Beach Tower
Beach Tower
(OP)
Call me crazy but I want to build something like this on my 10 acres so I can see all the way to the beach.
[img https://3dwarehouse.sketchup.com/warehouse/getpubl...]
Given my wind speed (155mph ult.) and seismic zone (D2) I am probably looking at some serious holdowns at the first level (HDU 11). I would have to run the numbers but it would probably work. I would probably also sheath it with 5/8" plywood inside and out for some serious shearwall action, at least on the the first two floors. I would probably also frame the first two floor with DF No.2 2x8 studs or 2x6 studs at 12" o/c. I'm thinking spiral staircases between levels to save as much floor space as possible and to make it more interesting. Minimal windows on the first three levels and then the top level would have a lot of windows for the view. 11-7/8 TJI 210 for the floors with 3/4 sheathing T&G, 16" o/c.
The structure is 16'x16' with grade to top plate height of 38'8".
The roof is 6:12 pyramid hip with 2x8 rafters, I may go with a steeper pitch though.
On a structure like this overturning is a serious threat, I would need to check the dead weight of the structure and see if the seismic or wind forces could potentially lift the foundation right out of the ground. I think the solution would be to to increase the dead weight of the structure especially at the base, by upsizing the footing and stemwall. You will notice my stemwall is 10" thick, 36" deep and a 24"x12" footing, even this may not be enough. I'm also thinking about some larger spread footings at the corners where the shearwall studs drop down.
Anyone design something goofy like this before. I don't know if my county building dept. would give it an approval though even if its engineered (stamped).
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
[img https://3dwarehouse.sketchup.com/warehouse/getpubl...]
Given my wind speed (155mph ult.) and seismic zone (D2) I am probably looking at some serious holdowns at the first level (HDU 11). I would have to run the numbers but it would probably work. I would probably also sheath it with 5/8" plywood inside and out for some serious shearwall action, at least on the the first two floors. I would probably also frame the first two floor with DF No.2 2x8 studs or 2x6 studs at 12" o/c. I'm thinking spiral staircases between levels to save as much floor space as possible and to make it more interesting. Minimal windows on the first three levels and then the top level would have a lot of windows for the view. 11-7/8 TJI 210 for the floors with 3/4 sheathing T&G, 16" o/c.
The structure is 16'x16' with grade to top plate height of 38'8".
The roof is 6:12 pyramid hip with 2x8 rafters, I may go with a steeper pitch though.
On a structure like this overturning is a serious threat, I would need to check the dead weight of the structure and see if the seismic or wind forces could potentially lift the foundation right out of the ground. I think the solution would be to to increase the dead weight of the structure especially at the base, by upsizing the footing and stemwall. You will notice my stemwall is 10" thick, 36" deep and a 24"x12" footing, even this may not be enough. I'm also thinking about some larger spread footings at the corners where the shearwall studs drop down.
Anyone design something goofy like this before. I don't know if my county building dept. would give it an approval though even if its engineered (stamped).
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com






RE: Beach Tower
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Beach Tower
RE: Beach Tower
Don't know how that would compare to the additional concrete required - probably a wash when all is said and done.
RE: Beach Tower
RE: Beach Tower
just to relieve the boredom of those big plain shearwalls?
... or supergraphics?
Something that suggests a V2 launcher?
Or something to suggest a platform on poles, as suggested.
Mike Halloran
Pembroke Pines, FL, USA
RE: Beach Tower
RE: Beach Tower
RE: Beach Tower
Both my wife and I would like a secondary storage structure and my wife was wondering if I could add some sort of perch onto the house so I naturally thought why not combine the two ideas...
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Beach Tower
External would deteriorate in our environment too quickly.
You can view the model here in 3D:
https://3dwarehouse.sketchup.com/model.html?id=e79...
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Beach Tower
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Beach Tower
RE: Beach Tower
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Beach Tower
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Beach Tower
RE: Beach Tower
Dik
RE: Beach Tower
However, out of pure curiosity I threw it into my shearwall program just to get a better idea on what kind of numbers we are talking about. As I expected the wind loads far out govern the seismic. I got it to pass if I used 15/32" sheathing (6 edges,12 field) interior and exterior on level 1 and level 2 shearwalls.
If I was to frame this I would probably use 2x8 lumber on the 1st level, with 8x8 shearwall studs at the four corners and a (2) HDU14 holdowns at each corner, this is probably a bit overkill but I would rather be conservative on a structure that is sure to take a beating. The second level, I would use 2x6 lumber but use 12" o/c stud spacing. The shearwall studs at the corners would be 6x6 with (2) HDU11 holdowns at each corner. The third level I would use 2x6 studs at 16" o/c with 4x6 shearwall studs at the corners and (2) HDU8 holdowns. At the 4th level (2) 2x6 studs at the corners and (2) HDU2 holdowns.
I would probably also run interior shearwall sheathing 7/16" on level (3) just for good measure but the numbers show that one exterior sheathing should be sufficient.
My soil is quite expansive in my estimation (I'm not a geotech) so I would probably install 42"x42"x12" spread footings at each corner of the building, integrated with the 24x12 footing. The one thing I haven't checked is the total overturning of the structure.
On the lower windows and doors I would probably running some strapping for force transfer around those openings.
So yes, I think one could platform frame this thing and actually make it work. The only thing that I don't have a good handle on is the overall deflection of the structure, it probably does not comply with the ASCE7-10 in that regard. Take a look at the numbers below:
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Beach Tower
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Beach Tower
RE: Beach Tower
I agree that an octagonal lighthouse could look better, if you get the proportions right.
I would start with a photo of an actual lighthouse that looks about right, and start overlaying a structure on that.
Maybe you could find an unused actual lighthouse and move it.
Or put up a slender guyed tower, and put a pan/tilt head on the top with a high resolution camera, and feed the image to a widescreen TV in your house.
Mike Halloran
Pembroke Pines, FL, USA
RE: Beach Tower
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com