StructuralJoe
Structural
- Jun 12, 2007
- 43
I have been asked to work on an interesting project. The client is a Dance Studio where dance classes are taught. The Architect (interior designer) originally received a permit from the building department to modify the floorplan for 3 dance studios on the 2nd floor of an old three story 1920's Hotel (in Florida).
1st Problem: Her plan required the demo of 3 load bearing walls.
2nd Problem: Existing structure was not designed for 100psf (Dance Hall / Ballroom - live loading)
3rd Problem: I was originally told that the floor loading was not an issue as the building department classified it as "business occupancy"
It turns out that the building department was actually speaking in turns of the life saftey plan.
Based upon the original permit the owner has already performed 90% of the construction and now she is being required to show that the floor can handle 100psf live load (this is where I come in... yeah!)
My 1st question is: Based upon knowledge of the intended use of the rooms (max size 610sf) and max occupancy (based upon 15sf/per person the Max room occupancy is 40 individuals. At 250lbs per person statically we are talking about 16.4psf live load. From what I can tell the original structure has at least 40-50psf capacity. This results in a 2.4 to 3 factor for impact loading (before any standard code saftey factors come into play)... Can this be used to modify the requirements of the code?
My logic is based on the fact that a stadium with fixed seating (approx. 6 sf per person) is designed only for 60psf... and using the same 250lbs person (drunk and jumping up and down screaming for their favorite team) results in 41.67psf static and a impact factor of only 1.44?
My belief is that the 100psf is for DANCE HALLS or BALLROOMS which are both assembly occupancies and as such can result in localized concentrations of people and therefore for saftey the entire floor should be designed to handle this.
In this this case the Client is only capable of teaching a MAX of 20 individuals which results in a static loading of 8.2 psf and a resultant SF of 4.87 (at 40psf LL).
I currently can rationalize this in my mind but I do not know my limitations when trying to prove this (or if it is even allowed by code).
Any and all help would be a great help,
Thanks, Joe
1st Problem: Her plan required the demo of 3 load bearing walls.
2nd Problem: Existing structure was not designed for 100psf (Dance Hall / Ballroom - live loading)
3rd Problem: I was originally told that the floor loading was not an issue as the building department classified it as "business occupancy"
It turns out that the building department was actually speaking in turns of the life saftey plan.
Based upon the original permit the owner has already performed 90% of the construction and now she is being required to show that the floor can handle 100psf live load (this is where I come in... yeah!)
My 1st question is: Based upon knowledge of the intended use of the rooms (max size 610sf) and max occupancy (based upon 15sf/per person the Max room occupancy is 40 individuals. At 250lbs per person statically we are talking about 16.4psf live load. From what I can tell the original structure has at least 40-50psf capacity. This results in a 2.4 to 3 factor for impact loading (before any standard code saftey factors come into play)... Can this be used to modify the requirements of the code?
My logic is based on the fact that a stadium with fixed seating (approx. 6 sf per person) is designed only for 60psf... and using the same 250lbs person (drunk and jumping up and down screaming for their favorite team) results in 41.67psf static and a impact factor of only 1.44?
My belief is that the 100psf is for DANCE HALLS or BALLROOMS which are both assembly occupancies and as such can result in localized concentrations of people and therefore for saftey the entire floor should be designed to handle this.
In this this case the Client is only capable of teaching a MAX of 20 individuals which results in a static loading of 8.2 psf and a resultant SF of 4.87 (at 40psf LL).
I currently can rationalize this in my mind but I do not know my limitations when trying to prove this (or if it is even allowed by code).
Any and all help would be a great help,
Thanks, Joe