Replies

1. 
   Piffin | May 23, 2009 01:27pm | #1

   I probably would not make it a box, but simplify things by laminating 3/8" ply with staggered joints.

   Since it carries only deadloads of the actual framing it will probably be over sized by time you make it proportional looking for appearance

    

    

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   Taunton University of Knowledge FHB Campus at Breaktime.
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2. 
   IronHelix | May 23, 2009 01:32pm | #2

   Welcome to breaktime!

   Do take some time and complete your profile, especially the region/state where you live as it gives us a clue of some of the needed building means & methods of the climate zone.

   Your description is short of dimensions, roof coverings, finish details, etc.  So the response from what I glean is that you need to hire an engineer or have a truss company provide you and engineered system instead of site-made box beams.

   Maybe someone else will weigh in with another opinion!

    

   ....................Iron Helix

3. 
   Piffin | May 23, 2009 02:10pm | #3

   The iron Helix points out a lot of questions I assumed or glossed over - maybe you plan a roof on this...?

   Also arrangement of beams/styles...

   Here are a couple to open discussion with - the arch beam is an 18'chord with 9'projection

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

1. 
   Piffin | May 25, 2009 08:48pm | #5

   Howdy there, you awake?maybe off for the weekend...was looking for feedback, like yes like this, not like that, yes roof over, no open to weather like a pergola..... 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   martyoc | May 26, 2009 11:52pm | #6

   Thanks for the reply....I have attached a couple of drawings of the details I was planning to use....(I don't have a drawing program so used Word)...the straight beams wood run out from the structure to meet the radius one and are parallel to each other...I was looking for input on the connections from the straight ones to the radius as they are flush together.....and is the build up of the radius enough to support the loads....the spaces between would have frames with a sunfabric to provide shade....Marty

1. 
   Piffin | May 27, 2009 12:46am | #7

   how 'bout that! I didn't know Word could be used to sketch.So the five parallel beams will be at the same level as the radiused one instead of extended over it. is there to be a roof on this? That is a critical element of the answer here, since a roof will hold a load, requiring a stronger structure. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   martyoc | May 27, 2009 02:10am | #9

   The covering will be for shade purposes....will be one of the sun fabrics on frames about 5 1/2 ' square that fit between the beams....

2. 
   Gene_Davis | May 27, 2009 04:28am | #12

   My goodness!

   I think I'll write my will using Chief Architect! 

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   "A stripe is just as real as a dadgummed flower."

   Gene Davis        1920-1985

3. 
   Piffin | May 27, 2009 01:02pm | #13

   Don't forget the clause that names me as chief executioner, oops, I mean Executor;) 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

2. 
   HammerHarry | May 27, 2009 02:00am | #8

   The curved beams supporting this porch and the roof are made from layers of ply laminated into a beam...approx 4" x 12" high, if I recall.  I'll measure it up later, if I'm brave I could mebbe get a shot of the beam from unnerneath.

   It's an 8ft radius.

1. 
   martyoc | May 27, 2009 02:12am | #10

   Thanks ....I am looking at an 18' radius supported  by two posts.....and the hiegth is about 16" for appearances....

2. 
   HammerHarry | May 27, 2009 04:17am | #11

   You won't be supporting much weight, so your box beams will likely do fine, you might want to consider more than one ply on each side to strenghten it.

   For the joints, you might want to think about a sort of mortise / tenon joint assembly, that's likely the cleanest-looking arrangement.

3. 
   RalphWicklund | May 27, 2009 04:43pm | #14

   This is the almost finished frame for a 6' radius curved beam. The verticals are placed to accommodate fastening 2 layers of 3/8" ply for the sides. The sides were attached after placing the frame because I needed access to the interior for fastening to the posts.

   Just lifting this frame into position require two guys. If I had applied the skins it might have taken another two men and a boy. You will definitely need that extra boy to lift yours. It wasn't practical (for me) to attempt to build the whole thing in place.

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   Edited 5/27/2009 9:45 am ET by RalphWicklund

   
4. 
   RalphWicklund | May 27, 2009 04:48pm | #15

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   Beam in position and skinned.

   Edited 5/27/2009 9:49 am ET by RalphWicklund

   
5. 
   RalphWicklund | May 27, 2009 04:55pm | #16

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   Beam wrapped for stucco application. First, the wood was protected by applying peel and stick membrane that self seals when nailed through. Then expanded metal lath, corner bead and standard stucco application.

   The posts will be wrapped later with metal studs and Dens Glas Gold with a lower profile corner bead for EFIS application. The color coats for both will be from the buckets.

    

   Edited 5/27/2009 9:56 am ET by RalphWicklund

   
6. 
   RalphWicklund | May 27, 2009 05:05pm | #17

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   Beam with stucco. The reason for the standard stucco is that it was much easier to finish the curve that if I used straight EFIS techniques. The EFIS adhesive base coat is normally no thicker that 1/8" and applied to flat surfaces. You could do it curved but I just found this combination easier.

    

   Edited 5/27/2009 10:06 am ET by RalphWicklund

   
7. 
   RalphWicklund | May 27, 2009 05:08pm | #18

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   Starting to come together.

   Edited 5/27/2009 10:09 am ET by RalphWicklund

   
8. 
   RalphWicklund | May 27, 2009 05:15pm | #19

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   A little bit of color, some trim the customer wanted, $850 for the 13 3x8's on top and it's almost done.

   This is sitting over a Koi pond. Had to build a platform to work and cut off the fishies from the sunlight for a while. Didn't lose any and nothing but shrubbery was hurt during the process.

   Edited 5/27/2009 10:16 am ET by RalphWicklund

   
9. 
   Piffin | May 28, 2009 10:08pm | #20

   Very nice there Ralph.Private residence or is that a porte cochere for a motel? 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

10. 
    RalphWicklund | May 29, 2009 12:16am | #23

    Thanks Paul.

    It's a private residence.

11. 
    martyoc | May 28, 2009 10:30pm | #21

    This is what I had mind except that because of the radius I was going to laminate 3" wide strips of staggered 1/2"ply together for the top and bottom chords and 2x4's for stiffeners.....

12. 
    RalphWicklund | May 29, 2009 12:13am | #22

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    I used my driveway to lay out a full size template for the semicircle, positioning the 3/4" plywood to get the most out of the product.

    Made a long trammel, drilled a hole in the concrete for the pivot point and scribed the ply at the proper measurements. The ply is layered, with offset joints. I didn't bother to square off any of the ends so I didn't waste material and the ends are long scarf joints, just not on top of each other.

    Edited 5/28/2009 5:14 pm ET by RalphWicklund

    
4. 
   oops | May 23, 2009 08:24pm | #4

   We have just gone though an extensive discussion about box beams a week or so ago, so I want go into that again. 

   Did you really mean 18'-0" radius? That would be a 36'-0" dia.,a circum. of 28+ ft., or 3 cords/spans of 9.5+ft. with a rise/middle ordinate of approx. of .63' or 7&1/2". Depending upon the loads involved, this could create some torque stresses that would need to be considered. Might simplify things if you added a column or two.

   As already stated, need much more info. Designing straight box beam is complicated enough, but a curved one is a whole nother story.

   If this is a pergola type structure and exposed to the weather, all elements must be moisture proof. Beware of covering with EIFS.

   I'm not only tired, but I'm retired.