I've been trying to calculate column size for a two-story building. I'm really not experienced for this and most of the places I've called seem to want to sell me an off-the-shelf garage, and seem convinced a two-story structure is a bad idea.

Hilarity ensues when the structure is 24'6" x 24'6" and contains about 160,000 pounds of live load.

In any case, the lower floor has an 8 foot ceiling, and the upper floor is 10 feet. With 1-foot joists, that's 20 feet from bottom of floor-1 joist to the bottom chord of the truss, roughly.

The walls on the upper floor have 10-foot-wide segments, two on each wall, carrying about 6,000 pounds of live load (it's 5,592 pounds). That's 44,736 around the perimeter, and comes to less than 90psf of live load.

In the center upstairs is a 15,360 pound live load. The bottom floor might hold 45,000 to 90,000 pounds of storage (I'm designing for 90,000 pounds).

There are six columns, spaced 12 feet apart, supporting the trusses. My math says I can use 6x6. To support the 115,000 pounds in the center, I'm planning on placing two beams perpendicular to the trusses, held up by four additional columns spaced 10 feet apart in the center, moving that load off the main columns. That makes my joists roughly 8 feet, parallel to the trusses, supported by beams which are supported by four 6x6 columns braced 3 feet. That center load segment is solid.

I intend to house the beams into the (24-foot!) sills, which will need a support column under the center due to the upstairs load. Nine in total around the perimeter, four more in the center. Brace will be three feet, leaving an 8-foot span for an opening 7-feet high. Unbraced span of the upstairs sill is thus no more than six feet.

My question is mostly how big are the columns, sills, and floor beams, reasonably?

I think 6x6 is fine in load-terms for the columns. AWC-WCD5 specifies all wood columns should be no less than 8x8, nominal; the floor beams shall be no less than 6x10; and no member of any of the three trusses shall be less than 8 inches in any dimension (if I brace the columns to the trusses, the trusses will carry floor loads). This suggests I should use 8x8 columns, 6x10 beams and sills, and 8x8 members for the trusses. I believe part of that is that WDC-5 specifies wood sizes intended to resist fire for several hours.

All of that should be perfectly fine with half-dovetail wedged tenon connections and housed dovetail and half-dovetail connections. I prefer hardwood wedges to pegs.

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IIRC WCD5 is the heavy timber publication over there, that is more for commercial/ industrial type IV (Type 4} construction. Those minimum dimensions are about fire rating in a type IV rather than load. You're probably really looking to build a type VB (5B) building. The IBC defines those building types and occupancies.

It would be hard to comment on the design without drawings but this doesn't sound particularly out of range. I see internal loads, also don't forget loads from snow or wind or..

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Yeah it's a class 1. Buildings and permits just wants a drawing of the plat with a box that says "BUILDING HERE". No plans desired, no engineer sign-off, just pay the permit fee and build it.

WCD5 is heavy timber, yeah. I'll probably put 0.080" aluminum sheet on the upstairs floor: slippery when wet, but I'll also likely be handling a can filled with burning paper, grass, wood chips, alfalfa hay, and other trash regularly inside there. "Don't drop this" right?

Working on the diagrams.

Live load of course doesn't include snow, building, wind, and seismic loads.

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Buildings associated with honey production, (is that an apiary?), would be ag exempt most places.

So just looking at the minimum columns size structurally. Columns are checked for crushing and buckling. As a column becomes tall and slender buckling greatly decreases its load carrying ability. The length of the column may not be its entire length, it is the effective length between points of lateral support. Your floors provide that lateral support, restraining the buckling length. So your longest columns appear to be 10' of effective length. http://forestryforum.com/members/donp/Simple_column.htm If you back out the 96" length and plug in 120 and select your species and grade you can adjust the load to see what the maximum allowable load is. Checking the bottom 2 lines,

2 Eastern white pine P+T will max out at about 8250 lbs for instance. The same post in northern red oak would be good for about 10,000 lbs. This is for an unnotched full dimension post.

Edit; I was thinking about how effective length (unbraced length) and dimension, change the capacity of a column.

The same 6x6 EWP column but 18' tall, capacity drops to 4500 lbs , it was 8250 at 10' tall.

Beefing them up An 8x8 column in

2EWP at 10' is capable of supporting around 16,500lbs, the extra 2" doubles capacity.

At 18 feet of unbraced height it is good for 12,500 lbs compared to 4,500 lbs capacity for a 6x6 of the same height.

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I just saw not design, but I have been sawing 12"X 12" for the lower columns and 8"X 8" for the second story columns.

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Which brings up a rule of thumb for columns. When slenderness doesn't factor into the equation you don't need to check for buckling, the compressive strength of the wood is the only check needed. 1" thickness in the least dimension per foot of height is that breakline. So for a 12x12 that is 12' or less in height that is loaded only axially you just need to check the column for crushing. An 8x8 at 8' tall or less, etc.

What are wooden pillars called?

The term column applies especially to a large round support (the shaft of the column) with a capital and a base or pedestal, which is made of stone, or appearing to be so. A small wooden or metal support is typically called a post. Supports with a rectangular or other non-round section are usually called piers.

What are the classification of columns?

Types of Columns Based on the Type of Reinforcement Based on the reinforcement, different types of columns are used in their construction. In this classification, we have 3 types of columns: tied columns, spiral columns and composite columns.

What is the V column structure?

The V shaped columns as a truss system lead to the separation of the column into two marginal bars, hence becoming the forked column. The forked column is jointed at the base and has its fork upwards, from the constructive point of view being still a V shaped column, following the same static lows.

What is the terminology for timber beam?

Girt: A key horizontal timber or beam used to connect posts or sills. A girt running in the wall direction is called a wall girt and a girt running in the bent direction is called a bent girt. This is where the modern term “girder” comes from. Vertical Posts: The legs of a timber frame.