Lower Roof Diaphragm - Chord Loads Mid-Floor Diaphragm Ht
Lower Roof Diaphragm - Chord Loads Mid-Floor Diaphragm Ht
(OP)
I have a 3-story hotel that has a lower lobby and pool roof that intersect the main building between the 2nd and 3rd floor diaphragms. In addition, my shear wall lines do not line up with the main building. Can I treat the lower lobby and pool roof as a separate building with its own shear walls, or do I need to add a floor to floor beam that transfers drag strut forces to the 2nd and 3rd floor diaphragm? Nothing lines up, so I am not quite sure how to treat these lower roof diaphragm loads. I have the shear walls to resist them, but what do I need to consider where it is part of the existing building? It would sure make it clean to just consider that the lower roof diaphragms are isolated from the main building and handle their own shear there.
Included is a print of the plan I am dealing with, if it helps. The main building shear wall lines are E, F, and G. The Lower Roof diaphragms are lines E.1 and G.1. The lower roof diaphragm top plates will be at 16' high. The 2nd and 3rd floors are at 10' and 20' high.
Included is a print of the plan I am dealing with, if it helps. The main building shear wall lines are E, F, and G. The Lower Roof diaphragms are lines E.1 and G.1. The lower roof diaphragm top plates will be at 16' high. The 2nd and 3rd floors are at 10' and 20' high.






RE: Lower Roof Diaphragm - Chord Loads Mid-Floor Diaphragm Ht
If the first floor diaphragm is wood though, you have to transfer out the shear walls above to the shear walls below as one building.
Mike McCann
MMC Engineering
RE: Lower Roof Diaphragm - Chord Loads Mid-Floor Diaphragm Ht
In this case there is no basement below. I have the problem with shear walls of the lobby and pool areas (lower roof elevation) intersecting the main building diaphragm between floors and not aligned with my main building shear walls due to the lobby and pool roof diaphragms.
RE: Lower Roof Diaphragm - Chord Loads Mid-Floor Diaphragm Ht
The shear walls in Room 216 and 218 - these terminate at the second floor. How are these forces transferred to the fist floor? If the only shear walls on the first floor are the pool and lobby walls then the force applied at the second floor by shear walls in room 216 and 218 need a load path to get to the shear walls that go down the first floor / foundation.
EIT
www.HowToEngineer.com