High-rise floor slab construction (circa 1920); structural clay tile? 1

[Ben29]

This is an existing 10-story building (circa 1920, Downtown Baltimore, MD). Can anyone recognize the structural system used here? Are those clay tiles structural? It doesn't look like the "TYPICAL ONE-WAY COMBINATION FLOOR" referenced in the thread linked below.

https://www.eng-tips.com/viewthread.cfm?qid=421128

 

[Ben29]

I think it looks like "standard flat arch combination"

 

[Ben29]

When used in a floor system, are these tiles always just filler/formwork/fireproofing? We want to install new vertical openings in the existing floor. I believe the floor system is comprised of steel beam girders spanning to wide flange steel columns, and then the small steel purlins spanning to the girders, with the structural tile installed between and around the purlins.

 

[bookowski]

They're not filler/formwork. Treat it like a fragile one way spanning system, with very little ability for load to make its way around openings. These are common in the northeast for early 20th cent buildings. For new openings I have always made them remove a slot from steel beam to steel beam, and then infill back around your new penetrations. I have seen others allow small openings but I don't know any justification so it would depend on your risk tolerance.

 

[BAretired]

I believe you are correct. The tiles are just filler/formwork/fireproofing; and not very good fireproofing on the bottom flange of the beams. I have seen similar framing except the beams were cast in place concrete, not steel. So fireproofing was not an issue.

Edit: Please ignore the above. I was under the impression that there was a thin reinforced concrete slab over the tiles. To be safe, assume the tiles are structural.

 

[hokie66]

I think bookowski is correct. They are not just formwork, they are the secondary structural system, the decking.

 

[bookowski]

Check this out, might help.

https://www.wje.com/knowledge/webin...air-of-historical-structural-clay-tile-arches

 

[Ben29]

@book that webinar was awesome. I feel like an expert now. Thank you for sharing!