyone, I'm the structural engineer for this building. I'm on an old account to not doxx my main account.

The large areas of metal panel facade are the auditorium (left) and the gym (center). The ceiling of the gym has 8 ft deep trusses on each column grid spanning parallel to the photo view supporting the columns of the upper stories. Additionally, the gym cantilevers beyond the brick face of the building (towards the photographer) about 15 ft, so the gym trusses also cantilever out to support hangers at the gym facade. All of these gym trusses hang from the multistory truss you see in the windows.

What you can't see from this picture is that the auditorium cantilevers about 40 ft over the school's main entrance (out of frame to the left). The cantilever is supported by the multistory truss you see. In addition to supporting the gym trusses, the part of the truss that you can see is also the backspan of the auditorium cantilever.

The stairwell has the OCBF because all the other locations would block classroom windows. Why is the transfer truss four stories tall instead of one or two? So that the blocked window impact on each classroom is equal.

This was by far the most challenging structural system I've done to date and it was a ton of fun. The school should be open in September for the new school year. I'll be presenting this building at the NCSEA Summit in November. I can also answer questions about the structural design here. https://www.reddit.com/r/StructuralEngineering/s/sG9u7ipM74
Click to expand...
 
Last edited:
You must log in or register to reply here.

Back
Top