Two story house - tall platforms, open underneath

[darinlwebb]

I'm trying to figure out the best way to build this, not finding a bunch of definitive answers in books and online, but lots of ideas.

I'm building a two-story house, 12' x 16' house on a 16'x16' platform, on wheels obviously...

What's troubling me are the best ways to structurally support the upper level - lots of action up there - while still providing a relatively open lower level.

For the lower level, the design calls for ~7 walls on the SR and SL sides, with a perpendicular dividing wall 4' in, like so:

http://imgur.com/a/CpKAx

The 12' x 16' area above the walls needs to support flats, similar to the walls, as well as several actors.

Originally I was thinking stud walls for the walls. One of the side walls will have a window, and the back wall will have a door. Augmenting that would have to be columns throughout the lower level.

Another idea would be to build it like a free-standing deck - with three rows of columns SL, Center, and Sr, supporting left-to-right joists, upon which the upper level's platforms would be seated.

Has anyone build anything similar? Know of any resources for learning here?

 

[BillConnerFASTC]

I think it would be easy to build using conventional stick framing, but having to be on a wagon probably makes that too heavy for a feasible number of affordable casters. A lot of air casters might work but $$. That would lead me to stressed skin panels - probably 4" foam and I'd try 1/4" ply but might have to go to 3/8 or even 1/2 for some parts. Lot of engineering. Not inexpensive no matter which way you go.

 

[Quillons]

A learning resource might be Structural Design for the Stage by Alys Holden and Ben Sammler.
Ch 3: Stress Analysis for Beams, with a section on overhangs and cantilevers.
Ch 6: Wood Column Analysis and Design
Ch 9: Steel Column Analysis and Design

 

[bobgaggle]

You have any art from the designer? Would probably help to see what this thing is supposed to look like.

 

[darinlwebb]

A learning resource might be Structural Design for the Stage by Alys Holden and Ben Sammler.

I just got this book last week. It's thicker than my college calculus book, and has just as much math :/

 

[JonCarter]

I'm trying to figure out the best way to build this, not finding a bunch of definitive answers in books and online, but lots of ideas.

I'm building a two-story house, 12' x 16' house on a 16'x16' platform, on wheels obviously..."

Worked on a show which did this some years ago. Email me off board-- [email protected]

 

[darinlwebb]

Thanks for the feedback everyone. Continuing with the stud wall plan, I upgraded the design to 2x6 framing for the SR and SL walls (keeping 2x4 for the interior wall). This helps support 2x6 joists running SR to SL.

Here's an exploded model, downstage to the lower left. The lower platform extends an extra 4 feet downstage from the rest of the unit, which is all stacked on the upstage 12 feet.

http://imgur.com/a/6W0zd

The window on the SL side is there to allow a slide from the trap door in the upper platform. The slide will turn 90 degrees downstage and continue to the floor.

We've got a while before we can start building this - apparently other folks don't want to work around a 12' x 16' x 20' box - so I'm going to continue workshopping this between myself and the scenic designer. Safety wins all arguments, and the interior designs are all still very flexible, and will work around whatever is needed structurally, I'd just like to keep the lower level as open as possible.

Oh, and I realized I didn't say what show. Sweeney Todd, not the musical. The large lower interior is the pie shop, directly above it the barber shop, both will see plenty of action.

On a lighting side note, we're thinking about hiding some LED strip lights or using practicals to get some illumination inside the pie shop, but otherwise just blocking to keep actors out of the shade.

 

[RonHebbard]

I just got this book last week. It's thicker than my college calculus book, and has just as much math :/

@darinlwebb And your point?
Are you saying math's a good thing or a bad thing??
Did you ever open your "college calculus book"?
If math's not your strong point, maybe the book alone will be strong enough to support your set?
Possibly you're saying you won't let a little learning hold you up from building a set that won't hold up on its own?
@Quillons What's your take on the poster's comments Re: the the relative thicknesses of college level texts?
I've heard concerns expressed regarding the relative stress levels of attending various colleges but I remain naively unaware of any such comparisons regarding the relative structural supporting capabilities of their actual tomes.
I guess this lends a whole new meaning to the term: "supporting documentation."
Toodleoo!
Ron Hebbard.

 

[darinlwebb]

@darinlwebb And your point?

Oh calm down

I just thought it was funny that the book suggested was one that I had just recently picked up. I loved calculus, and I'm excited to dive in to the book. That said, to use that book to help me with this problem would be an incredibly time-consuming endeavor because that would be starting at square one, and in the end would primarily serve to help me come up with less expensive and more efficient designs. Because I haven't become an expert on the topic, this design is going to probably end up being heavy, expensive, and more sturdy than it needs to be.

 

[BillConnerFASTC]

It looks like your 2x6s are 2 ft on center, which is equivalent to 2x4s 16 inches on center. This kind of bearing wall does depend on sheathing to support the floir above. Dont overlook that.

I question the 2x6 joists spanning 16' - a lot. Without looking, 2x10 seems close if 16 inches on center. May be an application for TJIs. (Or stressed skin panels.)

I also suggest you early on calculate the weight of the entire unit with props and, if on when moving, performers. More load on edges with bearing walls. A lot of casters and it will not be easy to move. I hope it is a atraight line move so you could add a hand winch.

Just saying, dont put off castering till last. It is the bigger challenge compared to building two stories.

 

[BillConnerFASTC]

Checked some span tables. No 2 SPF - typical of grade and specis in big box stores - 2 x 12 16 inches on center for 16 ft span. Home depot lists a doug fir that might make it in 2x10. This is a good calculator: http://www.awc.org/codes-standards/calculators-software/spancalc

 

[Quillons]

I just got this book last week. It's thicker than my college calculus book, and has just as much math :/

I haven't looked through all of it (I'm able to look at an e-copy through my school library), but... yeah. It's a textbook. From the classes I've taken so far I think this book combines Statics, Mechanics of Materials, and maybe a Structures class (Physics and some Calculus being pre-requisites). Call it a long-term project and look up youtube tutorials as you read.
And apparently I should have taken calc at your school!

I loved calculus

O.O
But in all seriousness, if you actually liked calc, you will be able to work your way through this. It may be rough at times, but you got this.

I remain naively unaware of any such comparisons regarding the relative structural supporting capabilities of their actual tomes.

I've got a nearly 1000 page Materials and Processes in Manufacturing you may like...
Or I could head over to the physics department and find a book on anti-gravity (or some such). I would guess that most actors wouldn't come near it with a ten-foot stick; therefore due to the anti-gravitational properties of the book and the reluctance of the actors, no structure is needed at all! Actors will merely float over and around the book!

 

[BillConnerFASTC]

I believe the book was based on the "structures" classes at YSD. It was published well after I, along with my trusty slide rule, took the class. I'm still enthralled by stressed skin panels and how far something wooden and so thin can span, which is my clearest memory from the classes.

 

[darinlwebb]

Thanks @Quillons for the overview. That gives me some expectations and I was also thinking of planning my reading of it to be more 'class-like' and supplemented with other reading/viewing.

@BillConnerFASTC - I appreciate the questioning of the materials choice. That's something I'll look in to, especially the span tables and making sure the joists are properly sized. When it comes to the stud walls, I was partly looking at just increasing the square inches that the joists would have available to sit on (bearing length?), and I wasn't super comfortable with them resting on a 2x4 top plate. Thanks a lot for the link to the AWC site, lots of good reading there.

 

[RonHebbard]

I haven't looked through all of it (I'm able to look at an e-copy through my school library), but... yeah. It's a textbook. From the classes I've taken so far I think this book combines Statics, Mechanics of Materials, and maybe a Structures class (Physics and some Calculus being pre-requisites). Call it a long-term project and look up youtube tutorials as you read.
And apparently I should have taken calc at your school!


O.O
But in all seriousness, if you actually liked calc, you will be able to work your way through this. It may be rough at times, but you got this.


I've got a nearly 1000 page Materials and Processes in Manufacturing you may like...
Or I could head over to the physics department and find a book on anti-gravity (or some such). I would guess that most actors wouldn't come near it with a ten-foot stick; therefore due to the anti-gravitational properties of the book and the reluctance of the actors, no structure is needed at all! Actors will merely float over and around the book!

***************************************************************************************
@Quillons : In all BUT seriousness; What you're saying is "therefore due to the anti-gravitational properties / magnetic reluctance of the book AND the reluctance of the actors, no structure is needed at all! Actors will merely float over and around the book!"
Understood, got it and essentially correct, right?
Masterfully explained for us mere mortals AND with nary a need for Calculus.
Are you sure you want to continue working in engineering rather than progressing into lecturing?
Anyone possessing your 'natural gift' for elegantly simplifying, expressing and explaining complex cross-disciplinary concepts perhaps ought to reconsider their end goals.
Keep it up Quill, your humor is much appreciated. There still may be a position at Tait in your future.
Toodleoo!
Ron Hebbard.

 

[BillConnerFASTC]

For thought, traditional western framing for house building generally presumes a double top plate (someone will correct this terminology as house building has more names for parts than theatre does) with 2 x 4 studs 16" oc and a rim joist and then the joist can then land anywhere on the plate If you use "optimum value engineering" framing it uses 2 x 6 studs 24" on center, a single top plate along with rim joist, but requires the joists and studs align. (More to it but really affecting you.)

Yes - the 2 x 6 vs 2 x 4 studs reduce span 4", from approx 15-7 top 15-3, and provides a little more bearing, but house framing has relied on joists bearing on 2 x 4 plates for a long time without major problems. Plus, looking around, its hard to find sawn lumber that will span 16' on 24" centers without getting into 1 and better or select structural grades - which I don't think I've ever seen other than in span tables.

 

[Crisp image]

I have made something like it for Addams family. Although the unsupported span was only half of what you want. The materials I used was a stick frame that was made to be 1200mm square column at each end that had supporting wheels mounted underneath on Laminated vernier Lumber (LVL) and then used engineered timber 'I' beams (45mmx 200mm) to support the load. The I beams are light and strong I had 4 at 400mm centers to do my job. you may be able to get the same style of beams that are larger for the span but lighter than solid timber. I can pick up each 4800mm beam at the balance point with one had and carry them easily.

The beams were only supported where the door recess is but canter levered over the rest of the ends of the set. See the next photo

I hope this gives you some ideas on making your set.
Regards
Crispy

 

[darinlwebb]

After reading up on engineered I-beams and the benefits of 2x6 vs 2x4 studs, as well as reviewing some of the design requirements (requests) for height and lack of support columns/legs, I've adjusted the design.

Everything is 16" on center, with some slight exceptions. Most joists are now 9.5' engineered wood I-beams, except the outer beams and two inner beams (might switch the inner beams too).

Walls are all 2x4.

These changes have significantly cut down on weight. What you see in the photos, not including the bottom platforms, would weigh in at about 1,040 pounds. I need to finish the math for the rest of the unit and figure out what casters are going to look like. Prior designs would have been closer to 1400 - using 2x6 studs and 2x12 joists.

http://imgur.com/a/MstC2

My original plan was to sit regular 4x8 platforms on top of the joists, but now I'm tempted to just skin the top of the joists with 3/4 ply. Cuts down a lot of weight, and I could use that platform inventory elsewhere.

 

[BillConnerFASTC]

Looks good. Just follow all the rules for the TJIs - squash blocks at bearing points, blocking, and deck glued IIRC. Its a great product but highly engineered and much less tolreant than sawn lumber to varying details. And i believe mixing sawn lumber with engineered is risky because it changes size so differently.

The thing that always deterred me from using them was the gluing, which made strike longer and basically meant no salvage of materials, all dumpster.

 

[Crisp image]

Glad the I beams are OK for you. I would like to ask why you have used full timber beams around the edge? I have not done any of the computations for your design so I am not sure of the span or the loading. When I used the beams they were at 16in centres (400mm in metric).
Make sure you share some photos of the finished set.
Regards
Crispy